30+ year old 38 special cases.

[Dvrjon]

This data is for 150gr bullet. 158gn is 3.6gr of powder. At least in my Nosler manual.

You’re right…I fat thumbed the calc. The range is 3.6 to 4.0. (Hodgdon calc) You’re still well below the starter load and splitting cases.
IMHO the juice isn’t worth the squeeze. Dump the brass.

 

[AR15barrels]

I loaded ten rounds. 158 gn fp with 2.9 gn of A#2. Some of the cases cracked.

I would stop shooting those loads immediatly.
When the cases are cracking, you are going to be getting gas cutting inside the chamber.
That's bad juju.

I will load up the rest and shoot it once. Very soft shooting.

View attachment 66928

By using such a small charge of that powder, all the powder is likely sitting on the side of the case of you are shooting the gun level,
The primer flame goes over the top of it and lights the powder all along the top of the powder which causes an explosion instead of a controlled burn that you get when the case is more filled or with powders that are not position sensitive.
The split cases are proof of your load being unsafe (likely due to the position sensitivity).
You could try that same load with some case filler to keep all the powder at the base of the case and you might get very different results.

 

[Pewpewwagon]

3.0 grains of AA#2 is the min load in the Nosler manual. Also the most accurate. I think the manual had another load with a smaller case density.

Yeah, looking at the cases again and those cracks are gnarly. Definitely don’t want to scar my revolvers. Thanks!