Short Barrel Cartridges

bob_dobalina

Handloader
Oct 6, 2009
285
1
Here's a naive question. I hear/read that some cartridges do better with short barrels, some with long barrels. For example, .308 and 7mm-08 are good with a 20" barrel, but you really should have a 26" barrel with a 25-06. Obviously all of them get more velocity out of a longer barrel, but maybe it's diminishing returns for the former examples. I would think all magnums like the slow burning powder, and you want a long barrel. But I also see the 7mm SAUM suggested for a short barrel, and the 300 RCM was built with short barrels in mind. Thoughts?
 

ShadeTree

Handloader
Mar 6, 2017
2,612
854
I'm no expert and wouldn't attempt to explain it in pressure curves, etc. But basically anything considered overbore needs a longer barrel to take advantage of the high charges of the slower burning powder that work well in overbore cartridges.

Overbore rate is generally determined by the ratio of powder capacity of the case, to the bore diameter.

A 25-06 would certainly do better with a 26" barrel, but 24" is not too short and usually considered a decent working length for that cartridge. It's somewhat overbore, but not horrible.

The 300 RCM you mentioned does indeed have magnum in it's name, but that's completely irrelevant as far as overbore. It is pretty much a 30-06 in case capacity and end velocity, housed in a short action. So magnum or not, it wouldn't be considered overbore by most, and behaves like a 30-06 in relation to barrel length.

The 300 RCM usually runs just 3-4 gr's heavier charge weight in manuals, than the 06 using the same powder and bullet weight. If it was loaded at the same 60,000 PSI instead of 65,000 PSI, you would see virtually no difference.
 

baltz526

Handloader
Sep 25, 2005
1,074
8
A shorter barrel tends to be stiffer if not a youth type pencil barrel. The 300 win mag I had cut from a 24" to 20" lost some velocity. 100-150fps. But It saved the rifle barrel from the scrap heap. going from a 2 1/2" at best shooter to 1 1/4" shooter. Since I did it, I have killed several Elk and a bear and a deer with it.
 

Guy Miner

Master Loader
Apr 6, 2006
16,543
1,041
An online resource well worth using is the Hodgdon Reloading Data Center. They show quite a few different "rifle" cartridges with mere 15" barrels in their pistol section.

Interesting how fast some cartridges remain, with that short of a barrel.

Regards, Guy
 

noslerpartition

Handloader
May 26, 2018
887
150
One thing to consider in low light situations is that with slow powder and short barrels you get a larger fireball in front of the muzzle
In addition, the bang and recoil will be higher.




Gesendet von meinem Pixel 3a XL mit Tapatalk
 
Top