Tuesday, January 09, 2024

One last thing before I try to get rid of this headache: more subsonic testing

The other day I was able to put some over a chronograph to find out just what they're doing.  Two groups were fired, both with 11.0 grains A5744, first group with magnum large rifle primers, the second with standard.

First, DISCLAIMER:
These are loads I worked up.  Some was from data on different bullets/cartridges, some from information I found online, some was figured on my own.  They worked for me, I can't guarantee they will for you.  So use with caution, if you do.

Mag primers,
909fps
909
869
877
867
849

Standard primers
898
866
846
861
864

Mag primers a little higher velocity, as in average 880fps vs. 867 for standard.  Which isn't enough to worry about.  Would the ignition characteristics mean better accuracy at longer range?  Might find out later.

On all the cases were clean enough to indicate high enough pressure for the cases to properly seal, no flat primers indicating high pressure.  So I think I'm safe in upping the charge a touch.  I'd like to get these to about 1000fps so they'd be in the envelope for expansion*.


*Hornady says these should expand down to 900fps, so want to be above that.


2 comments:

Justin_O_Guy said...

So use with caution, if you do.

I'm not a reloader. Not a marksman, either. But I like that stuff..
But I'm not sure I would know How to do that Cautiously. Close my eyes when I pull the trigger?

Firehand said...

Why I have that disclaimer: I'm just working these loads up from comparisons to other cartridges, thinking, and making that sometimes dangerous statement "Yeah, this should work."

Don't close eyes but do use good eye protection, and if I had a suitable stand I'd have the rifle locked in it for that first couple of shots so I could examine the brass before setting off that X-thousand PSI deflagration while I'm holding it.

I'd imagine some ballistics specialists/engineers are holding their heads and saying something like "No, don't do it that way!" as they read some of my stuff.