Building me a new AR-15 upper. I’m on the fence about a 13.9 with a pin and weld to make it rifle length or my other want is a 11.3 sbr or pistol. Talk me in the right direction and why. 5.56/.223
Guidance on barrel length
- Thread starter Dave550
- Start date
I would do 6.8spc if you are going that short. Barrel length doesn't have extreme effect on velocity like it does on a 223 or 556. But I know that ammo price and availability can be an issue sometimes. I will do short barrel rifle just because of the versatility and I really don't like the way pistols look. It's kind of like the bastard AR-15. I would do the 13.5 or 14 5 with the pin and welded muzzle brake. With the collapsed stock that's really good and short for new maneuverability but you also get to keep your velocity up and and probably have an easier time with gassing. It's totally up to you. There is a way to do everything and work it out. One thing with a little longer Barrel like that is you can hunt with it be a little more effective a little more accurate be able to get out there a little further. That's just my view on it but it's not my rifle.
I have a 14.5 with a short muzzle brake on it so it comes out to right at 16 in. It's in a 6.8 SPC. With the stock fully collapsed it's really nice and maneuverable around the house and I think it's the perfect length. Son-O-guns are loud though with that V6 two port brake on it. Holy Moses it's a ear popper. If the gun doesn't scare them off the noise will get their attention. Especially the 6.8. Nobody like to shoot that gun after they decide to shoot it when there is no ear protection around. All I do is turn my head and clamp my ears as hard as possible. 
Reminds me that short barrel rifle Val Kilmer was shooting in the movie Heat. It was noticeably louder than the other guns. Then I had about 30 to 50% somewhere in there more concussion and then you have a 6.8spc.
20” cause it vibe checks anything!
Don't get me wrong I'm not trying to say that the 5.56 it's not loud. It's just that shorter Barrel with the muzzle brake I have on it that's got two ports on each side of it when it's fully collapsed it's so close to your face it just makes it sound so much louder than just a standard flash suppressor on a 16-in barrel.
I think a pinned 13.8-9 is a very handy all around rifle
Yeah it is loud but it has the same kinetic energy at 200 yards as the 5.56 does at the muzzle. POWER, I LOVE IT....
I know going to a different caliber is a huge expense especially if you have stocked ammo. I have been building 6.8spc rifles and stocking 6.8 ammo for almost 10 years so it easy to recommend but hard to commit too late in the game. Unless you have the money to buy or build one and then just start ordering bulk ammo.
More on barrel length, I have a 6.8 with a 14.7 inch Wilson Combat S2W ( strength to weight ratio ) barrel. It has a V6 300 black out muzzle brake that's like 1.5 inches. So it's just a hair over 16 total. I think that's the perfect length barrel.
I know I am referencing the 6.8spc but other than the velocity and caliber the length and handling characteristics of the over all rifle should apply to each equally. I just have more 6.8's than 5.56/.223 guns. So just apply info to your caliber.
As you can see in the pic the 14.7 inch barrel with the 1.5 inch muzzle brake is a total of right at 30 inches. If you were going with a 12 inch barrel the only difference would be 4 inches. Not a whole heaping load of a difference when considering velocity drop and reach out and touch someone factor. You can also see a huge difference between 30 inches compared to a 18 inch rifle. Pics just for reference.
Please excuse the highly decorative linoleum floor.
It was a porch converted to a closed addition to the house. Now my shop. I will change it out at some point. However I have a few other projects in line before I worry about a shop floor.
What upper do you already own and why are you looking to go below 16"?
I never saw a reason to go with something pinned and welded to save a little weight and length, but then again I am neither an operator nor an AR expert.
I have a couple of short barreled uppers sitting on pistol lowers because I still haven't gotten around to getting stamps, but that's the only reason I own those lowers.
