07-21-2023, 10:07 AM
lot to lot consistency for powder does occur, but with the brass available today I haven't seen much of that within a same mfr.
A different brass mfr however, has a slightly different design than any other mfr...
See lots of that. Hornady, lapua, starline, peterson, nosler, sig sauer, winchester (stuff someone already has, they don't seem to make it any more), Remington. Heck even different years of lake city can be different. Mostly in overall weight, but also in interior volume. So generally speaking, each brass mfr will take a different load, by a few 1/10th's of a grain. Up to 1-1.5 grains in 308, which I have experienced. In grendel the rule of thumb is hdy is ~0.2 gr more powder to get the same MV... but the starline brass was more consistent than hdy. I think I'm seeing the hdy brass in 6Arc to be more consistent than the hdy brass in 6.5 grendel, don't have any starline to-date however.
The easiest way to compare is to work up a ladder of the 2, side by side. 1 shot per powder load, 1% delta in wt, then graph them out. Takes 5-6 shots per mfr. I tried once upon a time, to just shoot a duplicate load in 308 of win brass to hornady brass, I got a 150 fps delta!!! the hornady at that grain weight was way too hot. So I don't so that any more. do the single-shot ladders and compare the performance curve.
Powders, otoh, today don't differ by much lot to lot but they will still differ. Everything else being equal, I can load the same gr wt into my favorite good combo, of my next powder lot and see the diff, then tweak the load.
So, brass, yes, different mfr, be prepared to have separate load workup for that new mfr. You might end up close but don't bet on it, for 0.75-1.0 moa accuracy you'll need a separate wt load out for that new brass mfr. Keep a load diary/book.
Now if you're ocd like competitive shooters, you will chase consistency down to a much deeper level... but they are looking for 0.2 moa's or better every week in competition. or 0.1's.
A different brass mfr however, has a slightly different design than any other mfr...
See lots of that. Hornady, lapua, starline, peterson, nosler, sig sauer, winchester (stuff someone already has, they don't seem to make it any more), Remington. Heck even different years of lake city can be different. Mostly in overall weight, but also in interior volume. So generally speaking, each brass mfr will take a different load, by a few 1/10th's of a grain. Up to 1-1.5 grains in 308, which I have experienced. In grendel the rule of thumb is hdy is ~0.2 gr more powder to get the same MV... but the starline brass was more consistent than hdy. I think I'm seeing the hdy brass in 6Arc to be more consistent than the hdy brass in 6.5 grendel, don't have any starline to-date however.
The easiest way to compare is to work up a ladder of the 2, side by side. 1 shot per powder load, 1% delta in wt, then graph them out. Takes 5-6 shots per mfr. I tried once upon a time, to just shoot a duplicate load in 308 of win brass to hornady brass, I got a 150 fps delta!!! the hornady at that grain weight was way too hot. So I don't so that any more. do the single-shot ladders and compare the performance curve.
Powders, otoh, today don't differ by much lot to lot but they will still differ. Everything else being equal, I can load the same gr wt into my favorite good combo, of my next powder lot and see the diff, then tweak the load.
So, brass, yes, different mfr, be prepared to have separate load workup for that new mfr. You might end up close but don't bet on it, for 0.75-1.0 moa accuracy you'll need a separate wt load out for that new brass mfr. Keep a load diary/book.
Now if you're ocd like competitive shooters, you will chase consistency down to a much deeper level... but they are looking for 0.2 moa's or better every week in competition. or 0.1's.