338 Rem Ultra Mag.

Lazy D · April 12, 2006, 08:06 AM

Any Fans of this round here. I have a guy who is having me build him a rifle chambered in this. He plans to reload using 300 gr MK bullets. Sierra says it has a BC of .768

Anyone here have experience with this monster?
What can he expect out of this round?
Pros or Cons?

Zak Smith · April 12, 2006, 11:36 AM

I was just shooting a 338 RUM next to my 338 Lapua a couple days ago.

The two cases have almost the same capacity. The max pressure spec for the RUM (63800 psi) is lower than the Lapua (68000psi).

Based on this, you should be able to get the 250 Scenars to 2900fps, or the 300SMK's to 2700-2750, from a 27" barrel.

-z

Yuriens · April 12, 2006, 08:07 PM

If he has never shot one before or is recoil sensitive he should consider a brake strongly. I do not enjoy shooting mine from the bench much, but my 375 RUM with a brake I could shoot all day. If he's doing a lot of load development that will of course mean a lot of bench time and a lot of shoulder pounding.

My 338's accuracy with factory ammo is so-so. Handloading he will probably be happier, but that case swallows a lot of Retumbo.

It's a thumper, at both ends.

Mike

Lazy D · April 12, 2006, 09:32 PM

I'm installing a Holland brake on it. It should tame the recoil considerable. This guy is a Sniper in the Army and is use to shooting a 300 win mag and a 50. He's done his research on it and knows what he wants.

Seirra says you can push the 300 SMK to 2700. I can't wait to shoot it.

April 12, 2006, 08:06 AM	#1
Lazy D Senior Member Join Date: December 11, 2004 Location: Indian Territory Posts: 192	338 Rem Ultra Mag. Any Fans of this round here. I have a guy who is having me build him a rifle chambered in this. He plans to reload using 300 gr MK bullets. Sierra says it has a BC of .768 Anyone here have experience with this monster? What can he expect out of this round? Pros or Cons? __________________ "Fast is Fine but accuracy is final.".....Wyatt Earp.

April 12, 2006, 11:36 AM	#2
Zak Smith Senior Member Join Date: December 12, 1999 Location: Fort Collins, Colorado, USA Posts: 2,682	I was just shooting a 338 RUM next to my 338 Lapua a couple days ago. The two cases have almost the same capacity. The max pressure spec for the RUM (63800 psi) is lower than the Lapua (68000psi). Based on this, you should be able to get the 250 Scenars to 2900fps, or the 300SMK's to 2700-2750, from a 27" barrel. -z __________________ Zak Smith . DEMIGOD LLC . THUNDER BEAST ARMS CORP . COLORADO MULTI-GUN *My PM inbox full? Send e-mail instead.*

April 12, 2006, 09:32 PM	#4
Lazy D Senior Member Join Date: December 11, 2004 Location: Indian Territory Posts: 192	I'm installing a Holland brake on it. It should tame the recoil considerable. This guy is a Sniper in the Army and is use to shooting a 300 win mag and a 50. He's done his research on it and knows what he wants. Seirra says you can push the 300 SMK to 2700. I can't wait to shoot it. __________________ "Fast is Fine but accuracy is final.".....Wyatt Earp.

April 12, 2006, 08:07 PM	#3
Yuriens Member Join Date: February 1, 2006 Posts: 71	If he has never shot one before or is recoil sensitive he should consider a brake strongly. I do not enjoy shooting mine from the bench much, but my 375 RUM with a brake I could shoot all day. If he's doing a lot of load development that will of course mean a lot of bench time and a lot of shoulder pounding. My 338's accuracy with factory ammo is so-so. Handloading he will probably be happier, but that case swallows a lot of Retumbo. It's a thumper, at both ends. Mike