Reloder 7 and Sub-sonic 300 BO?

[kcofohio]

Has anyone tried Alliant's Reloder 7 for sub-sonic? I have some MBC 245 gr. and an unopened lb. of the powder with no other use for other than 8mm gas-checked loads.
The only load I have found so far with this powder is a 200 gr. Speer bullet.
This would be for a pistol lenght barrel. I think the burn rate is near AA1680 and IMR-4198.
Any knowledge would be appreciated.

 

[Englishmn]

Found this, I will be using some 220 gr pc bullets in my 300blk looks like ~9.5gr is a good place to start.

http://www.300blktalk.com/forum/viewtopic.php?t=84129

 

[kcofohio]

Found this, I will be using some 220 gr pc bullets in my 300blk looks like ~9.5gr is a good place to start.

http://www.300blktalk.com/forum/viewtopic.php?t=84129

Thanks for the link!

 

[Lennyjoe]

Oooh now this is interesting. I’m using a Reloader 7 in 45-70, 7.62x39 and now in .50 Beowulf. Would be nice if it works in my .300 BO as well.

 

[kcofohio]

I loaded up a batch of 20 rds. 5 rds. per powder weight. Starting at 10 gr. and increased by .5 grain to 11.5 gr. COAL was at 2.100".

10 gr. would not lock the bolt back on the last rd. 10.5 gr., 2 out of 5 locked the bolt back. 11 & 11.5 gr. ran fine. All loads extracted the casings.

I didn't bring a chrony, but all loads sounded subsonic.

Next I will load up 11, 11.5, and 12 gr. to run over a chrony.

Yesterday was about as a perfect day for the range as one could ask for. Lots of other folks must have thought so too!

 

[kcofohio]

I was able to get some chrony time today. I had loads of 11.0, 11.5, 12.0, & 12.5 gr. All using MBC 245 gr. Hi-Tek coated bullets. The COAL was 2.100".
I used CCI 400 primers and resized LC cases. All strings were 5 shots. The upper is a PSA 8 1/2" barrel, unsuppressed. At the end of the 5-shot strings, the bcg locked back each time.

11.0 gr.
Low-956
High-1012
Avg.-986
ES-56
SD-21

11.5 gr.
Low-1006
High-1034
Avg.-1026
ES-27
SD-11

12.0 gr.
Low-1050
High-1084
Avg.-1067
ES-33
SD-14

12.5 gr.
Low-1108
High-1138
Avg.-1123
ES-29
SD-13

Another great day to be at the range.

Edit: Temperature was 75' and mostly sunny.
Elevation, well the area use to be part of the Black Swamps near Lake Erie, so it can't be all that high.

2nd Edit: My lower has the KAK Shockwave stock kit that included the buffer, spring, and tube.