.338 Allen Mag Veloicty

bjlooper

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Mississippi
What kind of velocity does the .338 Allen Mag produce. Also what case is it based on. Is it enough diff over the 338 RUM and the 338 laupa to make it worth the extra work of a wildcat?
Thanks
DR B
 
BJ,

There are several posts on here that discuss the 338AM, 338Baer, and the 338 SnipeTac rounds, all are about the same case design made from the 408 Chey-Tac case. I have some test data on my website or send me an email. They will produce velocities 3400+ fps with the 300grn Sierra MK or over 3500fps with a 250grn bullet.

I have a carbon ABS barrel on order for a customers Snipetac project. I have heard all good things about his barrels.

Dave
 
What BD408 said. My test rifle has a 40" Lilja on it. I suspect I will break 3500 fps easily with a 300 gr ULD RBBT.

Looking to get 3300 fps or more with a 350 gr ULD RBBT.

BD408, Shawn C and I are all building lightweight rifles in these chamberings. BD408 with his 338 Sniper Tac wildcat and Shawn C. and I are using my 338 AM. Shawn and I are trying to get the rifle, ready to hunt with under 16 lbs!!! Thats scope, bipod and ready to pull the trigger on big game. We will see if we get it. I think we can.

Those rifles will have 32" barrels or similiar length. I am hoping to get +3350 fps with these barrel lengths with a 300 gr bullet and the 338 AM. Should be able to do this.

If we can you would be looking at roughly 450 fps over the 338 RUM, 400 Lapua and a solid 300 fps over the 338 Kahn. With a 350 gr pill the advantage will be even greater then this.

Is it worth it, thats up to you to determine. I will say though that adding +400 fps to the current top end of the 338 caliber magnums is pretty significant in my opinion.

Kirby Allen(50)
 
Kirby,
You will have no trouble at all getting 3350 out of a 32" tube. I am getting 3420 right now out of my 33" bbl and still am under top pressure, with BMG50 powder. My rifle came out at 16# 12oz. More than i was shooting for, but there is no restrictions here in Neb. I could of shaved off more weight, shorten the bbl a bit, lighten the contour (its a heavy palma, 7.5#)Mike Rock said he could make one around 6#, add a Ti muzzle break.
It really dont have much recoil at all, like a 270 maybe. I shot it without the muzzle brake and it wasnt all that bad either. Hunting purposes i would have no problem being brakeless.

Let me tell ya, its a big smack when the 300mk hits out at 750yds. To tell the difference here is an example: My friend has a 338-378wby shooting 300MK at 2800fps, my SnipeTac same bullet only 3400fps, (600fps faster!) at 750yds on a 5/8" thick gong, his will put big dents in it. The SnipeTac will go through with a 3/4" dia. hole (looks like you took a cutting torch and burned a hole through)
1000yds we have a T4 armor plate hanging on chains, no gun will penetrate this, the snipetac will put splash marks (dents) on the steel, all other guns at the range just knock off the paint, BMGS are not allowed on the range, and now my SnipeTac has been banned! HaHa.
This is horse power similar to the BMG 50's
hope to try the 350 wildcat bullets soon, more horse power! Varrooooom!

Dave
 
Chris Matthews told me he could shoot 300's / 34" / std lapua over 3200 fps. also said this was a little hard on brass.i'm thinkin you're gonna get 10% more velocity with 50% more powder.my way of thinking is this thing will be more efficient using the 350 gr bullets and barrel lengths over 30 really won't get you that much more velocity.
 
Dave:

I dont think you can get 3200 out of a standard Lapua case, if so great! Everyone i have talked to says 2950 is about tops.

It takes 32" to burn 98% of the powder in the 408 based 338 mags, anything shorter is fine but your velocity will drop.
Sure it takes more powder to gain the extra speeds, but so does the Lapua over a standard 338win mag. These guns are made for the ultimate long range BIG GAME rifles, the extra 400-600fps makes a big difference in MOA and energy at 1000+ yards. I can zero my rifle at 500yds, the come ups at 1000 are only 10.5moa(energy 3345ft#). 1500yds is a come up of 25.5moa (2100ft# energy).
 
Sounds awfully nice Kirby, you are making me reconsider that 338 Kahn,

Just to stir the pot here for a minute but do you think you could ever design something in hunting/carry wieght in the 416 cal. Something that would be good out to 1200yds on big game but not separate a prone shooters shoulders???

I know you always like to think bigger and better and since you are done with BJ's gun and I am sure you have tons of time on your hands /ubbthreads/images/graemlins/grin.gif /ubbthreads/images/graemlins/grin.gif just wanted to see what ya thought

I am ready to see that big sucker when ya get her all blackened up!!! i am really ready to our model with the smaller hole in the end

take it easy
steve
 
Kirby,

It "looks" like the new Stoney Point bipod has a small adapter that connects to the stock. The bipod then connects to it. They list extra adapters so as to be able to move the legs from one rifle to another.

I'm thinkin' I could stash or toss the legs after the shot quick enough that the fish cop would never see them. /ubbthreads/images/graemlins/blush.gif

They don't look very sturdy though.

Here I go dreamin' again /ubbthreads/images/graemlins/frown.gif
 
Lerch,

Only problem with going to a 416 caliber is the bullet weight you need to get the BC up to where it should be in comparision to the 338 bullets. 375 caliber would be a better choice in my opinion and we are working on that one.

We could certainly order in a BAT receiver that weighs 48 oz, add a 30-32" barrel and a light stock and you could pack the thing around easily. I would say possibly getting to the 12 to 13 lb range but there would be compromises that may effect the 1200 yard range requirements.

In the shorter barrels, the 375 caliber would be much more efficent and not as effected by velocity drop as the 338 AM. THe larger bores would be even better but again, you really have to jump bullet weight up to get the high BCs we want for long range shooting.

Simply put, if you want a 40 cal, I would simply look at the 408 CT and get Richards lead core bullets when they are ready. Would be much easier and affordable to get into then a full custom chambering.

In a packing weight rifle, 9 to 10 lbs, I still say the 338 Kahn is about as good as it gets. If the 338 Excalibur was more readily available from A-square that would be an even better design because of the lack of the belt but at +$40 per 10 cases its pretty spendy compared to 338-378 Wby cases.

Good Shooting!!

Kirby Allen(50)
 
Dave,

I would have to agree with BD408 on this one. 3200 fps is smokin with a Lapua in a 34" barrel with a 300 gr bullet. Even for the Improved version this is EXTREMELY high velocity.

The 338 Kahn will break 3100 fps with a 300 gr pill in a 34" barrel relatively easily but thats with 110 gr of powder. The Lapua is significantly smaller then the Kahn.

I am not saying that running the Lapua to Redline would not generate this pressure but I would not recommend it. The great thing and bad thing about the 338 Lapua case is that it will handle extremely high chamber pressures. It takes around 75,000 psi to loosen a primer pocket on a Lapua case. This is far over the appropriate working pressures of the 338 Lapua and any other shoulder fired rifle chambering.

This is great for long case life with proper pressure loadings but it can also give the loader a false sense of actual chamber pressure.

In my opinion, in a 34" barrel. The 338 Lapua should be held to 3000 fps max and this would still be a pretty hot load from what I am seeing with actual rifles.

Kirby Allen(50)
 
First of all I must say my hats off, you have me rethinking my .338 lapua that is almost complete. I have a few questions though.

1. Knowing that every shooter is different, how inherently accurate are you finding the .338 allen mag. Velocity is great but without an accurate round it is kinda pointless. Especially if you plan on sending a bullet 2000 yards downrange to a muley buck. Just curious on what kind of accuracy you are getting??

2. RECOIL, now I am never one to worry about recoil I have shot many LARGE rifles but this thing has to have ALOT of punch. You speak of putting it in a 16lb package and even with a muzzle brake...well.....I guess I cant even comprehend how hard it must kick. What are you finding for recoil and muzzle blast.

Ounce again I am awwed at what you guys are accomplishing and safely!!!!
 
Traks44,

I have been doing some early testing on 300MK's in fireforming the cases,(338 SnipeTac, twin sister to Kirbys 338AM) They seem to be running around .5moa so far, fine tuning is yet to come.



Recoil, My rifle is 16# 12oz complete. I have shot it without the brake, the recoil was not all that bad. With a brake it is very pleasant to shoot. I have a Holland style brake on it.
 
Traks44

As with all of my Allen Magnums, if they do not hold 1/2 moa or under they do not ship, plain as that. Most beat this by a fair margin, especially at extended ranges. I am not saying that it will be a consistant 1/2 moa rifle at 2000 yards but I will not say it will not have this potential either. At these ranges other variables beside the rifle result in how tight the groups are so that is out of my hands in most cases.

That said, my 338 AM is still in early development, translated, still in the process of building my heavy test rifle. Hoping to have it on the range here in a few weeks. Customers come first, most of the time anyway /ubbthreads/images/graemlins/grin.gif!!

As far as recoil, I think you would be suprised how little this chambering will kick with a properly designed rifle and muzzle brake. Most think that the lighter a rifle is the more it will recoil, even in spite of a muzzle brake.

This is simply not the case with a quality brake and properly designed rifle. The reason is because the lighter a rifle is the better a brake works. Or should I say, the greater the degree the brake can slow the rifle that is moving back toward the shooter.

The reason, momentum. Anyone that has shot a heavy rifle chambered in a heavy recoiling chambering such as a 50 BMG knows what I mean. Once that +25 lb rifle gets moving under recoil energy, the brake is very ineffective at stopping that large amount of weight once it has been started in motion.

Conversly, if you shoot a very light rifle that is chambered for something like a 30-378 wby with full tilt loads, the rifle will actually feel like it is being pulled away from your shoulder. Literally!!

This is because the lighter the rifle is the less momentum is generated under recoil and the better the brake will slow the rearward motion of the rifle.

If you want a muzzle brake to work its best, that being reduce felt recoil as much as possible, cut rifle weight as much as possible and keep muzzle pressure as high as possible.

If you have two rifles chambered for the same round, one being 25 lbs, the other being 10 lbs. While the unbraked 10 lb rifle may well pretty much kill you with recoil, it will "Move" you less when its fitted with a brake then a braked heavy rifle.

The reason, both rifles will have the same recoil energy transferred to them. The only difference is that the heavier rifle, once set in motion will have more momentum then the lighter rifle. As such, its much more difficult for the effects of the brake to slow the rearward motion of the heavy rifle then the light rifle.

May be hard to believe but thats how it works.

In shooting alot of heavy loads in 50 BMG I can tell you that for a fact. Its not the recoil persay that give you a sore neck and head, its stopping the moving +30 lb rifle with your shoulder/neck/face.

Recoil will not be a problem. I guarantee it will be less then a 12 lb rifle chambered for full tilt 300 RUM loads shooting a 200 gr bullet. Probably much less.

There will be many more reports coming soon with the 338 AM. I just got word dies will be ready around 6 to 8 weeks from now so thats on the way.

Good Shooting!!

Kirby Allen(50)
 
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