AI .338 conversion to .300 RUM possible?

[Skunkeye]

I have an AI 338 Lapua that I would like to rebarrel to 300 RUM. Couple of questions:

Can I just buy the barrels and have them chambered without sending the rifle in? I know you can do this with the Tubb 2000 and with AI factory barrels, just wondered if it was kosher with non-factory barrels.

What twist for 220 gr SMK? I burned out one 300 RUM barrel in about 1,200 rds shooting 190 SMKs at 3400 fps and thought I'd try a little heavier bullet.

Any mods necessary to the magazine to get 300 RUM to feed reliably?

Thanks.

 

[brand692]

Re: AI .338 conversion to .300 RUM possible?

RUMs and Lapua Mags have different bolt faces. If you did get a RUM bolt made for your AI (not sure if that's even possible as I'm no AI expert), you would also have to modify the mags. I had a thread on it here somewhere. I'll dig it up.

10 Twist for the 220s.

You are still going to burn up a barrel in 1200 rounds. Nature of the overbores.

If it was me and you had to shoot 30 cal, I'd have a 300 Lapua Magnum barrel made. 338 Lapua Necked down to 300. Then you wouldn't need to mod the mags, mess with the bolt, or any of that other nonsense. You could even just use your 338LM brass.

 

[Anchor Zero Six]

Re: AI .338 conversion to .300 RUM possible?

As far as I'm aware AI offers two bolt faces 338LM (.587) and 300 WM (.513). RUM is .550 so at face value (pun intended) I would say no.

I dont know if it would be possible to have the 300 WM face opened up to RUM and still be safe.

But AI will sell replacement and serial matched bolts, I beleive they were around 900.00 for those wishing to go from 338 to 300. So If you can find a smith who can do it I suppose you could get the 300 bolt and have it opened up...I would bet this isnt a practice AI would support in the event of damage in regards to repairs/waranty work LOL.

 

[brand692]

Re: AI .338 conversion to .300 RUM possible?

Here is the AI 338LM to 300RUM mag conversion thread.

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1965224


But as pointed out, you still have the BF problem.

Can I ask why? Why would you want the 300RUM? Are you restricted to 30 Cal in a comp? If so, I say stick with the necked down 338LM

 

[Skunkeye]

Re: AI .338 conversion to .300 RUM possible?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: brand692</div><div class="ubbcode-body">Here is the AI 338LM to 300RUM mag conversion thread.

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=1965224


But as pointed out, you still have the BF problem.

Can I ask why? Why would you want the 300RUM? Are you restricted to 30 Cal in a comp? If so, I say stick with the necked down 338LM </div></div>

Sounds like the 300 Lapua is the way to go, if I decide to pursue this. The reason for considering the switch is indeed a match (the ITRC) with a 30 caliber restriction.

I have a 300 RUM based on a Nesika action, but it is a single shot and heavy as hell. Since I have so much 300 RUM brass I was hoping to put it to use in a bit more convenient package. Thanks for the solid info.

 

[krlemas]

Re: AI .338 conversion to .300 RUM possible?

Another option is a 300 Norma Mag.brass is about 1/2 the cost of the Lapua brass.