Size expander plug .002 0ver bullet size. For a .376 dia. bullet use a .378 x .374 expander plug. this will give you .002 clearance to start your bullet and .002 neck tension.
Additional information
Weight
.25 lbs
Dimensions
1 × 1 × 1 in
376 Rifle Expander Sizes
376Cal (R) .378 x .374, 376Cal (R) .379 x .375, 376Cal (R) .380 x .376, 376Cal (R) .381 x .377, ..376 (R) .382 x .378, ..376 (R) .383 x .379