New build: 16in middie vs. 17in rfile?

[CJW]

I have a 16" carbine upper that I am going to turn into a project. My competition gun is a 20" barrel, so I want to keep this one on the short (but not SBR) side.

What I am wondering is, what kind of difference should I expect between a 16" with a mid-length gas system and a 17" with a rifle-length in terms of recoil, muzzle velocity, & reliability?

Also, if I put an adjustable gas block (probably a Syrac) and low mass bolt/BCG and buffer, how will that affect the above? I presume I get lower recoil and higher muzzle velocity with little to no effect on reliability, but I've not had an adjustable gas system before, so this would be a first.

Any input is appreciated!

Thanks.

[michael1778]

I've never had a rifle failure attributable to any of my adjustable gas systems; both Syrac blocks. One was 16" carbine length and the other is 18" rifle length gas.

I've heard some people discuss that 17" rifle gas could be unreliable in some cases because the dwell time is so short.

[Sleepswithdogs]

The difference between a 16 and a 18 in velocity is about 40'/sec, so I think between a 16 and a 17 should be about 20'/sec give or take a little.

Tar

[norbs007]

I've never had a rifle failure attributable to any of my adjustable gas systems; both Syrac blocks. One was 16" carbine length and the other is 18" rifle length gas.

I've heard some people discuss that 17" rifle gas could be unreliable in some cases because the dwell time is so short.

Hmmm... good to know, I'm also considering a 17" rifle over a 16" mid with a Syrac block.

[Stefan]

Go with the 17". You won't regret it.

[Blaise1]

Go with the 17"bbl and all the low mass goodies. Get the Syrac or a gas block that has a set screw cause it sucks when you loose the bleeder plug. Get a good tunable comp and you'll be amazed at how flat the gun stays when you shoot.

[MarkCO]

I have a 16" carbine upper that I am going to turn into a project. My competition gun is a 20" barrel, so I want to keep this one on the short (but not SBR) side.

What I am wondering is, what kind of difference should I expect between a 16" with a mid-length gas system and a 17" with a rifle-length in terms of recoil, muzzle velocity, & reliability?

Also, if I put an adjustable gas block (probably a Syrac) and low mass bolt/BCG and buffer, how will that affect the above? I presume I get lower recoil and higher muzzle velocity with little to no effect on reliability, but I've not had an adjustable gas system before, so this would be a first.

Any input is appreciated!

Thanks.

16" w/mid gas will recoil more, have less velocity and be more reliable than a 17" with rifle gas. Put an adjustable gas system (yes, Syrac is the best adjustable) on either and the velocity won't change, you will be able to reduce some recoil on the 16", not much on the 17" and the reliabilty (as far as function) will go down. However, if you give yourslef enough buffer zone in the gas adjustment, you can maintain reliability. This all depends on your load(s) and the size of the gas port in the barrel you choose.

[StephensOutdoors]

I'm running a 17" barrel on my Lancer upper & I like it a lot. Great accuracy & the slightly shorter barrel is more barricade & wall friendly than my 18" upper

[promod1385]

I am running a true Dissipator set up (16" barrel with rifle length gas system). People who talk about dwell time and reliability need to test out a few different buffer weights before they jump to the conclusion these systems dont work. I have a standard carbine weight buffer in my rifle and it runs like a top!