I'm interested in developing some better handloads for my 12 guage slug gun, but this seems to be a pretty gray area when I try to find out infomation. For example, what are common over-pressure signs when dealing with shotgun shells? Anything- loose primers, deformed plastic, sore shoulders? Is the pressure curve in shells much more dramatic than rifles? How about things like changing the wad, does it make a BIG difference?

Any information appreciated, other than asking where to send flowers.......

Mark,
I have been messing with slug loads for years and have very carefully avoided finding out the answers to most of your questions.

I AM TOLD that seemingly minor changes in components can cause major changes in pressure and that a 10-15% increase over a good working load can cause catastrophic failure. Plastic or paper just does not have the sealing capabilities of brass.

I have tried to avoid trouble by using very strong guns, a Martini actioned rifled 12 gauge for the most part, and I have just purchased a NEF rifled slug gun. I stick to published data, with the exception of being willing to sub solid projectile for shot, weight for weight.

So far, this has worked for me. I haven't wrecked any guns. I also have not gotten much in the way of concrete results. Best results have been with a .735 RB and a recipe I cribbed from Gil Sengel in a long ago Handloader article. This one works very well, but I have nightmares about one finding its way into a choked gun.

I've had a lot of fun at it, but aside from that one load, were I forced to hunt with slugs, I'd give up and pay the outrageous price for factory saboted rounds.

The problem with developing loads for shotguns is that the weapons and ammo are generating only 12000 PSI with maximum loads. Before you are going to notice any signs of excessive pressure the camber and or barrel will deform catastrophically. You could get a copy of the latest Lyman's "Shotshell Handbook" and search for loads that better fit your requirements. Playing with load data in a shotgun is a good way to ruin the fun of shooting and a good weapon - not to mention taking the fun out of living.

PaulS