Load data range report

[wnchstrtnfldvlle]

Ok. So ok day at the range.

1. Rookie mistake, forgot the 9v battery for the chronograph. So no velocity data.
Load one was,
210 gr Berger vld bullets
Converted .223 cases 1.36 +/- .002
IMR 4227 8.1 gr
Cci #41 primers
COAL 2.200 +/- .002 (pretty sure this is due to the bullet tips not being uniform)
No crimp
-all bullets cleared the barrel. Cases ejected fine. The bolt would not cycle back far enough to load the next round.

Load 2 was the exact same but with light crimp (lee factory crimp die)

- same results. With both loads the barrel we very dirty with what looked like powder that had not ignited.

So with this data what are some recommendations? I am thinking about a lighter spring and buffer. For the cycle issues. (This one will be strictly a subsonic platform)
Then for the powder that wasn't burned all the way, maybe a heavier crimp?

 

[reloader7.62]

I don't load for that cartridge but sounds like you have a port pressure issue for unburned powder. I used to shoot lot of 4227 in 357 mag. an even on a good day there is some unburned powder even with a heavy crimp applied. There probably are some better powder options that will get the bolt cycling. Your load using IMR-4227 is also on average 2.2 grs below the starting load listed for a comparable bullet weight or one slightly heavier. I suspect your chrono data would show that you were under 1K fps. if it were working.

http://sierrabullets.wordpress.com/2013/07/17/300-aac-blackout-medium-length-gas-tube/

http://data.hodgdon.com/cartridge_load.asp

http://ingunowners.com/forums/ammunition-reloading/240170-300-blk-240-gr-smks-subsonic-load.html

http://300aacblackout.com/

[url]http://www.300blktalk.com/forum/viewforum.php?f=141&sid=a867ab805f4d55fb2b61269b9506c13a
[/URL]

 

[wnchstrtnfldvlle]

Thanks for the info. I was following the data from the Hornady manual, but I did forget about the hodgdon site. I have the IMR 4198 to try, but it was making me a little nervous with the crunching sound as I seated the bullet. I will have to go back through and try some more recipes. I will look around for some of the other powder types as well

 

[ngcsugrad09]

If you're going for subs, start around the max listed and work your way down to where you are subsonic AND cycling. It sounds like you may not have enough powder, which can actually be a dangerous thing if you're not careful. The best powder for blackout subs is AA1680 if you can find it.

You shouldn't really worry about the crimp aside from a minor kiss on the case. In all reality, it's not that necessary on semi autos like everyone makes it out to be.

On another note, for optimized feeding you want the bullet contacting the rib of the magazine at the .25-.26 diameter portion of the projectile (assuming OAL isn't too long to fit).

I would work up a ladder of sorts of 2-3 rounds each from maximum and work down in 2-tenths increments to where you're at now to find your cycling and sub sonics. When you get a 2-3 that seem optimum, then load some more of each to refine your testing.

Just my 2 pennies worth.