How short is too short?

[Lrreloader]

I am torn on cutting stock and not into "rail" guns but I got the donor cheap enough so what the heck

 

[waspocrew]

One thing that may dictate how short you can go will be your suppressor - make sure it's rated for 300 BLK at 5".

 

[Lrreloader]

It's rated for .30cal magnum but good point I will look into that thanks

 

[Rflshootr]

I have also looked into getting a boyds thumbhole stock with correct spacing and cut stock off behind grip, sand and blend

It seems that the grip would be too far back, on the wrong angle and would probably be like shooting a sawed-off shotgun with a pistol grip. Look at a pic of one and compare the grip to a striker grip.

 

[Rflshootr]

I am torn on cutting stock and not into "rail" guns but I got the donor cheap enough so what the heck

I have an old saying..."whatever blows yer skirt up"....go for it if that's what you want. You only live once.

 

[dogbuster0006]

9" barrels are what the 300blk was originally built for I believe. If you've got enough twist rate to get the bullet one full rotation that should be enough.
1/8 you'd need 8"
1/9 you'd need 9"

 

[Lrreloader]

Thank you the barrel blank is 1/7 but I could look into 1/5

 

[Rflshootr]

I haven't looked into it, but what would you expect the velocity and ft/lbs of energy would be on a 5" barreled Blackout with subsonic loads?

Edit...I just found this info...

NEW: Sierra Bullets .300 AAC Blackout Reloading Data -

Sierra Bullets has updated .300 AAC Blackout reloading data to include sub-sonic information and a broader bullet selection.

www.thefirearmblog.com

 

[nksmfamjp]

I'm not a suppressor person at all, but my long range pistols are all 14-15" barrel built on the relatively short contender platform. I find that a good length for putting it on a rest. Any shorter and it will be hard to rest.

so, with a 6" suppressor, that would be about 8" barrel….

 

[squirrel_slayer]

Being manually operated I'd definitely look to faster powders. I know red dot is popular for bulkiness but if you have TB that's probably as good or better. 7 twist should be plenty fine. 5" should get you close to 1k ft/sec with that bullet using a powder like red dot. Trail boss was way slower before case fill became an issue.

Below is a quick snip of some red dot with said bullet. Going with a 7" barrel will maximize velocity at sane pressure levels with said powder. 6" might split the difference and keep you out of that transonic threshold. If you spinning up your own tube you could always start longer and see how it does then chop down till your happy then thread/suppress it.

At the end of the day 1k ft/sec is 1k ft/sec. It doesn't matter if its a 5" barrel or 16.5" barrel the external ballistics are the same.

Good luck and be sure to post pics of the build/kills

 

[purpledragon]

JMHO........... For powder in this scenario I'd use Re#7 or 1 of the 4198's...

 

[Lrreloader]

Finally got a barrel green mountain 1-7 twist
Did a little mock up, thinking I can open up the stock enough to drop the bull barrel down in, cut and threaded to just clear the end, add sig quick change muzzle device, and consider adding pic rail to the bottom of forearm. Thinking about a Manners style sponge paint scheme paint job to stock and possible cerakote on all metal.

Whatcha all think?

 

[Revolting Peasant]

As stated above, make sure to confirm your suppressor is rated for that short a barrel.
After the build, confirm your bullet is stable when exiting the muzzle before you attach your suppressor. Shoot paper at close range and look for oblong bullet holes indicating yawing.
Short short barrels and subsonic can lead to baffle strikes if the bullet isn't stable.
Keep us updated! Good luck.

 

[Lrreloader]

Suppressor rating is not an issue, thanks for the reminder about checking stability!