300Blk subsonic

[v0lcom13sn0w]

FYI guys, i just got my suppressor and have been reloading subsonic 300blk with excellent results... except for one thing... i dont have a chronograph. now before yall go sideways on me, i am no n00b to reloding and have done tons of research on 300blk subs... i decided i would work up my load from below starting charge(no brainer). i know its subsonic because there is NO sonic crack. maybe im being ignorant/wreckless/irresponsible for not having a chrono but i promise, i am going to get one.

Here's what i came up with:
Weapon: 10" Pistol Gas AR Pistol.
Primer: Winchester SR
Powder: 10.7-10.8gr Accurate 1680
Pill: Hornady .308 208gr BTHP Match
COL: 2.120"
Velocity less than 1100fps maybe 1050-1075fps?? it is subsonic for sure.

upon firing: super quiet thru thr SiCO hybrid, cycles 100% reliably, bolt holds open on empty mag.

**use my recipie at your own risk. always start with published data and work up your own load**



100 Rounds of Blackout Fits perfect in the Hornady box







^^ idk this photo wont delete. it keeps showin up every time i delete it.

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[Certaindeaf]

Nice. I think there's a thread here with a standing offer to run your data through their quickload program..
usually seems to come out pretty close

 

[Caveman Jim]

I'll subscribe to this thread as I'm building a pistol in 300 BLK & one day will have a suppressor.

 

[v0lcom13sn0w]

I'll subscribe to this thread as I'm building a pistol in 300 BLK & one day will have a suppressor.

they're fun man.

 

[Member 5605]

Make a trip to Albany and you can borrow mine. Get the app for Caldwell on yer phone and you can electronically log the data.

Break it you bought it.

 

[DizzyJ]

I'll subscribe to this thread as I'm building a pistol in 300 BLK & one day will have a suppressor.

I'm in the same boat.

 

[v0lcom13sn0w]

sorry. was using my AR pistol legally and trying to film at the same time.


video quality isnt so great either. looks good on my phone but not youtube for some reason

 

[v0lcom13sn0w]

here's another of my new suppressor attached to my glock 23.

unrelated to thread but just because:

 

[v0lcom13sn0w]

I'll subscribe to this thread as I'm building a pistol in 300 BLK & one day will have a suppressor.

hows your build going? are you doing a pistol length gas system?

 

[Caveman Jim]

hows your build going? are you doing a pistol length gas system?

I'll start into it this week since Ivery got all the parts & yes a pistol gas system on a 10.5" barrel. I need to.mill out my Noreen bullet lower with my new 5Dtacticle jig.

 

[DizzyJ]

sorry. was using my AR pistol legally and trying to film at the same time.


video quality isnt so great either. looks good on my phone but not youtube for some reason

Sweet.

 

[v0lcom13sn0w]

I'll start into it this week since Ivery got all the parts & yes a pistol gas system on a 10.5" barrel. I need to.mill out my Noreen bullet lower with my new 5Dtacticle jig.

ya man pistol gas is the way to go. i went with a 10" ballistic advantage barrel. i just posted a short vid of me shooting the blackout suppressed a couple posts ago. i was surprised. i dont even have the 7.62 end cap on this can yet. when i get it, it'll be even quieter than it is now.

 

[osprey]

With a 9" barrel using a 208gr amax it took 11.7gr of 1680 for me to get to 1050 fps. With an extra inch of barrel you probably gain 25 fps at most so I am guessing you are just below 1000 fps. But If they shoot accurate and cycle does it really matter if they are going 950 or 1050 fps?

 

[v0lcom13sn0w]

With a 9" barrel using a 208gr amax it took 11.7gr of 1680 for me to get to 1050 fps. With an extra inch of barrel you probably gain 25 fps at most so I am guessing you are just below 1000 fps. But If they shoot accurate and cycle does it really matter if they are going 950 or 1050 fps?

what is the overall length of your load?

ya its time to get a chrono.

 

[osprey]

RP brass
208 gr Amax
Cci 41 primer
11.7 gr A1680
2.250" col
1050 fps measured with magneto speed chrono.

Enough differences between our loads where if I were you, I would chrono yours before I changed anything.

 

[v0lcom13sn0w]

RP brass
208 gr Amax
Cci 41 primer
11.7 gr A1680
2.250" col
1050 fps measured with magneto speed chrono.

Enough differences between our loads where if I were you, I would chrono yours before I changed anything.

for sure! thank you for sharing! maybe me seating them to 2.120" is increasing my pressure a bit allowing them to cycle. im interested to see what the velocity is. i will chrono them as soon as i get a chance to.

 

[v0lcom13sn0w]

just bought a chronograph will post results hopefully this weekend

 

[v0lcom13sn0w]

ok guys i chronod my 300blk. avg velocity was 1047fps on a 30rnd testand my 40s&w is 930fps

looks like my load works just fine

 

[osprey]

You nailed it!

 

[B5Ben]

I just got into 300BLK so please bear with me as I figure this one out. I am starting some load development and am curious why all the subsonic loads I see are using 200+ grain bullets. I was looking at hodgdons online data and see some loads for lighter (110-150) bullets and running in the 1000 fps range using trail boss. I have never used TB for anything else but have some 147fmjs and 125 HPs that I think should work. I'm just curious why the bigger bullets get all the subsonic love when it appears that these might be ok as well.