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View Full Version : Legality of AR15 Gas Piston with Buffer tube...


Sir Stunna Lot
11-27-2012, 12:35 AM
No, i havent put together such firearm yet.

Just wondering if anyone out there can shed some light, thoughts, or penal codes on this matter.

I know that buffer tubes are legit on a DI ar pistol since the buffer tube isnt technically a stock, but can still be used as one.

Would a buffer tube still be allowed on a piston AR pistol so that i can still use the buffer tube as a faux-stock?

stix213
11-27-2012, 12:46 AM
Doesn't the bolt carrier still go back into the buffer tube on a piston AR?

RoundEye
11-27-2012, 12:51 AM
Doesn't the bolt carrier still go back into the buffer tube on a piston AR?

I pretty much had the same thought, unless it some kind of system on top like the old Olympic Arms pistols use to have.

12:13
11-27-2012, 1:11 AM
You mean like this one:
http://primaryweapons.com/store/pc/viewPrd.asp?idproduct=444&idcategory=43

You can get the above via SSE w/BB

I pretty much had the same thought, unless it some kind of system on top like the old Olympic Arms pistols use to have.

Or like the Rock River LAR-PDS:
http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=441

Sir Stunna Lot
11-27-2012, 4:47 AM
Humm. Maybe I'm missing something... Do most gas piston setups still need a buffer tube to operate?

artoaster
11-27-2012, 4:54 AM
I don't think you'll find it works too well trying to get a AR pistol buffer tube into your shoulder, if that's what you're going for.

strongpoint
11-27-2012, 6:21 AM
Humm. Maybe I'm missing something... Do most gas piston setups still need a buffer tube to operate?

where do you think the bolt carrier goes as the brass is being ejected? what do you think drives it forward to strip a new round off the magazine and chamber it? (i don't intend that to sound mean; i'm just saying think about the mechanics of such a system.) your basic piston setup essentially just replaces the gas tube with a pushrod that moves the bolt carrier in the exact same way to cycle rounds.

the RRA model uses a redesigned bolt carrier and places the spring above the barrel in order to dispense with the buffer tube completely, but that's RRA's own thing, far from "most gas piston setups." IMHO, it's starting to push the limits of what can be labeled an AR.

desertjosh
11-27-2012, 6:25 AM
I don't think you'll find it works too well trying to get a AR pistol buffer tube into your shoulder, if that's what you're going for.

Why not? I do with my pistol build and its pretty comfortable.

MXRider
11-27-2012, 6:28 AM
Why do you think it would make a difference legally? Technically speaking a DI AR15 is a piston operated system. All a piston kit does is relocate where those gasses act on the op rod.

Sent from my PC36100 using Tapatalk 2

artoaster
11-27-2012, 7:16 AM
Why not? I do with my pistol build and its pretty comfortable.

Your avatar is correct. :)

But, if you wanna you're gonna so what's the dif?

Quiet
11-27-2012, 8:53 AM
Humm. Maybe I'm missing something... Do most gas piston setups still need a buffer tube to operate?

Yes, they still need a buffer tube to operate.

Only ones that do not are the ones designed to operate differently (recoil system is on top of the bolt, not behind it); like the Olympic Arms OA-93, Rock River Arms LAR-PDS, Kel-Tec PLR-16 and SIG P-556.

JeremyS
11-27-2012, 11:46 AM
If the charging handle is in the normal spot, it probably (almost certainly?) requires a buffer tube. If the charging handle has been relocated to the front or to the bolt itself, it's likely a design that doesn't use the standard buffer tube design and if it's a rifle it probably has a folding stock on it.

I have an Adams Arms complete upper on a lower that I put together, and their piston uppers or piston conversion kits are designed to work with your standard buffer weight/tube/spring setup.

mif_slim
11-27-2012, 11:48 AM
Humm. Maybe I'm missing something... Do most gas piston setups still need a buffer tube to operate?

Yeah, like some said...you still need the BCG to move back. Changing DI to Piston doesnt magically change the BCG to be shorten. ;D

Only way you can eliminate the buffer tube is to go 22lr or the links above.

Saym14
11-27-2012, 11:53 AM
Why not? I do with my pistol build and its pretty comfortable.

I agree

Arkangel
11-27-2012, 12:38 PM
Just make sure that on a pistol AR the buffer tube has been modified to NOT accept a stock or use a pistol buffer tube (they are specifically designed not to accept a stock).

Sir Stunna Lot
11-27-2012, 11:47 PM
Ah, thanks for the clarifications guys. I was under the assumption that GP without a buffer tube was more common. I will stick with the more common type with the buffer setup.

1 SIG fan
11-28-2012, 12:15 AM
Only a select few models like the sig 556 pistol. All other ar pattern weapons use a buffer tube. Piston or DI....

Ak variants (like that sig) dont

SJgunguy24
11-28-2012, 5:25 AM
Ah, thanks for the clarifications guys. I was under the assumption that GP without a buffer tube was more common. I will stick with the more common type with the buffer setup.

Look at any AR upper, where is that big steel bolt carrier and bolt gonna go when that gun cycles? There isn't room for it to go anywhere but back.

Mr. Casull
11-28-2012, 5:57 PM
I have an CMMG AR pistol with a 7.5 inch barrel and use the buffer tube to put my cheek on. And it works great with a Eotech sight.

Sir Stunna Lot
11-29-2012, 1:23 AM
Look at any AR upper, where is that big steel bolt carrier and bolt gonna go when that gun cycles? There isn't room for it to go anywhere but back.

of course i know the ins and outs of an AR, like i said, i thought the buffertubeless is more common, but supposely theres only one version out there

JeremyS
11-29-2012, 10:21 AM
... i thought the buffertubeless is more common, but supposely theres only one version out there

No, there's a handful. Quiet listed 4 in his post, and there are more. It's just not as common as using the buffer since it requires a complete redesign of how the bolt and recoil spring system work.

duc748bip
11-29-2012, 10:59 AM
There are quite a few Piston upper that does not require a receiver extension.
Where the action spring sits in line with the piston or is actually around the piston pulling the bolt close almost AR-18 like.
I do think receiver extension is NOT a stock and having it in a AR pistol will not turn it into SBR. If some DA want to burn you having a mechanically un necessary receiver ext. on a AR pistol... they will have to put the whole AR pistol category into jeopardy

http://zmweapons.com/LR_KITs.jpg

Are these guys stil in business? ZM-weapon?

Tjfearl
11-29-2012, 11:30 AM
There are quite a few Piston upper that does not require a receiver extension.
Where the action spring sits in line with the piston or is actually around the piston pulling the bolt close almost AR-18 like.
I do think receiver extension is NOT a stock and having it in a AR pistol will not turn it into SBR. If some DA want to burn you having a mechanically un necessary receiver ext. on a AR pistol... they will have to put the whole AR pistol category into jeopardy

http://zmweapons.com/LR_KITs.jpg

Are these guys stil in business? ZM-weapon?

I don't know about ZM, but that looks just like the Para AR...http://www.para-usa.com/new/product_rifle.php