500 grs. in Gibbs Summit

[Jim]

I finally got a decent load worked up for my Gibbs Summit. Using IMR 7383 and LMR primers, I got a Rapine hard cast 500 gr. round nose bore rider up to 1600 FPS. I managed to shoot a 1.2 MOA. at 50 yds with 5 rds.
I don't mind tellin' ya', that'll push back.

[gunderwood]

What is your load? That seems kind of hot for an old rifle. A 500gr @ 1400fps give or take was usually the max for an old gun. Of course it was possible to load them up more, but you really have to know what you are doing.

These guys make some of the best .45/70 big game loads around. The load you are talking about is definitely +P and not usually recommended for anything other than new Marlin and Winchester firearms.
http://www.garrettcartridges.com/products.asp

That aside, .45/70s are lots of fun! I love mine (Marlin 1985). The pack a big punch, but what ever you shot is dead if you hit it (I'm exaggerating, but only a little).