300BLK - Bullet / Powder Suggestions

capreppy

capreppy

Sergeant
Full Member
Minuteman
Aug 18, 2011
384
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Princeton, TX
#1
Looking to build a 10" 300 BLK that will be run primarily suppressed. Trying to find a bullet / powder combination that would be best out of a 10" 300 BLK barrel. By best, what I'm looking for is
- clean burning
- actually subsonic

Bullets and Powder are coming back online (mostly) so getting it isn't my concern.

I'll likely pick up virgin Starline 300 BLK brass (seems about the only one available currently) OR do I pick up 223 brass that has been formed to 300 BLK? Obviously it requires a lot to mix up 300 BLK from 223, but I'm also one to prefer my headstamp say what it is.

I have tons of SRP and some SMRP (wolf magnums).
 
#2
Lots of data out there for this. Check out Johnny‘s reloading bench on YouTube he’s got quite the series on the 300 blackout. I think the go to powder is Winchester 296 or Hodgdon H110. Pretty much with any bullet you want. I have experience with VV N110 and I’ve had success using that with Nosler 110 grain Varmageddon bullets and the sierra 110 hollow points. Lil gun has been pretty good too. Gets the velocity up there. Groups good too but ES numbers leaves some to be desired.

Also tried some IMR 4227 as well to load up some subsonic rounds using 220 SMK’s and those were great. There’s really a lot combinations you can play with, just all depends on what you’re looking for and what’s available for you at the time. I definitely plan on picking up more VV N110 as I really like that stuff. But I’m also going to stop avoiding what is working for everyone else and just pick up some Winchester 296 or H110 which usually available places frequently.
 
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#4
patscrazy said:
Lots of data out there for this. Check out Johnny‘s reloading bench on YouTube he’s got quite the series on the 300 blackout. I think the go to powder is Winchester 296 or Hodgdon H110. Pretty much with any bullet you want. I have experience with VV N110 and I’ve had success using that with Nosler 110 grain Varmageddon bullets and the sierra 110 hollow points. Lil gun has been pretty good too. Gets the velocity up there. Groups good too but ES numbers leaves some to be desired.

Also tried some IMR 4227 as well to load up some subsonic rounds using 220 SMK’s and those were great. There’s really a lot combinations you can play with, just all depends on what you’re looking for and what’s available for you at the time. I definitely plan on picking up more VV N110 as I really like that stuff. But I’m also going to stop looking else and just pick up some Winchester 296.
Click to expand...

Thank you. I've tried looking, but the challenge I'm having is that the load data I'm finding is for 16" barrels. And some of those recipes don't do well with 10" barrels.

I assume 220 SMK's and H110 is a "go to" combination, but trying to see what else is out there. I'm likely to pick up an 8# jug of H110 as I need to load some 44 Mag rounds as well and I'm one to buy in bulk where possible.
 
#6
My sub load is 1680 with 208 amaxs. Don’t remember the actual charge but I’m pretty sure it’s sub 10 grains. I’m running 8” suppressed. Very quiet and decent accuracy. I loaded up 500+ rounds years ago and then stopped shooting 300blk after building a 9mm AR shootin my subs.

My super loads where 110 Hornady SP with h110

If I ever get back into the 300blk I would go with the plated bullets since it’s a waste to be burning up match bullets just to blast
 
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#7
VV Powders is what you want it you plan to do clean subsonic.
Depending if your gas port you might be able to do N110 or even N105. Otherwise N120 will cycle everything, just going to be a bit louder. Keep in mind that it’s all about the balance between the gas port and the bcg weight and the buffer. A really good investment is a JP SCS with the different weights and springs.

AA #9 is also a clean fast burning powder. It’s a little bit on the fast side for burn rate but if you can make it work with AA #9 you’re golden.

LilGun/H110/W296/IMR4227 not a bad choice for American powders.
They’re all better than 1680.

1680 will cycle everything but it’s loud and dirty.
 
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#8
I like AA1680 under a 208 gr hornady bthp. I'm loading 11.4 grs in Lake city cases with cci 41's. Barrel is 7.5". I haven't had a chance to shoot them suppressed yet, but mv is 1050-1075. You might need to back that charge down just a little with your longer barrel, to stay subsonic.
 
#10
Seekins 8”
Magnetospeed V3
69 F 28% 30.07 in

Hornady 190 Sub-X
A1680 12.5
205M
New Starline brass
BTO 1.680
1146, 1093, 1142, 1099, 1094
1” @ 50y

Berry’s 220 gr .300 Blk SP
A1680 12.4 gr
205M
New Starline brass
BTO 1.6620
1082, 1081, 1081, 1062, 1079 SD 8.4
1” @ 50y (4 shots 0.75”)

B60F6BE2-209D-4586-BFF8-B9CD0AEDDE8C.jpeg
AA38F1F8-F4C7-4A1C-B7FC-4ADEC69E0381.jpeg
1A6BECF1-EA6B-4985-9B35-9ECDE2BCF020.jpeg
 
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#14
padom said:
CFE Black and 220smk out of my 10.5" have been stupid accurate and stupid quiet. Had someone at the range ask me if I was shooting a nail gun when I was confirming my load 2 months ago. Lmfao




Click to expand...

Were the pictured targets shot suppressed? I just got my can last week, and want to try my loads, but the last time out with mine, I was not getting clean holes. They were not keyholing, but I was getting slight tears and smears. The mv is where I want it, and the barrel twist should be fast enough for 208gr bthp's, but I don't want to ruin a brand new can.

I'm gonna go back and shoot them at 50 yds unsuppressed again and see what the targets look like.

Should have mentioned. my bbl is 7.5", 1-7 twist.
 
#15
NCHillbilly said:
Were the pictured targets shot suppressed? I just got my can last week, and want to try my loads, but the last time out with mine, I was not getting clean holes. They were not keyholing, but I was getting slight tears and smears. The mv is where I want it, and the barrel twist should be fast enough for 208gr bthp's, but I don't want to ruin a brand new can.

I'm gonna go back and shoot them at 50 yds unsuppressed again and see what the targets look like.

Should have mentioned. my bbl is 7.5", 1-7 twist.
Click to expand...

As mentioned on the target yes....Rugged Surge 7.62
 
#16
db2000 said:
Mine loves 125 TNT’s but Hornady 150 ILSP’s have better ballistics and pretty decent accuracy for hogs.
View attachment 7898960
Click to expand...

I've been shooting 125 TMK supers for years out of this gun. 100% hit rate on steel out to 500M....ballistics are excellent. Same bullet Black Hills uses on their 125 300blk defensive ammo...

The 125 SMK is just as accurate but strictly for target shooting. They don't expand for shit...I did some expansion testing in water and in wet phone books covered in denim....100% intact just bent like a banana.... the 125 TMK on the other hand opens up like a Federal HST


here is first rounds out of this barrel breaking it in with 125 SMK before starting load development. Started top left and shot left to right moving down to next row then bottom row.. you can see how it really tighten up at the 25rd mark...










Here my 125 TMK H110 OCW I shot after breaking it in with the above target





Here a 7x5 125 TMK H110 final load confirmation test.


 
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#17
....many, and I mean MANY answers can be found here: https://www.300blktalk.com/forum/

Cans are verboten in my locale so it's all speedy's for me. LilGun w/TNT 125's primarily, economical, accurate and RELIABLE.

Have used H110, W296, 300MP, 4227, 5744, #9, all good...

Have used 125 SMK, 115 Brgr FB (accurate as hell but $$), Hdy 125 SST, Hdy 123 AK Vmax (both "as is" and resized to .308 w/Lee bullet sizer), Hdy 110 Vmax, Hdy 150/155 FMJ, Nosler 110 VGdn, Speer 110, M80 150 pulls, all good...

Have used CCI 400, 41, Tula KVB, Wolf, all good...

Tubes used 10.1" pistol gas, 9" pistol gas & 16" carbine gas, all good..

Brass, I converted RP, LC, WCC, Hdy, GECCO, Japanese SDF....hell, just about every brand. I quit converting and just started buying brass from John Bowman of Carolina Brass, all converted 1X fired LC....SUPERB brass, never an issue.

It's a versatile cartridge....
 
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#18
padom said:
I've been shooting 125 TMK supers for years out of this gun. 100% hit rate on steel out to 500M....ballistics are excellent. Same bullet Black Hills uses on their 125 300blk defensive ammo...

The 125 SMK is just as accurate but strictly for target shooting. They don't expand for shit...I did some expansion testing in water and in wet phone books covered in denim....100% intact just bent like a banana.... the 125 TMK on the other hand opens up like a Federal HST


here is first rounds out of this barrel breaking it in with 125 SMK before starting load development. Started top left and shot left to right moving down to next row then bottom row.. you can see how it really tighten up at the 25rd mark...










Here my 125 TMK H110 OCW I shot after breaking it in with the above target





Here a 7x5 125 TMK H110 final load confirmation test.


Click to expand...

Dom: Is this still your Rainer Ultra match barrel? I’m looking to build one currently. I definitely want something good for 400-500 yards for the supers. Yours is 10”, correct? What brass are you running?
 
#19
Lunchbox27 said:
Dom: Is this still your Rainer Ultra match barrel? I’m looking to build one currently. I definitely want something good for 400-500 yards for the supers. Yours is 10”, correct? What brass are you running?
Click to expand...

Yes it is. Gen 1 (shilen).....they don't make anymore....I also tested their Mod2 ( Criterion) and it Shot just as good with my same 125 loads....Craddock makes the Mod2's for them.....


www.rainierarms.com

Rainier Arms Ultramatch MOD2 300BLK Barrel - 10\

Rainier Arms Ultramatch MOD2 300BLK Barrel - 10\
www.rainierarms.com www.rainierarms.com
 
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#23
padom said:
Yes it is. Gen 1 (shilen).....they don't make anymore....I also tested their Mod2 ( Criterion) and it Shot just as good with my same 125 loads....Craddock makes the Mod2's for them.....


www.rainierarms.com

Rainier Arms Ultramatch MOD2 300BLK Barrel - 10\

Rainier Arms Ultramatch MOD2 300BLK Barrel - 10\
www.rainierarms.com www.rainierarms.com
Click to expand...

What do they mean: 'Ships from Distribution Facility"? Does it mean not in stock?
They ever put barrels on sale?
 
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