300 Blk + RE-7 or 10x?

[Ironduke]

Mornin!

So several days ago I went to the range with my trusty 300 Blk AR with ammo made of the 235 Lee and 11gr of RE-7.
This load produced an avg velocity of 1024 fps and would eject the empties, but would not pick up new rounds from the mag. Basically I has an auto ejecting single shot. LOL!

I figure i have two ways to go. First is to work up to a higher load with RE-7. I can go up in 1/2 grain increments until i run into excess pressure or my rifle cycles reliably. Hopefully my velocity will increase only a small amount so I can stay under SoS.

The other option is to try some RE-10x. Being a bit slower than RE-7, it might give me some more pressure at the gas port. If so i might be able to keep my velocity down and still get reliable function.

My question about option 2 is where to start for a load. Slower powders require more powder to reach the same velocity as faster powders, but I am long since past the days where I experimented willy-nilly. I figure i can start at 11 gr and work up since 10x is slower than 7. What do you guys think?

Paul

[felix]

Start at 12 grains. Won't hurt a thing. Make sure case neck is not too long. Make diameter measurements before and after as well, and this should be made a habit during load development. ... felix

[Ironduke]

Right on! Thanks! that saves me some time and money by reducing the number of test loads

[Ironduke]

Also, I weighed the bullets I had cast before I loaded them today. The average weight was only 220 gr. There was one freak at 214 gr, and another at 217, but all the rest weighed between 218.5 and 220.2. Not bad i don't think.

[Moonie]

Have you checked to make sure that the port is lined up properly with the gas block? I would think that much R-7 at that velocity should cycle and lock back on empty, but I haven't tried it.

What length is your gas system?