I was talking to a guy on one of Swiss Rifle FB pages that was printing K31 chargers, and I mentioned Krag chargers.  He wanted a sample, and I wasn't sending the only one I have from you!  He might be selling his printed K31 chargers on ebay now.  I have retweeked mine and have them working good with the short 150gr loads. OAL seems to play a role in the rim lock I was getting.  Closer to the OAL of original rounds, I might not have had the problem at all.  The OAL of the 150s @3.023" leaves some room for the rounds to move to and fro.  You must've used some pretty low temp solder.  I started to resolder where yours had came loose, about where the shoulder of the case is.  When I heated that part, not very hot with a propane torch, the soldered joint on the back came loose.  Not a big deal with the gauge of sheet you used, they could really be made without the solder.  I simply folded them over, which makes for easier tweeking, but the stock you used is still thick enough that the the cartridges can't come out the top.  If I don't get rained out Sunday, I'll only have to use the chargers twice, I'll just be careful how I put them in there, though they seem to be stacking right now.  I had room on the printing plate model I made to cut another front tab, so it's back in service for awhile.  Some thicker printing plate might be a good option for me too, this was only .011".