300 Blk - 16" Too Much Barrel?

['88Scrat]

I have a Sig MCX Virtus Patrol (the rifle length one) that long ago I swapped out the 5.56 barrel for one in 300 Blk because I thought it would make a good hog gun.

However since making the conversion I have yet to even pull the trigger on it, my SCAR 17 is my primary hog gun now.

My question is simple, do you think that having a 16" barrel on a 300 Blk AR is a bad setup?

Please disregard my ignorance, I've always been more of a milsurp guy and only in the last couple of years have REALLY delved into the modern stuff.

 

[rickyrick]

It’s not bad, I recently converted a 300aac pistol into a carbine just to get rid of the AR pistol legal specters that are hanging around.
My understanding is that the powder burn is complete long before 16 inches of barrel on the caliber.
With the 16” barrel you aren’t really gaining anything but legality. I’ve noticed that unsuppressed, it’s still a pretty quiet rifle especially with subs.

 

[MarkCO]

A 16" barrel in 300 BO with pistol length gas is kind of a waste. Like rickyrick said, and you will actually have lower velocity with some sub loads from a 16" than an 8 or 10 inch, but still pretty quiet.

Now, a 16" with mid-length gas...hard to get to run most subs, but you can shoot supers from it and it is a very viable out to a few hundred yards on pigs and deer. 125 Pro-Hunters from Sierrra, over 2400 fps without much effort. 110s are over 2500 fps. Run those same loads in a pistol gas 16" barrel, and you will have issues for sure.

 

['88Scrat]

I'm pretty sure the MCX has a carbine length gas system. That said it's a piston system so maybe it's a moot point.

 

[MarkCO]

I'm pretty sure the MCX has a carbine length gas system. That said it's a piston system so maybe it's a moot point.

Carbine is still too short for a 16" 300BO. Piston or DI. Not a moot point at all.

 

[HiBC]

Weigh your options. Unless its a pure,squeaky clean AR pistol with no features the BATF does not like (like a hand stop) a barrel shorter than 16 in puts you in BATF Short barreled rifle territory. "Pay tax and register or go to jail"

Ballistic efficiency may not be the #1 priority factor.
Folks here gave you good info/ feedback.

What choices do you have? Sort through the "Yeah,buts" and the "Gosh dang its" and pick the least imperfect option.

SCOTUS may decide to "tune up" the BATF power to change definitions and rules.But I would not hold my breath.

We have to deal with this moment. Now,one way to place it...

How do you feel about the M-1 Carbine? IMO,nice gun. They are kinda pricey.

I figure I could build two "cheapo" 300 BLK 16 in carbines for the going price of an M-1 carbine. ($1200/$1500 ) Ballistically,pretty close. Maybe the edge goes to 300 BLK.

I have a baby chop saw to cut the brass(see youtube) and a power case trimmer. For me, the 300 Blk has a very small advantage brass wise. 30 carbine brass can be hard to find. Starline is back ordered .Once fired?

Would I focus on building a pistol gas 16 in 300 BLK from scratch ? No. Its an escape from the AR pistol fiasco.
But still, a rough equivalent to an M-1 carbine is turning a lemon into lemonade.

You might try shooting it.

 

[taylorce1]

I like .300 BLK, still have a 7.5" AR pistol and it's pretty handy for using from a blind. I have a suppressor and that's the main reason for keeping a pistol. I wish it was more accurate, but that's mainly the RDS that I'm using.

I also have it in a Ruger American Ranch, this is my favorite way to shoot subsonic ammunition. With my suppressor it's no louder than a springer air rifle. It's way more precise than my pistol as well.

That said I've only shot one deer with each firearm. I used supersonic ammunition in both situations. I chose to use supers because I feel the bullets work better than the sub ammunition I tried. I do have some 190 grain Hornady SubX bullets to try this year. Hoped to use them last year but canceled my hunt because of a positive test for COVID. One of the guys I would have been around had just finished chemo, I didn't think I needed to be around.

All that said, the only reason I shoot .300 BLK is because I have a suppressor. The reason I got a suppressor is because I have the .300 BLK. I had the Ruger rifle for about a year before I got a suppressor, I even thought about selling it several times after I put my suppressor in jail. I'm glad I didn't as suppressed is where the cartridge really shines.

I have an M1 carbine and the .300 BLK is way more versatile and far out performs the carbine. There just isn't options with the .30 carbine round, 110 grain FMJ, HP, or SP is about it anymore. The .30 carbine just can't be as versatile.

 

[rickyrick]

I really liked my 300bo when it was a pistol. I turned it into a handy little carbine, so far. It had reliability issues at first trial with a 16” barrel, it was double feeding. I interpreted that as being over gassed. I added a couple of tungsten weights to the buffer and it seems to have corrected the issue. Trust in it is not 100% yet. I think a few more magazines run through it will solidify my trust.

I kept the caliber because I figured it was still a viable cartridge on par with the 7.62x39 and will perform well at short range. With the 16 inch barrel the, gun it’s quieter than a handgun even with supersonics. With subsonic it’s just a mild pop. So it has some of the noise reduction benefits even without owning a suppressor.
Ammunition is wildly available and outside of the barrel, parts for the entire action are standard AR15.
I think it’s and easy and inexpensive way to get an AR in a different flavor, especially if you aren’t looking to take down a gazelle across a savanna.

Now if I didn’t live in a dense southern forest, I might have taken the receiver in a different direction. But this actually suits my needs very well.