338 Lapua mag build

[mattman215]

Hello I had a couple questions I could not quite find online or this forum. I am going to build a 338 Lapua mag.

I am planning on using a defiance deviant tactical action ordered from defiance a mpa matrix pro 2 and a brux 9 twist barrel.

Does anyone have any experience with this action and set up in 338lm and will it feed from a cip 3.850 magazine if I load 300gr Berger elite hunter's or otm ?

Any thoughts on a 9 twist barrel ?

Looking at data it looks like oal of these cartridges will be 3.650 so I think all cip mags will take a 3.750 cartridge?

Thanks

 

[Terry Cross]

Hello I had a couple questions I could not quite find online or this forum. I am going to build a 338 Lapua mag.

I am planning on using a defiance deviant tactical action ordered from defiance a mpa matrix pro 2 and a brux 9 twist barrel.

Does anyone have any experience with this action and set up in 338lm and will it feed from a cip 3.850 magazine if I load 300gr Berger elite hunter's or otm ?

Any thoughts on a 9 twist barrel ?

Looking at data it looks like oal of these cartridges will be 3.650 so I think all cip mags will take a 3.750 cartridge?

Thanks

I am building all of the LongSwords on a branded action Defiance produces for the shop. It is more closely spec'd to the Ruckus rather than the Deviant but the Deviant should work fine. Just make sure the bolt face size and mag cut is correctly specified for your project.

No experience with that stock.

No experience with Brux but I know from other builders that they are great tubes. I build all the .338LMs on a 1-9" twist and they are performing just fine.

 

[mattman215]

I am building all of the LongSwords on a branded action Defiance produces for the shop. It is more closely spec'd to the Ruckus rather than the Deviant but the Deviant should work fine. Just make sure the bolt face size and mag cut is correctly specified for your project.

No experience with that stock.

No experience with Brux but I know from other builders that they are great tubes. I build all the .338LMs on a 1-9" twist and they are performing just fine.

Thank you and when you say correctly specified I just tell defiance it’s for a 338lm cip mag cut correct ? Or am I missing something ?

 

[Wannashootit]

Does anyone have any experience with this action and set up in 338lm and will it feed from a cip 3.850 magazine if I load 300gr Berger elite hunter's or otm ?

Action is irrelevant, all that matters is the mag length in the context of your question.

I recently chambered/rebarreled one (Bartlein blank), SAAMI spec reamer. Berger 300 Hybrid OTM's were one of the load-workup choices, along with 250 Scenars and 300 A-Tips. The burned-up barrel it replaced liked the A-Tips and 285 ELDMs.

You can load any bullet to mag length (within reason of course), it's just a matter of how deep you're seating it into the case.
300s will be seated well below the neck/shoulder junction. With a SAAMI chamber, your limiting factor isn't mag length- it's the chamber itself/freebore. I don't recall the OAL (I load to ogive length and don't worry about OAL unless that's the limiting factor), but there was probably fifty thou or so of mag length left, with .020 of jump. Best with N570 was a lightly compressed load.

It shot like a raped ape- legit 5-shot groups in the 2's.

 

[375fan]

I have a 338LM built on a Defiance Deviant action and use 3.85CIP mags with no issue. 9twist is good too.

 

[mattman215]

Awesome thank you all for your input. I think I will have about .020 of jump as well due to mag length which I am not worried about.