School Me On AR Buffers Rifle vs Carbine

[Straightbolt]

I have a Rock River standard A2 20" HBAR AR I bought complete 15 years ago.
I want to put a 16" "Dissipator" HBAR upper on it with a carbine length gas system.
Will I need to change the buffer ? and if so to what

 

[jawn]

You shouldn't have to, if you're going to run the A2 stock. If anything, carbine-length gas is more overgassed than a rifle-length gas, so you might be a tad overgassed. It'll only be problematic if you have cycling problems. It's unlikely.

If you want to add a collapsible stock, you're going to need a buffer tube, castle nut, end plate, carbine buffer spring, and a buffer of your desired weight.

 

[Shazam]

I've run 16" carbine gas uppers with rifle buffer, spring and stocks on numerous occasions. It always worked well for me. The greater mass of the rifle buffer seems to slow the action a bit. I also find that the heaver rifle stock balances well with a HBAR barrel.

Now a real, old style dissipator with the gas port up near the end of the barrel is a much fussier animal.

 

[Straightbolt]

Thanks !
I only have 2 AR rifles and I bought them new and complete so mix matching uppers/lowers is all kinda new.

 

[Biggfoot44]

Two different (primary) variables with AR buffers, length and weight.

If you are using a standard A2 stock, rifle length remains correct.

Standard weight will *probably* be fine with that 16in carbine gas upper. Bur IF there are issues in actual use of your specific gun/ upper, buffer weight is one of the variables that can be fine tuned.

 

[Melnic]

Clandestine had a post here somewhere on selecting buffers.
I have a Delton Dissipator and somehow I had an H2 buffer on it after swapping around lowers. I think the H2 came with a Lower/stock kit I got early on and did not notice or know about buffer weights.
Well, the H2 sometimes would not cycle with the dissipator. Dissy has a rifle length gas on it and maybe that is why it did nto like the H2. Swapped out to a Carbine buffer and problems went away.
This was using reloads which are just about 2700fps which is NOT what many factory 5.56 runs at so that may have had something to do with it.

Question is, do you know what buffer you have now? You can weigh it if its not marked.

 

[outrider58]

I must have misread the OP so I'm changing my post. It sounds like he wants a 16'' rifle with a longer sight radius ergo, the 16'' ''dissipater'' upper . In that case, I agree with Jawn.

 

[Biggfoot44]

The OP can correct us, but the way I read it was :
1. Stock remaining standard ( fixed) A2 .
2. Upper only being changed to a 16in with carbine gas system.

Not the currently sexy / popular set up , but has plenty going for it * as long as the user has average length adult arms -*, and is satisfied with "reasonably short" oal vs " slightly shorter to fit into a specific dimension" , such as a vertical mounted quick release mount in a compact patrol vehicle.

 

[bkuether]

Not an expert by any means, but I *had* a non dedicated lower with an A2 stock, and I "Barbie Dolled" all of my carbine and mid length rifles on it, at one point. All of them ran fine. In fact, my Stag Piston upper, which usually hit pretty hard with a carbine buffer, actually smoothed out a bit with the rifle length buffer.

I am actually thinking of moving that piston upper to an A2 stock permanently.

 

[sailskidrive]

It could be my imagination but the recoil impulse on the standard A2 length buffer always seems smoother to be me than the carbine length buffer. Maybe the 5-7 extra coils spread out the tension more evenly.

I personally would not go for a dissipator with a carbine length gas system. If the rifle length gas tube system ushers in anxiety around being under gassed, at least consider a faux dissipator with a mid length system. I would probably just go rifle length and open up the gas port....

 

[outrider58]

It could be my imagination but the recoil impulse on the standard A2 length buffer always seems smoother to be me than the carbine length buffer. Maybe the 5-7 extra coils spread out the tension more evenly.

I personally would not go for a dissipator with a carbine length gas system. If the rifle length gas tube system ushers in anxiety around being under gassed, at least consider a faux dissipator with a mid length system. I would probably just go rifle length and open up the gas port....

Isn't a faux dissipater and a dissipater with a carbine gas system the same thing?

 

[FlatsFlite]

Isn't a faux dissipater and a dissipater with a carbine gas system the same thing?

Yep. A true dissipator has a full-length rifle gas system on a 16" barrel. Longer sight radious and softer impulse for faster follow-up shots.

 

[Magnumite]

The rifle length system should be less resistance to the reciprocating mass. I agree with being a longer smoother impulse.

I have an 18" barrel with a rifle length gas system upper. With an unshrouded, short skirt carrier it ran fine with the carbine extension tube, spring and carbine buffer. I changed to an M16 full skirted carrier (only change) and it was a manually operated repeater. I wanted the stability of the fixed stock, so I changed to the A1 extension tube with the A2 stock, recoil system and spacer - the rifle runs fine with it. Just my experience.

 

[clandestine]

Remember that the buffer travel is the same +/- variance of about 1/16" unless something is wrong. The bolt cant travel more in a rifle buffer because the gas key will strike the lower.

 

[clandestine]

Not an expert by any means, but I *had* a non dedicated lower with an A2 stock, and I "Barbie Dolled" all of my carbine and mid length rifles on it, at one point. All of them ran fine. In fact, my Stag Piston upper, which usually hit pretty hard with a carbine buffer, actually smoothed out a bit with the rifle length buffer.

I am actually thinking of moving that piston upper to an A2 stock permanently.

It could be my imagination but the recoil impulse on the standard A2 length buffer always seems smoother to be me than the carbine length buffer. Maybe the 5-7 extra coils spread out the tension more evenly.

I personally would not go for a dissipator with a carbine length gas system. If the rifle length gas tube system ushers in anxiety around being under gassed, at least consider a faux dissipator with a mid length system. I would probably just go rifle length and open up the gas port....

Unless you have a custom heavy carbine buffer, a rifle buffer always weighs more (unless its weights are removed or its a lightweight model).

Its likely your guns were overgassed and a rifle weight balanced things out.

 

[WSM]

I'll ask in this thread rather than create a new one. Can I run a true Dissy upper with a standard carbine buffer setup? Specifically this stock set. http://www.primaryarms.com/zm48988-a/p/zm48988-a/

I can't find any definitive answer about buffer/spring. I would assume rifle length gas would take a rifle buffer.

Sent from my Nexus 5X using Tapatalk

 

[OrbitalEllipses]

^That is a carbine buffer tube, it uses carbine buffers. Gas vs. buffer shape/size is irrelevant. Buffer shape and size is based on buffer tube length. Gas system will impact buffer weight.

 

[WSM]

^That is a carbine buffer tube, it uses carbine buffers. Gas vs. buffer shape/size is irrelevant. Buffer shape and size is based on buffer tube length. Gas system will impact buffer weight.

So....if carbine/rifle determine length, what determines the weight? How do you know what buffer weight you're looking at for the given length?

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[clandestine]

So....if carbine/rifle determine length, what determines the weight? How do you know what buffer weight you're looking at for the given length?

Sent from my Nexus 5X using Tapatalk

Unless you know the gas port size, its almost impossible to say what buffer weight to use. There is no standard outside what Colt uses. You need pin gauges to check port size. Most companies go really large on the gas port to ensure they cycle weak port pressure ammo. There are other variables such as gas system efficiency, muzzle devices, ans such.

If you have a carbine buffer system buy this and its all of the weights possible except the custom heavy buffers.

https://www.kakindustry.com/ar-15-parts/lower-parts/buffer-tubes-and-parts/ar15-buffer-system

 

[outrider58]

Unless you know the gas port size, its almost impossible to say what buffer weight to use. There is no standard outside what Colt uses. You need pin gauges to check port size. Most companies go really large on the gas port to ensure they cycle weak port pressure ammo. There are other variables such as gas system efficiency, muzzle devices, ans such.

If you have a carbine buffer system buy this and its all of the weights possible except the custom heavy buffers.

https://www.kakindustry.com/ar-15-parts/lower-parts/buffer-tubes-and-parts/ar15-buffer-system