Mr_Flintstone
Member
I'm still in the beginning stages of reloading, and I made a mistake at the store. I was at a local gun store buying some bullets, and I picked up a box from the row that had 150 gr LFP. When I got home and opened the box, I realized that I'd actually picked up 158 gr JSP.
While this won't cause a problem loading 38 spl, my intention was to load some 38 LC. There doesn't seem to be any data for jacketed bullets in 38 LC, and the data I I'd have is for lead. As I don't want to go buy another box of bullets, I started reading my Lee manual. It gives the load work up formulas as:
10% change in bullet weight causes -4% change in velocity, and 8% change in pressure.
10% change in charge weight causes 8% change in velocity and 20% change in pressure.
10% change in case volume causes -3% change in velocity and -13% change in pressure.
I started with a low 38 spl load using 158 gr FTX and 3.5 gr Titegroup @704 fps and 12400 CUP. Hornady says I can use JHP interchangeably with JSP or FMJ with the same weight.
Using the formulas, if I change the case volume -15.2% from 23.7 gr to 20.1 gr, I get 14848 CUP and 736 fps. To get back to the original pressure, I change the pressure by -16.5% resulting in a charge weight of 3.2 gr @ 686 fps at 12400 CUP.
Recalculating for the max charge, I started with 3.9 gr Titegroup @ 798 fps and 15900 CUP, and got a new max charge of 3.6 gr Titegroup @ 779 fps and 15900 CUP.
I don't have software to check these values, so I'd like some opinions from you guys. Do these seem like reasonable values? I'll be shooting them in a modern 38 Special that is +P rated.
While this won't cause a problem loading 38 spl, my intention was to load some 38 LC. There doesn't seem to be any data for jacketed bullets in 38 LC, and the data I I'd have is for lead. As I don't want to go buy another box of bullets, I started reading my Lee manual. It gives the load work up formulas as:
10% change in bullet weight causes -4% change in velocity, and 8% change in pressure.
10% change in charge weight causes 8% change in velocity and 20% change in pressure.
10% change in case volume causes -3% change in velocity and -13% change in pressure.
I started with a low 38 spl load using 158 gr FTX and 3.5 gr Titegroup @704 fps and 12400 CUP. Hornady says I can use JHP interchangeably with JSP or FMJ with the same weight.
Using the formulas, if I change the case volume -15.2% from 23.7 gr to 20.1 gr, I get 14848 CUP and 736 fps. To get back to the original pressure, I change the pressure by -16.5% resulting in a charge weight of 3.2 gr @ 686 fps at 12400 CUP.
Recalculating for the max charge, I started with 3.9 gr Titegroup @ 798 fps and 15900 CUP, and got a new max charge of 3.6 gr Titegroup @ 779 fps and 15900 CUP.
I don't have software to check these values, so I'd like some opinions from you guys. Do these seem like reasonable values? I'll be shooting them in a modern 38 Special that is +P rated.