338 Allen Magnum at +1 mile

[Fiftydriver]

Finished a customers 338 Allen Magnum XHS Repeater this week and decided I wanted to do a complete load development using the new Bertram brass. Since Jamison International stopped making my custom 338 AM brass, I have had to switch to Bertram brass. This is not a bad thing as this brass is actually a better match to my reamer specs and has proven to be a bit stronger then the Jamison brass.

How much stronger I really did not know as I had not done a real complete load work up with the new brass to find its limits, until this morning. First off, a bit of gun porn.

I did the velocity testing at the shop using the 300 gr berger Hybrid bullet and H-50BMG lit with a Fed-215 primer. OAL for the ammo was 4.280". My standard "accuracy" load for the 338 Allen Magnum is 142.0 gr H-50BMG and 3270 fps when loaded in the old Jamison cases. Max load in the Jamison cases was generally in the 3320 fps range with acceptable case life, that being at least 6 firings per case.

In the new cases I started at this level and worked up until the primer pockets let loose. Again, the top loads listed are for education purposes only, I am in no way recommending loading any 338 Allen Magnum to levels higher then the loads I list as max working load. Here are the results:

142.0 gr.........................3264 fps
143.0 gr.........................3292 fps
144.0 gr.........................3316 fps
145.0 gr.........................3358 fps choosen test load
146.0 gr.........................3384 fps
147.0 gr.........................3427 fps Max working load (Faint ejector ring)
148.0 gr.........................3445 fps (slight ejector ring on case head)
149.0 gr.........................3461 fps (heavy ejector ring on case head)
150.0 gr.........................3483 fps (loosening primer pocket)

In the end of the testing, the 145.0 gr load (3358 fps) resulted a load that allowed 6 firings on a single case with more firings left in the case. After 6 firings, the primer pocket had loosened noticeably but there was still plenty of resistance when seating a primer in the case and there was no gas leakage of any kind. I am sure this load will allow 8 firings per case, very similar to the accuracy load in the Jamison cases but roughly 100 fps more velocity with same case life.

I decided this would be the load I tested for accuracy in this customers rifle so I headed up to the range. By the time I got to the range the temp had increased from 60 degrees which it had been at the shop to roughly 84 degrees on the range. I wanted to stretch this big rifle out so I decided to set up at 1790 yards. Bore sighted the rifle and took a few shots to get the point of impact close to the point of aim.

I set up the video camera and let the barrel cool down. Then fired a three shot group at this range. The first and second shot landed pretty much on top of each other, the third shot landed around 1 1/4 moa to the right. Not uncommon to get a few fliers as the fresh rifles settling in.

Let the barrel cool and fired another three shot group. This one was much better measuring just over 3/4 moa. Very good.

Let the barrel cool and then fired the last three shot group out of the rifle. Prior to this group I made a scope adjustment but the wind had shifted abit and fooled me. Missed the target rock by a couple moa but these three shots easily went into a 1/2 moa group. If someone can tell me how to upload a video made on a Windows Live Movie maker program to Youtube, Facebook or Photobucket, please fill me in and I will share the video of the last group with all. Pretty happy with the rifle and very happy with that last group. Looks like she will be a serious shooter.

With the new Bertram brass, it looks like the 338 Allen Magnum is able to get back very close to the original performance using the TTI brass. This new Bertram brass is very close to the strength of the old TTI brass and nearly identical in dimensions so it matches my reamers much better then the Jamison brass which had slightly thicker case necks.

Anyway, one more ready to fly to a new home. Onto the next round!!!!

 

[ccsykes]

Kirby, email it to me and I'll get it up. I want to see it too.

 

[Fiftydriver]

See if this works.

https://docs.google.com/file/d/0ByQeen1CpHeoTjM2LVBYZzlnVDA/edit

Again, I am not trying to hit the target rock. This is an accuracy test. I can see the impacts more clearly on video if I DO NOT hit the rock and instead land in the loose dirt around the rock. Plus, if I intentionally hit all the target rocks, I will run out of targets!!!

Not sure if this will work but we will see.

 

[marioq]

It worked!!! Thats awesome!!!!

 

[peashooter]

Very impressive Kirby! Looks like the 338 Allen just got a performance boost.

 

[ChrisAtl]

Wow!

 

[new shooter]

Kirby you have had this 338 AM out for about 5 +years so what is the life of the barrel at a vel. 3358. Thanks Joe

 

[wyomingblizzard]

Dang Kirby you are makeing it evan harder to wait for the one I have ordered from you! What is your altitude? Do you think there will be much velocity gain at 7000 + feet, where most all of my shooting will be? Thanks Storm

 

[Fiftydriver]

Kirby you have had this 338 AM out for about 5 +years so what is the life of the barrel at a vel. 3358. Thanks Joe

Oh, the 5 million dollar question.....

Accuracy life at this performance level. I can say in all honesty, barrel life in the 338 Allen Magnum is much more dependent on how the rifle is used and cared for then anything else. Yes this chambering is hard on barrels, no way around it, you can not put 145 to 150 grains of powder down the bore without some wear.

Still, if a 338 AM is limited to three shot strings and allowed to cool between strings, cleaned often properly, you will see on average 800-900 rounds and if your really careful with the barrel, 1000-1100 rounds of accurate barrel life.

Last I checked I have around 70 of my XHS rifles out in the field. Of those about 70% are 338 AMs and 30% are 375 AMs. Of all those, I have had 5 rifles returned that had legit barrel wear problems and three of those are in shop right now that just need to be rebarreled and shipped back out the door.

Please keep in mind that the cost of a complete new barrel installation is around $1200. That's new fluted 32" stainless steel barrel, complete machining of barrel and installation on receiver, install muzzle brake and bead blast matte finish barreled receiver.

So for roughly the cost of a new factory Remington Sendero purchased at any local sporting good store, you basically have a brand new 338 AM for 1/4 the original price of the rifle. Certainly not saying this is cheap but for the performance level you get, its not all that bad to pay $1200 and get the most potent 338 magnum back in brand new condition.

I would also like to state that the 338 Allen Magnum is not a do it all rifle. Its a very specialized weapon system. I talk 10 times more customers out of 338 Allen Magnum rifles then I build for customers simply because in 90% of the time, there are better choices out there for the goals that the customer has for the rifle.

Generally, when I recommend a 338 AM, it is to a customer that already has a medium performance level rifle and has a good amount of experience out to 1000 yards. The 338 AM was really designed for use from 1/2 mile out and especially at ranges PAST 1000 yards. In all honesty, most have no use for a rifle with this performance level and if that is the case, the rifle is really a novelty item. Now, nothing wrong with that, I have two 50 BMG rifles that are pretty much novelty items, that's what makes our sport so fun, we do not NEED them, we want them but I do try to stress to potential customers that these are extremely specialized weapon systems and not high volume shooting platforms.

Used as they are intended, they will last a very long time. If they are abused or heated up and continue shooting, you can burn out a throat in as little as 100 rounds. Take care of them and keep them cool and you will get 10 times that many down the pipe. There is a price for performance and you can not get totally around that.

 

[Fiftydriver]

Dang Kirby you are makeing it evan harder to wait for the one I have ordered from you! What is your altitude? Do you think there will be much velocity gain at 7000 + feet, where most all of my shooting will be? Thanks Storm

I am at 3400 ft, you will see a noticeable decrease in drop at your elevation and may need a slight load tweaking but you will see better performance then I am seeing at my elevation.

I am very sorry for the long wait, its been a hard year with this mess that was started in Washington early in the year but working hard to keep projects heading out the door. My main goal is that when you get your rifle, you never think twice about the wait!!!

 

[bfr4570]

wyomingblizzard
I had a wait on a 338AX. Every min is worth it. When you pull the trigger for the firstime and it feels like perfection.

Iv got 3 of Kirbys guns now and wanting more.

 

[Fiftydriver]

wyomingblizzard
I had a wait on a 338AX. Every min is worth it. When you pull the trigger for the firstime and it feels like perfection.

Iv got 3 of Kirbys guns now and wanting more.

Thank you for your kind words. I do know the wait can be a serious PITA but I do my best to make sure that when the rifle arrives, the wait is forgotten.

 

[MMERSS]

I know powder is a tough market now but when stock comes available N570 may be worth the effort to try in the 338. Any plans?

 

[Fiftydriver]

I know powder is a tough market now but when stock comes available N570 may be worth the effort to try in the 338. Any plans?

It may be a great powder in the 338 Allen Xpress which is an improved version of the 338 Lapua. That said, it will fall on its face in the 338 Allen Magnum.

With the 338 Lapua Improved your talking about a usible powder charges in the 100 to 107 gr range depending on throat length. Again, this is using a conventional throat and leade angle.

The 338 AM has a full 50% larger powder charge. It will take 145 to 150 grains of powder under each 300 gr berger. That is FAR out of the relm of N570s burn rate. While it may be magical in the smaller 338s, maybe even possibly my 338 Raptor with its 125-130 gr powder charge size, it will not work with the huge 338 AMs capacity.

Another reason I know that is because the best all around powder I have tested in the 338 AM, and I have tested IMR-5010, RL50, VV20N29, US869, WC578, WC860 and WC872. The best I have tested is H-50BMG for all around use. Great velocity, great consistency, great stability over temp changes, relatively easy to get, decent price.

Some powders produce a bit more velocity, some powders are more affordable but none of the listed powders are as good all around.

That said, H-50BMG pressures out at around a 93-95% load densities. H-50BMG is slower in burn rate then N570 so it would pressure out even faster then H-50BMG with less powder which means gas volume will not be as high, which means velocity will drop off compared to H-50BMG. Not to mention, its a powder that is pretty much a ghost, a myth, a rumor here in the US and when you do run into it, its $50 a lb.

Not saying its a bad powder or that it is not amazing in the right application, that application however is not in the 338 Allen Magnum. In the 338 Allen Xpress however, yes it will be very impressive but from what I am hearing, I am going to try RL33 first and from what I am hearing, it will do 99% of what N570 will do with much less cost.

We will see.