New guy having trouble with 220gr subsonic loads.

[Brian Ski]

I have been reloading for years. I just started on the 300 BO this fall. Trying to work up a subsonic load. It is an AR platform 18" barrel, with a 12" 9mm suppressor. I thought I would get a jump on troubles and found some Shooters World Blackout powder, and some 220 Gr bullets. I am using CCI standard rifle primers. I am loading to a 2.260 OAL. 10.2 GR.
https://www.evergladesammo.com/bullets/ ... llets.html

It is kind of cold here, 40s?? The first round I fire is slow. Then the rounds gain speed. (???) From what I remember (wrote down upstairs) 860, 917, 1017, 985, 990, 1030, 986, 1005. The variation is quite high especially when you add in the first 2. I need to fire a few off without the suppressor and see if it is more consistent. BTW the AR cycles perfectly. It is an older chrony. I don't know anyone around with another to try. I see a lot of people post their average velocities, but never really see the spreads posted.

I searched all over the site, but haven't found any pet loads for the S/W blackout powder. There is a bullet powder thread, but did not seem to find anything there. (It looks like the thread started fine with a standard format for loads, but got sidetracked.) From what the powder bottle shows is 10.5 gr is about 1050 FPS. But I am a little higher than that, but the spread is what I am concerned about. Any ideas??

[cdl]

My son loads those bullets to 2.075" with 11gr A1680 with no crimp and gets 1000 fps from an 8.5" barrel. Can't say that's good or bad because I've never shot one. I suspect yours might shoot a little better with a shorter OAL.

Also the everglade plated bullets I've used have been pretty soft and maybe not quite the oversize diameter I'd prefer. So I take the extra step of using an oversize NOE mandrel to make sure the bullets don't get swagged undersized when seating them in the case. I also crimp to remove bell but not enough to crimp into the bullet.

A few thoughts anyway.

[cwlongshot]

I agree try adjusting OAL

Also know subs are backwards from conventional
Loads. Meaning. A conventional Load ya start low and work up... A sub load ya want high and drop Powder till to get velocity and functionality your pleased with.

Good luck

CW