Rifle Scopes What distance is a 20 MOA base needed?
- Thread starter Winny94
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Talk half of your scope travel and see if it's more than you need at 600. This will be a rough start.
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My suggestion, FWIW, is to think seriously about putting some angle into your base, as then you won't need to replace it later. You should look at your projected ballistics chart, and see the MOA needed to reach 600yd, then compare that to what half the scope vertical adjustment range is. You do also want to remember that your clearest and least distorted picture may be in the center of the scope adjustment, depending on the quality of the scope(some may be good virtually anywhere in the lense area).
Hope that helps....
Hope that helps....
If you don't have an adj cheek pad and you don't need the canted base, the flat base will require a lower head position. Or, don't give up 6 mil of travel (that you will never/seldom use) for a poor cheek weld on every shot.
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That's going to be lower by less than a mm, right? Not really enough of a difference to be the reason why you'd go with a flat base.
Once you have your scope zeroed count the clicks you still have for elevation. Then look at your dope and see how far you can shoot just using the turret for elevation. As an example my 20 MOA base installed under my PST leaves 15 mils left going up from zero. Shooting at sea level on a cold day I needed 12.7 mils for 1000 yards so no problem. Without the base I would have had to use my reticle plus the turret at it's max limit (or just under to not cause possible issues).
Here's how I think about it. If your scope has 100 MOA of travel then a flat top gives you 50. Let's subtract 10 for margin of error (some scopes are wonky at the extreme edges of their travel). At 600 yards shooting 175s in a 308 you will need 15.58 MOA. You won't run out until you hit 1000 yards.
However if you run with a canted base then you will be shooting the center of your scope travel at 600 yards, and you won't run out of scope travel until about 1300 yards. So I say go with the slanted base.
Save yourself some head scratching and get a damn 20 MOA base under your scope, zero it and forget about if you need it or not.
Cheers.
Cheers.
Depends on what scope you have and how much elevation adjustment it has. Just get the 20 MOA base.
Are any of you guys using 40 minute rails? Or 20 minute mounts in conjunction with an additional 20moa rail??
I have a rifle fitted with a 20moa rail and recently ordered a 20 moa spuhr mount to put an nxs (100moa/without a zero stop) scope in. The way I figured, it should put my "zero" damn near at the bottom of the elevation range then give me close to the full 100 moa of adjustment for dialing.. I intend to re-barrel this particular rifle to a 338L down the road & hope to use the combination for dialing past 1500 (hence wanting that full adjustment range)
Some say using the extreme ends of a turrets elevation range can cause problems, I'm curious whether anyone has seen this with NF at all ? Was my thinking a good idea, or did I open the door to possible turret/scope trouble now?
Many have set up Hensoldt's without zero stops to bottom out the elevation turret thru the use of 40+ moa cants.. it obviously hasn't seemed to be a problem doing that with Hensoldt, but am curious if NF internals may be of concern ? (can't imagine NF be one to worry about, but figured I'd ask) ...anyone with experience on this 40+ cant combination, do chime in*
I have a rifle fitted with a 20moa rail and recently ordered a 20 moa spuhr mount to put an nxs (100moa/without a zero stop) scope in. The way I figured, it should put my "zero" damn near at the bottom of the elevation range then give me close to the full 100 moa of adjustment for dialing.. I intend to re-barrel this particular rifle to a 338L down the road & hope to use the combination for dialing past 1500 (hence wanting that full adjustment range)
Some say using the extreme ends of a turrets elevation range can cause problems, I'm curious whether anyone has seen this with NF at all ? Was my thinking a good idea, or did I open the door to possible turret/scope trouble now?
Many have set up Hensoldt's without zero stops to bottom out the elevation turret thru the use of 40+ moa cants.. it obviously hasn't seemed to be a problem doing that with Hensoldt, but am curious if NF internals may be of concern ? (can't imagine NF be one to worry about, but figured I'd ask) ...anyone with experience on this 40+ cant combination, do chime in*
I had the 44.4 MOA Spuhr mounts when I had Schmidts. No issues. U will have less windage available at you zero, but if everything is inline and you hold wind, it shouldn't be an issue.
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Most 1" scopes will have enough travel to get you out to 600 yards with a 0 moa base. Most 30mm tube scopes will get you to 1000 yards. Keep in mind you will be using the edge of the travel range and your windage will be limited at the extreme range (scope tubes are round: when you move toward one edge the sides get closer).
Another consideration is to stay optically centered in the glass. You'll want the best clarity when shooting at distance and the best clarity will be when the mechanisms are centered.
If you're going to be shooting much at 500 yards or more, go with a 20 moa base. But of you already have a flat base just shoot it. Practice is what you need.
Another consideration is to stay optically centered in the glass. You'll want the best clarity when shooting at distance and the best clarity will be when the mechanisms are centered.
If you're going to be shooting much at 500 yards or more, go with a 20 moa base. But of you already have a flat base just shoot it. Practice is what you need.
I have a NF NXS 8-32x56 with Zero Stop. I have it on a 25 MOA Base. I have plenty of adjustment to reach 1600 yards with 300gr Bergers on my 338LM. This scope has 75 MOA total height adjustment, so it adjusts out at 1825 yards, and then has 24 MOA of reticle holds--- enough to get past 2000 yards. I have considered getting a 20MOA mount set-up, but am not sure I will need to do so. If you have a 5-25 NXS, you should have no problem with adjustment out past 2000 yards, which is well into the subsonic range.
just buy one, i found this out the hard way this past weekend.
i have a 20moa base on mine, and shots up close (100-200yds) is not an issue. i don't see how it could be. it is better to have it and not need it, than to not have it and need it some day.
do you have a base already? if not, having the 20moa base wont hurt anything by just having it on the rifle. you never know, you may get an invite to someones 1400yd range someday.
So, I'm wondering how much cant is too much? I'm looking to shoot ELR with my 300WM (Rem700 5R 24 inch), most likely using 230gr. Berger Hybrids. I originally bought a 20MOA Nightforce base which I have not installed yet. After reading about all the adjustment needed for ELR, I ordered a 40MOA base which is also still in the box. I need to install one and return one of them, but after reading some of this post I'm wondering if the 40MOA is too much cant? I'm planning on using the new Vortex 4.5-27X, which has 122 MOA of total adjustment.
So, is 40 MOA too much for up to 1800 yards and will a 20 MOA base work for that, or do I just install the 40MOA and dial way down for close shots?
So, is 40 MOA too much for up to 1800 yards and will a 20 MOA base work for that, or do I just install the 40MOA and dial way down for close shots?
40 MOA means your zero should be 20 MOA off maxed out, which ought to be fine on the Vortex for 100 yards.
At 1800 yards you're probably looking at about 80 MOA of adjustment (guessing at 2700 FPS for the Bergers). So that's right on the margins with 20, just fine with 40.
And why the hell would you ever shoot those monsters at less than 600 yards anyway? You might as well walk up to the target and make holes in it with a hole punch. : )
You're welcome! Glad I could help.
A 20 MOA base with a good scope (one with a lot of adjustment range) is all you need. 40 MOA bases are needed for extreme long range shooting (beyond a mile) on larger calibers (e.g. 50 BMG)
so i read this hole page, and what i was wondering is....... with a 5-25x56 msr scope 34mm on a 0 moa rail on the rifle mounted on a 40moa base, would the zero be out to 600/700 meters?
Read my post a few back on this - for his range, scope and bullet he's going to need that 40 MOA.
I don't understand your question.
With a 40 MOA base your zero will start 40 MOA off "normal". Every adjustment for elevation for the first 40 MOA will be moving the reticle towards the center of its range of travel. At 41 MOA of adjustment you will be moving the reticle away from its center again.
No, it just means you have 90 up and 10 down (when you at your 100 yard zero) instead of 50 up and 50 down.
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I have two issues to address with my AR 10 and I hope someone can answer both. One is, I'm going to put a 30 mm IMS Mark AR sku # 171986 mount on this rifle with a VX -3i LRP 6.5 -20 X 50 scope. I don't see the need for the 20 MOA version of this mounts Leupold has available since I don't mind dialing in the turret using a ballistics calculator. Am I wrong making this assumption. Two is this. with the stock bird cage flash suppressor from the factory the guns cycles perfect and I do not have any jams or misfeeds. When I run the Surefire muzzle brake I get misfeeds and jams. Has anyone experience this issue with muzzle brakes or silencers on their AR 10? What is the cure other than take the muzzle brake off.
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Well glad you updated an almost 7 year old thread. LOL
Yes you are wrong. 20 MOA bases have nothing to do with wanting to dial. It has to do with redistributing your available internal elevation in the scope and giving you more elevation to be able to dial. so if you had 100 MOA it's 50 up and 50 down on a flat base. On a 20 MOA base it would be 70 up and 30 down.
Misfeeds and jams from just changing the brake? No. If you mean when you put the suppressor on then you might need an adjustable gas block. You might want to go down to the Semi Auto section and ask also.
Okay, I'm sticking with a flat base since most of my shots will never be beyond 300 yards. I will back at the range Monday to try the muzzle brake once again after I do about 10 single shot lock back test first. According to the Leupold website this scope has. I think I'll be just fine. Thanks for the come back.
| Elevation Adjustment Range (MIL) | 23.3 |
| Windage Adjustment Range (MIL) | 23.3 |
If not going beyond 300 yards you will be fine. You should have around 11.5 mils up and with that it should get you out farther than you will probably shoot.
For reference, on my Savage 308 chassis rifle with a 24" barrel, my 100 yard zero DOPE exceeds the Nikon Black FX1000's elevation adjustment capability after 1,100 yards. With a 20 MOA rail, I can go all the way to 1000 and then the bullet begins to drop something fierce and I can just get to the adjustment for 1,100 with the turret... barely. And honestly I never go past 1000 yard dope adjustment because it's easier to hold over and I'm not confident in the accuracy of the last few MILs at max elevation on this scope. Up to 1,000... dead nuts, though. The round for that dope (which was very reliable) is the Federal GMMK 168 gr. The Nikon Black series is not known for having "the most" elevation adjustment. I still get to 1,000...
Call me crazy, but for me, if I don't have an adjustable cheek piece the first thing I do to a rifle involves electrical tape, cardboard, and cut up camping foam. A well set up rifle is too fundamental to me enjoying my time shooting it much less my increased success.
Beyond that, just get the 20moa base. It won't hurt you. Maybe someday you will shoot to that Herculeic distance i know you dream about (you're on this forum
) and you won't have your gear working against youLOL amazes me some think the amount of difference between a 20 moa base and a 0 will change your head position dramatically. It doesn’t. I bet I could put a 20 moa base on a rifle and a 0 on an exact same rifle and you wouldn’t be able to tell the difference.
While it should never apply to a long range optic, you do have to be careful on some scopes. I had a Weaver about 5 years ago (don't remember the model but it was not overly cheap $800ish). I put a 20moa base on it and the rifle went from 3/4 moa to 1 1/2 moa. Apparently, on that scope the range of adjustment was so bad that 20moa would cause the adjustment to go out of the usable range. I thought the scope was bad. But when I called Weaver they new exactly what the problem was. It was a nice scope for hunting; but not so much for long range. Just something to be aware of. That said, I always start with at least 20 moa of cant and haven't had a problem since I sold that Weaver.
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