length of gas systems..
Posted 26 November 2012 - 08:26 PM
but you guys just give the best info and advice..
so on a 16" barrel what is the main reason you chose your gas system length? It is performance? wear/tear? the front sight distance?
Posted 26 November 2012 - 08:35 PM
Of all my "shorter" ARs, the only one that has a carbine length gas system is a dedicated .22 LR gun w. red dot and no BUIS.
Posted 26 November 2012 - 08:38 PM
My Colt 6940 (16" barrel, carbine gas system) has some stout ejection. Maybe that is why it doesn't like steel cased ammo and the Spikes is OK.
I have read that article before and think it is pretty dead on.Next time around I would swap and get the 14.5 in carbine and 16" in mid-length and save having to tinker with different buffers.
A government that robs Peter to pay Paul can always depend on the support of Paul. -George Bernard Shaw
"The state that separates its scholars from its warriors will have its thinking done by cowards, and its fighting by fools." - Thucydides.
Posted 26 November 2012 - 09:35 PM
okay i'm clear on that.. but what are guys other preferences between the two? Is there some sort of tactical reason? or is it just a comfort preference on reliability and functionality?
Posted 26 November 2012 - 11:45 PM
Mid or rifle length are the ways to go. I don't know of any advantages with carbine length unless its necessary when building a SBR.
I own 14.5", 16", and 18" barrel length AR's all with mid length gas systems, and I couldn't be happier. All use the standard carbine buffer. I shoot everything from silver bear 62's, surplus 55's, and hand load 69's.
Its all about the tune state of the rifle. The balance of gas being sent back to the BCG, and the force it needs to move the buffer and spring back. Too much gas and/or not enough buffer weight to compensate equals a harsh recoil of the BCG (beats the gun and you up for no good reason). Too little gas and/or to heavy of a buffer weight will result in short stroking and jams, the BCG won't be sent all the way home for the full ejection/reload cycle.
Length of barrel, length of gas system, weight of buffer, and type of ammo (especially bullet weight) all come into play when it comes to how an AR's gas system in general will operate. You would want a setup in which ample gas is sent back to keep the rifle reliable, yet not overdone to the point that so much gas is being sent back that its just needlessly beating you and the gun up. From a performance perspective, over-gassed AR's I would think would have a disadvantage during quick follow up shots.
For the most part, any quality pre-built AR upper that you would purchase would already be good-to-go with any commercially available or surplus 5.56 ammo we can get. Building the upper from scratch, there is a chance that some tuning may need to take place , for instance with the gas port on the barrel and/or using an adjustable gas block.
Posted 26 November 2012 - 11:59 PM
Posted 27 November 2012 - 12:04 AM
"I never learned from a man who agreed with me" - RAH
Posted 27 November 2012 - 07:26 PM
Posted 27 November 2012 - 09:23 PM
Technically you can tune the rifle from either end, the gas port location(how much gas is sent through the system) or at the buffer. However, adjusting the gas port location is more beneficial. Limiting the gas is better then compensating for it, you get a more efficient rifle with less kick, and for all purpose your internals see a lot less stress. The carbine system is technically for short barrels, i'm not sure why they put them on 16" barrels other then a popularity thing with "looks". Personally i don't even see the need for it on a 14.5" My BCM 14.5" is mid and it replaced a 16" mid with no other mods and works flawless.
18" seems to be the compromise for mid/rifle gas systems, and companies like Noveske came up with the "intermediate" gas systems, because they found the rifle cycles the best is that config, the compromise between recoil, cycle time and reliability. with a rifle length you would use a lighter buffer and for a mid a heavier one. So switching to intermediate gave less recoil then mid, and cycled better then the rifle length. But we start to loose standards here which is important in the AR world. If another company makes an Intermediate... is it the same as Noveske? They even include the tube and gas block with the barrel( and rightfully so at that price!) Do i have to by my gas tubes from noveske? or take the task to make my own?
there are gas blocks with adjustable pressure options, not sure how they fair though.
Posted 28 November 2012 - 07:45 AM
0 user(s) are reading this topic
0 members, 0 guests, 0 anonymous users