Roll VS Fold

[woodweasel58]

Does roll crimping cause an increase in pressure? Most data calls for fold crimp. many years ago I used to get buckshot and slugs with roll crimps. If there isn't a concern does the case length need to be trimmed, and how much? I would like to be able to load Buck and slugs with roll and birdshot folded. Again many years back when I was a kid my stepfather got some reloads from a friend of his. Several of them would open enough for shot to leak out. I wouldn't shoot them after that. I figured that he was doing something wrong, too much powder or shot or wrong wad. your knowledge and thoughts would be much appreciated.

 

[243winxb]

If a fold crimp opens, wrong wad or to much shot. Slug data will list what kind of crimp to use. We can only guess at the pressure. I remember an older guy using "pumpkin balls" when i was a kid back in the 1950s. The earliest shotgun slugs were just lead balls, of just under the bore diameter, allowing them to pass through the barrel. Often called "pumpkin balls",they had a roll crimp.