.338LM Load Info Requested

[VTi]

Hello everyone. I have a .338LM GAP (30.5" tube) being delivered today and would like some help regarding load data, specifically powder selection.

I know there's many threads out there with 338lm load info, but I think they're mostly shooting 27"-28" barrels. I'd like to know from some of you with experience loading for this, or similar, cartridges -- what's the best powder behind a 300smk to get the most efficiency out of this 30.5" bbl?

I think I've narrowed it down to either RL25 or Retumbo. Any info would be GREATLY appreciated.

Thank you, and happy holidays to you and yours.

[wc872]

Congrats on your new rifle. I've only heard really good things about GAP. As far as reloading goes. Start low and work up. 300gr. SMK work well with RL25. I've used Rem 9 1/2 Magnum primers for the last few years and am very happy with them. Ramshot Magnum, H50BMG, H1000, VV24N41, & N170 all work. Lapua 250gr. Lockbase should be tried I think. Also had good luck with 225gr. Nosler Accubond for hunting.
Semper Fi

[G-gear]

Get the Sierra manual:
Sierra Bullets - The Bulletsmiths

338 Lapua Magnum
Savage 116 rifle, 26" barrel 1x10" twist
Trim to length brass 2.714"
Federal 215 primers
Max COL 3.680"

Sierra lists three bullet weights: 215-gr., 250-gr., and 300-gr.
Sierra Bullets - The Bulletsmiths
215 SBT (Spitzer Boat Tail) max velocity 3,300 fps - ME 5,200 ft.lbs.
250 SBT (Spitzer Boat Tail) max velocity 3,000 fps - ME 4,997 ft.lbs.
250 HPBT (MatchKing) same as SBT
300 HPBT (MatchKing) max velocity 2,750 fps - ME 5,038 ft.lbs.

I assume that you will be using match bullets, so, here's Sierra's load data for Retumbo (No Reloader 25 data listed).

[26" barrel]
250 grain HPBT MatchKing
Retumbo 89.6 = 2,750 fps - ME 4,199 ft.lbs.
Retumbo 92.1 = 2,800 fps - ME 4,353 ft.lbs.
Retumbo 94.6 = 2,850 fps - ME 4,510 ft.lbs. Max Load.

That's all they have for Retumbo. And, only in that bullet weight (250 grains.)
I would get the Sierra manual, and try other powders for more velocity and/or accuracy.
After finding the best accuracy load, I'd chrongraph that load, and plug in that load data into Sierra's software "Infinity" to find the trajectory and other bullseye info for your custom load/weapon.
Sierra Bullets - The Bulletsmiths


Maybe this will help:
Sierra reloading data 338 Lapua - Google Search

Good shootin'!

[phildo6000]

I am loading 88.5 gr of RL25 behind a 300SMK with 215m primers with lapua brass. My gun shoots 1.1 to 1.3 inch groups @ 300yds with this load. My gun is a CZ 550 416 action with a 28" Loather Walther barrel on it. Nightforce 5.5-22x56. no brake and can shoot all day long. Don't know the velocity, but is very accurate.

[dbrush]

Sierra 300smk over 86grn RL 25 Fed 215M.
Has been outstanding in several rifles

[BHP9]

I'm having success Using H1000 and a 92.5gr weight under a 250gr Lapua LockBase or Scenar.