30 X 338 Rem Ultra Mag

gabane · Rookie Member Joined: Jan 26, 2005 Posts: 5

Any one ever build a 30 X 338 Rem Ultra Mag? I think this would be an excellent long range rifle. If you have one can you comment on how it shoots?

Regards,
Geary

Dimitri · Super Member Joined: Nov 25, 2005 Posts: 5946

Gabane,

Question why build a 30/338 RUM ??

The 338RUM is a smaller case then the 300RUM so any real need to wildcat this ??

Looking at the drawings it looks to me like it would be between the 300WM and the 300RUM in size. Perhaps just down load the 300RUM and it will provide the same results without the need to buy expensive dies and form brass ??

Dimitri

gabane · Rookie Member Joined: Jan 26, 2005 Posts: 5

Thanks for your reply Dmitry,

The length of the 338 case is a littler shorter than the 300 RUM. In order to maximize the use of handloading you cannot effectively use the 300 RUM case due to the magazine box being too short. I think the 338 UM case would be somewhere in the range of ~ 2.75 as opposed to the 2.85 300 RUM. Even with opening up the magazine box on a 700 Rem
Action you cannot obtain the optimum bullet seating depth you would like.

I also believe the velocity would be equal to the 300 UM because the case is largely over bore.

Regards,
Geary

Dimitri · Super Member Joined: Nov 25, 2005 Posts: 5946

Geary,

Well I see that there will be a additional .100" of room to load your ammunition. Smile

But the size of the cases execpt for the 338RUM being shorter are nearly identical (to within .001"). So you will lose case volume.

The 338 RUM

The 300 RUM

Dimitri

Deleted_User_2665 · Super Member Joined: May 06, 2006 Posts: 380

The Rum's are built from the same parent case with the .300 being slightly longer to keep the Clueless from chambering a round of .300 in a .338.

Lawyerisms........

I'm thinkin' here it'd be tough to outsmart a .300 ballistically by wildcatting a .338 to .308.

Pointless as well, in a .308 cal "supermag", my Rum was plenty of gun...............

Dimitri · Super Member Joined: Nov 25, 2005 Posts: 5946

Chambering a 300RUM in a 338RUM would be safer in my head then putting a 338RUM in a 300RUM. Myself if I was designing the rounds I'd have made the 338RUM just a tad longer myself then the 300RUM. But thats just me. Smile

Its sort of like putting a 8mm Mauser round which is shorter then the 30-06Spring in a rifle chambered for the 30-06Spring, the 8mm Mauser will chamber, BUT it will cause EXESSIVE pressure, and can result in injury. Shocked

Dimitri

Deleted_User_2665 · Super Member Joined: May 06, 2006 Posts: 380

There's no safe/safer way to chamber the wrong ammo.

Manufacturers could include a waffle head claw hammer with every ammo/gun sale for with to hit yourself in the noggin' every time you do so....

But' I doubt many would use it...................................

Dimitri · Super Member Joined: Nov 25, 2005 Posts: 5946

Wildswalker,

Not saying it doesn't mean its going to be "safe" or "safer" if the 300RUM chambered in the 338RUM, but it beats the over pressure when the 338RUM tries to get that 338cal bullet through that 308cal barrel. Shocked

Dimitri

gbsjr · Rookie Member Joined: May 07, 2010 Posts: 2

gabane wrote:

Any one ever build a 30 X 338 Rem Ultra Mag? I think this would be an excellent long range rifle. If you have one can you comment on how it shoots?

Regards,
Geary

I built one 3 yrs ago: McMillan bench stock, Geske action, Jewell, Krieger 30"/Vais brake, 16X MK 4. 300 reamer was used .092" short. Rem cases necked down, turned to clean, and trimmed to 2.748".
90.0 gr of Retumbo will usually get 3-shot group of .200" w/Lapua Scenar 250 gr bullet. Never bothered to chronograph it and been gathering dust for over 2 yrs.

slimjim · Posted: Fri May 07, 2010 4:07 pm Post subject: Re: 30 X 338 Rem Ultra Mag

gbsjr, dust it off and show us a picture!

gbsjr · Rookie Member Joined: May 07, 2010 Posts: 2

slimjim wrote:

gbsjr, dust it off and show us a picture!

First of all, the bullet should have read "190 SMK". Doing too many things at once. I will get my wife's camera and learn how to post the picture. This computer thing is still a learning curve.

slimjim · Posted: Thu May 20, 2010 5:33 am Post subject: Re: 30 X 338 Rem Ultra Mag

gbsjr, you have a rifle I dream of. I hope you can adjust your priorities to get out to the range more often after you dust it off. Make sure the recoil keeps the dust off it vice a rag.

Suggest using photobucket.com to host your picture. Its easy to creat an account, upload, then copy the pictures direct link to paste into your post. You can't link to pictures you post in this forum's gallery.

slimjim · Posted: Thu May 20, 2010 5:43 am Post subject: Re: 30 X 338 Rem Ultra Mag

There is another way to post a picture directly from the website. I haven't used it before. When you click on "post reply" there will be an "Add an Attachment" section below where you type in your text. Use "Browse" to select the photo. You can then add some comments and select "Add Attachment". I just used it for the first time.

Vince · Posted: Thu May 20, 2010 7:34 pm Post subject: Re: 30 X 338 Rem Ultra Mag

Welcome aboard gbsjr...grab a beer and pull up a stump mate.

I've used both methods of posting pics and both are good. Main differenec is with Photobucket you can intersperse your pics throughout your text, whereas with the Add an Attachment method they tack onto the end of the post. With the Add an Attachment method you need to resize any pics to under 250kb and have them in JPEG format.

Cheers, Vince