Here are the specs on the .338
Parent case .375 H&H Magnum
Case type Belted, bottleneck
Bullet diameter .339 in (8.6 mm)
Neck diameter .369 in (9.4 mm)
Shoulder diameter .491 in (12.5 mm)
Base diameter .513 in (13.0 mm)
Rim diameter .532 in (13.5 mm)
Case length 2.50 in (64 mm)
Overall length 3.340 in (84.8 mm)
Case capacity 86 gr H2O (5.59 cm³)
Rifling twist 1-10"
Primer type Large rifle magnum
Maximum pressure 65,000 psi (450 MPa)
I put 10 rounds through it later yesterday. Well one thing for sure it does kick pretty hard. Had limited time so only got a 50 yard target set up. Probably try again over the weekend to check sighting but it seems pretty darn close.. Thanks for all the comments.