338 RUM vs 338 Edge questions

[aaroncarp]

Will someone please explain what the difference between the 338 edge and the 338 RUM is? I have looked all over the internet and for some reason cannot find the answer. Obviously the 338 RUM is a 404 jeffery case necked down to 338, where a 338 edge is a 300 RUM case necked up to 338 (in other words a 404 case necked down to 300, then back up to 338). So basically the same cartridge? Then why the difference in performance? My best guess is the shoulder but I have no idea. Just a question that has been bugging me for awhile.

Thanks

 

[Buttermilk]

The 338 RUM is a 300 RUM, but with a case body length that is 0.050" shorter for the 338 RUM, and of course the neck sized appropriate for caliber.

The 300 RUM case necked up to make the 300 Edge, and thus the slightly longer case body, allows it to have slightly more velocity than the 338 RUM due to larger case capacity.

 

[highridge1]

The RUM and Edge are very close with same barrel length. After owning both I would just go 338 RUM

 

[Edd]

There is about 4.5 gr difference in case capacity.

 

[Franklin]

After owning both, I would do the edge for the simple fact, it's easier to find 300rum brass ( it's never going away) and you have the option of lapua quality brass from bertram that defensive edge sales, plus about a 50-100fps gain. The 338RUM case is .090 shorter than the edge.

 

[Buttermilk]

Correct Franklin. My memory failed me...

Nosler shows 0.091" difference.

 

[Shumba]

I have both cartridges and I will say although there is a negligible difference in case capacity, it seems that the line between efficiently running a 250g bullet and a 300g bullet is between the RUM and the EDGE. The EDGE easily pushes a 300g bullet to 2830-2850 with extreme accuracy and low ES. Actually the 300g can be pushed to 2900+ but brass life is short if any and accuracy suffers. The RUM cannot push a 300g bullet in a 28" barrel to 2830 without PUSHING it, in which case accuracy and case life and ES all suffer. IMO the RUM is optimized with a 250 where the EDGE is optimized with a 300. If you are building a full custom, there is no question go with the EDGE, if you are using a Rem 700 go with the RUM. You can make a 700 run the EDGE, however your OAL will have to be shorter blurring the line between the EDGE and the RUM. The EDGE is at it's finest with a throat cut to allow a very long OAL. Seekins DBM is the ideal length for 300g bullets in the EDGE.

 

[HARPERC]

My partner shoots the "Edge", I shoot the standard "RUM". He gets about 1-2% more velocity with the extra powder. Add barrel length for another 1-2%.

For me component availability is the decider. I picked the standard and was wrong about that.

 

[AZShooter]

Another reason for going to the Edge might be my situation. I have a beautiful SS #5 fluted Lilja with a Vais brake in 300 RUM. When the barrel is worn out I can have Dan Pederson rebore/rifle it to .338. I would have to do minimal chamber work to make it an edge saving me quite a bit of money for a comparable barrel built from scratch.

 

[Outlaw6.0]

My partner shoots the "Edge", I shoot the standard "RUM". He gets about 1-2% more velocity with the extra powder. Add barrel length for another 1-2%.

For me component availability is the decider. I picked the standard and was wrong about that.

I was thinking similarly. I shoot the RUM as well. Running 300's @ 2780, the 50-70fps different is pretty moot to me however, the 300RUM brass should be far easier to find.

Then again, RUM brass of any kind is akin to unicorn tears any more. I don't think a person can go wrong with either provided they have a resolution to the brass availabililty issue.


t

 

[Azprc]

I was in Bob Wards and Capital the other day and both have tons of 300 RUM brass but no 338 RUM brass. But that is only 2 stores.

 

[Deleted member 46119]

The Edge edged out the RUM when I made my decision. The stories regarding accuracy had a great deal to do with it. I also needed to match or exceed the 338LM so I can win comps against my buddy with out copying him. Yes, I have to be different. Personality trait, yes. Positive/negative is not for me to say.

The 338 Edge is now finished. As soon as I can I'll post about it. So far expectations have been met.

A plug for Harrels: Spiral brake, 1" diameter, blended works great. I think I'm at about 14.5 LB for the rifle. Recoil fatigue was less than my unbraked 300WSM.

Summary:
338 RUM will usually be a factory barrel at 26" or less. Leaving at least 50fps on the table and having accuracy challenges.
The Edge will be a custom barrel of 28" or more, combined with the additional case capacity get are at at least 100fps more than the RUM at the same pressure.
The COAL (spec) of .1 shorter in the RUM will not make the world better for mag fed.

IIWM: go Edge

 

[HARPERC]

Then again, RUM brass of any kind is akin to unicorn tears any more.

I'm stocked up OK, but last time I bought, Nosler was selling 300 RUM in boxes of 50, and 338 RUM in boxes of 25-at nearly the same price. I found that hard to take.

 

[Deleted member 46119]

I'm stocked up OK, but last time I bought, Nosler was selling 300 RUM in boxes of 50, and 338 RUM in boxes of 25-at nearly the same price. I found that hard to take.

Ouch.