338 LAI / 300 grain bullets: barrel length for max velocity?

[Sgt. Brumbaugh]

Any real-world numbers on barrels 30 inches plus? Of course, more barrel length / velocity does not mean the combination will tune up there, but it might.

If you have data, I would appreciate powder charge and barrel length info.

 

[El Matador]

No firsthand experience with the Lapua case but maybe a few data points to help you out. I have a 338-378 which is similar, and found great velocity with RL33. I was getting 2960 from a 26" barrel and Berger 300's. Do a google search for the 338 Allen Express, which is a version of the Lapua Improved done by Kirby Allen. The 338 Terminator is another version that has the "+P throat" and is supposed to give a bit more velocity by moderating the pressure spike at the throat. The consensus on barrel length seems to be that longer than 30" isn't worth doing. You'll gain about 20 fps per inch. So for an extra 100 fps you need 5 more inches of barrel, which becomes cumbersome in a hurry.

 

[El Matador]

This article by Dan Lilja is pretty good on 338 barrel lengths.

Barrel Lengths in the 338/378 Weatherby Magnum

 

[Sgt. Brumbaugh]

I have seen that article by Lilja and forgot about it, thanks for the reminder!