Should be a simple Question...

[krs]

With all else equal - as in same powder, same seating depth, same crimp, does pressure go up with bullet weight or does it go down?

I'm pretty sure that heavier bullet = higher pressures because it takes more energy buildup to get the heavier bullet moving, right? And so powder charge should be reduced if bullet weight is increased.

Or am I all turned around?

 

[Eagle103]

You are correct. Heavier bullets will increase pressure if the powder charge etc. stays the same.

 

[rcmodel]

No, you are correct.

Tested & Published load data reflects this in lower weight powder charges of the same powder to maintain the same pressure when bullet weight goes up.

rc

 

[krs]

OK, good.

This comes up because a buddie gave me almost 300 265 gr. JSP bullets in .44 and I so seldom shoot .44 mag anymore that I am thinking to shoot them up in .44 Spl. from my model 24.

Turns out that I don't have listed loads for such heavy bullets in .44 spl. so I'd have to adlib. (Deja vue, Elmer Keith).

I just want to punch paper with them and knowing the SAAMI pressure is only 15,500 for .44 spl. I thought I'd better be sure of what I was doing or just shoot them from my 629 that could probably better handle if I overpressured the loads.

Does any of that make sense?

I've got lots of Bullseye so I like to use it but there's not a lot of data for .44 mag that uses the powder at all, and none that I have in four manuals that use it for bullet weights over 240 gr. I couldn't find much to help convert a load into the shorter case of .44 spl.

 

[ranger335v]

Our goal is, or should be, to pretty well maintain the same pressure with any bullet weight. That means we will use a faster (burn rate) powder with light (for caliber) bullets and a slower power with heavy bullets.

Why so? Powders are formulated to burn most consistantly at a design pressure. That is the usually the highest rated pressure for the normal cartridge it will be used in.

I mean Bullseye works great at pistol pressures but it's dangerous at rifle pressures. And, 4831 works poorly at pistol pressures, it simply can't come up to pressure in a small cartridge even with heavy bullets. Those are extremes but they do illustrate what I'm saying.