Curious about the 7mm RUM..

J

Jake in NC

Well-Known Member
Joined
Oct 25, 2002
Messages
328
The long one..
.. I searched the archives and found a few
threads on this cartridge.. Seems interesting .. What were the results of some of you all's experimenting.?? Is it really over bore.?? I saw there may also be some powder issues.. Dies are readily available.. What other problems have surfaced.?
..Second.. Is $693 a good deal on a new Rem SF in that cartridge.??
.. Thanks for any input.. JiNC
 
The case is about 10% bigger then the 7STW, which is already hard on throats. Performance will be about 100 to 150fps more when long barrels are used. Definitely use it for 162gr and heavier bullets in 28" and longer barrels. In shorter barrels or with lighter bullets, you are just going to make a lot of noise.

You are going to be limited to the H870 or WCC 872 for max performance with these heavy bullets. Barrel life would be in the 1000 to 1500rd range.

I am planning to put together an STW in the future. That is as big as I want to go with a 7mm bore.

Enjoy...

Jerry
 
Factory Rem 700 Sendero SF with 26 inch barrel.

Hodgdon Retumbo works great.

These are at the high end, but not max'd out. No real pressure signs on the cases or sticky bolts.

150 Nosler Partition at: 3400+ fps
160 Nosler Partition at: 3300+ fps
162 SST at: 3320 fps
175 Nosler Partition at: 3150 - 3200 fps

The 162 AMAX shot the best, but I haven't chrony'd it yet.

I have some 168 Bergers in the queue for when I get the rifle back form the smith.

Having a 28 inch Pacnor Super Match with muzzle brake put on and the action blue printed.

Gearing up to be able to reach out there.

Doug
 
Jake,
A friend of mine just bought one here in Tucson for $845 new, your price looks much better.
Take care,
Wayne
 
Howdy Jake,

I have worked up loads for 3 different rem 700 7mm Ultra Mags. All of them shot 162 A-Max bullets faster than 3,360 with the stock 26" stainless factory barrel using Retumbo. Thick recoil lug, anti-torque brake, and some careful bedding brought all three of these rifles under 1/3 MOA.

I think it is one of the best low cost, high performance, long range options available. Supersonic past 1,600 yards at sea level, and very cost effective.
wink.gif
 
..Hmmm.. Interesting.. I'm sure you all know I've been fishing for a cannon to play with.. This may be an inexpensive way to wet my feet.. Tuned factory rifle (only problem being that by the time I get thru messing with it I'll be in close to the same money as a used custom gun when they're available) with readily available dies and brass using bullets I already have.. I guess it comes down to "is the extra 250 or so fps worth the extra expense.?"
.. Any input as to the over bore question.?? Thanks all..!! JiNC
 
Jake,

Regarding the overbore question, it really is dependent on the powder you use. We're very fortunate to have such a variety these days. From my perspective, with a 30" barrel, the optimum powder burn speeds fall between kinda slow (RE25, MRP-2, IMR7828) and the really slow (50BMGs, etc.) with the median leaning toward the REALLY slow.

A longer barrel is an obvious help, since you're burning 85-95 gr of powder through a .284" bore. A short barrel & moderately slow powder would lead to a fireball of powder burning OUTside the muzzle & not upping the velocity. The RUM has the advantage (as Jerry pointed out) in that heavier bullets are more efficiently driven by it over an STW. Mine is driving 176 gr projectiles at just under 3,400 fps.

I had to modify my case trimmer & buy a Redding Ultramag press due to the case/ OAL cartridge length with VLD bullets. Small things really, but they add up to be noticable.

All-in-all, it's a performer - with a price.
 
I am not an expert on the overbore issue, but I have ready a lot of posts on this forum that talk about super big cases and 30 caliber bores.

They have got to be way more overbore than the 7mm RUM.

As with all overbore catridges, using really slow burning powder and keeping the temperature down makes the throat/barrel last longer.

In my opinion, the 7mm RUM is the biggest and fastest little bullet thrower available in a factory rifle.

The heavier 7mm bullets are very long and have good sectional density and ballistic coefficents.

I can't come up with a use for a bullet heavier than 180 grains.

A premium 180 grain bullet out of a 7mm RUM will take out anything in NA even at considerable distances.

I am really surprised that I don't find more written about them for long range work. I have one and would like to read more about them.

I know the really big - 30+ caliber heavy bullets have the advantage way, way out there, but I have trouble finding places to shoot over 300 yards.

That's why I chose the 7mm RUM.

Doug
 
My friend and I bought our RUMs at the same time. I have the 300, he has the 7. Mine is much more versitle with so many 30 caliber bullets on the market. Just look at these stats. For the max loads, if you are looking for speed, the 7RUM spits a 140 grain bullet out with 95grains of H1000 at 3160fps. The 300RUM will propell a 150 grain bullet 3520fps with 102grains of H1000. The only disadvantage is recoil.
 
smoak said:
My friend and I bought our RUMs at the same time. I have the 300, he has the 7. Mine is much more versitle with so many 30 caliber bullets on the market. Just look at these stats. For the max loads, if you are looking for speed, the 7RUM spits a 140 grain bullet out with 95grains of H1000 at 3160fps. The 300RUM will propell a 150 grain bullet 3520fps with 102grains of H1000. The only disadvantage is recoil.
Click to expand...
I have a 7 RUM that's shooting the 139 SST at 3479 FPS. Unsure of the powder, as it's a Factory load though
 

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