Dispelling the myth that you can't use a carbine buffer/spring in a A2 stock

[BobbyJ]

I've seen many posts and videos stating that you can't use a carbine buffer in a A2 stock. They seldom give reasons for this stating just don't do it.

The main issue is the A2 rifle stock tube is longer than the carbine so its buffers are longer too. Just dropping in a Carbine buffer is going to leave a space. That extra space will cause the BCG+Buffer to bottom out on the gas key instead of the bottom of the stock tube.

To do it without issues you must use a SPACER with the carbine buffer + Carbine spring.
Spacers:
- A roll of quarter -+ 2 quarters as not all A2 tubes are exactly the same depth (they should be) Mine took 41 I think.
- 1" delrin rod of Approximately 2.625 - 2.75" length.
- Buy one from Brownells ROCK RIVER ARMS - AR-15/M16 FIXED STOCK TO CARBINE SPACER $18.00


Some people think that the A2 buffer is best to use in a A2stock. If you think about it most ARs are carbine length gas system and are typically over gassed from the factory. A rifle gas system is "Lower" pressure so if anything you would think you could use a lighter buffer. Most Rifle buffers weigh 5.2 Oz while carbines are 3oz and some how over gassed carbines work with lighter buffers and shorter springs.

The travel of both systems in the tube is the same I would keep the springs match to type of buffer as they are not the same lengths.

I've tried both ways on a 16" carbine + A2 stock. I preferred quarters over Delrin spacers as it adds a little bit more weigh 8oz which helps with recoil. I switched back to Rifle spring + Rifle buffer and really not much difference in feel while shooting. Over all Quarters + H2 buffer + carbine spring felt the best.

I think the myth stems from people that just pop a shorter carbine buffer and spring into a A2 stock and go shooting. This is the worse case and it will work but your BCG gas key will hit the lower causing damage to gas key or lower. BTW i've tested it and after 20 shots no damage but over time I'm sure it would cause issues.

 

[VA_XTC_Shooter]

The AR was designed for rifle length, not carbine. Carbine was developed later and shown to have issues, so midlength was introduced.
What you are talking about is matching up your load, which did not say what you are shooting, and the buffer weight. The buffer length as you prove is important, the delrin or quarters make up the length to rifle length.

So if you want less weight that rifle buffer, why not remove a weight in the buffer instead of storing vending machine tokens in the buffer tube?

 

[PigButtons]

Thank you for your excellent explanation.

 

[BobbyJ]

The AR was designed for rifle length, not carbine. Carbine was developed later and shown to have issues, so midlength was introduced.
What you are talking about is matching up your load, which did not say what you are shooting, and the buffer weight. The buffer length as you prove is important, the delrin or quarters make up the length to rifle length.

So if you want less weight that rifle buffer, why not remove a weight in the buffer instead of storing vending machine tokens in the buffer tube?

I was just showing that you can use a carbine buffer in a A2 stock. The tokens/quarters were just something I had laying around they were not a thought out plan.
They are about the perfect diameter too. Its was not for weight it was just to use a spacer. The weight was just a bonus effect.

I might have been confusing in what I was trying to explain.
1. Can a carbine buffer be used in A2 stock? - Yes with a spacer.
1a. Spacer price and weight -
- $10 in quarters (8 oz)
- $20.00 + shipping delrin rod (?1oz)

2. I probably should not even have mentioned gas system driving buffers. I had read some people thinking you cant use a Rifle buffer in a carbine and can't use a Carbine buffer in a rifle gas system. That is more a function of the stocks tube length than it is what kind of gas system one has. Sorry for the confusion on that.

"So if you want less weight that rifle buffer, why not remove a weight in the buffer instead of storing vending machine tokens in the buffer tube?"
ans: You can't use a rifle buffer + spacer (coins or delrin) in a rifle or carbine tube. They won't fit, too long you wont be able to eject a round. The coins only apply to using a carbine buffer in a A2 rifle tube and not a Rifle buffer in anything.

- Carbine buffer + cabine tube = OK
- Rifle buffer + rifle tube = OK
- Carbine buffer + Rifle Tube + spacer = OK
- Rifle buffer + Carbine tube = not ok (wont fit)
- Rifle Buffer + carbine tube + spacer = Not ok (even worse)

With any combo you can tune it as you suggested by adding or removing buffer weights. The Rifle buffer and spring might be softer as it has more coils than a carbine spring and not sure on longevity on one vs the other. I've swapped them on 6 ARs and never had an issue most likely due to over gassed guns. It can slightly change the ejection pattern but that is to be expected as the springs and weights are not identicle but usually close enough.

- Quarters + H2 buffer = 8 + 4.6 = 12.6 oz
- Rifle Buffer = 5.2 oz (Weighs less not more)

 

[ebb]

Why would you want to?

 

[BobbyJ]

Why would you want to?

Lots of reasons but for me it was I had a couple of A2 stock with no buffers or springs. Old ones and wanted to use use one on a XM651 clone. I had extra carbine buffers and springs but no A2 buffer or Spring.

I was going out to the range and wanted to test that particular gun along with others. So its was a Free buffer vs finding a A2 buffer and spring waiting for mail etc. I just used the carbine buffer + plus spacer with carbine spring and had a great day at the range with it.

Many people have extra carbine buffers laying around why let them go to waste when they work fine?

Later I did get a Rifle buffer and spring but found out they are not really needed and found no benefit over the carbine + spacer.

Or did you mean why would people want to promote the myth that you can't use a carbine buffer in a A2 stock?
I think they were just parroting what they saw on you tube or other sites, most of them never explain the reason. I tried to do that here.

 

[ebb]

Ive watched several of Ian's videos about the Knights rifles that are tuned to use the long buffer and springs. The results are very impressive, no muzzle rise and no recoil. They are so smooth as they cycle that there seems to be no sight picture interruptions. While you may be able to get the carbine length to function, and like it I would be looking to miniplate spring tension and buffer weight to make sure that the buffer never hits the end of the tube and all bolt thrust is stopped before the collision at the end of the tube.