Modification question...

[wgerber44]

Hello, first of all if this is the wrong forum, please feel free to move to the correct one and/or inform me so.

<Moved from Gunsmithing Area>

My question: I have a DPMS Lo Pro Classic AR-15 (16" mid-length) and am wanting to switch from the A2 stock to an adjustable carbine stock. I have all of the parts req, with the possible exception of the buffer. What buffer do I use? I've done several hours worth of searching and can't come up with a fuzzy, nevermind clear, answer.

The buffer I have is a "308" buffer, but as far as I can tell, that doesn't matter, it is the length and weight that are important. It is at home currently so I'm not 100% sure on the length, but it weighs 3.2oz. According to heavybuffers.com, the AR-15 carbine buffer weights 3.0oz. and is 3.25" long, the same length as the AR-10 carbine buffer. Seems to me, I could use the buffer I have, as increased weight serves only to slow the fire rate, if I interpret all this mumbo-jumbo correctly. BUT, a lot of the information I found recommended an 'H' buffer (3.8oz/3.25") for a 16" midlength upper. I confess I have no idea why the length of the gas system would affect the buffer at all, except to possibly decrease the time between firing and the action cycling???

Any help on this topic would be greatly appreciated... I really wana put my new parts on!!...but not if they wreck my gun...

 

[JR Hartman]

your A2 didn't have a buffer in it already?

 

[Rhutch]

I'd start with an H buffer or the ST-T2 which is between the H and the H2. H will slow it down allow a little more dwell, if I ran into any reliability issues I would go the the ST-T2, but I'd start with the H.

 

[wgerber44]

Yes, it has a rifle length buffer

I would be ok to use the one I have as far as compatibility, but I may have some reliability issues? Is that correct?

 

[dusticles]

I'd say you're probably fine with that buffer but it also depends on the final compressed length of the spring. I had an issue building my rifle because I purchased an out of spec buffer tube without knowing so. Everything looked to work OK until I realized that the bolt catch was actually catching the carrier and not the bolt...

Make sure you have approx. 1/8" clearance between bolt and catch at full rear stroke.

Once you get to the range and start testing keep an eye out for the angle the brass is ejecting. You want to see brass landing at about 4 o'clock. If it's closer to 1 o'clock, you want to go heavier on the buffer.

Last thing to consider is bullet weight. If you want to shoot heavier bullets (62-80gr) you might want to look into the H2 right away

 

[wgerber44]

Turns out the buffer I have is just shy of 2.5" long. Based on everything I've seen here & other places, it couldn't possibly work for any AR so, I'm not sure what its for.

Thanks for your help on this, dusticles.

 

[Conte]

Unless it's some oddball version, like a Vltor A5, you have a carbine buffer tube with that Adj stock, and need a carbine buffer and spring.

If you find yourself in need of a buffer, go back to heavy buffers dot com, order their 6.5oz, and a WolffXp spring for good measure, and call it a day.

I bought their Adjustable kit and played around a lot, settled on the max weight of 6.5oz, and use it across the board on all my uppers.

I don't have a midlength, but I have a 20" Rifle, and a couple diff length carbines. It works equally well on all systems.

A 16" mid should have plenty of gas pressure to drive that system, so I'm confident that setup will work very well for you.