pressure listings for mid range loads

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brybenn

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I'm going to try loading 350gr hornady fn interlocks in my 4570 that is rated at 28000CUP. The lee manual for this weight and varget lists :54grs 1786fps and 60C grs for 2013fps at 29500CUP. I want to load to around 1900fps so impact velocity will be above or at 1800fps for reliable bullet expansion. Is there any way to find out the ballpark pressures for the mid range loads? 60grs is over the rating for my gun I'm thinking a 1900fps load will be less then 28000CUP but I don't know for sure
 
I got 56g in Quickload, but it's telling me it's still over pressure for your gun.
I can't find a powder load combo for that bullet that will break 1800 without going over.

I'm thinking a bullet that heavy won't have trouble expanding at a lower velocity.

I don't know the 45-70 very well, just ran some numbers thru my program for you to see what I could come up with.
 
Be careful when trying compare CUP loads to PSI loads ( or CIP from Europe), which is what a lot of manuals show nowadays, there isn't a reliable, safe way to convert one to the other. The accuracy of the measuring deviations between the two is a little suspect. If you are playing with something like a trapdoor or a rolling block, you could wind up in iffy territory in that regard.
 
Thanks for the scans. I tried 54gr of varget today and clocked 1645fps. The lee manual says 1785fps. I've got almost 24" of barrel. It also states 55grs under a 400gr jacketed bullet hits 1845fps at 25000cup. I may just switch powders
 
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