Quantum theory is more like, "One can only increment a load by a granule of powder."

String theory is combining Hot Core's and Denton's posts in a unified AR theory.



But the answer you seek may be in a thread entitled, "How do you convert cup to psi?"



Use the search function, Browningguy, use the search function.



Or... and answer might be from my 1903 Turkish Mauser 8mm, 200 gr. 50 gr. IMR4895 slightly sticky bolt, 52 gr., very sticky bolt. 47 gr., 2630 fps, 1" 5 shot group at 100 meters. You could increase the load until the bolt gets very sticky, reduce by 5 gr., and there is the load... But I forgot, you don't have your overloading license yet

LeftoverDJ, Just checked again, this is the Lee book copywrite 2001 and it shows 43.6-49 grains of H4350 for 160 gr. bullets. I just wanted to make sure, I've been pretty neurotic about checking everything multiple times to make sure I don't screw up a gun or hurt myself.

Thanks though, better to be safe than sorry.

I own 3 different 7 x 57s. Two Ruger 77 Mk 2s and a Winchester Featherweight.

The winchester will shoot one hole groups with whatever goes down the barrel.

The Rugers were as accurate as slinging gravel and that was about it.

Just before they got traded off ( and I was taking advantage of their long throats), I tried a load of 40 grains of IMR 3031.

Well I still own those two rifles.

From 139 grain bullets to 175 grain bullets these two rifles take the 40 grain loads, and they are one hole shooters if I do what I am suppose to do, that is with ANY bullet I have tried and I have tried all I can get ahold of which is available stateside.

The other thing I love about this 40 grains of IMR 3031 in this round is the consistency. I get about 2750 fps with the 139/140 grain bullets, but with the 160 or 175s I get about 2650 fps. So there is not a lot of variation in point of impact which means I can use a lot of different bullets and weights and not worry about playing with scope adjustments.

I am sure the pressure is higher in the 175 grain bullet loads, but it is well within specs. The Lyman 47th manual was my source for this info. I think it lists 38 grains instead of 40 for the 175 grain bullets but since the pressure was listed in one of the sources as 44,000 CUP and I know the rifles are capable of taking a lot more, I worked up the two grains and life was happy.

Work up etc, but I almost believe that the best powder for the 7 x 57 available in the USA is IMR 3031. It sure sold me!

Cheers and Good shooting
seafire

Hello Browningguy,

I still use velocity as a benchmark for reloading. That doesn't mean I attempt to achive the max velocity listed and disregard other signs, but velocity is still the best measurement of pressure. If if your reduced loads match the velocity given in load manual XYZ pretty close you have a good gauge.

If load manual XYZ lists 2800 as with a max load I will use that as my benchmark. Now of course all guns are diffent but lets say 49grs gives that velocity in said manual, but in working up loads I discover that I get about 2800 with 47 grains, then that is the max load for said gun, even though it is 2 GRAINS below book max. This is a bit simplified but I am sure you grab the idea.

For what it is worth I find 2750-2800fps my velocity range with 154gr Hornady bullets in my 7x57. I get that with 47gr of H-4350. I get 2780 to be exact and that is all I need or want.

Good luck.