9mm barrel length - 16" or 10.5". Which is more accurate at 100yds?

[markt]

I'd like to get a 9mm AR-15 and am trying to decide between a 16" barrel and a 10.5" barrel.

Has anyone direct experience with the difference in accuracy between the two at 100yds?

What accuracy can I expect out of each length?

Cheers,

MarkT

[Lefty223]

Either one will shoot better than you can ... meaning offhand at 100-yards ain't easy. FWIW my Oly has the 16+" overall barrel, but the last 5" is the CAR-type mizzle device. Regardless using w/ open sights on the A2 carry handle she'll shoot groups offhand the size of a baseball - all day long at 50-yards.

I have not, as of yet, tried for groups at 100Y, although I'll plink at gongs on the range backstop from 100-200 yards and hit them when "I make the good shot"'...

[markt]

Thanks for the insight. I want to source both a 9mm upper and 22LR upper and have them more or less the same config. It seems that the 22LR uppers mostly come with 16" barrels so I'll likely standardise on that length for both.

[Dionysusigma]

Barrel length these days has more effect on velocity than accuracy - accuracy seems to be more dependent on quality and "other factors" (optics, free floating, barrel profile including its effects on heat absorption and harmonics, etc.)

[Clint]

Accuracy is unaffected by barrel length.

The 9mm doesn't gain much velocity in longer barrels, so you get the most utility out of the cartridge at ~8.5" for a pistol or SBR.

Obviously 16" is the choice for a non NFA rifle.

[markt]

Thanks for the information. It's given me some thought as to length. Having a non-NFA rifle has its merits and that's likely the direction I'll go.

[bfoosh006]

Deleted

[markt]

BTW.... you will find the bullet drop of the 9MM and 22LR is about the same past 100yds.

Also... in my 16" , different brand ammo dramatically changed accuracy.

The difference between Winc. 147gr FMJ ( Train and Defend ) and Perfecta 115gr FMJ was dramatic at 100yds.

Perfecta was Shotgun pattern, and the Winc was a respectable group.

On a side note GECO Swiss routinely shoots fantastic for the 16" Carbine and various Handguns.

I tested about 8 different on hand 9mm factory rounds... and was very surprised at the POI differences as well as accuracy differences.

The one that really surprised my was Browning 147gr FMJ and Winc. 147gr FMJ ... ( I had assumed it was basically the same ammo manufacturer ) clearly the Browning was faster... totally different POI.


Sooooo... be sure to try a bunch of ammo.

Good advice. I currently have a decent supply of CCI Blazer Brass 124gr FMJ. I hope it does ok when I finally get the rifle.

[Bushy24]

I'll be trying several hand loads too. I wonder if a hand loaded hot load with a muzzle brake would be a good combo for accuracy, speed reduced muzzle climb and a somewhat effective brake with the extra gas? I wonder if I'd need a heavier buffer weight too?

[bfoosh006]

Deleted