[william]

I am getting ready to load 125 gr Hornady Match .308's for this 10.5" and only find loading information for 16" barrels. While i have been shooting store bought, which functions, I would like to start tuning for accuracy. Any and all help will be appreciated.

ALSO, I realize that reloading is a dangerous activity and that I am at risk using someone else's data. I will look at your suggestions and take the responsibility for my own safety.

Thanking Everyone in Advance

William

P.S. Sifted though the archives and didn't find anything, so if you do, please post a link. ty

 

[Czechbikr]

I'm in to watch...my 300 BLK pistol is also a 10.5". I've loaded primarily 150 grain FMJ so far.

 

[Yissnakk]

If you're doing 125gn projectiles, then just standard load data is fine. As for tweaking the load, there are so many factors that can be tweaked and each is unique to the gun you are tweaking for. Since I have 2 .300BLK pistols (10.5" and 11.5") I go for middle of the road with loads that work well in both for plinking around. If you are looking to really wheedle on your loads and run for straight accuracy, you'll need to play with seating depth - some gun like some bullets to have a longer jump to the lands and others like to be up close and personal; some are more accurate with tighter neck tension, some just like on particular bullet. There are even accuracy gains to be had with certain types of primers. As for powder loads (which is the main place I concentrate due to no time to fiddle around with the other stuff!) I go as much as a grain or two below the minimum published load and walk my way up to max in .2- .3gn increments to see where accuracy can be found.

The two main areas that I've found that impact accuracy the most are in seating depth and powder charge though.

 

[Yissnakk]

I am getting ready to load 125 gr Hornady Match .308's for this 10.5" and only find loading information for 16" barrels. While i have been shooting store bought, which functions, I would like to start tuning for accuracy. Any and all help will be appreciated.

ALSO, I realize that reloading is a dangerous activity and that I am at risk using someone else's data. I will look at your suggestions and take the responsibility for my own safety.

Thanking Everyone in Advance

William

P.S. Sifted though the archives and didn't find anything, so if you do, please post a link. ty

What powders do you have available? Completely forgot to ask that

 

[olfarhors]

HMM?
OK so you are wanting to load standard loads form a 10.5 Blackout then?
see the reason that i ask is that i intentionally got a 7.5 inch to load it subsonic for house use.
so I can be of little help to you in that super sonic area except to mention that i woulsd start at listed loading levels for the full size weapon and work from there.
accuarcy from mine with 208, 200,220 and 240 grain projectiles out to 25 yards (intended use range) has been excetionally good.
the only real problems that i encountered was getting the bolt to lock rearward on the last round. a little tweaking by a .02 grains and all that went away.
I am right at 11.3 Gr of Accurate 1680.
those are 20 round groups and the weapon uses a Red Dot non magnified sight.
enjoy, I love the round myself.

 

[stupimlico]

I just start with a load whether it's for 16" or for 10.5" and go from there. Since you are trying for accuracy and not subsonic you should be fine.

I did 17 grains of lil' gun with 125 grain sst's and had good results. That's the minimum charge and I never got the opportunity to work up any.

Sent from my SM-G960U using Tapatalk

 

[william]

The rifle powders I have available that have been mentioned for 16" barrels are: H 110, AA #9, 2400, H 4227, H4198. I also have other rifle powders; Accurate 1680, Accurate 2230, CFE 223, Varget, W760, H 4831, H 380, H 450, IMR 4895, IMR 4821, IMR 4320, IMR 4064, and Reloader #7, on the shelf

I was thinking that through a 10.5 I might want to move to a slow pistol powder, which is where I hit the brick wall. Pistol powders on the shelf; Blue Dot, Red Dot, Unique, VV 3N37, VVN350, VVN340, W231, Bullseye, Power Pistol, CFE Pistol, HP 38, Hi Skor 800X, Titegroup, Long Shot, HS 6, Accurate #7.

So that's what I've got to work with.

 

[Yissnakk]

The rifle powders I have available that have been mentioned for 16" barrels are: H 110, AA #9, 2400, H 4227, H4198. I also have other rifle powders; Accurate 1680, Accurate 2230, CFE 223, Varget, W760, H 4831, H 380, H 450, IMR 4895, IMR 4821, IMR 4320, IMR 4064, and Reloader #7, on the shelf

I was thinking that through a 10.5 I might want to move to a slow pistol powder, which is where I hit the brick wall. Pistol powders on the shelf; Blue Dot, Red Dot, Unique, VV 3N37, VVN350, VVN340, W231, Bullseye, Power Pistol, CFE Pistol, HP 38, Hi Skor 800X, Titegroup, Long Shot, HS 6, Accurate #7.


So that's what I"ve got to with.

I've worked up loads using the marked powders. I've also concentrated mostly on getting subsonic heavy bullets to cycle and be accurate in mine. I found that IMR4227 (really close to H4227, which I believe has been discontinued) provided good accuracy using 123gn fmj's and a 15.7gn charge - this was the listed minimum charge.

My primary focus with .300 BLK had been to shoot as cheaply as possible so I've done a bunch of .223 ==> .300BLK case conversions and have been concentrating on polymer/hi-tek coated lead cast bullets - SNS Casting 158gn 30-30 bullets, and 195gn+ coated lead bullets so I'm afraid I don't have too much workable info for 125gn fmj's but as I said before: loading supersonics isn't a real challenge and it's really just a matter of fiddling with the listed to get the accuracy dialed in. I've had good results (in general) with A1680, CFE BLK, W296 (the same thing as H110) and IMR4227. BlueDot works okay but I got really variable accuracy out of it - I only fired coated lead bullets with BlueDot though.

Sad thing is that I still have about 200 rounds of test loads that I need to run across the Chrony, including AA11FS, which is supposed to be the new hotness for all things 300BLK...

 

[william]

I've worked up loads using the marked powders. I've also concentrated mostly on getting subsonic heavy bullets to cycle and be accurate in mine. I found that IMR4227 (really close to H4227, which I believe has been discontinued) provided good accuracy using 123gn fmj's and a 15.7gn charge - this was the listed minimum charge.

My primary focus with .300 BLK had been to shoot as cheaply as possible so I've done a bunch of .223 ==> .300BLK case conversions and have been concentrating on polymer/hi-tek coated lead cast bullets - SNS Casting 158gn 30-30 bullets, and 195gn+ coated lead bullets so I'm afraid I don't have too much workable info for 125gn fmj's but as I said before: loading supersonics isn't a real challenge and it's really just a matter of fiddling with the listed to get the accuracy dialed in. I've had good results (in general) with A1680, CFE BLK, W296 (the same thing as H110) and IMR4227. BlueDot works okay but I got really variable accuracy out of it - I only fired coated lead bullets with BlueDot though.

Sad thing is that I still have about 200 rounds of test loads that I need to run across the Chrony, including AA11FS, which is supposed to be the new hotness for all things 300BLK...

:hand2: Thank You for the information

That's more information than I had after 4 hours of interwebz. Your results with Blue Dot reflect my own with 357 Sig, 10 mm and 9 mm calibers, both with accuracy and velocity.

 

[Yissnakk]

:hand2: Thank You for the information

That's more information than I had after 4 hours of interwebz. Your results with Blue Dot reflect my own with 357 Sig, 10 mm and 9 mm calibers, both with accuracy and velocity.

Yeah, nobody seems to have any info on Bluedot. I have a couple of lbs of it, just looking for a use, since I've replace it for all pistol applications by more effective powders - got it back during the great powder shortage of 2014 when it was all that was available.

300BLKTalk had a couple of mentions of it - one guy claiming to get good subsonic performance with it and 235gn Missouri bullets but after trying all sorts of tricks, I decided that he was exaggerating - could not get it to cycle at all and remain under 1100 fps

 

[william]

Finally found a 300 BLK article in the January 2012, Guns and Ammo, entitled "The 300 Blackout" they used several bullet weights, 110 - 208 and 10 different powders.

So it's off to the reloading bench for me.

 

[JStacy]

If you look up 300 Whisper , basically same case as 300BO , you can find a lot of loading data for the Contender 10" barrel. The difference in velocity between a 10" and 16" is minimal due to the efficency of the 300BO. I have always had good luck with H110 and WW296 for that case . 18.5/H110/125 Sierra SP grouped in 1/2--3/4" range from my Contender . Like everything else work up your loads slowly and you will find the sweet spot where your gun groups the best. I have a Ruger American Ranch rifle and it likes the Remington 120 OPE loads and shoots them less than 1" at 100.

 

[Yissnakk]

Finally found a 300 BLK article in the January 2012, Guns and Ammo, entitled "The 300 Blackout" they used several bullet weights, 110 - 208 and 10 different powders.

So it's off to the reloading bench for me.

The Hodgedon reloading site has good 300BLK data, as does the Accurate Arms site - they even have a downloadable PDF.

 

[olfarhors]

The Hodgedon reloading site has good 300BLK data, as does the Accurate Arms site - they even have a downloadable PDF.

yep several of the powder companies have issued updates that cover the 300 Blackout since its becoming more popular.
I have been using ACC 1680 but am going to try the new ACC 11FS, it is suppose to build pressure a bit faster and that's what I am looking for in the 7.5 barrel.
ACC 1680 is working fine for me now that I have it tuned in though.--this is all sub sonic loads.

 

[Yissnakk]

yep several of the powder companies have issued updates that cover the 300 Blackout since its becoming more popular.
I have been using ACC 1680 but am going to try the new ACC 11FS, it is suppose to build pressure a bit faster and that's what I am looking for in the 7.5 barrel.
ACC 1680 is working fine for me now that I have it tuned in though.--this is all sub sonic loads.

I've actually gotten a bit better results out of mine with IMR4227 but only a little

 

[Airgatorck55]

My 16” and 10.5” both like Lilgun and 120gr Barnes TacTx or 125gr Hornady SST pills. The Lilgun works well with the 147-165gr bullets as well. Lilgun is supposed to give higher velocities with lower pressures than H110. Start mid/low range of posted loads and work up. I never made it to max loads as I stopped when I got the groups I was after. 👌 The 8 pt I shot with the TacTx earlier this season never knew what hit him.

 

[Airgatorck55]

I also had very good results with 2400 and IMR 4227. Extremely good accuracy but not quite the velocity and in the case of the 300blk and bullet expansion with the bullets I’m using you need as much velocity as accuracy will allow which I found to be in the mid to upper range of published load data for Lilgun. Made for some scary accurate ammo.

 

[Yissnakk]

I also had very good results with 2400 and IMR 4227. Extremely good accuracy but not quite the velocity and in the case of the 300blk and bullet expansion with the bullets I’m using you need as much velocity as accuracy will allow which I found to be in the mid to upper range of published load data for Lilgun. Made for some scary accurate ammo.

That's where the fork in the road comes with 300 BLK - either velocity and accuracy or sub sonic and accuracy which adds a whole new dimension to the equasion - is it sub sonic? Is it accurate? Does it cycle the gun?

I generally have a lot of fun working on these types of issues.

 

[CJS3]

Best results I've had are with 18 gr. of H110 pushing Sierra 125HP. I've also used 17.5 gr. of IMR4227 on the same bullet. That's with a 10.5 inch barrel.

 

[GreenWolf70]

My only concern about slow powders with a 10.5" barrel would be unburned powder, which is usually not a concern with the .300BLK. I would start with the H110 you have and go from there. If you get any unburned powder or any flame, drop to Lil Gun, 2400 or AA#9. Most of the slower powders are going to be compressed loads if you want to try those. If your load is overgassing (cycles the action roughly), an adjustable gas block can tame that.

Just remember, Max SAMMI is Max SAMMI, regardless of barrel length.