[375Carp]

I have been thinking about trying some StaBall in my 03-A4 loads. While cleaning out Dads old reloading spot, I ran onto 200 30 cal 150 gr Core Lokt bullets. I also found 50 brand new WW cases a few weeks back. I like carrying round by sporterized Enfield, so off to the reloading cave I went.

I have done a few posts on the StaBall powder. I am always intrigued by the high velocities that are posted in the data.

Hodgdon data shows starting of 58.5 @ 2,929 fps with Max of 63.0 @ 3,126 fps

I loaded 1 round from 58.5 to 62.5. My velocities are showing 125 fps (ish) slower than the data. My barrel is 24" long. I would say my Win cases may have a little higher capacity or the BD of the powder is a little different. 63 gr is showing as a compressed load, but with 62.5 gr of powder, I still had some room between the bullet and powder. Powder poured through a funnel straight from the pan.

No "signs" of pressure at this point. The velocity looked to climb very consistently. No big jumps or deviations. I thought about going up another gr, but I don't see much benefit in going over the published max load. I will most likely back down to 61.5 grains and start tinkering around in that area to see what accuracy looks like.

I am starting to think that either I have a bad chronograph or reloading manuals are consistently optimistic.

 

[Darkker]

Certainly could be a capacity difference.
From my personal testing, Hodgdon doesn't seem to have a great handle on a couple of the newer GD ball powders.
Until the purchase of Western and a modern ballistics lab, several of their things were estimated or unable to be properly tested for use.

Don't know if that is at play here, but also a possibility.

Cheers

 

[unclenick]

Powder makers pretty consistently test in SAAMI spec pressure barrels these days. They have chambers that are at the minimum SAAMI dimensions within half a thousandth of an inch. They are fired with the cartridges manipulated so the powder is back over the primer during firing. What both those factors do is tend to produce the highest pressure (and velocity) they can expect to see, as most production guns are looser fits to the cartridge. It tends to produce the worst-case high pressure, which gives them a margin of liability comfort that pressure will not exceed what they measure in actual guns.

Regarding StaBall 6.5 density, it is not uncommon for bulk density of powders to vary ±5% or so from lot to lot.