I'm loading on a Dillon 550 and have never had a problem with the thousands of 9,40 or 45 I've loaded over the years. I guess anything's possible.None of my other guns have aftermarket springs in them though.I loaded some with CCI's and all OK with them. Had a couple WLP's fail to fire again today. This is also virgin star line brass so no residue in the pockets. Guess I'll put the factory spring back in until I can pick up some Federals to try. I was surprised though that the CCI load made one ragged hole at 15yds compared to the WLP load. Thanx for the help so far.