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18-20" 300 RUM: change my mind..

7.62 Gunner

Well-Known Member
Joined
Jan 9, 2022
Messages
1,010
Location
Idaho
I'm running a 24" 30 Nos that I'm head over heals for, except that it's stupid frigging long with my Nomad LT suppressor.
The suppression and recoil reduction is amazing to the point that I refuse to ever put the brake back on.
Soo I'm looking to go with a short barrel and continue the suppressed goodness with 225 eldms around 2800 fps.
I don't buy into the "Efficiency" crap, and 700-1000 rounds will take me 4-5 years of shooting.
I have a 3.850 mag box
What do you all think?

And please for the love of Jesus don't recommend a 30 Sherman Mag...
 
How about the 30 Sherman mag ? 🤣 there you go-- now it's out of the way and we can get on with your question

I run a short barrel 308, 30-06, and 300 wsm bolt actions and real short 223, 6.8, and 300bo on ar's....people will complain about the short barrel loss in velocity, the "huge ball of fire" from the muzzle and the deafening muzzle blast from short barreled rifles. They will also say you need very fast burning powders and light weight bullets for short barrels.

I have not had any issues with any of those things.

The reasoning of a large caliber short barrel is a compromise to shorten the oal of a suppressed rifle. Yes you loose mv with less barrel-- but the same thing could be argued for a 24" vs 30" barrel.

Make sure your suppressor is rated for the cartridge / barrel length combo you choose and you should be good to go.

I have found that even in short barrels- a faster burning powder seems to pressure out before you reach max muzzle velocities compared to "normal" powders for cartridges-- why wouldn't it? Your max pressure is reached in the first few inches of barrel --- for example in the 308 I tried quite a few "faster" powders but my best accuracy/speed combo ended up being with varget. -- and the 300wsm likes rl 23 or 26 even though it has a short barrel.

I also find if you run the numbers for retained velocity and energy and drop/wind -- the short barrels still seem to accel with heavier bullets vs light ones.

Only thing I do notice with short barrels is if you have a light gun-- you do get considerably more muzzle jump/hop and you may need to change the techniques you use to accurately shoot the rifle. My heavier longer guns I shoot "free recoil" style-- my short/light guns semi to like the "hard hold" technique

In the end--- "you do you"
 
How about the 30 Sherman mag ? 🤣 there you go-- now it's out of the way and we can get on with your question

I run a short barrel 308, 30-06, and 300 wsm bolt actions and real short 223, 6.8, and 300bo on ar's....people will complain about the short barrel loss in velocity, the "huge ball of fire" from the muzzle and the deafening muzzle blast from short barreled rifles. They will also say you need very fast burning powders and light weight bullets for short barrels.

I have not had any issues with any of those things.

The reasoning of a large caliber short barrel is a compromise to shorten the oal of a suppressed rifle. Yes you loose mv with less barrel-- but the same thing could be argued for a 24" vs 30" barrel.

Make sure your suppressor is rated for the cartridge / barrel length combo you choose and you should be good to go.

I have found that even in short barrels- a faster burning powder seems to pressure out before you reach max muzzle velocities compared to "normal" powders for cartridges-- why wouldn't it? Your max pressure is reached in the first few inches of barrel --- for example in the 308 I tried quite a few "faster" powders but my best accuracy/speed combo ended up being with varget. -- and the 300wsm likes rl 23 or 26 even though it has a short barrel.

I also find if you run the numbers for retained velocity and energy and drop/wind -- the short barrels still seem to accel with heavier bullets vs light ones.

Only thing I do notice with short barrels is if you have a light gun-- you do get considerably more muzzle jump/hop and you may need to change the techniques you use to accurately shoot the rifle. My heavier longer guns I shoot "free recoil" style-- my short/light guns semi to like the "hard hold" technique

In the end--- "you do you"
Thanks Yeah I have two sub 20" magnum hunting rifles that I run suppressed and I agree with all of your points.
The whole smaller efficient cartridges for short barrels argument has been debunked
 
Is the can rated for that short a barrel? All of my cans other than TBAC 338 Ultra are 22" or longer for 300 RUM. 16" for short mags and 18" for normal mags, but jumps to 22" for the RUMs and Norma/Lapuas, basically anything that butts up against 90-100gn of powder charge.

3.850" would feed almost all of my 300 RUM loads except for the longest VLDs, so not an issue if you're set on the ELD-Ms. The RUM might be the best choice to stay on the smaller bolt face for a short barrel because nothing will beat its displacement, but in the max power game case efficiency does come in to play so I'm changing to the .590 bolt face because the fatter Lapua/Norma derivatives can beat the RUM. 30-338 Lapua Improved, 300 Terminator, etc. But other than a bigger fireball they're not going to offer you anything from a 20" barrel that a RUM won't.

And please for the love of Jesus don't recommend a 30 Sherman Mag...
Just to poke you, my RUM actions are all getting new barrels. One has a 30 Sherman already on, and I'm doing a second 30 Sherman plus a 338 Edge to repurpose my RUM brass.
 
In playing around with a buddies QL I found 20 inches to be a real sweet spot regarding losses and gains.

I think it's a great idea but not sure why you wouldn't stick with the 30 nos. It's a great round which only suffers from poor marketing. Side by side in 20 inch barrels they'd likely shoot to the same or nearly same velocity.

Best of luck and post up your build. Sounds like a great one.
 
I've built the 300 rum and 30 nos on 20" barrels and 22" and no the 30 nosler will not shoot the same speed as the 300 RUM in any barrel length.

I think a lot of folks forget the rum is a 112 gr case cap where as the 30 nos is 97 as well as the other counter parts are 97-98 gr.

I would do it and not look back..

I dont care how you shake it or what degree of shoulder angle you put on em there isn't a replacement for displacement!!!!
 
 
Is the can rated for that short a barrel? All of my cans other than TBAC 338 Ultra are 22" or longer for 300 RUM. 16" for short mags and 18" for normal mags, but jumps to 22" for the RUMs and Norma/Lapuas, basically anything that butts up against 90-100gn of powder charge.

3.850" would feed almost all of my 300 RUM loads except for the longest VLDs, so not an issue if you're set on the ELD-Ms. The RUM might be the best choice to stay on the smaller bolt face for a short barrel because nothing will beat its displacement, but in the max power game case efficiency does come in to play so I'm changing to the .590 bolt face because the fatter Lapua/Norma derivatives can beat the RUM. 30-338 Lapua Improved, 300 Terminator, etc. But other than a bigger fireball they're not going to offer you anything from a 20" barrel that a RUM won't.


Just to poke you, my RUM actions are all getting new barrels. One has a 30 Sherman already on, and I'm doing a second 30 Sherman plus a 338 Edge to repurpose my RUM brass.
I'll double check of course but I believe the Nomad is rated for it.
I'm a former 30 SM owner and the juice definitely wasn't worth the squeeze, my current 30 Nos is faster.
No SS for me either ! Lol

I have a buddy doing this same thing or getting parts to try it ..
I have a few 300 Rum factory take offs ..this might be fun to try also !! Hmm

Really the "RUM " just kicks Butt ! Lol


Rum Man
Nice I've read some of your posts about your 338 rums.
I've been hesitant to dable with a 300 Rum cuz I always hear you need a 4" mag box to get anything out of it, and I see a lot of claims that barrel life is sub 500 rounds.
Really it's kinda all over the map in terms of what people think about the cartridge.
One thing I do know is the 300 NM has a lot of drawbacks with case stretching, and I have no desire to screw around with improving it..
 
I've built the 300 rum and 30 nos on 20" barrels and 22" and no the 30 nosler will not shoot the same speed as the 300 RUM in any barrel length.

I think a lot of folks forget the rum is a 112 gr case cap where as the 30 nos is 97 as well as the other counter parts are 97-98 gr.

I would do it and not look back..

I dont care how you shake it or what degree of shoulder angle you put on em there isn't a replacement for displacement!!!!
Agreed
I'm a huge fan of H1000, and my though is I'd probably get the same barrel life running it in a Rum as I'd get stomping on a 30 Nos with N570 trying to match its performance
 
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