300 blackout subsonic cb load data?

[petroid]

I've really been thinking about getting one of the new Ruger Am Ranch rifles in 300BLK or a barrel for my Encore just for the fact that most of the tinkering folks have to do loading for the blk is due to getting an AR to cycle reliably with powders other than 1680.

I too would love a 300BLK Bolt gun. And I also load some with fast powders for super quiet without action noise. Just pull the charging handle each time. But my AR is quite heavy and slow to manually cycle compared to a simple bolt action.

donald150. I have had good luck with H110, IMR4227, and Re7 in my 12.5" 1:7 CMMG pistol gas. I found Re7 to be dirty burning at these low charge weights but functioned more reliably than anything else. Alas, I don't have any 1680. With subs you have to work backwards. Start at the max listed loads, which are very low to be sure, and verify function and work down until you are subsonic and functioning. You may have to go over the "max" to actually obtain good function depending on the gas system. New components may require some breaking in as well before everything runs smooth. This is usually not the case for supers, you may want to work on those first to get some break-in done and come back to the subs. It goes without saying that a chronograph is your friend. Without a suppressor, it is nearly impossible to differentiate between supersonic and subsonic just by listening for the "crack". And a suppressor will add a few feet per second as well as increase back pressure to help with cycling, but I always want my AR loads to cycle without a suppressor just in case.

[donald150]

It goes without saying that a chronograph is your friend. Without a suppressor, it is nearly impossible to differentiate between supersonic and subsonic just by listening for the "crack".

I agree, I may be putting the cart before the horse. I have been loading 110gn, 147gn and 150gn in my 300AAC for a while and I REALLY like the 110Gn Hornady V-Max. I don't currently have a chronograph but I hope to this summer.

I am in the process of setting up a NFA trust so I hope to be starting the process on a suppressor this summer also.

[Sticky]

A chrono is really a critical tool for handloading, especially subs.. I can't tell the difference unsuppressed by ear, so the chrono tells me for sure and it also gives you a baseline to compare your velocities (and correlate to pressures) to the load data as you are working up loads. It's not always the same!