Originally Posted By Raidersgone:
Has anyone experimented differences for smoothness an reliability? First time with a carbine gas length, I know about and do own mid-length also. I tried a Spikes ST-T2 tungsten powder 4.0 oz. and don't care for the dead blow impulse.

Originally Posted By TonyAngel:


The cycling of a 16" with carbine length gas is just plain more abrupt than that of a 16" with  midlength gas system.

Unless you are willing to go down the rabbit hole of going with an adjustable gas block and/or modifying the size of the gas port in your barrel, you pretty much tune the rig for reliability and live with what it is.

The aftermarket parts market for the AR15 is HUGE and everyone has a product they're trying to sell you because it's just going to change your world.

I really don't understand the "dead blow" effect that you're describing. Whatever that is, you can always just replace the buffer with a standard H2 buffer and see if you like that better. Yes, tuning kits are a thing, but an AR isn't a car that you can tune for comfort without concern for reliability. Generally speaking, an H2 buffer with a standard or maybe springco white hot spring is a good middle of the road setup for the way most 16" carbine barrels are gassed.

Just remember, however you tune, you have to allow for variations in temperature and a bit overgassed is better than a bit undergassed in terms of reliability. If you have a satisfactory closed bolt lock time, but just want to slow the bolt speed down a bit, maybe try a springco blue spring.

Originally Posted By HighpowerRifleBrony:
Standard spring, H2 or H3 with a LARB cap .  (holee shit, $40 now?!)

Originally Posted By arfn:
I have a standard 6920 that I got in 2016. OEM 1. It appears to be a soft shooter with the supplied H buffer and standard spring. I have thought about putting in an H2, but it ejects to right at 4 o'clock now. This is with PMC X Tac 193. It doesn't seem a whole lot gassier than my BCM 16" mid-length and a couple of 20" rifles I have built, which are all soft shooters. I don't know how much an H2 would improve it, really. I'll probably just leave it alone. On the other hand, I have a Windham Bushmaster A2 Patrolman's Carbine that I have had forever. It shoots best with an H2 and standard BCM spring. I figure the gas port sizing in the two carbines are a little different.

Originally Posted By Raidersgone:


Yours sound to be set just right how they are. The same Bushy was my first in 2004, perfect right out of the box. I've leaned more toward lightweight using pencil barrels on my 16"s.

Originally Posted By arfn:

Does it make a lot of difference?

Originally Posted By SMT85:
I have quite a few 16" carbine gas gov profile colts and they run great with just an H buffer very reliable and smooth as designed with good ammo in wide conditions
socom profiles should be H2 .62 gas ports on a carbine are gassed properly unless your tuning for personal preference.

but on one COLT rifle I did do an amphibian style set up with a 16" carbine and it a nice impulse and a bit slower.  though i dont mind the fast cycle impulse of just how it was either.

its a costly setup to experiment with -A5 receiver extension, tubbs spring, kynshot RB5000, SUREFIRE OBC BCG.. fun to play around with i use it for local 2 gun practical division here and there. can always add a spacer and just go back to carbine buffers/springs and milspec bcg or play with A5 stuff or the longer stroke carriers if you want.  

its a nice combo even mechanically makes sense for a 16" carbine gives it a little longer unlock time

another amphibian suggested set up for a smooth impulse is A5 EXTENSION, RB5007, TUBBS spring with a milspec carrier.

but I would start i like suggested above, heavier buffer and spring and see or the eztune gas tube. depends on your barrel and port size

Originally Posted By MS556:
Of my various AR platform rifles, two are still 16" carbine gas system builds.  One is for HD.  It is built to intentionally cycle any available .223/5.56 ammo including weak bulk stuff.  I just run an H2 buffer.  The barrel's gas port is a bit larger than ideal, but it just flat reliably feeds anything.  I have left it alone.  It is snappy with full power 5.56 ammo.

The other is a precision "Recce" ish build.  It is based on the supremely accurate 16" actually 17" Lilja M4 Navy "Recce" SEAL barrel, which was spec'd by NSWC with a carbine gas system for armory compatibility with handguards of the era, and a hoggishly gigantic .080" gas port.   They wanted absolute reliability.  On that build I use an H2 buffer and a screw adjustable gas port to slow it down to reliably cycle my match handloads, and then lock it in place under the handguard.

Both rifles use a standard carbine mil-spec buffer spring.

I see no need to change anything.

Originally Posted By TonyRumore:
How 'bout just using a standard GI spring and buffer and calling it a day.  It will run just fine.

Tony

Originally Posted By W_E_G:



This is correct.

If your 16” gun isn’t running correctly with standard spring and standard 3.0 ounce carbine buffer, there is something else wrong with your gun other than the spring or the buffer.

Consider alignment of gas-key/ gas-tube and alignment of barrel-extension/bolt-head.

Confirm integrity of extractor and tension of extractor spring.

Originally Posted By Raidersgone:

It ran and functioned correctly with the standards, had 12:30-1:00 ejection  though. Reading like everyone else that is overgassed and going to wear parts out much sooner they say, along with more muzzle rise for follow ups. I went up to H2 and blue spring and that put it at 3:00 pattern. I'm still testing different spring and buffer combos, with various ammo for the info and fun of it. I have an adjustable gas key installed out of curiosity also. I really didn't want to go adjustable gas block, or adj. BCG, A5 set up, or smaller gas tube on this rig. It's been 100% reliable with everything and the brass looks good.

Originally Posted By DevL:
Buffers and springs have very little effect on felt recoil overall.
Heavier buffers are slower cycling but harder hitting on either end of the carrier movement, resulting in a porpoise / shake weight type effect. You already seem to have experienced this and dont like it.
Heavier springs generally should be thought of as just increasing the closing speed of the carrier as they do almost nothing to delay bolt opening and very little to reduce rearward bolt speed.

The #1 thing to control recoil is to get the gas volume in check. Once I tune a carbine gas system, I really can't tell a difference, as the shooter, compared to a propperly gassed midlength. At least unsuppressed with the intended ammunition.

So my advice is ALWAYS start with gas control, never use extra power springs, and tune the last little bit with a buffer or tune cyclic rate for full auto or FRT use with a buffer. A spring is just to change bolt closing speed and/or increase full auto cyclic rate.

Things like midlength gas are nice to aid with adding a suppressor or making the gas tune a bit finer in resolution for unsuppressed use, but it is not critical or even very important for reliability and shootability in a 5.56 16" AR15.

You can do the gas tuning right via a reliable gas block like a Superlative Arms gas block set to restrict mode or choose a cheaper option like an EZTUNE gas tube. Either way, you will be able to achieve propper gassing which is really the foundation of a propperly gassed gun that is reliable with the ammo YOU shoot.

Don't listen to anyone who tries to dissuade you with lies about theoretical reliability issues. If you do it right and use the right parts, gas tuning is the ONLY way to get what you want to achieve if you have an overgassed barrel.  It's just most people handicap themselves with tuning to run steel cased .223 Tula, adding "extra clicks for reliability," and other such nonsense.

Originally Posted By DevL:
Buffers and springs have very little effect on felt recoil overall.
Heavier buffers are slower cycling but harder hitting on either end of the carrier movement, resulting in a porpoise / shake weight type effect. You already seem to have experienced this and dont like it.
Heavier springs generally should be thought of as just increasing the closing speed of the carrier as they do almost nothing to delay bolt opening and very little to reduce rearward bolt speed.

The #1 thing to control recoil is to get the gas volume in check. Once I tune a carbine gas system, I really can't tell a difference, as the shooter, compared to a propperly gassed midlength. At least unsuppressed with the intended ammunition.

So my advice is ALWAYS start with gas control, never use extra power springs, and tune the last little bit with a buffer or tune cyclic rate for full auto or FRT use with a buffer. A spring is just to change bolt closing speed and/or increase full auto cyclic rate.

Things like midlength gas are nice to aid with adding a suppressor or making the gas tune a bit finer in resolution for unsuppressed use, but it is not critical or even very important for reliability and shootability in a 5.56 16" AR15.

You can do the gas tuning right via a reliable gas block like a Superlative Arms gas block set to restrict mode or choose a cheaper option like an EZTUNE gas tube. Either way, you will be able to achieve propper gassing which is really the foundation of a propperly gassed gun that is reliable with the ammo YOU shoot.

Don't listen to anyone who tries to dissuade you with lies about theoretical reliability issues. If you do it right and use the right parts, gas tuning is the ONLY way to get what you want to achieve if you have an overgassed barrel.  It's just most people handicap themselves with tuning to run steel cased .223 Tula, adding "extra clicks for reliability," and other such nonsense.

Originally Posted By TheQuadfather:
If it’s a Colt barrel it will be an exceptionally snooth shooter with the stock spring and buffer.  Anything else is anyone’s guess.  The spring and buffer have nothing to do with the gas drive.

Noticeably better than most any midlength and even more so as the spring and buffer get heavier and heavier.  

Chamber, bore, and port dimensions are are much more influential on carrier velocity than port location.

Originally Posted By DevL:
Buffers and springs have very little effect on felt recoil overall.
Heavier buffers are slower cycling but harder hitting on either end of the carrier movement, resulting in a porpoise / shake weight type effect. You already seem to have experienced this and dont like it.
Heavier springs generally should be thought of as just increasing the closing speed of the carrier as they do almost nothing to delay bolt opening and very little to reduce rearward bolt speed.

The #1 thing to control recoil is to get the gas volume in check. Once I tune a carbine gas system, I really can't tell a difference, as the shooter, compared to a propperly gassed midlength. At least unsuppressed with the intended ammunition.

So my advice is ALWAYS start with gas control, never use extra power springs, and tune the last little bit with a buffer or tune cyclic rate for full auto or FRT use with a buffer. A spring is just to change bolt closing speed and/or increase full auto cyclic rate.

Things like midlength gas are nice to aid with adding a suppressor or making the gas tune a bit finer in resolution for unsuppressed use, but it is not critical or even very important for reliability and shootability in a 5.56 16" AR15.

You can do the gas tuning right via a reliable gas block like a Superlative Arms gas block set to restrict mode or choose a cheaper option like an EZTUNE gas tube. Either way, you will be able to achieve propper gassing which is really the foundation of a propperly gassed gun that is reliable with the ammo YOU shoot.

Don't listen to anyone who tries to dissuade you with lies about theoretical reliability issues. If you do it right and use the right parts, gas tuning is the ONLY way to get what you want to achieve if you have an overgassed barrel.  It's just most people handicap themselves with tuning to run steel cased .223 Tula, adding "extra clicks for reliability," and other such nonsense.

Originally Posted By Raidersgone:


Good advice. I've read the A5 buffer system is an answer also to an over gassed barrel for smooth reliability and less muzzle rise. I wouldn't put it on a 16" carbine gas though. I've also read the EZ tune gas tubes wear out and open up faster than an adj, gas block, but they can have their issues also. If I end up not satisfied with the parts I have now on this I've made up mind on the YHM 0.063" suppressor gas block and just drill it out to 0.070 or somewhere near that. Does anyone know the recommended gas port size for 16" carbine length gas running unsuppressed using M193 and .223 high performance quality hunting ammo?

Originally Posted By DevL:


The A5 receiver extension and buffer is just the original Armalite AR10 receiver extension and a 5.56 carbine buffer extended to take 4 weights instead of 3. The internal spring in the A5 buffer IMO does nothing.

Also the A5 allows the use of a 5.56 rifle spring instead of a 5.56 carbine spring. This allows for a more linear and less progressive spring rate moving from fully in battery to fully compressed at the rear of the operating cycle. You can get the same effect (more linear spring rate) by using a flat wire carbine spring instead of a round wire carbine spring.

Since you have 4 weights instead of 3, the lowest weight A5 buffer is basically an H1 carbine buffer weight. As you swap each steel weight to tungsten, you will get the equivalent of H2, H3, H4 and H5 equivalent buffer weight (approximately).

Each time you increase the weight you decrease the delta between suppressed and unsuppressed operating speed, increase reciprocating mass/momentum, and slow the full auto cyclic rate.

More mass requires more gas. If you get the cyclic rate too low without enough gas you can get into a short stroking zone or failures to feed. More mass increases the shake weight effect. More gas increases recoil.

There is really no reason an A5 cant work wonderfully on a carbine, midlength, or rifle length gas system, provided it is tuned right. It is just another means to alter your overall mass and use a rifle spring instead of a carbine spring. Perhaps think of it as a rifle buffer and rifle spring... that can use various weight buffers like the carbine buffer... and fits carbine stock tails... because that is EXACTLTY what it is.

It is not special. It is just another means to an end.

Compared to the 5.56 carbine receiver extension and carbine 5.56 buffer, the A5 receiver extension and buffer increases the open and closed length of the stock. It increases the overall weight of the rifle, it does not allow for lighter than H1 buffer. Those are the negatives.

As for the gas block... you may want to tune for a particular ammo, tune for your particular bolt carrier tail clearance/efficiency, or tune any of a number of things and a fixed gas port just limits you IMO.

You can avoid all that by just using a Superlative gas block. Every gas port or block erodes over time. But with the Superlative you could always just remove it, clean it if it gets carbon locked, and close it another tick if you wanted. A drilled YHM is not going to allow for that. Once it is opened it can never be closed without major welding and redrilling. It is just not a practical choice IMO. It is a cheap $22 choice like an EZ tune gas tube but more durable and harder to swap.

I run a Superlative Arms gas block on my duty rifle, which I stake my life on. I reccomend you go that route too, because you will learn a lot more tuning for different mags and ammos and seeing first hand what various changes to gas settings and different buffers do. The YHM drilled out to X diameter is just rolling the dice based on what you HOPE the specs are on your own BCG, ammo, and magazines. And M193 and .223 hunting ammo will NOT have the same tune setting... you will always want to tune for the weakest ammo you want to run. For me it is 55 grain .223 brass cased FMJ.

Would you tune a carburetor based on some preset screw positions reccomended by someone else on a different vehicle? Or would you tune until you get a perfectly running engine with YOUR engine, YOUR fuel, and YOUR location?

With an adjustable gas block you can retune if you swap springs, carriers, buffers, etc. Why give up the ability to tune perfectly and retune later? Spend the extra $50-60 on the SA gas block. IMO the reliability concerns are just from overactive imaginations.