300 BLK suppressed AR Pistol subsonic reloading

[GreyBeardBiker]

Greetings all! I just posted this a little while ago and it disappeared... Sorry, in advance, if this ends up duplicating the post.

I am an experienced reloader having rolled my own ammo for over 20 years. I have loaded 300 BLK subsonic/supersonic for carbine length ARs for five years - with very good results.

Last May I purchased a SIG Sauer Rattler with an 8" barrel. I have only shot the pistol a few times as I was waiting for my tax stamp for a suppressor. After nine months I finally picked up my suppressor last Wednesday. Taking it to the range with 208gr HPBT reloads, which worked for my 16" barreled AR, provided quiet shots, but they are obviously too under-powered to cycle the pistol. I have tons of new reloading guides from Hodgdon, Speer, Hornady and Lyman. Unfortunately, none of the manuals provide a starting point for an 8" AR 300 BLK. Where does one even begin?


The carbine length subsonic recipe for the AR is:
208gr Hornady BTHP
8.1gr Vihta Vuori N110
Remington 5 1/2 small rifle primer
New Starline brass
COAL 2.250"

I also have Hodgdon H110 which works well for the carbine. Accurate 1680 seems to be the most popular powder, but burn rates for the H110/N110 seem similar to 1680. Has anyone worked up subsonic loads for 8" 300 BLK with either of the powders I have?

Mike
Clarksville, TN

 

[rustyinbend]

Greetings all! I just posted this a little while ago and it disappeared... Sorry, in advance, if this ends up duplicating the post.

I am an experienced reloader having rolled my own ammo for over 20 years. I have loaded 300 BLK subsonic/supersonic for carbine length ARs for five years - with very good results.

Last May I purchased a SIG Sauer Rattler with an 8" barrel. I have only shot the pistol a few times as I was waiting for my tax stamp for a suppressor. After nine months I finally picked up my suppressor last Wednesday. Taking it to the range with 208gr HPBT reloads, which worked for my 16" barreled AR, provided quiet shots, but they are obviously too under-powered to cycle the pistol. I have tons of new reloading guides from Hodgdon, Speer, Hornady and Lyman. Unfortunately, none of the manuals provide a starting point for an 8" AR 300 BLK. Where does one even begin?


The carbine length subsonic recipe for the AR is:
208gr Hornady BTHP
8.1gr Vihta Vuori N110
Remington 5 1/2 small rifle primer
New Starline brass
COAL 2.250"

I also have Hodgdon H110 which works well for the carbine. Accurate 1680 seems to be the most popular powder, but burn rates for the H110/N110 seem similar to 1680. Has anyone worked up subsonic loads for 8" 300 BLK with either of the powders I have?

Mike
Clarksville, TN

My best subsonic 300-BLK load is:

Starline brass
IMR 4227 - 9.0 gr
CCI Mag SRP's
COAL 2.20
Sierra MK 220's

Groups great - super quiet. You can usually find the IMR 4227 pretty easily ... it my best subsonic powder.

 

[GreyBeardBiker]

My best subsonic 300-BLK load is:

Starline brass
IMR 4227 - 9.0 gr
CCI Mag SRP's
COAL 2.20
Sierra MK 220's

Groups great - super quiet. You can usually find the IMR 4227 pretty easily ... it my best subsonic powder.

I actually have some stock of 4227. I will give that a try. What barrel length is this working in for you?

 

[rustyinbend]

I actually have some stock of 4227. I will give that a try. What barrel length is this working in for you?

Works in both my 16" AR, and my 8" AR pistol.

 

[rustyinbend]

Works in both my 16" AR, and my 8" AR pistol.

Just checked ... the AR Pistol is actually 8.5".

 

[GreyBeardBiker]

Just checked ... the AR Pistol is actually 8.5".

I appreciate your time and the information. H110 and N110 are normally good for subsonic & suppressed ARs. I am going to play around a bit over this holiday weekend. I do not believe I am far off from a quality dope with either of these powders. I really wish Hornady and others would add 300 BLK to their pistol loading data!