Sierra Load Data 300Blk

Thread starter #1

JeffinPTC

Senior Member
New from 21 Dec.
It doesn't say if these loads will cycle or lock back the bolt though.
I haven't had luck with H110 cycling a subsonic load from the Hornady data, even though to Hornady #10 says it will. Several FTFs.
Evidently AA1680 is the best choice.

https://sierrabulletsblog.com/2017/12/21/sierra-bullets-300-aac-blackout-load-data/

PDF pages for your Sierra Manual 5. They print as 2 pages per sheet and didn't print so you could cut to fit 2 sided. recommend one side only

https://sierrabullets.files.wordpress.com/2017/12/300-aac-blackout-12212017.pdf
 

transfixer

Senior Member
Thanks, I'm using Lyman's 50th and Hornady 10th, so that gives me something to compare to , are you running an adjustable gas block ?
 

fishtail

Senior Member
1680 is reputed to be best for subsonic loads but I've found it to be ideal for my purposes.
In my 16" pistol length gas system it has no problems cycling Sierras #2124 135gr HP with 20.0gr at 1940fps muzzle velocity.
Remingtons 150gr PSPCL also does well with 19.0gr at 1870fps muzzle velocity.
Even Noslers 220gr #30181 RN with 11.5gr at 1195fps muzzle velocity cycles just fine.
All of these loads lock the bolt back after the last round and throw the brass to the 4 o'clock position.
 
Thread starter #4

JeffinPTC

Senior Member
We're not using an adjustable gas block, but are using a Silencerco Octane, so subsonic a must. Hornady 208s are the only bullets consistently working well, but more work to be done with this new data after deer season ends sunday.
We also have a Night scope to try out on the yotes in the neighborhood. It was $400 during christmas.
 

transfixer

Senior Member
I'm new to the .300blk, had this one put together last year, had the guy build it with the adjustable gas block so that I could use a variety of loads if I wanted to, if they pass the hearing act I'll spring for a suppressor and start loading the heavier bullets. Wouldn't you benefit from being able to tune the rifle to the load you like ?
 
Thread starter #6

JeffinPTC

Senior Member
Just got this reply from Sierra about cycling and BHO:

They should.

Duane Siercks
Ballistic Technician
1400 W. Henry St. Sedalia, MO 65301
Questions? Call us toll free 800-223-8799 x544
 

Jester896

Senior Member
I use A1680, as mentioned above is the best for subs, for the longest time it was hard to get. I used it in the 16" I used to have and whatever I could get my hands on in the 208-220gr area. 208 A-Max mostly....followed by 220gr SMK.

I still use it but my barrel and gas system are shorter.
 

Jester896

Senior Member
I use 10.2 and I think that may be close to a tad too much for this one. I didn't have an issue with the 16" carbine. In my case I am using LC cases and #41 primers.
 
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