Subsonic 300BO

[orbitup]

Thanks for the data. What's your 308 Trail Boss load? Did you enlarge the flash holes or use magnum primers?

Sent from.... RIGHT BEHIND YOU!

 

[orbitup]

LC converted brass
Blackout Bullets 220gn HP
H4198 10.6gn
OAL 1.96

814
883
861
883
822
ES-69
SD-32

I guess this load just need to be faster. Should I decrease the OAL or increase the powder? Should I try adjusting the formula with another powder?

I've loaded up some more loads with the 150gn but I want to play with this 220gn also.

 

[KiloKilo]

I don't use cut down .223/5.56 brass, I stick with 300BLK brass for consistency. If SHTF and I needed brass I am setup to cut down .223, but that would be the only time.
I use only CCI 400 for my 300BLK.
The problem with Trailboss and a 208gr AMAX is that in order to get the bullet to a point where it will reliably stabilize, you end up with a compressed load.
Your H110 with a 208gr A-Max loaded with 8.6gr at COL 2.180 should get you right around 1062fps with a 90% burn rate and a 56% case fill.
The 4227 with a 208gr A-Max loaded with 8.8gr at COL 2.180 should get you around 1064fps with an 85% burn rate and a 67% case fill.

I ran those based on a 16" barrel. I have not loaded these myself so don't know how they will cycle.

Thanks for the info Flashbang...........I am shooting thru a 16" barrel as well.
KK

 

[orbitup]

I loaded up some 150gn with Red Dot, Trail Boss, and Unique. I'm thinking about trying the 220gn with Unique also.

It lloks like I'll have my chrono set up at Hicksville next weekend.

 

[Younggun]

Can I shoot it?

 

[orbitup]

Can I shoot it?

My chronograph? No!

 

[Younggun]

Jerk

 

[BIGPAPIGREG]

Jerk

see sometimes it is better to ask for forgiveness than it is to ask for permission, just sayin....

 

[KiloKilo]

I failed to mention that the 155 gr Hornady BTHP have a canalure....should I crimp for the 300BO or not ? I'm not looking to load these for subsonic because I don't think I could get a sub load that would cycle the AR....
If it is not a good idea to crimp for the 300, then I will save these pills for the .308.
Thanks,
KK

 

[orbitup]

I don't think a little crimp will hurt. I had to get a crimp die because I had to flare the cases to get flat base bullets in.

I don't know about enybody else but I am getting a lot of neck tension. I had to pull some AMAX bullets and they took a few really hard whacks to get out.

 

[KiloKilo]

Orbitup.......are you getting your chrono's with the suppressor on/off or both ?

 

[orbitup]

I don't have the can yet. Just trying to get ready for it.

 

[KiloKilo]

Okie dokie.....thanks. I'm thinkin' 'bout gettin' speeds both ways = more trigger time.....which is a good thing.....hah hah.......
KK

 

[FlashBang]

Thanks for the data. What's your 308 Trail Boss load? Did you enlarge the flash holes or use magnum primers?

Sent from.... RIGHT BEHIND YOU!

10gr of Trail Boss works good with a 208gr A-MAX. I do not enlarge the primer hole or use magnum primers... there is no reason to.
.

 

[FlashBang]

I guess this load just need to be faster. Should I decrease the OAL or increase the powder? Should I try adjusting the formula with another powder?

I've loaded up some more loads with the 150gn but I want to play with this 220gn also.

I like to push my rounds around 1040-1080, but will go up to 1100 depending on elevation/weather/etc.

 

[FlashBang]

I loaded up some 150gn with Red Dot, Trail Boss, and Unique. I'm thinking about trying the 220gn with Unique also.

It lloks like I'll have my chrono set up at Hicksville next weekend.

Unique is dirty... it is often referred to as flammable dirt.

 

[FlashBang]

If you are new to loading subsonics, one piece of sage advice that was given to me is: anytime you are trying a new subsonic load out, fire one round from 10 feet into a clean target without your can on. Look at the hole it makes and ensure it is a clean and round hole. If it is jagged or key holed, do NOT fire the rounds through your can. I follow that advice with any new subsonic load I am experimenting with. And knock on wood, I haven't had a baffle strike yet.

.

 

[FlashBang]

Here is a fun subsonic round I use in one of the Mosin Nagant custom rifles I built.

Cartridge : 7.62 x 54 R Russ.Nagant
Bullet : .308, 208, Hornady A-MAX 30712
Cartridge O.A.L.: 2.820 inch = 71.63 mm
Barrel Length : 16.0 inch = 406.4 mm
Powder : IMR TrailBoss
63% fill with 100% burn pushing the round at 1062fps.

Started out with a Chinese T53 Mosin Nagant, cut it down to 16", cut and threaded 5/8x24, stripped to the white and Duracoated, custom bent bolt and mated to the Archangel Mosin Nagant stock with a Timney trigger and a Nikon 4x16x40 scope.

 

[orbitup]

10gr of Trail Boss works good with a 208gr A-MAX. I do not enlarge the primer hole or use magnum primers... there is no reason to.
.

What barrel length/twist?

 

[FlashBang]

What barrel length/twist?

Savage 11/111 Hog Hunter... 20" 1 in 9