338 Lapua short barrel (18") load data

[dallastxracer]

I know it sounds crazy, but I'm having a shortened 338 made for me and I prefer to "load my own". Rather than re-inventing the wheel, I'd like to know if any others here have done the same. If so, who has found good load data for this as I want all the powder (or as much as possible) burned before it exits the barrel.

Thanks in advance & try not to hate on this one too much.

CG

 

[Dogtown]

I added an 18" .338LM barrel to my SRS conversion collection last year. It's a 1:9 twist versus 1:10 for the other 26" barrel. Both my 250 and 300 Scenar loads that I developed for the long barrel seem to shoot about the same in the shorty. The shorter barrel is super handy but the blast is significantly increased through the same brake as the longer barrel, as you would expect. Velocity loss is enough to make it a 1400m barrel vs 1800m I can do with the longer barrel. Running a can is definitely the way to go BUT if you do, make sure it's rated for the much higher pressures associated with a short .338LM barrel. At least one guy here on the Hide blew apart his top-of-the-line suppressor because it was rated for standard .338LM and nothing higher pressure. And along those lines, it's so easy to develop a seriously quiet subsonic load with a short barrel.

250 Scenar
GM215M
Lapua Brass
94gr RL-25
3.861" COAL

300 Scenar
GM215M
Lapua Brass
92.7gr N570
3.735" COAL

The latter is touching the lands in my rifle, so I would back off a bit if you try to duplicate. Also, common sense says to back off on the powder charge and work up.