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338 Allen Xpress, RL33 load development

 
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  #15  
Old 09-05-2013, 07:57 AM
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Re: 338 Allen Xpress, RL33 load development

Quote:
Originally Posted by MontanaRifleman View Post
It's a 5C Broughton, only 27" long for mobility. I am having it nitrided so hoping for a little velocity gain there as well. I'm guessing my case capacity, based on some other reports, to be right about 99-100%. 3325 is smoking.
I would still think you would come pretty close. Broughton barrels tend to be pretty decent in velocity, I assume your rifle has a conventional throat length or is it set up as a single shot. Even with 27" barrel length, I would still think you will land right between 3100 and 3200 fps with top loads. Now you may only get 4-5 firings per case but that is not a HUGE deal with no fireforming needed.

Ya 3325 fps is smoking. That 230 gr Berger is a pretty fast bullet, similar to the 300 gr version but even seems a bit easier down the bore. I would have loved to see them make a 250 gr version in 30 cal but I understand their resistance to make a bullet that may require a non standard twist rate in some chamberings.

Personally, I think a 250 gr OTM would stay on point in a 1-10 twist out of anything the size of the RUM or faster. May be close but I think the larger magnums would do it. A 1-9 would certainly be enough.
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

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  #16  
Old 09-05-2013, 07:58 AM
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Re: 338 Allen Xpress, RL33 load development

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Originally Posted by TXAoudadKlr View Post
Can't wait to see the results out of the 300AX.
I am looking forward to it as well.
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Kirby Allen(50)

Allen Precision Shooting
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Farther, Faster and Flatter then ever before.

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  #17  
Old 09-05-2013, 08:03 AM
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Re: 338 Allen Xpress, RL33 load development

Thanks for the additional information. I am a big fan of the 6mm-284. Did those 105 gr Bergers stay accurate at 3485 fps? I tried them in my 1-8 lilja and they were limited to around 3250-3275 fps. Much over that and accuracy went away dramatically.

With the 107 gr SMK however I drove them to just shy of 3500 fps in the 30" lilja using a heavy charge of RL22. I will admit, this load is on the warm side!!!

That is certainly good velocity out of a very short 24" barrel. Basically 3K. Very nice.
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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  #18  
Old 09-05-2013, 08:20 AM
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Re: 338 Allen Xpress, RL33 load development

Yes the 105 match target hybrids worked well at that velocity. The barrel is a #11 28" Bartlein 5R
1 in 7.5 twist. Shot it at our Tucson Rifle Club range 500 M rams with tiny clusters. Can't tell you much beyond that distance.



6mm-284 pic
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  #19  
Old 09-05-2013, 11:10 AM
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Re: 338 Allen Xpress, RL33 load development

Quote:
Originally Posted by Fiftydriver View Post
I would still think you would come pretty close. Broughton barrels tend to be pretty decent in velocity, I assume your rifle has a conventional throat length or is it set up as a single shot. Even with 27" barrel length, I would still think you will land right between 3100 and 3200 fps with top loads. Now you may only get 4-5 firings per case but that is not a HUGE deal with no fireforming needed.

Ya 3325 fps is smoking. That 230 gr Berger is a pretty fast bullet, similar to the 300 gr version but even seems a bit easier down the bore. I would have loved to see them make a 250 gr version in 30 cal but I understand their resistance to make a bullet that may require a non standard twist rate in some chamberings.

Personally, I think a 250 gr OTM would stay on point in a 1-10 twist out of anything the size of the RUM or faster. May be close but I think the larger magnums would do it. A 1-9 would certainly be enough.
Yeah, I think I can get to 3200 with the nitrided barrel. The throat spec is .3085 x .200 with a 1*30 angle. The 230's barely fit in the 3.820 mag box about .010 off the lands.

In making the 230, Berger kept the same nose and tail as the 215, only lengthened the bearing. I think Berger tried to cram as much bullet in the Hybrid design as they could and make it work in a 10 twist. At our elevations they work OK, but I've read some other reports that guys were having some stabilization issues with them in a 10 twist. Using worse case inputs like 0 degrees temp and 0 pressure altitude @ 3200 fps, the Berger twist calc gives an SG of 1.33 which is marginal for terminal performance. With more normal inputs like 20* and 3000' altitude, the SG goes to 1.55 which is perfect. Upping the velocity to 3400 fps only boosts it to 1.58 I'm finding out that velocity doesn't have a huge affect on stability, whereas temp and altitude do.

So bottom line is, to make a hybrid style bullet in a 250 gr would require a 9 twist. Heck, I would like to see them do a 260. I would consider 30/338 LM Imp build for that.
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  #20  
Old 09-05-2013, 04:34 PM
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Re: 338 Allen Xpress, RL33 load development

Quote:
Originally Posted by AZShooter View Post
Yes the 105 match target hybrids worked well at that velocity. The barrel is a #11 28" Bartlein 5R
1 in 7.5 twist. Shot it at our Tucson Rifle Club range 500 M rams with tiny clusters. Can't tell you much beyond that distance.



6mm-284 pic
Very nice rig and shooting range!!
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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  #21  
Old 09-05-2013, 04:44 PM
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Re: 338 Allen Xpress, RL33 load development

Quote:
Originally Posted by MontanaRifleman View Post
Yeah, I think I can get to 3200 with the nitrided barrel. The throat spec is .3085 x .200 with a 1*30 angle. The 230's barely fit in the 3.820 mag box about .010 off the lands.

In making the 230, Berger kept the same nose and tail as the 215, only lengthened the bearing. I think Berger tried to cram as much bullet in the Hybrid design as they could and make it work in a 10 twist. At our elevations they work OK, but I've read some other reports that guys were having some stabilization issues with them in a 10 twist. Using worse case inputs like 0 degrees temp and 0 pressure altitude @ 3200 fps, the Berger twist calc gives an SG of 1.33 which is marginal for terminal performance. With more normal inputs like 20* and 3000' altitude, the SG goes to 1.55 which is perfect. Upping the velocity to 3400 fps only boosts it to 1.58 I'm finding out that velocity doesn't have a huge affect on stability, whereas temp and altitude do.

So bottom line is, to make a hybrid style bullet in a 250 gr would require a 9 twist. Heck, I would like to see them do a 260. I would consider 30/338 LM Imp build for that.
When Richard Graves still owned Wildcat bullets we talked about a new bullet for a possible 300 Allen Magnum. As most of you know, there is not a 300 Allen Magnum in the stable here at APS. That is not entirely true, there is a 300 Allen Magnum reamer, its simply the 338 AM necked down to 30 cal. Being based on the 408 CT parent case its a HUGE case capacity.

Working with Richard, he sent me some simply AMAXING 290 and even 300 gr ULD RBBTs in 30 cal. These things looked like pencils they were so long. In testing the 300 AM, it was a serious pain in the rear to be honest. We were testing these in 1-7 and 1-8 twist barrels and at lower velocities the bullets were shooting OK. 1 moa or so. But pressures were so low that velocity spreads were terrible and the WC872 powder we were using was burning like wet coal!!!

As we upped pressure, we ran into the problem that these bullets were so long, that the forward portion of the bullet would engage the rifling and begin to rotate but because the bullets were so long and heavy, the rear of the bullet would resist this rotational force and the bullets, in my theory, were being wrung like a wet towel. This really weakened the core jacket bond and accuracy went south or there was total bullet failure. We know this because we found several partial bullets down range that were only the OGIVE of the bullet. They had ripped from the body of the bullet where the ogive contacted the bore.

We saw this in lesser calibers as well (107 gr .224 cal). Richard was going to fix this by ordering custom jackets that had a heavy tapered jacket that was roughly 0.070" thick at the base, roughly 0.050" at the body/ogive and then tapered to 0.030" at the meplat. To top things off he sent me some with aluminum tips installed. These were so long that I never even shot them, did not have a barrel that would keep them on point.

Soon there after, Richard sold his business and the heavy tapered jacketed bullets never got off the ground.

When you get a bullet to a certain length, lead core/cup jacketed bullet anyway, it seems that you run into many other issues that you would never expect but slap you right in the face anyway.

I have still not given up on the 300 Allen Magnum, perhaps someday we will have the right combo of bullet and powder that could handle the velocity potential of this wildcat but for the time being, its not practical.
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Kirby Allen(50)

Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.

Farther, Faster and Flatter then ever before.

Web Page: www.apsrifles.com

allenmagnum@gmail.com
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