Mixed feeling about mine.

On the plus side, its' short, looks cool and seriously cuts down on the overall lenth of the pistol.

On the negative side, mine had problems with the GSE spring not staying put on the modified bolt carrier. Also, with the spring up over the bolt carrier like that, the forward assist just hits the spring and doesn't work well.

OK so I read most of this thread and maybe I missed it ...

Is there any mod that could be done to a standard 6 position buffer tube so that it could be used on a pistol lower? Some way to make it so that a stock could not fit on it?

I have a Gunsmoke 7.5" pistol kit with the short, pistol spring buffer. It works great. There is an insert for the carrier that allows a small diameter pistol spring to run inside the bolt carrier. It makes for an extremely compact package. The only difference is you have to unscrew the rear cap and dump the spring before you can split the upper and lower. If you oil the insert properly it is easy enough to remove. I have run several hundred rounds through it with no issues. Very loud and huge fireball at night.

Why not just use the set screw mod? Tap the takedown pin detent hole with a #4-40 tap to a depth of about 1/64" longer than your set screw, clean it out thoroughly, then shorten the detent spring to accommodate the length of the set screw. Now put in the takedown pin, the detent, and spring, and hold it in place with your setscrew. Make sure you lubricate that tap VERY well, and go slowly, because you don't want to have it break in your lower.

My Aero Precision Lowers come already threaded - simple as it gets and a GREAT mod even if you have to tap your lower (no more hunting for flying springs and detents).
I use the Phase 5 Tactical Pistol Buffer Tube - has a nice Logo, foam cheek weld cover and says "Pistol" for the bitchie little girls who want to argue about ATF rulings on barrel lengts, Pistol lowers and the likes
I run H buffers with Sprinco Blue springs on all my pistols - 7.5 and 10.5 barrels in my 5.56 family and 7.5 and 11.5 for my 7.62 barrels.
They all run 100% reliable even with Wolf (the WPA) ammo - I did have to polish the chambers on all of them to increase the reliability to 100%.

Does anyone have a Spikes ST-9BS Buffer Spacer? Need to know how long it is. I was thinking of using a Phase5 Tactical Pistol Buffer Kit and cutting off an inch or so off of the threaded end and just using a standard buffer for my 9mm AR build. This would both shorten the buffer tube and eliminate the need for a long 9mm buffer or buffer spacer. What do you think?

I know there was an earlier posting trying to collect the lengths of various pistol buffer tubes, but I'm looking for a different measurement. I'm looking to see if anyone here with a PSA buffer tube can give me an accurate OD measurement. I'm looking to build two pistols, and am doing one with a Spikes kit and the other will be PSA whenever their pistol build kits come in. I'm asking because they don't show up on this chart: Pistol Buffer Tube Cover Fit Chart, and the specs aren't on PSA's website.

I did find a post here where somebody said the PSA pistol tube is an RRA tube. If anybody could confirm that, it would answer the question as well since RRA is on the chart.

Thanks in advance.

i built a tube for mine and its the same size as the bushmaster carbon pistol but its aluminum and uses a custom buffer and smaller m4 spring. need to get out and run some rounds to see if it works for more then a couple rounds
video