If it's only after shooting 38s it may well be a combination of excessive fouling from the round and a b/c gap that is at the very lowest end of the acceptable range. Try feeling the gap before shooting and right after it binds. Mine runs between .007 and .008 but there's many GPs that are in the .01 range. (That's.0.18, 0.19, and 0.25mm)This week it blocked even on the S&B .38's. I contacted the seller, and he is willing to take it back for the price i bought it. Nice gesture, but getting a license for a weapon has a cost of over 100 euros, so even if he takes it back i will be 100 euros lighter.
Tomorrow ill take it to a gunsmith, see what he has to say, and then decide whether i keep it or not. Im hopefull that a thorough cleaning will fix it