Convert Weatherby Accumark .30-378 to .338 Lapua

[wareagledg96]

I have been a long time reader but this is my first post. I live in the Florida panhandle and am looking for advise and a great gunsmith that can do this work. Someone close would be nice but I would rather have experience and quality. I want to go ahead and have the action blue printed and trued in the process. The gun will be used for long range hunting either suppressed or with muzzle break. I already have a Thunder Beast 338BA ready to go. Obviously this not going to be a carry rifle and will used from shooting houses on utility easements and agricultural fields so I am not concerned about weight. What would be the best barrel and length combination? I searched other posts and got some ideas but nothing I could settle on and could not find contact info for and of the gunsmiths that have posted.

 

[lazylabs]

There are many many options for smiths. Is there a reason you don't just go with 338/378 or one of the wildcats based on that round? I know the lapua brass is the best of the best and the standard 338 lapua is a great round but so is the 338/378. I have one on a remington action(regret that) but it's still a great gun and a fun round to shoot.

 

[wareagledg96]

My primary interest in the .338 Lapua is reloading and brass life as well as the pressure issues for the supressor. My initial thought was go with the 338/378. I have found myself doing a lot of experimenting with loads and the weatherby brass just does not hold up. I am not sure why but the manufacturer of the can states it is not rated for the .378 Weatherby variations. I know the Weatherby variations typically run about 3000 psi more in max pressure than the lapua so I am figuring that is the reason. I have actually been shooting the can on a .338-08 which is super quiet since it is way more can capacity than what that round will generate. Any other guidance or direction is greatly appreciated.

DG

 

[lazylabs]

I am willing to bet that the pressures would be just the opposite. The folks shooting the lapua do so because the brass will take more pressure than the norma brass will.

I know Kirby with APS has done a bunch of stuff with the 378 case and most of his mags are based off the lapua case, give him a call.

 

[Broz]

I can not recommend a smith in your part of the woods. But can attest to what a great rifle you are wanting to build. I did one myself. I used a stainless Mark V action and a 28" Lilja barrel with a 1 in 10 twist chambered in .338 Lapua. It was and still is a great rifle with many kills over 1000 yards, all one shot from a cold bore with either the 300 SMK or the 300 Berger OTM. Having owned many 378 Wby rifles I totally under stand why you choose Lapua brass. When loaded to max the Wby, Norma brass will have loose primer pockets in 2 or 3 firings. The 338 LM brass however went 15 firings with full house loads.

If I were to build this rifle again the only changes I would make would be to go with a 30 or 32" barrel and also I would look strongly at doing a 338 Lapua AI. The added velocity coupled with high BC Berger makes the wind drift much more manageable.

Here is a pic of the rifle we dubbed " Ole No Sneak"

Jeff

 

[Hired Gun]

http://www.longrangehunting.com/for...ter-supply-338-lapua-mark-v-96512/index5.html

It's a small shop that knows it's way around the MK5 in 338LM. You might PM Autorotate and see if he still likes them.

 

[sinarms]

I have a Mark V that I am about ready to take apart too. I already have the barrel and donor rifle. It was originally a 300 WBY but I am going to go with a 338 Sin just because it will do nicely and I want to build another. I have a No 4 Brux barrel fluted and I will probably have it 24-25" long with a small muscle brake.

 

[madman]

Great photo Jeff. I think I need a copy of the original please.

--Mark