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.338 Allen Magnum...WOW!

 
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  #29  
Old 05-09-2013, 08:27 AM
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Re: .338 Allen Magnum...WOW!

Don't have answers to all your questions but here are a few I do have.

1. Barrel whip.

DO not use carbon wrapped barrels to control barrel whip. I have tested this several times to prove it to customers. Take an all steel barrel and a carbon wrapped barrel, clamp each in the chuck of a lathe or in a padded vice by the first two inches of the breech, then hang 10 lbs of weight off the end of the muzzle with a dial indicator on the muzzle, see which barrel flexes the most, it will not be the all steel barrel unless your comparing a HUGE wrapped barrel to a very small contour all steel barrel. Same contour barrels, the all steel is by far more resistant to flexing and whipping. Carbon wrapped barrels have their purpose but its often misleading about what those are. Carbon fiber, pound for pound is stronger, stiffer and lighter then steel, problem is, if you take a 5 lb steel barrel compared to a 5 lb carbon fiber barrel, the carbon fiber barrel would be so huge in diameter it would not be usible for a rifle barrel. A bit misleading.

2. extreme barrel length vs velocity results in 338 calibers

I have alot of data on this as well, I have tested my 338 Allen Xpress and 338 Allen Magnum with barrels up to 40" in length. For example, my huge 338 Allen Magnum with its "Up to" 150 gr powder charges, will still only gain single digit FPS per inch over 36". In something like the 338 AX which is very comparible to your 338-378 in performance, you will be looking at 5-6 fps velocity gains, not worth it and you will likely pay the price in barrel rigidity. For my 338 Allen Magnum, I do not recommend any barrel length over 36". In all honesty, 34" is really the most practical as there still is not much worthwhile velocity gains over 34". For the smaller 338 magnums, its really not worth it to go much over 32" in barrel length. Just not enough velocity gains to make it worth while.

Have never tested the gain twist barrels on my wildcats so can not offer anything meaningful there.

The design of the desert tactical rifles would make it a challange to build using manual machines. It may be possible but would take more time then I have at the moment so would have to decline such a project.

You want to top the 338-378 Wby with a 280 gr Barnes at 3180 fps. A single shot 338 Allen Magnum with same bullet in a shorter 30" barrel length would likely still break 3300 fps. In a 32" barrel length you could push a 265 gr Barnes LRX to +3500 fps and a 280 gr LRX to 3400 fps......
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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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  #30  
Old 09-21-2013, 05:43 AM
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Join Date: Jan 2009
Posts: 7
Re: .338 Allen Magnum...WOW!

[quote]
Quote:
Originally Posted by idaho elk hunter View Post
I ampresently using a custom 338-378 Weatherby shootin th 280 gr barnes over a stout load of h570 powder. 3138 fps through several chrongraphs. Great load and caliber. My next rifle I am much considering, if Kirby could build a 338 on a Desert tactical arms bull pup chassis to allow for a barrel of 36 to 40 inches and maintain a standard length rifle. If I do this I am very worried about "Barrel whip". Would having a carbon wrap that is done in Montana on the last 50% of the barrel help with this? How bout a Bartlien Progressive twist rifling tube on it? Kirby,,,your thoughts? What a flat shooter to surpass the MK5 chassis and 338-378 Weatherby!
Mark Gordon at Short Action Customs has built several custom barrels for me for my DTA SRS. The standard chassis will take up to 338 Lapua. He does a great job. All have been shooters. He generally uses Bartlein barrels.

I am currently doing a 6.5 SAUM barrel for mine with a 28" barrel that will be shorter than most rifles. Love my DTA.

You could do a 34" barrel in a 338 Lapua based caliber. Should work fine. He would be the guy to do it.

Short Action Customs | Your Foundation for Precision
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  #31  
Old 09-23-2013, 10:40 PM
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Join Date: Feb 2008
Posts: 210
Re: .338 Allen Magnum...WOW!

So after reading some of these post I seen another 338 or maybe a 375 which I though was built maybe on a 416 barret case. Is this case larger than the 408, or is the barret case just a remodel of the 50 cal with some work done to the brass. I think I read it would hold something like 186 grains of powder which is freakin wild to say the least. Also does the 338 edge produce more volicity with the 300 grain pills than the AI or Kirby version of his AX or are they all within 100 fps of each other? Just curious.
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  #32  
Old 09-24-2013, 08:22 AM
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Re: .338 Allen Magnum...WOW!

The Barrett case is MUCH larger in capacity then the 408 CT case, BUT, it can not be loaded as high in chamber pressure so the end result is surprisingly similar to the wildcats based on the 408 CT, usually less then 100 fps difference. Add to this, the Barrett requires a 50 BMG class receiver and rifle platform whereas the 408 CT based rifles can be built in much lighter and smaller platforms.

All things equal, the 338 Edge will get you 2900 fps on average with a 300 gr berger out of a 30" barrel length.

The 338 AX will get you into the 3050 fps range with same barrel length and bullet. There are some special throat designs that can bring the edge up to the performance of the 338 AX and 338 AI but those same throats can also be used on the 338 AX and 338 AI to give them an additional boost in performance so that is why I said, if all else is equal, the 338 AX and AI will be roughly 125 to 150 fps faster then the Edge.
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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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  #33  
Old 10-31-2013, 09:42 AM
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Join Date: Oct 2013
Location: Ghazipur-U.P-INDIA
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Re: .338 Allen Magnum...WOW!

Quote:
Originally Posted by dogdinger View Post
I had the distict priviledge of not only seeing a .338 AM this weekend, but actually got to shoot it! WOW! was this one impressive beast! A J Peacock stopped on his way back from his easter visit to his family and brought the AM along. It was a beautiful day with no wind so naturally we had to burn some powder. we both shot sighters on the steel @ 650 yds and the gun was right on the money after him not having shot it since last elk season. we then moved out to milk jugs @ 800 yds.....not a problem....2 dead jugs.....he then wanted to check his windage just to be sure and shot my hanging plate over on the edge. this is a peice of 3/4" cast steel that is called a mucking plate in a mine.....the AM shot right thru it at 800 yds! my 6X284 barely even scratches it!

this is the first Kirby Allen build i have had the pleasure to see/shoot, and i want you to know that it is a work of precision shooting art..... thanks for the fun AJ.......aj
Really very impressive at that range
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  #34  
Old 10-31-2013, 03:23 PM
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Join Date: Dec 2012
Location: washington state
Posts: 3
Re: .338 Allen Magnum...WOW!

I am the owner & designer of a cartrage named the .285 tyrannos. it pushes the 180 gr vld at 3654 fps the cartrage hold 27.5 grs. more powder than the 338 lapua. I will soon be testing it on the new 195gr berger. should be around 3500 fps. will soon know. With a few points shy of .800 b.c. transonic should be around 2900 yards. I am the father of 12 other cartrages all very nasty.
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  #35  
Old 11-10-2013, 06:58 PM
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Location: Colorado USA
Posts: 11
Re: .338 Allen Magnum...WOW!

Sounds impressive, can you start a thread and tell us some more?
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