Randy:
Make sure to check your forcing cones. Most older guns have steep angled, short forcing cones which can lead to hull damage as seen in one of the responses above when using 2 3/4" hulls in 2 1/2" chambered guns.
To avoid such hull damage, simply trim down the 2 3/4" hull length to 2 9/16", use your existing reload data, toss in an overshot card, and crimp as you always do for 2 3/4" hulls. Any increase in pressure from the overshot card should be slight. And the hull should fully open in the existing chamber without damage from the forcing cones.
