AR pistol -> No buffer tube

[MrNiceGuy]

I want to build a AR pistol with the "Diablo".



But I understand even though it's a piston upper, it still "need" a buffer tube and buffer in the back (sticking out the back on the receiver like a broom handle).

I've seen other piston based AR pistols like the Sig556 that doesn't require the buffer tube and buffer.



So the question is "why" does some piston pistols need a buffer tube and buffer in the back while others don't?

And what other options I have for a buffer tube-less AR pistol other than the Sig556 (keeping in mind I only want the upper since I'm building a pistol lower myself)?

Thx for tolerating my noobness (in AR pistols anyway).

[Addax]

It boils down to the design of the weapons system.

The Diablo is piston driven, but utilizes the standard AR bolt and bolt carrier, thus the AR buffer / buffer tube is required to return the bolt carrier/bolt into battery.

The Diablo was intentionally designed this way, so it could be used with AR lowers, and since virutally all LE and Military clients who shoot full auto have M4 Full auto lowers, it was the most sensible idea to make the Diablo work with the conventional AR set up.

The SIG Pistol is also a piston driven weapon, but it uses a different bolt, op-rod, buffer/spring design, thus, the lower receiver is also different from a standard AR.

Hope this helps to answer your questions...

Here is my new specially built 6.8 SPCII Diablo with a WOA 1:11 twist 6.8 SPCII barrel

I want to build a AR pistol with the "Diablo".



But I understand even though it's a piston upper, it still "need" a buffer tube and buffer in the back (sticking out the back on the receiver like a broom handle).

I've seen other piston based AR pistols like the Sig556 that doesn't require the buffer tube and buffer.



So the question is "why" does some piston pistols need a buffer tube and buffer in the back while others don't?

And what other options I have for a buffer tube-less AR pistol other than the Sig556 (keeping in mind I only want the upper since I'm building a pistol lower myself)?

Thx for tolerating my noobness (in AR pistols anyway).

[Fate]

Sweet mother of pistol porn! That's so beautiful!

[TacFan]

If you want an AR pistol without the tube you need an OA-93

[thedrickel]

But the OA93 is hideous!

[50CalAL]

The Sig 556 Pistol GP design is closer to that of an AK vs AR and the GP, tube and OP rod are all located in the front of the pistol (above the barrel).

GP ARs (most of them) don't utilize a recoil spring on the OP rod so the BCG moves into the buffer tube and the buffer/spring push the BCG forward into the ready position.

[MrNiceGuy]

Understood.
Appreciate all the great info.
Still gonna build an AR pistol regardless....the one from Addax is too bad azz!

[tankerman]

But the OA93 is hideous!

But it looks like a mod to that rail would help the appearance a bit.

[aplinker]

Understood.
Appreciate all the great info.
Still gonna build an AR pistol regardless....the one from Addax is too bad azz!

Look on the bright side... These pistols really do suck as pistols, but with that receiver extension you can get a decent shoulder weld.

It's the closest we can come to an SBR or SMG.

[goober]

The Sig 556 Pistol GP design is closer to that of an AK vs AR and the GP, tube and OP rod are all located in the front of the pistol (above the barrel).

GP ARs (most of them) don't utilize a recoil spring on the OP rod so the BCG moves into the buffer tube and the buffer/spring push the BCG forward into the ready position.

yup.
and add the HK416 GP design in with the "GP AR's" category; also has the buffer & spring (and thus BCG travel) in the "receiver extension tube"

[Q]

And what other options I have for a buffer tube-less AR pistol other than the Sig556

I like the old zm weapons. They still make one but I like the old style better..

[Rukus]

You could do a .22 pistol which would not need to utilize the buffer, but IMO its a waste of a beautiful Diablo upper.