16", 20" or 24" AR-15 barrel for lead-free bullets

[michael1one]

I am building a new upper for my AR15 (.223) to do some varmint shooting in Condor country. It seems like you don't gain a lot more accuracy with a barrel longer than 18 inches with lead bullets, but since I will be shooting lead free bullets, how important is barrel length? Will be shooting from a bench rest or tripod.

[foreppin916]

Hi Michael,

Barrel lengths does not really effect accuracy, it effects velocity. If your shooting an 16" gun vs a 20" gun at 200 yards your group should not open up. ( multiple factors come into play. bullet weight, twist rate etc ) It might shift, but not be "less accurate"

It really depends on the distance your shooting. The velocity difference between 18" to 20" is around 80fps to 100fps. 24" with .223 (not 5.56) your looking at 3200 fps.

any of those velocities will kill a varmint further than you would probably be comfortable shooting at it for a clean kill.

And all the lead free ammo iv shot has been more accurate than I am. Iv mainly stuck with Nosler 40 gr ballistic tip.

Good luck OP!

[Spyder]

24" with .223 (not 5.56) your looking at 3200 fps.

Awful vague. My varmint gun in .223 chronos at ~3800.

[michael1one]

Thanks or the response. Shooting ground squirrels about between 100 to 200 yard. So velocity isn't a big concern. I've just heard people complaining about lead free bullets so I figured maybe a longer barrel would be important.

[Mesa Defense]

70 grain tsx shoots outstanding in 7 twist 14 & 16" barrels

[ExtremeX]

I have owned a 16, 18, 20, and 24" barrel lengths and I really started to dislike the 24".

Its just too long for a rifle length gas system... it recoils a lot harder than it should and for varmint shooting takes away from spotting your own shots. With a bull barrel and a PRS stock it was still unbalance as it was still very front heavy.

The 18" with rifle length gas ended up being my favorite for that type of shooting.

[NapalmCheese]

Longer barrels generally lead to increased velocity.
Increased velocity generally leads to flatter trajectories and less time spent in the air.
Flatter trajectories and less time spent in the air generally lead to fewer missed shots due to range and wind estimation errors.

[smoothy8500]

Don't the "lead-free" projectiles have a longer bearing surface requiring the faster twists like 1-8, vs the average varmint barrel having 1-12?

[Spyder]

Don't the "lead-free" projectiles have a longer bearing surface requiring the faster twists like 1-8, vs the average varmint barrel having 1-12?

That's part of why I'm considering selling my Model 70 HV. 1:12, and I haven't found any lead free loads that it likes.

[mif_slim]

The 36gr VG are as 55gr lead. The 55gr VG are as long as the 75gr lead. Both VG boxes has a label saying shoot at least 1:10 twist. My 1:8 24" were sometimes ripping the 36gr bullets apart though, fyi.