18" barrel owners

[cbx]

I have been thinking seriously of an 18 bcm ss set up for shooting at longer ranges.

Is the extra velocity over a 16 noticeable at say 500-700 yards? Would you do again, or just stick with 16"? Thanks.

[markm]

Extra velocity is always nice. But a 16" will get you there too... with good ammo.

If you're going to get a steady diet of 500+ yards, you might like the 18" a little more.

[Onyx Z]

A quick estimation from the app on my phone: 2,700fps from my 18" (chrono'd) vs 2,600fps from a 16" (assuming ~50fps/in. of barrel) = ~15" difference in drop @ 700yds.

This may be incorrect, but I did it really quick while making a lot of assumptions.

[davidjinks]

All of my "Longer range" 556 shooters have an 18" barrel (MK12's built by HCS). They all shoot better than I will ever shoot. The velocity difference between those barrels and my 16" Colt 6920 barrels (Shooting MK262) averages out to ~ 60 FPS slower in the 16" barrels.

I haven't noticed a huge difference in performance out to 300 yards with either barrel lengths. However that is the farthest I can shoot in my neck of the woods.

I would venture to say if you're going out further than that, and 18" might give you a better advantage.


I have been thinking seriously of an 18 bcm ss set up for shooting at longer ranges.

Is the extra velocity over a 16 noticeable at say 500-700 yards? Would you do again, or just stick with 16"? Thanks.

[MistWolf]

If velocity were the primary reason to choose an 18 inch barrel over a 16 inch barrel, I'd say no, the juice ain't worth the squeeze. If you want a real velocity advantage over a 16 inch barrel, get a 20 inch

[thecolter]

If velocity were the primary reason to choose an 18 inch barrel over a 16 inch barrel, I'd say no, the juice ain't worth the squeeze. If you want a real velocity advantage over a 16 inch barrel, get a 20 inch

It's been my observation that you'll get a bigger gain in velocity going from 16" to 18" with only minimal gains going beyond 18" to 20". I only see a 20-30 fps difference between my 18" and 20" barrels whereas I see a 60-80 fps difference between my 16" and 18" barrels with my loads.

[Iraqgunz]

I just shot a precision rifle course a few weeks back and two of us had 16" carbines. Strangely, both of us were able to whack steel plates all day long with our feeble 16" barrels.

[Sticks]

Quality Barrel + Match Ammo + Skilled Operator = Accuracy.

Length of the barrel plays a part, but not that much. So long as the ammo is matched to the barrel (length, twist, harmonics) then you'll have an accurate rifle.

I have not had an opportunity to dial in my MK262 loads for my MK12 (2 years and counting), but my 16" middy with my own M193 home cooking I get sub MOA groups, and it's a simple Centurion CHF barrel/upper from when they still made them.

[TehLlama]

2" of barrel worth of velocity on a 69gr or 77gr load at 700yd is probably worth a tiny amount of user error in a wind call being forgiven, but at such a tiny margin I wouldn't consider that useful unless hitting stuff at 600m or more is the primary intended use. The nominal MV difference with Mk262 between a Recce and SPR setup is tiny (double digit), and the difference in handling (especially with a can) isn't that tiny.

I have two 18" barreled uppers, and for the most part they've become safe queens since getting 16" analogs of each (My Centurion Mk12 barreled upper sits idle now that I have a 16" HCS Recce - same barrel basically, but the shorter one sees use suppressed and unsuppressed).

For unsuppressed, or with a reflex can being able to run at half a click or more as the primary role - I'd take the 18" in a heartbeat - but look used since tons of really nice 18" uppers are constantly showing up. If the use at distance is just occasional, and having a handier rifle matters, then something like the BCM KMR Recce is arguably a better answer. If you're considering it a weight constrained setup, I'd rather have a 16" barrel and 2.5-10x32mm glass than an 18" where I'd have second thoughts about heavy optics (although 18" plus 2.5-10x32mm type glass is seriously fun to shoot).

[dentron]

Quality Barrel + Match Ammo + Skilled Operator = Accuracy.

Length of the barrel plays a part, but not that much. So long as the ammo is matched to the barrel (length, twist, harmonics) then you'll have an accurate rifle.

I have not had an opportunity to dial in my MK262 loads for my MK12 (2 years and counting), but my 16" middy with my own M193 home cooking I get sub MOA groups, and it's a simple Centurion CHF barrel/upper from when they still made them.
This right here. Are you talking about a stainless 16" to a stainless 18" then no. But if you are talking about a CL to a stainless barrel (or rather a rack grade to match grade barrel) that will have more of an impact.

[Metric Matt]

I really like my FN CHF barreled 18" upper for long range shooting, the combination of rifle length gas, the muzzle brake, and an H2 buffer make for quick follow up shots. The recoil impulse is noticeably softer than my 14.5" carbine upper, although I suspect the muzzle brake on the 18" is the biggest factor there.

[MistWolf]

It's been my observation that you'll get a bigger gain in velocity going from 16" to 18" with only minimal gains going beyond 18" to 20". I only see a 20-30 fps difference between my 18" and 20" barrels whereas I see a 60-80 fps difference between my 16" and 18" barrels with my loads.

Using your numbers, the difference between 16 and 20 is 80-110 fps. If you're going for velocity, might as well go for the 20 inch. If you're going for handiness, might as well go for a 16 inch. There are reasons to use an 18 inch barrel, but it's velocity advantage over the 16 and handling advantage over the 20 aren't enough to bother with

[Onyx Z]

I really like my FN CHF barreled 18" upper for long range shooting, the combination of rifle length gas, the muzzle brake, and an H2 buffer make for quick follow up shots. The recoil impulse is noticeably softer than my 14.5" carbine upper, although I suspect the muzzle brake on the 18" is the biggest factor there.

Gas length makes a huge difference in recoil. A lot more than a muzzle brake. My intermediate is A LOT softer than my mid-length, and even more so than my carbine.

[Little Creek]

On another forum there was an individual who compared similar 18 and 16 inch barrels and documented about a 100 fps difference. I bought a DDM4V11 S2W to not only get the 18" heavy barrel, but the rifle length gas system, and the 15" SLiM rail. I have 16" guns in regular and lw. I will shoot the 18" as soon as I can save up money for a proper 500 yard optic and mount.

[ryantx23]

I love my 18 inch SPR. It will shoot lights out and is currently my favorite rifle to shoot. For me, the difference in being handy and the negligible amount of added weight still worth it. In general I would feel just as comfortable taking it to a gunfight as I would one of my 14.5's or 16's. The downfall would be if you are doing constant CQB, but if that was the case you would want a Commando length gun / SBR for that mission profile anyway.

[cbx]

Thank you all for your input.