Difference in barrel length for 3g. 16, 18, or 20.

[Tranford]

Is the majority of the difference between a 16", 18" and 20" barrel the weight and distance shots, or is there something more that I should consider for my 3g build?

[suesstech]

The difference is either rifle length or mid-length gas system. The 18" and 20" are rifle length gas, while 16" is mid-length gas system. Rifle length is much less felt recoil however people run both.

[Dan Sierpina]

The majority of 16" barrels come with carbine length gas systems.

[bikerburgess]

Its mostly about balance then bullet velocity, unless you are shooting irons then its about sight radius and longer is better.

Mike

[carbon9]

Just to throw a wrench into it I have one 17" build (intermediate gas) with polygonal rifling that makes 3018 fps(average) no problem with a pretty moderate 55gr load. I shoot tac-irons with a Prismatic because who runs irons anymore Alright, Alright, I run irons on my .308 and my 19" polygonal rifled build.

I would run whatever length barrel feels best to you handling wise with the longest gas length you can for reliability. The only time I would go longer then your handling comfort level is if you are going to run iron sights or a 1x optic. At that point you want the flattest trajectory you can get as you won't have a bullet drop compensating reticle in your 1x optic or irons, makes it a little more forgiving. bikerburgess said it in much better straightforward terms. If you are going to run a scope? 16" with midlength gas and adjustable gas block would be fine. YMMV.

[B_Ayers]

usually 16" and 18" have carbine length (mid length) gas systems. a 20" will have a rifle length gas system. The 20" will have less recoil. Some like to take a 20" barrel and cut it down to a 17-18" length and still have the rifle length gas system. You will be able to get around close quarters but still have the reduced recoil.

[EkuJustice]

carbine length is not mid length.

You can find the following combinations

16 inch carbine and mid length (rifle length too but rare and dosent always work)

18 inch mid length, rifle length

20 inch rifle lenght

[Sleepswithdogs]

usually 16" and 18" have carbine length (mid length) gas systems. a 20" will have a rifle length gas system. The 20" will have less recoil. Some like to take a 20" barrel and cut it down to a 17-18" length and still have the rifle length gas system. You will be able to get around close quarters but still have the reduced recoil.

Not my understanding either. Carbine length is shorter than mid length and is the only gas system that will work on the 14'' - 14.5" stuff. Carbine length or Mid length is found on 16's and the 18's use Mid length or Rifle length. 20's and up are mostly all Rifle length.

You could use a shorter gas length, say a Mid length on a 18'', or even a Carbine length for that matter, but you can't use the longer length on a shorter barrel, say a mid length on a 14.5". It will not cycle reliably because the round does not stay in the barrel long enough after passing the gas port to allow enough time for the pressure wave behind the round to cycle the bolt. You gott'a remember, this stuff is happening faster than a New Yorker can take your money.

The shorter the length of the gas system, the closer it is to the initial burn and pressure spike, the more the impulse is felt. So the Rifle length will yield the softest shooting action, and I'll go a little way out on a limb here and say, the Carbine length is the most reliable because it would be the least effected by weak, crappy ammo.

As far as which is best, I think it comes down to the distances you shoot most, and what floats your boat.

Tar

Edited January 7, 2013 by Sleepswithdogs

[Lead-Head]

It has been said many times here over the years, if you rifle will shoot 1.5 MOA consistently, and you know your holds, it will work.

I have to say that I prefer a 20" barrel. There is a little extra velocity and I never felt like the gun was too long with a 15" HG. The rifle length gas system is also very nice. I like a GI profile, so it is light but still has some mass towards muzzel.

That being said, I just put together a 16" gun with a mid weight ML gas sys barrel, 15" evo HG, JP comp, and prismatic. I have only put about 100rds thru it, but its balance is sweet. From 50 yd plates to 250 yard autopoppers, it impressed me more than I expected,

And it looks pretty cool too.

[promod1385]

I shoot a dissipator as its the best of both worlds. Very soft shooting (with a Nordic Corvette comp there is little to no muzzle rise) and I get the little extra bit of sight radius which is absolutely clutch when shooting irons. Most of our local events are shot on pistol bays so there is no need for anything longer, I think my next rifle will be a 20" Blackhole in the LRT profile with a Lipinsky front sight base and a globe