if you make the crimp over deep on them it can increase the pressure dramatically.
the difficulties of 410 are you have a small case capacity so it's hard to load if you lack dexterity. fibre wads are notorious in 410's to get right in terms of right stack height and crimp depth.
feddo one for the roll crimp. 410 is the hardest to reload as the are small and generate very high pressures vs a 12 bore.
the other thing you can look at is a gaep finisher and crimp starter. what they use in the factory's, that will make life a lot easier for you if you want star crimps
will be doing more on the 22, it's a boar is somthing in the pipeline for when I can eventually go!
I think I'm going to find somewhere that does them and see if I can have a look through one.
cheers for all your responses so far, overall they seem quite positive!
hi mate, if you want an mec I'd recommend the 600 jr from clay and game in Hull.
the bloke who owns it created gamebore with his dad before selling it on. fantastic bloke and will set you on the correct path with everything you need.
I get all my reloading bits shotgun wise from there...
my zeiss victory diavari went wrong, I was the second owner. the asv turret came off in my hand, the glue holding the pinion gear to the elevation screw failed. so it eventually came loose.
phoned zeiss up and they said no problem send it to east coast binocular repair (approved fixeruppers)...
you want to change out your wad for the correct case length and make your your stack height in the shot cup is correct - level with the top
I'm guessing that's the main culprit by the sounds of things
I tend to pop an over shot card on top as I find I get a better crimp, gives it a level...