It's 4-40 tread, have it done on all my ARs

considering the state of things right now

does this need to be stickied?

I am just trying to learn, and this appears out of date

It is.

Per current ATF regulatory opinion, OAL with folding and collapsible braces is measured folded and collapsed, and on a bare buffer tube when a removable slip on brace is used. Muzzle devices only count when permanently attached.
https://www.recoilweb.com/measuring-the-overall-length-of-a-pistol-atf-has-altered-the-deal-151346.html

It is contradictory to their criteria for anything else, and contradicts their previous methods in dealing with manufacturers.
https://www.thefirearmblog.com/blog/2018/05/24/oal-brace-folded/

For my firearm build with an SBM4 I used the MI 9" long tube.

I just use a 4-40 set screw and so don’t have to drill a hole in the end plate.

Hey! New here, can anyone identify this buffer that came out of a pistol build I purchased? Thanks!

https://share.icloud.com/photos/0cdfpXkGQH8fgOMk_MXKODXwA

That is the weirdest buffer I've ever seen. The deadblow weights are on a central post and are exposed instead of inside a cylindrical body.

Reverse google search comes up with nothing.

Your image isn't showing... Here's the image:

Hey, thanks for the help with the image! It is weird, but I think I just came across it after a deep dive into the google machine. I believe it’s an AAC rate-reducing buffer. Apparently, the sliding weight is a bit heavier to reduce rate of fire which would help kill bolt bounce.

i tried a search even on google with 0 results.

with the "brace" outlawed or grey area. as per the new law if you just remove the brace...its an actual pistol. just the tube.
so with that. is it still a pistol with a tennis ball on the end of the stock?

thats not a stock nor a brace?

Having anything covering the rear of the tube is suspect.

Back in the 1980's, when AR pistols started becoming popular, the short pistol tubes included a padded tube, but it did not cover the rear of the tube, as it was an open ended padded tube.

The early arm braces were also open on the rear.

Later braces started to just cover the rear of the tube, in a questionable manner.

Also there is an implied tube length limit.

Putting anything on a carbine length tube would likely exceed the length limit.

I added an extended, padded recoil pad to a shooting vest, not to the firearm.

What is the “implied tube length limit?”

There is language in the doc that implies that a round "pistol" buffer tube should not exceed 6-1/2".  I am fairly certain that this is to rule out the extended round "pistol" buffer tubes that became popular for those who wanted to add a vertical foregrip to their 10.5" AR "pistols", as well as those who would like to use a rifle receiver extension on their "pistol" with a tennis ball on the end.  Any standard 6-pos buffer tube is fine, even though they are longer than the 6-1/2" arbitrary limit placed on the round "pistol" buffer tubes.

Clead as mud, and intentionally so.....

Not sure of a question, but I really like the Vltor pistol buffer system, as it's a smooth tube, making it legal.

https://www.vltor.com/shop/ar/receiver-extensions/pistol-a5-the-vltor-a5-pistol-kit/

A smooth tube is not required to be "legal", the standard 5 or 6 position buffer tube your brace was attached to is perfectly legal to remain.

I have been wondering if the A5 would be legal as it adds length that is not required for function of the action.

Not as I've read it. It states something like remove the brace and eliminate the ability to reattach it. The Vltor A5 has no attachment point, and is a smaller diameter tube. Seems like it is spot on legal. IMO.

Im curious why you say "perfectly legal". Is there some legal definition somewhere on legal tubes?

What it says:

When you get some free time:

https://www.atf.gov/rules-and-regulations/docs/undefined/factoringcriteriaforfirearmswithattachedstabilizingbracespdf/download

I'm guessing the answer to my question is just going to be, "no one knows" and the ATF will get to decide on an ad hoc basis. But here it is:

I would like to know if a bare pistol buffer tube (no dimples, no foam, just threaded on one side and smooth to the end) on a sub 16" barreled AR-15 is allowed under the new rule and if so how it is measured/how long can it be?

1) A bare buffer tube can still have older braces slid onto them. So does that not comply with this:

"Permanently remove and dispose of, or alter, the “stabilizing brace” such that it cannot be reattached, thereby removing the weapon from regulation as a “firearm” under the NFA." p. 271

https://www.atf.gov/rules-and-regulations/docs/undefined/factoringcriteriaforfirearmswithattachedstabilizingbracespdf/download

What if the pistol never had a brace on it? If it did, how would you "permanently remove and dispose" of it? Does that just mean you take it off, throw it away and never put it on again? Does this even matter if one doesn't have a brace?

2) There are bare pistol buffer tubes that are some 7 and 1/4" or so in length. Installed they are between 6 &1/4" to closer to 6.75" depending on if you measure to the castle nut, or the receiver itself.

"...an AR-type pistol with a standard 6- to 6-1/2-inch buffer tube may not be designed, made, and intended to be fired from the shoulder even if the buffer tube provides surface area that allows the firearm to be shoulder fired." p 162

I've read some posters say something like, "Well that is to go against pistols that have extended buffer tubes that aren't hollow all the way to the end." Which I hope is the case. It would be clearer if they said the 6.5-7.5 range or described how to measure this length.

https://www.ar15.com/forums/ar-15/-/122-778257/?r=&page=5#i8516698
https://www.ar15.com/forums/AR-15/-Keep-all-new-ATF-Brace-rule-change-discussions-HERE/122-778257/?page=7#i8518007
https://www.ar15.com/forums/AR-15/-Keep-all-new-ATF-Brace-rule-change-discussions-HERE/122-778257/?page=7#i8518182
https://www.ar15.com/forums/AR-15/-Keep-all-new-ATF-Brace-rule-change-discussions-HERE/122-778257/?page=7#i8518341

I've read through those posts above, but I don't suppose there has been any more clarity since then?

In that case there is no action needed, as long as the buffer tube isn't the extended variety that has added length that is not required to cycle the weapon.