162 Amax vs. 162BTHP w/amp

[mwroseberry]

So A-maxes are hard to find right now while they re-tool for the new amp jacket with the A-max. So I ordered some the of the BTHP Hornady match 162s. I shoot in competitions out to and including 1200yards out of my 7mm-08. For me the A-max inconsistancy in the plastic tip has been a matter that has bugged me for a while now. I can see differences in the tips with my naked eye so I know they are affecting bullet flight. Especially since when reading the Litz book on bullet flight and overtwist of a bullet (which I am for the 162s). So I'm giving up 0.01 in the BC department but I figure I'm picking up MUCH more in consistancy and predicatbility at max range.

What do you guys think on this logic? Does it make sence?

I know a range report is the only thing that will help with this so Range report will follow once they come in. I'm going to use the same identical charge I currently use to compair.

Good Luck,
Merritt

 

[josephberry]

Re: 162 Amax vs. 162BTHP w/amp

where did you find the new bullets?

 

[notquiteright]

Re: 162 Amax vs. 162BTHP w/amp

I remember when the Amax first came out. Many very anal interweb X-spurts were trimming the SMK meplats because they disparaged the ragged noses the Match winning SMKs had and flocked to the plastic nosed Amax!

I wont argue with Litz as he knows soooo many more big words than I do. I havent seen 'overtwist', do you mean a very fast rotation of the bullet as it goes downrange? Thats a combination of velocity and rifle twist.

I am sure he has great examples of this problem. I have always thought it takes pushing a bullet extremely hard in a super fats twist. A few years ago I used the JBM deal to check my rotations per second and found a rather wide margin before hitting any theoritical problem.

But I dont do extreme benchrest. I get all fuzzy if I can hold 1MOA at 1000. (I dont get fuzzy that often)

What discipline do you shoot where you see the plastic tips being a problem?

 

[mwroseberry]

Re: 162 Amax vs. 162BTHP w/amp

The plastic tips seam to come into play from 1000 out to a mile. I'm holding 1MOA very well with my rifle at 1000 and then its like it goes to hell in a hand basket. I know I'm still at 1000fps at 1700 yards so it's not the fact that it is going trans-sonic. The only other reason I can figure is that the slight difference in bullet length and angle because of the plastic tip is making for in-consistancies. I do long range tactical style shooting at TVP and Rayners in Ohio.

I'll test the new bullets and give a range report at 1000 and beyond. As long as they are as consistant as advertized I believe it will correct my issues but you never know.

Thank you,
Merritt

 

[mwroseberry]

Re: 162 Amax vs. 162BTHP w/amp

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jdberry</div><div class="ubbcode-body">where did you find the new bullets? </div></div>

Grafs and Sons has them in stock. Midway had them in stock for a while also, haven't tried them lately as they are expensive in the shipping department.

Thank you,
Merritt

 

[bohem]

Re: 162 Amax vs. 162BTHP w/amp

Merrit-

I've had issues with the 162 Amax creating transition problems when the bullet hits appx Mach 1.2-1.25, 1000fps is subsonic at Tom's place pretty much any time during the year. Using that bullet at a mile is no surprise why you are having trouble hitting the target at 1740.

How do you do when the bullet is above about 1400fps?

My 7/300 WSM does fine with them to about 1440-1500yd but when the bullet falls below appx 1400fps in my area (which is very close in atmosphere to TVP) the repeatability takes a shit fast.

I'm not sure that the new 162 is going to fix that. Transonic issues are strongly influenced by tail shape, not nearly as much by the nose. If those 2 bullets share the same boat tail you may well find the same results.

I'm looking forward to what you find as your 7-08 results are similar so far to my 7/300, they just happen sooner because of the MV difference.

 

[mwroseberry]

Re: 162 Amax vs. 162BTHP w/amp

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

I've had issues with the 162 Amax creating transition problems when the bullet hits appx Mach 1.2-1.25, 1000fps is subsonic at Tom's place pretty much any time during the year. Using that bullet at a mile is no surprise why you are having trouble hitting the target at 1740.

How do you do when the bullet is above about 1400fps?

My 7/300 WSM does fine with them to about 1440-1500yd but when the bullet falls below appx 1400fps in my area (which is very close in atmosphere to TVP) the repeatability takes a shit fast.

I'm not sure that the new 162 is going to fix that. Transonic issues are strongly influenced by tail shape, not nearly as much by the nose. If those 2 bullets share the same boat tail you may well find the same results.

I'm looking forward to what you find as your 7-08 results are similar so far to my 7/300, they just happen sooner because of the MV difference.

</div></div>

1050 yards = 1404fps so this would hold true with your results. We'll see how the BTHP does and see if your tail theory is correct.

Thanks,
Merritt

 

[mwroseberry]

Re: 162 Amax vs. 162BTHP w/amp

Well just got the BTHPs in the mail today. They are not bright and shinny like the amax but I could care less if they are more consistant.

Above from left to right (168 berger, Hornady 162 bthp, Hornady 162 Amax)

It's very hard to see but the BTHP has a more defined boat tail more like the Berger than the A-max. The amax BT is a very smooth transition almost as if someone sanded down the defined line at the transition.

Range report will follow.

Thanks,
Merritt

 

[bohem]

Re: 162 Amax vs. 162BTHP w/amp

Thanks for putting up the pic, I'm looking forward to hearing how they perform at transonic particularly.

 

[mwroseberry]

Re: 162 Amax vs. 162BTHP w/amp

These bullets definately have a different O-give. I set my dies up off of a Amax loaded at 2.905 OAL and then ran a round with the BTHPs. OAL on that round was 2.870. I ran 15 of these and will use them for testing. If they don't group well I'll try necking them out to Amax length and trying again.

Load:
162 Hornady BTHP
OAL 2.870
46.5g H4350
Winchestor brass
CCI200

Good luck,
Merritt

 

[mwroseberry]

Re: 162 Amax vs. 162BTHP w/amp

Well I tested the BTHPs this morning. My POI was .75min right from my amax zero and elevation correct. I had one 5rd group that was a little under 1/2MOA that I shot rapid fire. I also had one 8rd group that was right at or a hair under 1/2MOA. So if my estimation is correct and since the bullets are the same length using identical powder charge (much higher compression), I'm assuming I'm running at a bit faster speeds than my Amax 2700fps. I am guessing I'm closer to 2775 or faster.

I'll post back when I get my pictures uploaded and then later when I can very speed at longer ranges.

Thanks,
Merritt

 

[264win]

Re: 162 Amax vs. 162BTHP w/amp

I am also trying these bullets back to back with the a max out of my 7~08 this weekend.
I will post 1k results later.

 

[mwroseberry]

Re: 162 Amax vs. 162BTHP w/amp

Here are images from today.

100yard 8 rd group using BTHP:

Older 5rd Target using A-max (this is after load developement - BTHP above was not developed)

If I'm getting more speed out of the BTHP with basically the same group max spread I think we have a new winner. Now need to test them at max range.

Good Luck,
Merritt

 

[prescottmarksman]

Re: 162 Amax vs. 162BTHP w/amp

Has anyone considered the rpm/stability theory.

If I remember my formula correctly its velocity times rotations per foot times 60= RPM

We know that at the muzzle with a 1 in 8 twist at 2700fps your turning some 243k rpm. very stable.

But at 1k yds at 1440fps same twist (the rotation only slows slightly) your only looking at 129k ish rpm. Which is getting to the bottom of the stability range for a bullet of that length.

If I remember correctly Length is more important than weight when it come to determining twist.

Just a thought

 

[mwroseberry]

Re: 162 Amax vs. 162BTHP w/amp

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: fMoL</div><div class="ubbcode-body">Has anyone considered the rpm/stability theory.

If I remember my formula correctly its velocity times rotations per foot times 60= RPM

We know that at the muzzle with a 1 in 8 twist at 2700fps your turning some 243k rpm. very stable.

But at 1k yds at 1440fps same twist (the rotation only slows slightly) your only looking at 129k ish rpm. Which is getting to the bottom of the stability range for a bullet of that length.

If I remember correctly Length is more important than weight when it come to determining twist.

Just a thought </div></div>

You make a very good point. 1100 Yards accurately may prove to be my max.

Thanks,
Merritt

 

[244]

Re: 162 Amax vs. 162BTHP w/amp

Isn't the RPM's of the bullet determined by the twist rate and MV? Of course there will be some slowing of RPM over flight time, but it will be slight.

Or am I missing/forgetting something?

 

[JC Steel]

Re: 162 Amax vs. 162BTHP w/amp

I shoot the 162 amax's right now and love them. I have stock piled a nice collection of 3k sitting on my shelf. I dont plan on buying any of the other bullets. The 162s are shooting great out to 1375 yards for me. I am shooting them out a a .284 win at about 2950 FPS. 1-9 twist barrel.

 

[bohem]

Re: 162 Amax vs. 162BTHP w/amp

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: fMoL</div><div class="ubbcode-body">Has anyone considered the rpm/stability theory.

If I remember my formula correctly its velocity times rotations per foot times 60= RPM

We know that at the muzzle with a 1 in 8 twist at 2700fps your turning some 243k rpm. very stable.

But at 1k yds at 1440fps same twist (the rotation only slows slightly) your only looking at 129k ish rpm. Which is getting to the bottom of the stability range for a bullet of that length.

If I remember correctly Length is more important than weight when it come to determining twist.

Just a thought </div></div>

The rotational velocity decays MUCH slower than the flight velocity does, somewhere in the 25-50x's slower realm depending on bullet, rifling, shape, etc.

Therefore, just because the forward motion at 1100yd has slowed to 1400fps, the spin rate is still somewhere in the 200-225krpm range easily, not down at 129k.

This is where the idea that an "overspun" bullet will not trace at long ranges but will actually resist "tipping in" on the flight path and hold a nose "high" attitude.

There may/may not be creedence to the tipping in theory, but calculating spin rate based upon flight velocity downrange by simply running the same formula you did at the muzzle is highly erroneous.

 

[raptor99]

Re: 162 Amax vs. 162BTHP w/amp

jcvibby,
What are you using for a load in your 284 with the AMAX??

 

[264win]

Re: 162 Amax vs. 162BTHP w/amp

quick update with a little field data:
i tested the 162 amax and bthp back to back @ 620 yds and 1040 yds out of my benchmark barreled 26" 9 twist 7-08.
i did not chrongraph the loads , but i did confirm 100 yd zero with both. bullets were loaded to the same specs .
@ 620 i had less than a .1 mil difference in elevation and no preceptible differece in wind drift [full value 10-12 mph ]
@1040 the a max shot .3 mil flatter , with no noticable difference in wind drift .
i am very happy with how both bullets performed overall.

 

[bohem]

Re: 162 Amax vs. 162BTHP w/amp

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 264win</div><div class="ubbcode-body">quick update with a little field data:
i tested the 162 amax and bthp back to back @ 620 yds and 1040 yds out of my benchmark barreled 26" 9 twist 7-08.
i did not chrongraph the loads , but i did confirm 100 yd zero with both. bullets were loaded to the same specs .
@ 620 i had less than a .1 mil difference in elevation and no preceptible differece in wind drift [full value 10-12 mph ]
@1040 the a max shot .3 mil flatter , with no noticable difference in wind drift .
i am very happy with how both bullets performed overall. </div></div>

This leads me to believe that the new bullets have more than the new AMP jacket technology. The older 162 BTHP's had a substantially lower BC when I saw test results from a friend's 7 WSM.

This is all good news so far, keep it coming!

 

[264win]

Re: 162 Amax vs. 162BTHP w/amp

keep in mind that my " data " is very subjective. Since i did not chornograph the a max load, it is very possible that it was going slower then the bthp. Making the bc seem closer than it actualy is . I will have more data soon , and try to post anything relevant here.

 

[prescottmarksman]

Re: 162 Amax vs. 162BTHP w/amp

That is a very good point. I was wondering if there was a direct correlation or if it was only due to slight surface resistance. Very slight slowing in rpm would effect spin drift but not stability. I sit very happily corrected.
Thank you sir.

 

[mwroseberry]

Re: 162 Amax vs. 162BTHP w/amp

Went to my personal range yesterday with the BTHP and the Amax for direct compairison. Set up steel at 575.

162 a-Max
46.5g H4350
Winchestor brass
CCI 200 primer
2.905 OAl

12.0min up correction at 575
Estimated 2700FPS (.620 BC used in cal)

162 BTHP
46.5g H4350
Winchestor brass
CCI 200 primer
2.870 OAL

12.25min up correction at 575
Estimated 2775FPS (.610 BC used in cal)

At this range the BTHP was slightly more consistant even with brand new brass (a-max had fire formed and neck sized brass) I'm giving up a tad on BC but for now consistancy is easily better on the BTHP. I'm going to load up the BTHP for the Intimidator at TVP for the 15th and see how she does out to 1200 yards. I'll post back once the competition is complete.

Good Luck,
Merritt

 

[264win]

Re: 162 Amax vs. 162BTHP w/amp

A quick update on the 162 bthp out of my 7mm. Shot out to 1300 yds this past weekend. I was very impressed with the bthp. Runnning 2825 out of my 9 twist benchmark barrel , they were very stable and did very well in a gusty wind.
I am still trying to establish a bc that seems accurate at both medium and long range. If anyone has shot these at over 1k i would like to hear what you are using .

 

[mwroseberry]

Re: 162 Amax vs. 162BTHP w/amp

Well I went to TVP this weekend. The BTHPs were deadly consistant. I couldn't figure out why I couldn't make a wind call to save me though. Finally this afternoon when I sat down with my data book and my ballistic calculator I figured out why. My old speed was 2700. Well I'm now at 2780.

My old drift was 6.99 at 1000 and my new wind drift is 6.77. I think I'm completely sold on the BTHP. More consistancy than the A-max, less drift and less drop at 1000.

Also before I had stability problems at 1165 and now I have none.

Good Luck,
Merritt