How do they do it???

[jpuke]

How do companies like Garrett and Buffalo Bore make loads for the 45-70 that don't exceed the pressure capability of the guns?   I'm specifically thinking of their 530(?) gr Hammerhead that will fit in a lever gun - how do they get 1500 fps with it?  I looked at an old issue of G&A and they show the 530 gr bullet next to a 45-70 case - it looks like it takes up the majority of the powder space - I'm just wondering how they get the performance they claim.  They must have different powders or something.  One more thing - is that kind of performance something a handloader can duplicate?  (It may not be advisable, I just want to know if it's possible)

[Nobade]

They may be using non-canister grade powders, but mainly it's because they have the proper pressure measuring equipment and can tell when they have gone too far. And of course they're loading for the Marlin, not the Trapdoor Springfield. BTW, it's no big trick to get a 500gr. bullet going 1500 fps in a Marlin using AA2200. Does kick a bit though...

[jpuke]

Thanks for the reply