Got a question for the gurus out there.

Are there specific buffers that should be used for various barrel lengths?  I.e., I have a carbine buffer in my collapsible stocked 16".  If I switched to a fixed, A1 style stock, would I continue to use the carbine buffer with the rifle spring, or switch to a rifle buffer?

What about a 20" with a collapsible stock?  Have to use the carbine buffer and spring?

16" midlength.  Same as a standard carbine?

This enquiring mind would like to know.

With a collapsible stock you'll use a CAR buffer and spring.  I recommend an H buffer from LMT $13 or so and a regular CAR spring.  I'm pretty sure that if you stuck a rifle buffer and spring into a CAR stock that it couldn't even move back far enough for operation.  The CAR receiver extension (buffer tube) is shorter than a rifle length one.

You should always use the collapsible size buffer with a collapsible stock, and vice versa with the rifle.  For a carbine I would recommend a heavier buffer, such as the Colt H buffer, in order to slow things down a bit and aid in reliability.

EDIT- my link saved  to favorites is mess up, or beyond a time limit.

It had a listing of buffers and weights and uses.

Please excuse for any dificulties that may have come about.

SBR7_11
 You know, I do read this board every day, sometimes more than once, and I do know how to use the search function.  Since I couldn't find the answer to my question, I asked it.  Unfortunately, while I appreciate your desire to help, your link was less than helpful.  If you had provided a link to the thread regarding buffers, it would have helped.  A link to the AR discussion forum, with a direction to look halfway down, doesn't help.  If you hadn't noticed, the order of threads changes every minute with every response.

Thanks Tweak.  You confirmed my assumption that buffer type is tuned to the barrel/gas tube length.

BUFFER WEIGHTS

Rifle - 5.15oz, made of aluminum

CAR - 2.9oz, made of aluminum

H - 3.77oz

H2 - 4.7oz

H3 – 5.6oz

9mm - 5.47oz, made of steel


Special purpose buffers designed for suppressed SMG's or 9mm carbines using high pressure (+P+) ammunition

9mm A - 6.3oz  CAR style buffer

9mm B - 7.1oz CAR style buffer

9mm X - 7.9oz CAR style buffer


IMHO... If I had a carbine, with a carbine length gas system, and wanted to use a telestock, I would START with the 5+ ounce 9mm buffer.  If that setup was reliable, i would STAY with it.  I might even start with the X buffer.

Chen Lee (SMGLee), did an EXCELLENT thread a while ago about: carriers (enhanced, regular, m16), buffer weights (H, Regular, 9mm), and gas tubes (carbine, fat boy), and different combinations there-of.  His posts were well written and VERY informative.

The gas pressure at the gas port of a carbine length gas tube system is around 26,000 psi.  The pressure of a rifle length is around 13,000 psi.  The AR is a system, and a system needs to be in balance to work reliably and not tear itself apart.  If you are increasing the pressure acting on the system, you need to INCREASE the countering force (the weight of the parts this force acts upon).

You can increase the weight so much so that the system becomes unreliable… short stroking, and unreliable with certain types of under-powered ammo.  So you want a certain amount of “over-power” so it remains reliable with all ammo and under all conditions.

FWIW, when I finally get the $ for a Magpul stock for my 20”, (rifle length gas system mind you), I am starting with the 9mm buffer.  If the weapon functions with all ammo, then I am not changing a thing.

Have a good one.

Stainless

Stainless,

Got a link?  Sounds like something that should have been tacked.

Quoted: Stainless, Got a link?  Sounds like something that should have been tacked.

a link for??


I put that stuff on buffers together, piece by piece by what I have seen posted on the web, and at this site, and then saved it as a Word doc, with the Board code already in there.  Then when the topic comes up, I just cut and paste my "standard" answer.

The rest is some freesytle by me, mixed with a little bit of this....
Technical Note 48, The Effects of Barrel Design and Heat on Reliability

The following quotes accurately describe what I am trying to explain:

Armalite The heart of the M-16 operating system, the carrier group, was designed to function well with the original 20 inch long barrel of that rifle.  The carrier group and the location of the gas port were carefully balanced to provide outstanding reliability with the ammunition that was designed for the M16. The carbine gas port is located closer to the chamber than the gas port of the rifle:  7.5 inches instead of the 13 inch distance on the rifle.  The gas pulse therefore enters the gas tube sooner and reaches the carrier group earlier than it does in the rifle length barrel.  In addition to reaching the carrier sooner, it reaches it at higher pressure.  The gas pressure at the carbine’s gas port is double that of the rifle:   26,000 psi vs. 13,000 pounds per square inch.

have a good one.

Stainless

Quoted: [FWIW, when I finally get the $ for a Magpul stock for my 20”, (rifle length gas system mind you), I am starting with the 9mm buffer.  If the weapon functions with all ammo, then I am not changing a thing. Stainless

This is what I am planning on building next.  Where are you buying your 9mm buffer from?  I assume you are not the first one to put a magpul on a 20" rifle, what do most people use?  why not just a carbine buffer?

Quoted: This is what I am planning on building next.   Where are you buying your 9mm buffer from? Wherever I buy my Magpul, and if they dont have one, there are dealers on here I have purchased from in the past that might be able to help me. I assume you are not the first one to put a magpul on a 20" rifle, what do most people use? Most people use the standard A2 length, or MAYBE an A1 length stock, for their 20's.  The majority of people will call us "gay" for wanting a telestock on a 20. I have my reasons: #1 adjustability when wearing different clothes... T-shirt-summer.  2 sweat shirts and a coat- winter in PA #2 so 6'3" me AND 5'4" girlfriend can shoot same weapon comfortably. #3 I want a shorter stock, my shooting style is "different" and a shorter stock would be more comfortable for me. #4 when space is at a minimum you can collapse it all the way down. ex: car, truck, cqb.   why not just a carbine buffer? My 20" currently has the rifle buffer, which is around 5 ounces.  I would like to keep the reciprocating weight as close to the same as I can.

I only have 1 (one) AR.  I only WANT 1 (one) AR.  I have other hobbies than shooting, and “get um both” is UNACCEPTIBLE.

I USED to have a 16” but re-barreled after the sunset to a 20” with threads.  I just like the 20” better for reliability and less wear on parts.

People who shoot carbine length gas systems sometimes have to “do things” to the weapon to get it to “work properly”.  Examples of this include: fat boy gas tube, pig tail gas tube, “enhanced” bolt carriers, heavier buffers, D-fender extractor “enhancers”, “extra power” extractor springs… with the “special” insert, and the list goes on and on.

Look at the “midlength” gas system.  These are “the hot thing” right now.  This is a solution to a problem that the rifle length gas system ALREADY SOLVES.

I just didn’t want to get into that.  The 20” does for ME what I need it to.  There will be those who will argue.  That’s fine.  My rifle is what I like to call “MY-spec”… it is better than milspec… cause it is MY-spec.

Have a good one.

Stainless

Stainless I agree 100%.  All the data you've posted is very true.  

Of my wife and my 5 ARs two I've experimented with.  Her 20" A2 rifle has a Sully stock which uses a CAR length buffer.  I put in a LMT H buffer, Wolff XP extractor spring and regular Bushy AR carrier.  This rifles been 100% reliable.  

On my Franken M4gery 16" I'm running a Colt M16 carrier, PRI fatboy gas tube, Wolff XP extractor spring and a LMT H buffer so far it's been 100% reliable using AE.223, Wally World Win white box Value pack, Q3131a and XM193.  

Quoted: Stainless I agree 100%.  All the data you've posted is very true.   On my Franken M4gery 16" I'm running a Colt M16 carrier, PRI fatboy gas tube, Wolff XP extractor spring and a LMT H buffer so far it's been 100% reliable using AE.223, Wally World Win white box Value pack, Q3131a and XM193.

What I would like to hear from you, is your comments on the recoil "feel" of this set-up.  It doesn't have to be exact, or scientific.  Just lemme know what your "gut" tells you.  I am thinking the above weapon is going to "feel" a lot less recoil.



Oh yeah, on a COMPLETELY different note.  When I switched from the 16" carbine length gas system, to the 20" rifle gas system... I can TOTALLY feel a difference in the way the action "feels" as it is operating.  I swear, the rifle length gas system... is... for lack of a better phrase... "Smooth as Buttah."

have a good one.

Stainless

Quoted: Quoted: Stainless I agree 100%.  All the data you've posted is very true.   On my Franken M4gery 16" I'm running a Colt M16 carrier, PRI fatboy gas tube, Wolff XP extractor spring and a LMT H buffer so far it's been 100% reliable using AE.223, Wally World Win white box Value pack, Q3131a and XM193.   What I would like to hear from you, is your comments on the recoil "feel" of this set-up.  It doesn't have to be exact, or scientific.  Just lemme know what your "gut" tells you.  I am thinking the above weapon is going to "feel" a lot less recoil. Oh yeah, on a COMPLETELY different note.  When I switched from the 16" carbine length gas system, to the 20" rifle gas system... I can TOTALLY feel a difference in the way the action "feels" as it is operating.  I swear, the rifle length gas system... is... for lack of a better phrase... "Smooth as Buttah." have a good one. Stainless

My shoulder o'meter says...........j/k   It's working so well that I cannot tell the difference in recoil between my M4gery with this setup and my 20" A4gery which has a rifle buffer and a new RRA enhanced carrier.  To me they feel about the same.  I had the same set up on my postban upper back during the AWban but it was a Bushy 14.5" barrel w/A3 TacBrake from KKF.  It had muzzle dive and way more flash and noise from the brake.  Many people here disagreed that this could happen.  I could easily tell the difference I put about 2500 rounds through it with a CAR gas tube and a CAR buffer.  Then I installed a LMT H buffer and PRI fatboy gas tube and put another 500 rounds through and was very suprised at how much louder and much more flash it had.  If you think about it, it totally makes sence.  With the Fatboy gas tube and heavier buffer bolt was staying closed longer thus more energy is making it to the muzzle instead of it pushing the bolt backwards as early as it would with a regular CAR buffer and CAR length gas tube, this caused more flash and which made the A3 Tacbrake work much more efficiently.