Undersize bullets

[schofieldbob]

A friend asked me for some help, her Hi Wall in 38-55 started losing accuracy using all the same components. Upon looking at it it's really leaded up. She originally was using .379 dia bullets but switched a while back to .376. Would undersize bullets cause severe leading. She said the accuracy improved initially when she switched to .376. The barrel slugs at .376-.377. Thanks

[Txcowboy52]

Undersized bullets would definitely cause leading , normally you would like .001. to .002 over the actual bore size .

[stubshaft]

Being undersize can definitely be the cause of leading but it also depends on the alloy, lube and pressure too.

[.45Cole]

hard, undersized boolits will def cause you problems. Softer, oversized boolits will be your friend. The undersized boolit will skip or turn "sideways" and skid down the bore. RB17 and steel wool will take care of the leading. Try to stay away from the crayon-cast boolits if possible, they're cast to 10,000bhn and will not disform to your firearm at all. What's her velocity and boolit weight, lube?