If they were keyholing, my guess would be that the bullets were slightly undersized, which in .38 special is worthy of the "crap" designation. In .44 magnum there is a case where keyholing can happen and the ammo is still at least "OK" in quality. Unjacketed .429" lead bullets may not obturate properly in .44 magnum rifles, which for reasons unknown to me have slightly different SAAMI specs for the bore than .44 magnum handguns. I don't think that's the case in .38/.357, or at least I don't know it, but my guess is that quite generally the bullets in cheap, soft lead, factory loads are sized to the same diameter as the jacketed loads when the soft lead loads ought to be at least 0.001" larger.
