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338 Allen Xpress, RL33 load development

 
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  #22  
Old 09-05-2013, 05:35 PM
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Re: 338 Allen Xpress, RL33 load development

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Originally Posted by Fiftydriver View Post
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.
Yeah, you can only stretch a bullet so far. You can get more structural integrity with the mono's but you loose SD and BC with them and need tighter twist rates. I've followed most all the bullet threads in here for a few years now and the new experimental super long bullets are always having issues, cup and core or mono. You can generally stretch a mono a little longer than a jacked bullet but you need a really tight twist

CE just sent me some 6mm variations for testing in my 7 twist 6-284 which I received yesterday. They are all 100 gr in 3 different lengths. The longest is .060 longer than the 105 Hybrid. It should be very interesting to test them head to head. I'm guessing I'll get more than 100 FPS increase in velocity over the 105 with a similar BC. Not sure they will stabilize in the 7 twist?

I did notice you didn't show a 300 AM. That 408 CT case seems so huge for a 30 cal. You would need a good heavy bullet for that. Maybe Berger will get a 260 Hybrid going here before too long.... like maybe in the next 5 years

Heck, you'll still be a young man
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  #23  
Old 09-05-2013, 07:17 PM
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Re: 338 Allen Xpress, RL33 load development

Maybe this is the answer to the overbore issues. Its a project that I have been working on. It is my own design and concept.

It will give you the option to shoot .30 cal pills out of the big actions. While not having the huge case capacity of the .300 AM it should do the job in the accuracy department being designed similar to a scaled up version of the 6mm Dasher!

Once the barrel turns up and is chambered I will let you know how it goes.

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  #24  
Old 09-05-2013, 09:30 PM
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Re: 338 Allen Xpress, RL33 load development

I assume your using the 505 gibbs case??

You have fun shortening that one and necking down to 30 cal!!!

The Gibbs case is not generally made to handle much more then 50,000 psi so you may run out of case strength pretty soon. For your sake, I hope I am wrong.

When I was working with testing my 300 Allen Magnum, I tested it at the full length 3.050" case length, 2.850" case length and finally I shortened it back to 2.750".

The shorter length cases may have worked but they were a lot of work to shorten the brass and I had no desire to pay to have a large supply of custom brass made at that time. Shortened to 2.750", it had slightly larger case capacity then the 30-378 Wby case but still required a full Chey Tac receiver because of the case diameter so I did not see a reason to move forward with that project.

The 300 Raptor may also be to large in capacity, have to run that one through the wringer and find out what it will do but at least that one can be chambered in a conventional sized receiver and should outperform the 300 AX and 30-378 Wby by a fair margin with bullets in the 200-240 gr range.

Have fun with your project, keep us posted.
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  #25  
Old 09-06-2013, 01:14 AM
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Re: 338 Allen Xpress, RL33 load development

Kirby,
Although it is called a .30/505, I have done that to nominate it parent case rim size more than anything.

The brass I will be using is Bertram 408/505 brass and is very strong, as is his straight 505 brass as I believe he makes it to the same pressure standard as his Cheytac brass. This should be great news for 505 shooters!

I have a .375 Cheytac and I have got over 15 loadings with the Bertram brass and it is still good. I don't think the strength of the brass will be an issue at all.

I have talked about forming the Brass for this cartridge with the Bruce Bertram and using his 408/505 brass is the easiest option. Partially formed brass may also be an option as they can be removed from the process mid way.

I was in the Bertram factory Yesterday. It is an amazing place with all sorts of goodies.

Here is just a "few" .338 Lapua cases in the process of being made. I don't think we will be short of them for a while down here!

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  #26  
Old 09-06-2013, 02:08 PM
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Re: 338 Allen Xpress, RL33 load development

Bruce has been running Lapua brass for over a year now and not much else!!! From what I hear he is still way behind on Lapua orders!!!

If his 505 is made to the same as his Cheytac brass, you will be just fine. I am using his brass in my 338 and 375 Allen Magnum and it is very good brass.
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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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  #27  
Old 09-24-2013, 12:06 AM
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Re: 338 Allen Xpress, RL33 load development

Kirby, thanks to this thread and MontanaRifleman's encouragement I gave RL33 a try in my brand new full custom Rem 700 300 RUM. It wears a 32" Broughton 5C 9 twist. I was able to push the Berger 230 Hybrid Targets at 3100fps when I hit the end of the road with Retumbo. With my custom throating design and this long barrel I felt that it would do better in the velocity department. I decided to try RL33 and like you, I loaded up until the pressure signs on the case equaled the Retumbo loads. At 102 grains of RL33 the barrel would not burn any more powder as 103 and 104 grains produced about the same velocity. Might I mention that velocity was 3250fps. I backed down to 101.5 grains and it is now a .5MOA shooter and is running 3240fps with NO visible signs of pressure on the case head. Through the chronograph ES seems to be a little on the wild side but my targets are showing me otherwise and I suppose that is the final word.

700 yards, shifting 1mph wind, vertical dispersion is only .375"
338 Allen Xpress, RL33 load development-img_20130923_073617.jpg
338 Allen Xpress, RL33 load development-img_20130921_185926.jpg
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  #28  
Old 09-24-2013, 12:32 AM
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Re: 338 Allen Xpress, RL33 load development

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Originally Posted by Tumbleweed View Post
Kirby, thanks to this thread and MontanaRifleman's encouragement I gave RL33 a try in my brand new full custom Rem 700 300 RUM. It wears a 32" Broughton 5C 9 twist. I was able to push the Berger 230 Hybrid Targets at 3100fps when I hit the end of the road with Retumbo. With my custom throating design and this long barrel I felt that it would do better in the velocity department. I decided to try RL33 and like you, I loaded up until the pressure signs on the case equaled the Retumbo loads. At 102 grains of RL33 the barrel would not burn any more powder as 103 and 104 grains produced about the same velocity. Might I mention that velocity was 3250fps. I backed down to 101.5 grains and it is now a .5MOA shooter and is running 3240fps with NO visible signs of pressure on the case head. Through the chronograph ES seems to be a little on the wild side but my targets are showing me otherwise and I suppose that is the final word.

700 yards, shifting 1mph wind, vertical dispersion is only .375"
Attachment 25769
Attachment 25770
Your results look very encouraging for the 300AX.
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