The primer part is easy - just pick one.

You might get by with trying to make one powder do it it all but why? One of the reasons for handloading is to make superior quality ammo and that means optimizing the components to the application. An example of this is to use a fairly fast burning powder like Clays or Red Dot in the 7/8 Oz - 1 Oz 12 guage loads and then a much slower powder like Universal Clays or 20/28 in the 28 gauge.

its not like your going to save any real money by just using one powder so why compromize on performance and get outside the recommended operating pressure range?

Look at Alliant 20/28 powder in Winchester 12 ga and winchester 28 ga loading data

Gary

You could do it with FFFG black powder. JW

Thanks, Gary. I hadn't looked at 1 1/8 thinking they'd be thumpers. However, the reported psi is low but still offering 1200 fps.

Larry

Larry, 'tis a piece of cake: PB. Hodgdon has published loads for PB from 28ga to 10ga, and I have used it in a 32ga and "light" 8bore.

Alliant's 20/28 will stretch, too, with published loads.

Green Dot tends to get a little pressury, and, in fact has been a culprit in cracking 20ga tubes.

Bob

The only thing I have found that will properly interchange between the two gauges without compromising performance is 209 primers. I use Clays, International and Universal in 12 ga., Longshot and International in 20 ga. and ProReach in 28. That being said I load for two different games, trap and sporting. The International and Clays for trap while the Universal @ 1300 for sporting. 20 ga. gets Longshot for 1300 fps sporting and 28 ga gets ProReach for 1300 fps sporting. I too wish one powder would do it all however, I have never experimented with PB like others on here have suggested. Hope this helps, Mike.....

20/28 will work, but your pressures with 1 1/8oz 12 ga. 1200 fps loads is very low. I've also found that 20/28 takes a larger bushing than Longshot for the 28 gauge HSAA hull which affects crimps. It will work , but I prefer Longshot.

Unique should do the trick.Maybe not the very best choice, but it should work.

That's what the reloading manuals are for....BUY ONE.