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Rifle Scopes S&B question

clinto

Sergeant
Full Member
Minuteman
Jan 16, 2010
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Lubbock, TX
Why does the model with the 1/4 moa turrets have less elevation travel than the mil based turrets?
 
Re: S&B question

Because of the scale. S&B mil turret has 14 mil per full turn, and MOA turret has 35 MOA per turn. If you do the math:

14 mil * 10 notch/mil = 140 notches per turn
35 MOA * 4 notch/MOA = 140 notches per turn

So the tradeoff is more total adjustment for mil, but finer increments for MOA.
 
Re: S&B question

I see, Thanks. So since the moa only has 56 moa of elevation it would not work with a 40 moa base, is that correct?
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: clinto</div><div class="ubbcode-body">I see, Thanks. So since the moa only has 56 moa of elevation it would not work with a 40 moa base, is that correct? </div></div>
<span style="font-weight: bold"><span style="font-style: italic">clinto</span></span> -

Specifically which model PMII are you mounting/referring to? There is widespread misinformation about the Elevation travel of PMII scopes (largely due to a mistake on S & B USA's web site), as well as how the actual base cant should be determined.

The MOA-based versions of the PMII 4-16X42 and PMII 4-16X50 have 56 MOA of Elevation and should be used with 28-33 MOA bases to get the most travel out of them.

<span style="font-weight: bold"><span style="text-decoration: underline">Notice that the Elevation Turrets read to <span style="font-style: italic">"56" MOA.</span></span></span>


<span style="font-size: 11pt"><span style="font-weight: bold"><span style="font-style: italic"><span style="color: #FF0000">MOA-based PMII 4-16X42 (Elevation Travel = 56 MOA):</span></span></span></span>
PMII4-16X4225MOALSRA798x464.jpg

PMII4-16X4225MOALS798x380.jpg


<span style="font-size: 11pt"><span style="font-weight: bold"><span style="font-style: italic"><span style="color: #FF0000">MOA-based PMII 4-16X50 (Elevation Travel = 56 MOA):</span></span></span></span>
PMII4-16X5025MOALSRA798x494.jpg

PMII4-16X5025MOALS798x380.jpg



The MOA-based version of the PMII 5-25X has 65 MOA of Elevation and should be used with a 40 MOA base to get the most travel out of it, but a 45 MOA base should also work just fine as there is only a 5 MOA/approximately 1.4 MIL difference between the Rails. Below are two LEFT SIDE photos of an MOA-based PMII 5-25X56. Look closely at the photos and/or use your browser's <span style="font-style: italic">"Zoom"</span> tool.

<span style="font-weight: bold"><span style="text-decoration: underline">Notice that the Elevation Turret reads to <span style="font-style: italic">"65" MOA - NOT "56".</span></span></span>

<span style="font-size: 11pt"><span style="font-weight: bold"><span style="font-style: italic"><span style="color: #FF0000">MOA-based PMII 5-25X56 (Elevation Travel = 65 MOA):</span></span></span></span>
PMII5-25X25MOALSRA798x462.jpg

PMII5-25X25MOALS-798x418.jpg


Most shooters aren't shooting a caliber that requires the full range of a PMII's Elevation range to be utilized, so they don't really "need" the more aggressively-canted base. The most commmon caliber around today is probably the .308, and as such the majority of shooters' running 20 MOA bases under their PMIIs whether MOA or MIL-based without issue. <span style="font-style: italic">This is because they never need to dial-out all the way.</span>

However, if someone does need the full Elevation range and their using a 20 MOA base, they will find that their Elevation dial will "bottom" before their scope reaches full travel. The base cant required by a PMII scope is determined by the scope's internal travel, not by the caliber of the scope the rifle is being mounted on, period.

Feel free to <span style="text-decoration: underline">email</span> me about this. There are endless threads here about this very subject just in the past month.


Keith
 
Re: S&B question

aries- thanks for the reply, that helps a lot. The scope is a pmII 5-25 moa/moa. I plan on using it on a 300 win mag, the action has 20 moa rail built in and I was wanting to use a Near 20 moa mount. I would like to have the full elevation range available if possible.
 
Re: S&B question

Just to clarify things a bit, both the 3-12 and 5-25 PM II have between 100 and 105 moa of <span style="font-weight: bold">internal travel</span> which is about 30 mil while the 4-16 only has about 65 moa or 19 mil of internal travel which is why there is no double turn mil choice for the 4-16.
The usable range of the weapon system should dictate the angle of base cant.
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jerry R</div><div class="ubbcode-body">Just to clarify things a bit, both the 3-12 and 5-25 PM II have between 100 and 105 moa of <span style="font-weight: bold">internal travel</span> which is about 30 mil while the 4-16 only has about 65 moa or 19 mil of internal travel which is why there is no double turn mil choice for the 4-16.
The usable range of the weapon system should dictate the angle of base cant.
</div></div>
Thanks for posting Jerry. Everyone should listen to <span style="font-style: italic">Jerry R</span> about S & B scopes. Jerry worked at Premier for years and knows the PMII lineup very well - much better than I ever will.

I have to admit that I'm only using a 25 MOA base under the PMII 5-25X on one of my .22 LR Kimber Model 82s', as the farthest I ever shoot with a .22LR is 400 yards, and I only need to dial to about 21 MILs' to get there with 40gr. Winchester T22. 40gr. Wolf MT needs a lot more but is useless at that range anyway...


Keith
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: clinto</div><div class="ubbcode-body">aries- thanks for the reply, that helps a lot. The scope is a pmII 5-25 moa/moa. I plan on using it on a 300 win mag, the action has 20 moa rail built in and I was wanting to use a Near 20 moa mount. I would like to have the full elevation range available if possible. </div></div>

That seems like an ideal setup.

I might be looking into a NEAR mount in the near future;)
 
Re: S&B question

What moa base would a single turn SB scope with 13 mrad need?
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: clinto</div><div class="ubbcode-body">aries- thanks for the reply, that helps a lot. The scope is a pmII 5-25 moa/moa. I plan on using it on a 300 win mag, the action has 20 moa rail built in and I was wanting to use a Near 20 moa mount. I would like to have the full elevation range available if possible. </div></div>
No problem, <span style="font-weight: bold"><span style="font-style: italic">clinto</span></span>. I think you may have just missed-out - <span style="font-weight: bold"><span style="font-style: italic">THUNDERBOLT68</span></span> just sold a 34mm High Alpha Mount. <span style="font-weight: bold"><span style="font-style: italic">THUNDERBOLT68</span></span> still has a Medium-High Alpha Mount, but it might be too low for the 5-25X56. Click-on this link -> <span style="font-weight: bold"><span style="font-style: italic">34mm Medium-High Alpha Mount</span></span>.


Keith
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ruth</div><div class="ubbcode-body">What moa base would a single turn SB scope with 13 mrad need? </div></div>
If you're asking me, I already answered this very question <span style="font-weight: bold"><span style="font-style: italic">in my reply to you</span></span> in cali_tz's <span style="font-weight: bold"><span style="font-style: italic">S&B question on zeroing and max elevation...</span></span> thread five days ago. The answer and physics haven't changed in that time.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Aries64</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ruth</div><div class="ubbcode-body">Does anyone know what moa base I would need for s&b scope with 13 mrads total elevation? </div></div>
A 28-30 MOA base would be ideal, but a 20 MOA base will also work (you'll probably be around 2.8 MILs' shy of the full [13 MILs'] of travel once you're zeroed, but it isn't a huge deal unless you need access to the full range of travel). I prefer to use the correct base whether I can make use of the full Elevation range or not.


Keith </div></div>

You can use a 20 MOA base, but you'll probably be around 2.8 MILs' shy of the full (13 MILs') of travel once you're zeroed (e.g., .308). A 25 MOA base is closer to S & B's recommended base cant (S & B recommends a base cant approximating 1/2 of a PMII's total Elevation travel) to compensate for the PMII's mechanical Elevation bias.

However, the 25 MOA base doesn't take into account any "UP" that you'll use when zeroing (5-7 MOA? on a .308 at 100 yards), so a 28-30 MOA base would be ideal because it would help compensate for the "UP" travel you'll use during zeroing. You could probably go with a 33 or 35 MOA base MOA base without "losing" any travel on the bottom end of the Elevation range.


Keith
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jerry R</div><div class="ubbcode-body">Just to clarify things a bit, both the 3-12 and 5-25 PM II have between 100 and 105 moa of <span style="font-weight: bold">internal travel</span> which is about 30 mil while the 4-16 only has about 65 moa or 19 mil of internal travel which is why there is no double turn mil choice for the 4-16.
</div></div>

YES sir.

But not to start a fight or anything, but if that was the case, why is this 4-16 being advertised with 1cm adjustments in a double turn?
http://www.cstactical.com/index.php?page...&Itemid=146
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: clinto</div><div class="ubbcode-body">I'm the one who bought the high mount from thunderbolt </div></div>
Doh!


Keith
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Paramil</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jerry R</div><div class="ubbcode-body">Just to clarify things a bit, both the 3-12 and 5-25 PM II have between 100 and 105 moa of <span style="font-weight: bold">internal travel</span> which is about 30 mil while the 4-16 only has about 65 moa or 19 mil of internal travel which is why there is no double turn mil choice for the 4-16.
</div></div>

YES sir.

But not to start a fight or anything, but if that was the case, why is this 4-16 being advertised with 1cm adjustments in a double turn?
http://www.cstactical.com/index.php?page...&Itemid=146 </div></div>
<span style="font-weight: bold"><span style="font-style: italic">Paramil -</span></span>

<span style="font-weight: bold"><span style="font-style: italic">Jerry R</span></span> knows what hes' talking about and is correct. The specification on that page listing the Elevation and Windage increments as <span style="font-style: italic">"1 cm"</span> is incorrect. The .25 MOA versions of the PMII 4-16Xs' (both 42mm and 50mm Objectives) only came in DT (Double Turn). The reason for this (also as <span style="font-weight: bold"><span style="font-style: italic">Jerry R</span></span> said) is that the PMII 4-16Xs' only have about 65 MOA/19 MILs' of internal travel, which isn't enough to require a DT Turret on the 0.1 MIL versions. And not that it matters but the photo of the scope for the link you provided has .25 MOA adjustments.


Keith
 
Re: S&B question

I have several questions for Keith regarding the 5-25 PMII DT. I originally ordered the 44.4 moa Spuhr mount but was sent the 24 moa version by mistake. Having a match to shoot I chose to run the 24 moa mount. After zeroing at 100 yards (I did not reset the turret like you described, just dialed the zero to match the triangle) I was left with 12.5 mils of "up" elevation and 13 mils "down".

First question is, what does "resetting the turret" do, because I'm assuming I zeroed incorrectly? 12.5 mils allows me to shoot a 338 LM to roughly 1250 yards centering the cross hair on the target so adding another 6 mils with the 44.4 moa mount still only gets me to about 1575 yards.

Also, there is mention on "zeroing further-out" to allow using the cross hair on target at longer range without running out of usable elevation. But by zeroing further-out are we not using more internal travel to do that which would leave less "usable elevation in the turret?

Sorry for being confused on this, and it all may be just my own incompetence but maybe you can clear this up?
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dark Horse</div><div class="ubbcode-body">I have several questions for Keith regarding the 5-25 PMII DT. I originally ordered the 44.4 moa Spuhr mount but was sent the 24 moa version by mistake. Having a match to shoot I chose to run the 24 moa mount. After zeroing at 100 yards (I did not reset the turret like you described, just dialed the zero to match the triangle) I was left with 12.5 mils of "up" elevation and 13 mils "down".</div></div>
The PMII DT Turret is different from other scopes - you don't just set the Elevation Turret to "0" once your POI coincides with the POA. The DT Turret should be reset after you "zero" the rifle. Depending upon where the DT Turret was set when you received it and/or how much "UP" you used zeroing, you may or may not need to reset it. I always do. I surmise that the "windows" of your DT Elevation Turret turned "Yellow" and your scope "bottomed". You said that you were <span style="font-style: italic">"left with 12.5 mils of "up" elevation and 13 mils "down"</span> after zeroing. The way PMIIs' come set-up from the factory you should only have about .5 MIL below zero.

Your 13 MILs' of "DOWN" is most likely the result of not resetting the DT Turret. <span style="font-style: italic">However, even if you had reset the DT Turret after zeroing the rifle, you still wouldn't be able to dial the your scope to it's top end of 27.3 MILs without the proper amount of cant applied to the scope.</span> The PMII 5-25X56 is designed to be used with a 45 MOA base.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dark Horse</div><div class="ubbcode-body">First question is, what does "resetting the turret" do, because I'm assuming I zeroed incorrectly?</div></div>
<span style="font-style: italic">"Zeroing"</span> the scope (setting the Elevation and Windage Turrets to "0" once your POI coincides with the POA) and "resetting the turret" on a PMII DT is different from others scopes. You already know how to "zero" the rifle so you just need to know how a PMII DT Elevation Turret works and how to reset it.

On the underside of the "window-type" PMII DT Turret Knob/Cap there is a little machined "barrel" with a slot on it's side. The slot in the "barrel" is engaged by a pin mounted on the Elevation Turret Assembly and actuates the revolution indicator on the inside of the DT Turret Knob/Cap ("Black"/"Clear" windows indicate that the DT Elevation Turret is on the first revolution, while "Yellow" windows indicate that the DT Elevation Turret is on the second revolution). Never force past the STOP or you'll damage the scope.

<span style="font-weight: bold"><span style="font-style: italic">To reset the PMII DT Elevation Turret:</span></span>

(1) Loosen the two (2) set screws on the Elevation Knob/Cap. Be sure to back both screws out sufficiently so that turning the Knob/Cap doesn't turn the Turret itself (and mess up your zero).

(2) <span style="font-weight: bold"><span style="font-style: italic">Without lifting the Knob/Cap</span></span>, rotate the Elevation Knob/Cap <span style="font-style: italic">in the opposite direction of "UP" until the windows change from "Yellow" to "Black"/"Clear" and the Turret comes back around to "0".</span> (For a CCW [Counterclockwise] scope you turn CW [Clockwise], and for a CW [Clockwise] scope you turn CCW [Counterclockwise]).

<span style="font-weight: bold">Its' important that the DT Elevation Knob/Cap <span style="text-decoration: underline">IS NOT</span> lifted since the pin on the Elevation Assembly must engage the barrel on the underside of the DT Elevation Knob/Cap to actuate the Revolution Indicator on the inside of the Knob/Cap.</span>

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dark Horse</div><div class="ubbcode-body"> 12.5 mils allows me to shoot a 338 LM to roughly 1250 yards centering the cross hair on the target so adding another 6 mils with the 44.4 moa mount still only gets me to about 1575 yards.</div></div>
You can access more of your scope's Elevation adjustment range by resetting the DT Elevation Turret's Knob/Cap by following the directions I outlined above, but so long as you only have 20 MOA of cant you'll never be able to access the full range of elevation adjustment built into your PMII. That would be a shame, as the .338 LM is a caliber that can take advantage of the Elevtion travel a PMII 5-25X has.

You didn't mention what action your .338 LM is built-on, but I'm guessing that since you ordered the 44.4 MOA SPUHR mount you aren't running a custom action with an integral 20 or 30 MOA rail. That said, if your PMII 5-25X56 is only canted 20 MOA, you should get the 44.4 MOA SPUHR Mount. Without the correct amount of cant its' impossible to access the full range of elevation adjustment built into a PMII.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dark Horse</div><div class="ubbcode-body">Also, there is mention on "zeroing further-out" to allow using the cross hair on target at longer range without running out of usable elevation. But by zeroing further-out are we not using more internal travel to do that which would leave less "usable elevation in the turret?

Sorry for being confused on this, and it all may be just my own incompetence but maybe you can clear this up? </div></div>
I believe that the thread your are referring to was <span style="font-weight: bold"><span style="font-style: italic">"S&B question on zeroing and max elevation..."</span></span>, posted by <span style="font-weight: bold"><span style="font-style: italic">cali_tz</span></span>. <span style="font-weight: bold"><span style="font-style: italic">cali_tz</span></span>'s scenario is totally different from your's. <span style="font-weight: bold"><span style="font-style: italic">cali_tz</span></span> was using an MOA-based version of the PMII 5-25X[56mm], which has much less Elevation travel (65 MOA of Elevation adjustment in .25 MOA increments) than the MIL-based versions of the PMII 5-25X[56mm], which have 26 MILs' (about 93 MOA) of Elevation adjustment in 0.1 MIL increments.

<span style="font-weight: bold"><span style="font-style: italic">cali_tz</span></span> was also using a 20 MOA base instead of the 40-45 MOA base that would be appropriate for use with his PMII 5-25X[56mm]. Using the appropriate (40-45 MOA) base would allow access to the full 65 MOA of Elevation adjustment built into the MOA version of the PMII 5-25X[56mm]. It should be noted that the distance at which a rifle is "zeroed" does not affect the <span style="font-style: italic">"usable elevation in the turret."</span> Regardless of the zero distance, a scope always has the same amount of travel it left the factory with, so a more distant zeroed will not affect a scope's travel.

In the end, I said <span style="font-style: italic">"Personally, I would suck it up and sell the MOA-based PMII and buy a MIL-based version."</span> <span style="font-weight: bold"><span style="font-style: italic">cali_tz</span></span> may have taken my advice, as he sold a PMII 5-25X[56mm] in his <span style="font-weight: bold"><span style="font-style: italic">"Schmidt Bender PMII 5-25x, P4F MIL, MOA DT"</span></span> thread on 12/5/[11].


Keith
 
Re: S&B question

Keith

What is the point about recomending 40 MOA cant for a scope with only 56 moa elevation?

SBs recomendation is maximum 1/2 the elevation.
And in many cases it's better to stay off half the elevation if it's not needed.
The problem with canting the scope to the maximum is that not that few scopes gets optically less desirable on shorter distances like 200-300 yards.
I have seen more than one of the best quality scopes getting oval pictures.

So when deciding the cant for a scope, my recomendation would be to let the actual use deciding it.
If you never use more than 8 mils of elevation, it's maybe not the smartest to mount your scope for 26 mils of elevation with the degrated close range picture.

Håkan
 
Re: S&B question

Spuhr, that is what I was thinking. if the 5-25 moa scope has 65 moa travel, Then wouldn't that mean that it can only move 32 moa down and cause the 40 moa base to not work? Sorry that I'm still not getting this, I just want to get it right.
 
Re: S&B question

Clinto

The Maximum movement is actually larger, but you have some extra travel, but due to the two turns you have on the knob you are limited to 65 moa from where you are sighted in.

But there is still as I see it no reason to have more than needed tilt on the mount/base

Håkan
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: clinto</div><div class="ubbcode-body">Spuhr, that is what I was thinking. if the 5-25 moa scope has 65 moa travel, Then wouldn't that mean that it can only move 32 moa down and cause the 40 moa base to not work? Sorry that I'm still not getting this, I just want to get it right. </div></div>
They have over a 100moa of travel.
 
Re: S&B question

I had planned on building a rifle on a Surgeon 591R action with the integral 20 MOA base, and putting a S&B 5-25x56 DT CCW P4F mil/mil scope on it.
Yep, I thought I had it all figured out.

After reading this and all the other stuff about S&B's "recommended cant" on the bases, it looks like I need to go back to the drawing board and start over....with a different scope, or a different action.
confused.gif
 
Re: S&B question

Keith,

Thanks for the explanation on the PMII...my fault for assuming it zeroed the same as other scopes. Always thought the window was to keep track of what rotation the turret was on and never it gave it a second thought. Guess I should have opened the little white book that the scope came with.

However, I still think I'm missing something with one of your statements on zeroing and internal adjustment.

As stated: "Regardless of the zero distance, a scope always has the same amount of travel it left the factory with, so a more distant zeroed will not affect a scope's travel".

That is actually what is confusing me, so I will throw out some theoretical numbers, none of which are actual, but just a reference.

Scope "A" has 26 mils of total elevation adjustment and the shooter zeroes at 100 yards. After resetting the turret we find that the scope has 5 mils of "down" travel and 21 mils of "up" remaining. We realize that all of our shooting will be at 600 yards or greater, so the decision to re-zero at 600 is made. It requires another 4mils of "up" elevation to zero at 600 and the scope now has 9 mils "down" and 17 mils remaining for "usable" "up" elevation. Either way the total amount of travel hasn't changed so this statement ("Last question... with this 40-45MOA base then, I won't be able to have scope zero at 100 yards and also be able to use the reticle crosshairs at 2000 yards.. because the 65 MOA just won't get there. So I'll have to zero at more like 300-400 yards, right"?) doesn't make sense to me.

It sounds like he is suggesting by zeroing at a further distance it will allow him to use the reticle cross hair on the target because he will have more "up" elevation left in the scope.

If the PMII allows for this because of resetting the turret then I get it, otherwise I guess I have some learning to do.
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Spuhr</div><div class="ubbcode-body">Keith

What is the point about recomending 40 MOA cant for a scope with only 56 moa elevation?</div></div>
Oh boy, here we go again. I really enjoy the Sniper's Hide web site. I've learned a lot, and I think I've also given back a fair amount - when I have time and I'm feeling up to it I'll chip-in help by imparting first-hand knowledge about a product or procedure through personal experience. However, it can sometimes be taxing when the same questions are asked over and over again <span style="font-style: italic">when the most simple of searches could have garnered the info sought, and/or people post without knowing bothering to understand what is going-on within the context of a process and/or thread.</span> This includes those who are "too busy" to read.

I expect a somewhat higher level of experience and knowledge from a manufacturer and/or dealer of a product designed to mount rifle scopes - especially riflescopes in the 34mm tube flavor as scopes with 34mm maintubes tend be be pretty expensive, specialized pieces of equipment.

That said, <span style="font-weight: bold"><span style="font-style: italic"><span style="text-decoration: underline">Håkan</span></span></span> - what scope did I recommend a 40 MOA base for that has 56 MOA of total Elevation adjustment?

<span style="font-weight: bold"><span style="font-style: italic">clinto</span></span> said hes' running a MOA-based PMII 5-25X[56mm], which has about 65 MOA of Elevation travel. Obviously, 1/2 of 65 MOA = 32.5 MOA, so <span style="font-style: italic">theorietically</span> a 33 MOA base would be perfect. However, a 33 MOA base doesn't allow for any Elevation "UP" Elevation travel that will be used while zeroing. <span style="font-weight: bold"><span style="font-style: italic">clinto</span></span> said that he <span style="font-style: italic">"would like to have the full elevation range available if possible."</span> An "extra" 5-7 MOA will help compensate for travel used while zeroing.

<span style="font-weight: bold"><span style="font-style: italic">cali_tz</span></span> was also running a MOA-based PMII 5-25X[56mm] (obviously, also about 65 MOA of Elevation travel, so the same amount of base cant is applicable). <span style="font-weight: bold"><span style="font-style: italic">cali_tz</span></span>'s MOA-based PMII 5-25X[56mm] was mounted on a 20 MOA base on a Steyr SSG .338 LM, and maxed-out at around 1,600 yards.

Both of these shooters were using 20 MOA bases and could not get the most travel out of their scopes because the 20 MOA bases that they were using didn't cut it. 40-45 MOA would have been much better base cants for their rifles. Had they done more research and/or happened upon accurate information about the equipment they planned to use perhaps they would have made other equipment choices. <span style="font-weight: bold"><span style="font-style: italic">cali_tz</span></span>'s .338 LM is fully capable of 2,000 meter shooting utilizing the full Elevation adjustment range of a 26 MIL DT PMII 5-25X[56mm] on a 45 MOA base, but he bought the [65 MOA] MOA-based version of the PMII 5-25X[56mm] without knowing that it has substantially less Elevation travel than the MIL-based PMII 5-25X[56mm].

The only PMIIs' that have 56 MOA of travel are the MOA-based PMII 4-16X42mm and 4-16X50mm DT MOA scopes, and I recommend a 33-35 MOA base as the optimum. While 28 MOA is 1/2 of a 56 MOA-travel scope, the 28 MOA doesn't take into account any Elevation adjustment used during "zeroing".


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Spuhr</div><div class="ubbcode-body">SBs recomendation is maximum 1/2 the elevation.</div></div>
Yes, I know that and I also understand why.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Spuhr</div><div class="ubbcode-body">And in many cases it's better to stay off half the elevation if it's not needed.
The problem with canting the scope to the maximum is that not that few scopes gets optically less desirable on shorter distances like 200-300 yards.</div></div>
WTF, over? I believe what you are trying to say is that the aggressive cant makes the shooter look through the lenses at an angle and closer to the outside edges of the lenses rather than viewing the image through the "sweet spot" at the center of the lens, causing image quality degradation. Personally, this has't been my experience with my former Premier Heritage 5-25X[56mm] 27 MIL DT MTC, my two PMII 5-25X[56mm] 0.1 MIL DT LP CCW Gen 2 XRs', or any other PMIIs' mounted on 40 and 45 MOA bases.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Spuhr</div><div class="ubbcode-body">I have seen more than one of the best quality scopes getting oval pictures.</div></div>
Again, that hasn't been my experience.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Spuhr</div><div class="ubbcode-body">So when deciding the cant for a scope, my recomendation would be to let the actual use deciding it.</div></div>
I agree, but I also think that people - starting with PMII dealers, should be informed about PMII specs and and understand that PMIIs' are designed to use specific base cant ranges before recommending a 20 MOA base as the one-size fits all. I see people on Sniper's Hide and other internet sites complaining about how their expensive, defective PMII is short on travel. Typically, their PMII is mounted on 20 MOA base.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Spuhr</div><div class="ubbcode-body">If you never use more than 8 mils of elevation, it's maybe not the smartest to mount your scope for 26 mils of elevation with the degrated close range picture.

Håkan </div></div>
One of my PMII 5-25X[56mm] 0.1 MIL DT LP CCW Gen 2 XRs' is mounted on a .308, and the majority of the time I'm dialed to less than 8 MILs'. However, my sight picture is perfectly clear. Maybe I need a new prescription - my corrected vision is only 20/15.


Keith
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: clinto</div><div class="ubbcode-body">Spuhr, that is what I was thinking. if the 5-25 moa scope has 65 moa travel, Then wouldn't that mean that it can only move 32 moa down and cause the 40 moa base to not work? Sorry that I'm still not getting this, I just want to get it right. </div></div>
<span style="font-weight: bold"><span style="font-style: italic">clinto</span></span>: I'm sorry, but you're killing me dude. Its' clear that you either didn't read the <span style="font-weight: bold"><span style="font-style: italic">"2006 PMII User Manual"</span></span> (so you don't know that PMIIs' are adjusted at the factory to have an UPWARD travel bias), or that you read it but don't understand how the PMII's mechanical offset design works with canted bases and why. <span style="font-weight: bold">PLEASE READ EVERYTHING BELOW, AND IF YOU DON'T UNDERSTAND IT EMAIL ME AND I WILL EXPLAIN IT OVER THE PHONE <span style="text-decoration: underline">ON YOUR DIME.</span></span>

<span style="font-weight: bold">PMIIs' are designed and engineered to be used with aggressively canted bases. PMII variables' are preset at the S & B factory with their reticles' adjusted out-of-center by HALF of their FULL Elevation travel, giving them UPWARD Elevation bias. In order to compensate for this mechanical bias/offset, a base that approximates one half of each respective scope's full Elevation travel should be used.</span> <span style="font-weight: bold"><span style="font-style: italic">(Which, for a non-Locking Turret .25 MOA PMII 5-25X is 65 MOA)</span>.</span>

<span style="font-style: italic">Theorietically</span>, you want a 32.5 MOA base. However, its' a good idea to get a base with a few "extra" MOA built-in to allow for the 5-7 MOA you'll probably use to zero at 100 yards. Now you're at a 38-40 MOA base. You could probably use a 45 MOA base too but a 38-40 MOA is the safe bet. The 0.1 MIL version of the PMII 5-25X was originally designed to be used on a 45 MOA base and the .338 LM. Schmidt Bender only developed the .25 MOA version under pressure from the U.S..

Selection of a base with the correct cant is all detailed in the <span style="font-weight: bold"><span style="font-style: italic">"2006 PMII User Manual"</span></span> beginning on page 3 under <span style="font-weight: bold"><span style="font-style: italic">"Section 4.2"</span></span>, <span style="font-weight: bold"><span style="font-style: italic">"Adjustment range and forward angle"</span></span> and concluding on page 4. Italicized and in quotation marks below is the section I am speaking of. I've also high-lighted certain text of particular relevance in <span style="color: #FF0000"><span style="font-weight: bold">RED</span></span>. Below the text of Section 4.2 is a diagram from page 19 of the PMII User Manual showing <span style="font-style: italic">"picture 2"</span>, <span style="font-style: italic">"picture 3"</span>, and <span style="font-style: italic">"picture 4"</span> as referenced in the (2006) User Manual. Keep in mind that the Manual does not allow for any travel used to "zero" the scope as I did in my paragraph above.

<span style="font-weight: bold"><span style="font-style: italic">"4.2. Adjustment range and forward angle

Scopes for high precision shooting are often used for shooting at great
distances. In this case the elevation adjustment is used to compensate for bullet
drop. To provide an extensive elevation range in these scopes Schmidt &
Bender has increased the main tube diameter from 30mm to 34mm.
Nevertheless the elevation and windage range like in any other scope is limited.

In scopes for hunting the reticle is generally centered optically and mechanically
in order to receive the same amount of travel in all directions and to make the
mounting of the scope to the firearm easier (see picture 2).

<span style="color: #FF0000">In order to make the elevation adjustment range usable in its full extent it is
necessary to preset the reticle of the PMII scopes out of the center already at
the Schmidt & Bender factory (see picture 3).</span> As a consequence the gunsmith
is obliged to consider the preset position of the reticle in the elevation range
when mounting the scope to the firearm (see picture 4). <span style="color: #FF0000">With this setup the full
elevation range is usable in one direction allowing to shoot at distances up to
2000m depending on the used calibre and scope type.</span>

Determining the correct forward angle
The necessary forward angle is depending on the used type of elevation
adjustment. <span style="color: #FF0000">At the Schmidt & Bender factory the reticles of PMII scopes are
adjusted out of center by half the amount of the full elevation range. This value
must be compensated in the mount system.</span>
Forward angled mounts or rails for every Schmidt & Bender PMII scope type
are available from all renowned mount manufacturers.

<span style="color: #FF0000">Example for determining the required forward angle:
A standard elevation turret (Single Turn) with an elevation range of 13mrad
(equals 130cm at 100m distance) requires a forward angle of 65cm at 100m
(equalling the half of the full elevation range).</span> For a gunsmith compensating for
this value using the mounts the following rule of thumb applies: If the space
between the two mount rings is 100mm the front mount should be 0.65mm
lower than the rear mount.

If the gunsmith is using a forward angled rail standard mount rings without
forward angled can be used."</span></span>

<span style="font-weight: bold"><span style="font-style: italic">"picture 2"</span>, <span style="font-style: italic">"picture 3"</span>, and <span style="font-style: italic">"picture 4"</span> as referenced in the <span style="font-style: italic">2006 PMII User Manual:</span></span>
SBPictures800x531.jpg


<span style="font-weight: bold"><span style="text-decoration: underline">NOTE:</span></span> <span style="font-weight: bold"><span style="font-style: italic">In the diagram above:</span></span>

<span style="font-weight: bold">"<span style="color: #FF0000">Picture 2</span>"</span> shows a scope mounted on a rifle with a flat (non-canted base). The drawing illustrates a typical scope with optically-centered reticle and erector. Personally, I always use canted bases, as they have no downside - they dont adversely affect 100 yard zeroing and shift a bit of Elevation travel to the upper end of the scope's adjustment range.

<span style="font-weight: bold">"<span style="color: #FF0000">Picture 3</span>"</span> shows a scope mounted on a rifle with a flat (non-canted base). The drawing illustrates the effect that the PMII's Reticle offset (PMII reticle's are preset at the factory <span style="text-decoration: underline">biased towards the top of the scope tube</span>) has upon the PMII's operation and the PMII's requirement for specific cant scope bases. This mechanical offset is engineered into the PMIIs' and requires use of specific cant bases in order to get optimum Elevation travel out of respective PMII scopes. The Reticle's off-center orientation (towards the top of the tube) means that you're actually looking very slightly upward when you look through a PMII at the bottom of it's travel, and that the Reticle's LOS (Line-of-Sight) won't intersect the projectile's trajectory without a lot of "UP" adjustment. Obviously, the scope's offset over the bore will require the shooter to use a lot of "UP" adjustment to zero the rifle. Use of a correct cant base eliminates these issues and allows the PMII to function as designed.

<span style="font-weight: bold">"<span style="color: #FF0000">Picture 4</span>"</span> shows a scope mounted on a rifle with a canted base. The drawing illustrates how the use of a base with the correct cant affects the PMII Reticle's LOS (Line-of-Sight) and allows the respective PMII access to it's full Elevation adjustment range. The Reticle is still oriented at the top of the scope tube, but the canted base has angled the scope (and Reticle) slightly downward in relation to the axis of the bore, allowing the Reticle's LOS (Line-of-Sight) to intersect with the projectile's trajectory. The scope can now be "zeroed" with minimal Elevation adjustment. After the scope is zeroed, the Elevation Turret shoud be set to "0". Scopes with DT (Double Turn) Elevation Turrets should be reset.

Also, the illustrations show the bullets arcing upward from the axis of the bores. This, of course - does not occur in real life. I'm sure that the gravity-defying bullets were drawn in that manner to simulate the arc of the rounds as they travel downrange.

I hope this post clears-up any confusion you and any other members may have about the use of canted bases and the correct base cant for use with PMIIs', as well as to help guide new PMII owners' and would-be PMII owners' towards the selection of the correct base for use with their PMII.


Keith
 
Re: S&B question

Keith, thanks for posting that, it makes a lot more sense now. I haven't read the owners manual because I haven't received my S&B yet, hopefully it on its way now. I tried to send you a pm the other day but I think your inbox is full.
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dark Horse</div><div class="ubbcode-body">Keith,

Thanks for the explanation on the PMII...my fault for assuming it zeroed the same as other scopes. Always thought the window was to keep track of what rotation the turret was on and never it gave it a second thought. Guess I should have opened the little white book that the scope came with.</div></div>
Never ass/u/me. However, the window is the revolution indicator on the "windowed" PMII DT Turrets.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dark Horse</div><div class="ubbcode-body">However, I still think I'm missing something with one of your statements on zeroing and internal adjustment.

As stated: "Regardless of the zero distance, a scope always has the same amount of travel it left the factory with, so a more distant zeroed will not affect a scope's travel".</div></div>
The MOA-based version of the PMII 5-25X[56mm] has approximately 65 MOA of Elevation travel when it leaves the factory. The MIL-based version of the PMII 5-25X[56mm] has approximately 26 MILs' of Elevation travel when it leaves the factory. Both of these scopes will never have more, or less travel than what they left the factory with. The <span style="font-weight: bold"><span style="font-style: italic">total</span></span> amount of travel never changes.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dark Horse</div><div class="ubbcode-body">That is actually what is confusing me, so I will throw out some theoretical numbers, none of which are actual, but just a reference.</div></div>
Dude, not you too. I'm starting to get loopy...

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dark Horse</div><div class="ubbcode-body">Scope "A" has 26 mils of total elevation adjustment and the shooter zeroes at 100 yards. After resetting the turret we find that the scope has 5 mils of "down" travel and 21 mils of "up" remaining.</div></div>
Thats' not what resetting the PMII DT Turret does or what its' designed to do, but once you have your zero you <span style="font-weight: bold"><span style="font-style: italic">can</span></span> set the Elevation Knob/Cap to be 5 MILs' above absolute "0" to compensate for different loads, dialing closer-in, ect if you want. All you have to do is zero for the range you want, loosen the Turret Set Screws so they don't engage the Turret, align the Elevation Knob/Cap's "0" with the little index triangle, then re-tighten the Turret Set Screws.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dark Horse</div><div class="ubbcode-body">We realize that all of our shooting will be at 600 yards or greater, so the decision to re-zero at 600 is made. It requires another 4mils of "up" elevation to zero at 600 and the scope now has 9 mils "down" and 17 mils remaining for "usable" "up" elevation.</div></div>
You can easily change the zero distance by following the steps in my reply to my last paraphrased quote of you above.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Dark Horse</div><div class="ubbcode-body">Either way the total amount of travel hasn't changed so this statement ("Last question... with this 40-45MOA base then, I won't be able to have scope zero at 100 yards and also be able to use the reticle crosshairs at 2000 yards.. because the 65 MOA just won't get there. So I'll have to zero at more like 300-400 yards, right"?) doesn't make sense to me.

It sounds like he is suggesting by zeroing at a further distance it will allow him to use the reticle cross hair on the target because he will have more "up" elevation left in the scope.

If the PMII allows for this because of resetting the turret then I get it, otherwise I guess I have some learning to do. </div></div>
<span style="font-style: italic">If I understood him correctly</span>, <span style="font-weight: bold"><span style="font-style: italic">cali_tz</span></span> was talking about using a 40-45 MOA base and zeroing at 100 yards, but then not being able to use a dead-on crosshair hold at 2,000 yards because 65 MOA isn't enough to get him to 2,000 yards. Unfortunately, while he can zero further-out, that won't change his <span style="font-style: italic">total</span> elevation, so he'd still have to use holdover to get beyond 1,600 yards with his existing load. I believe that <span style="font-weight: bold"><span style="font-style: italic">cali_tz</span></span> sold his MOA-based PMII 5-25X[56mm] and will be buying a MIL-based PMII 5-25X[56mm] so he'll have more Elevation travel.


Keith
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: clinto</div><div class="ubbcode-body">Keith, thanks for posting that, it makes a lot more sense now. I haven't read the owners manual because I haven't received my S&B yet, hopefully it on its way now. I tried to send you a pm the other day but I think your inbox is full. </div></div>
I glad that my last post helped make sense of the way PMIIs' are designed and engineered to work in conjunction with canted bases. The manner in which the PMII User Manual explains things isn't the most clearly written piece I've ever seen, but it also seems that a lot of people don't want to think about or understand how their equipment works. I've rarely bought a piece of equipment that wasn't exactly what I needed or wanted because I research the hell out of everything before hand to be sure it will perform as I need it to. And again, you can always download the <span style="font-weight: bold"><span style="font-style: italic">"2006 PMII User Manual"</span></span> off the Schmidt Bender USA, Inc. web site.


Keith
 
Re: S&B question

Keith

When looking through a 5-25 Mil scope it's pretty apperarnt that the picture is oval at both 0 mil elevation and 26mil elevation.
Regardless of magnification.
This not perfect picture is a price that has to be paid in order to get all the extreme travel out of the scope and not really a problem.
But what I said was that unless needed because of shooting at great distances there is really no reason to mount with maximum tilt.

I do agree with you that always choosing 20 moa is wrong, but my opinion is that the tilt should be choosed depending on the distances that are going to be shot at.

A friend of mine have mounted his 5-25 in a 7mils/24 moa mount.
That gives him 24 mils of elevation, and a perfect round picture at 100 yards. It also takes the bullet out to 1500 yards, so staying of the full tilt is not really a problem as he gets a better picture at close range and he can still dial the scope out to distances further than he shoots at.

I asked Hensoldt what tilt they recomended for their scopes.
Their answer was, all depending on the shooting distances, the less the better.

But it's fully possible that you know this stuff better than Hensoldt.....



Håkan
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Spuhr</div><div class="ubbcode-body">Keith

When looking through a 5-25 Mil scope it's pretty apperarnt that the picture is oval at both 0 mil elevation and 26mil elevation.
Regardless of magnification.</div></div>
<span style="font-weight: bold"><span style="font-style: italic">Håkan</span></span> -

Who am I to argue with you about what you see, or what you think you see. People do see things differently when looking at the same thing at times. Sometimes they see what they want to see, sometimes they see what's there, and sometimes they see something because someone said it's there.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Spuhr</div><div class="ubbcode-body">This not perfect picture is a price that has to be paid in order to get all the extreme travel out of the scope and not really a problem.</div></div>
I don't think that <span style="font-style: italic">any</span> scope's image is "perfect", but as far as rifle scope image-quality go I think that S & B, Hensoldt, and Premier are about as good as it gets across their magnification range. I really don't "see" any image quality problems with any of them. Comb height and Head position also have an effect on perceived angular image.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Spuhr</div><div class="ubbcode-body">But what I said was that unless needed because of shooting at great distances there is really no reason to mount with maximum tilt.

I do agree with you that always choosing 20 moa is wrong, but my opinion is that the tilt should be choosed depending on the distances that are going to be shot at.</div></div>
If people don't see/perceive the "oval" image that you're referring to (and you're the only one I've ever heard insist is there) - I don't understand what the harm is in a user mounting a PMII or other scope by following the manufacturer's guidelines. These guidelines there to help users mount their optics to take advantage of the manufacturer's mechanical design. I think the manufacturers' know their products better than anyone else. Do you disagree?

<span style="color: #FF0000">BTW, <span style="font-weight: bold"><span style="font-style: italic"><span style="text-decoration: underline">Håkan</span></span></span>, you didn't answer my question: What scope did I recommend a 40 MOA base for that has 56 MOA of total Elevation adjustment?</span>

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Spuhr</div><div class="ubbcode-body">A friend of mine have mounted his 5-25 in a 7mils/24 moa mount.
That gives him 24 mils of elevation, and a perfect round picture at 100 yards. It also takes the bullet out to 1500 yards, so staying of the full tilt is not really a problem as he gets a better picture at close range and he can still dial the scope out to distances further than he shoots at.</div></div>
Hmmm. I guess my former Premier Heritage 5-25X[56mm] 27 MIL MTC DT and my two PMII 5-25X[56mm] [0.1 MIL DT LP] CCW scopes are defective, because I get a round "picture" throughout the magnification range. I have friends with PMIIs', Premiers', and/or Hensoldts' who also have defective scopes - maybe I should call them and tell them to sell their defective scopes and overly-canted bases.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Spuhr</div><div class="ubbcode-body">I asked Hensoldt what tilt they recomended for their scopes.
Their answer was, all depending on the shooting distances, the less the better.

But it's fully possible that you know this stuff better than Hensoldt.....



Håkan </div></div>
Touche'. Now you've decided that following a manufacturer's recommendations is the correct thing to do? You can't have it both ways - its' one way or the other. So which is it?


Keith
 
Re: S&B question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Spuhr</div><div class="ubbcode-body">I do agree with you that always choosing 20 moa is wrong, but my opinion is that the tilt should be choosed depending on the distances that are going to be shot at.

A friend of mine have mounted his 5-25 in a 7mils/24 moa mount.
That gives him 24 mils of elevation, and a perfect round picture at 100 yards. It also takes the bullet out to 1500 yards, so staying of the full tilt is not really a problem as he gets a better picture at close range and he can still dial the scope out to distances further than he shoots at.
</div></div>

Spuhr,
going by your friend's scope/base combination, I should have approximately 23 mils of elevation available with a 5-25 DT on my integral Surgeon 20 moa base?
I'm guessing that after zeroing the rifle and resetting the turret, he started on 0 on the first turn, and then ran out of travel about midways of the second turn?


Please pardon the dumb questions, but I've never owned an S&B, and I don't want to screw up on my first one.
I can change bases if needed on my other rifles, but not the Surgeon.