Quote Originally Posted by pjinoz View Post
If you want used 12G cases then:
1. Choose a brand that has reloading data published for them!
2. Do not mix case types.!
3. You cannot "work up a load for them" as pressures do NOT show up like rifle cases.
4. If you find a suitable PUBLISHED load then stick to it! For example changing primer type may cause adverse changes in pressure.
5. Is your gun proofed for such loads? How was your proof derived?
6. Do not be deceived into thinking "fast" loads will be of benefit; lead shot has the ballistic qualities of a heavy ping pong ball! E.g. if you don't believe this then
consider the extreme range of lead shot!
7. Some published factory data is "enthusiastic" to say the least.
8. All my reload data has been put through a pressure gun (piezo) and stacks up with my chrono data. No, I will not detail this as it suits my gun , choke and
pattern requirements. But I can tell what to look for.
9. Stay away from the higher pressure loads!!!!!!!!!!!!
10. And finally I still have about 10000 once fired Winchester AA 70mm cases; in my opinion the best for reloading (scarce as hens teeth now) and have just
finished reloading 4500 shells (32 gram @ 1250 f/s). Yes, I have seen factory ammo rated at high velocity but have you ever fired a one ounce load at 1500+
f/s (over the chrono?).
11. And finally please don't "screw around" altering cases (changing crimp to roll) UNLESS YOU HAVE THE PRESSURE DATA!

Cheers

pjinoz

Are the "AA" Winchester the ones that are tapered inside?
If so they need the special "AA" wad. (I'm sure you know this but the OP probably does not).

Phil384:-
As said, keep to the load data.
If there is a bit too much shot in a case adjust the wad column. Don't force it to crimp, it will swell the section of the case where the shot is.
If the crimp dips in, again adjust the wad column.

If you start with a soft wad do not swap if for a hard wad it will put your pressures up, and vice versa, if you start with a hard wad and swap it to a soft wad it will lower the pressure.
Don't play about with the wad column by trying different things, stick to recommended wads.
Many years ago a gun at a clay shoot blew up.
The gun and cartridges were sent to the proof house.
It turned out the the person that had reloaded the cartridges had put a layer of rice between the wads to act as a cushion.
When the gun was fired the pressure compressed the rice and forced it outwards against the barrel wall and it acted as a brake.

Reloading shotgun cartridges is safe if you stick to known data.