Buffer Tube Questions

[Mr. Waverly]

Some basic AR buffer tube questions as I try to learn more about this platform.

As I look at AR's, how do I know what buffer tube it has? And, how do I tell the difference, from just looking, between pistol, carbine and rifle buffer tubes?

Assume that I pick up an AR pistol lower, and let's also assume upcoming laws do not impact AR pistols. Would there be any advantage, or disadvantage, with using a carbine buffer tube in place of a pistol buffer tube? From what I think I know, I cannot put a stock on a pistol buffer tube - that would require a carbine or rifle buffer tube, correct? But, if I really wanted to, a brace would work with a carbine buffer tube, right (but not that I would really want to)?

There is probably a lot more to learn about buffer tubes, so I would appreciate any help.

Thanks.

[GreaseMonkeySRT]

A pistol tube is smooth and about 5 inches, a carbine tube is 7.25" and can accept every type of stock out there. A rifle tube is the longest and only used for fixed stocks like an A2, Magpul PRS, or other variants. It's very easy to see which kind you have just by looking.

A carbine buffer tube will give you the most versatility. Unless only wanting a pistol setup, a carbine tube could have that lower being used later as a rifle or whatever else.

[wizzi01]

Then there are commercial and mil spec buffer tubes. The commercial tubes are .02" wider than mil spec.

[GreaseMonkeySRT]

Then there are commercial and mil spec buffer tubes. The commercial tubes are .02" wider than mil spec.

Pretty much all tubes are mil-spec now.

[MCPO_SOCM_RET]

In a pistol caliber only build, the traditional gas system of an AR is missing outright - or, pistol caliber only ARs utilize a direct blowback system which applies more pressure to the bolt carrier group than a gas system would. Furthermore, the bolt carrier group is typically heavier.
To smooth the action and ensure reliability, a larger buffer weight is a must-have.
5 oz - 8+ oz depending on the pistol round.

A standard carbine buffer weight is around 3 oz for reference.

So, if the buffer is heavier in your hand - you've got a pistol buffer. I know it's not just looking like you asked, but still another way to tell.

[special reserve]

Suppressed or unsuppressed also makes a difference. Heavier buffer for suppressed.

[XDM 40 cal]

A pistol tube is smooth and about 5 inches, a carbine tube is 7.25" and can accept every type of stock out there. A rifle tube is the longest and only used for fixed stocks like an A2, Magpul PRS, or other variants. It's very easy to see which kind you have just by looking.

A carbine buffer tube will give you the most versatility. Unless only wanting a pistol setup, a carbine tube could have that lower being used later as a rifle or whatever else.

[BillR]

Pretty much all tubes are mil-spec now.

Still many commercial tube and stock makers out their . Really verify if buying at a gun show.