Airsoft Sniper Forum banner
1 - 3 of 3 Posts

· Registered
10 Posts
Discussion Starter · #1 ·
Hello everyone.

I occasionally play at a field that has an FPS limit substantially lower than most of the other fields in my area. Therefore, I became interested in the PCS bolt concept. Unfortunately, my Tanaka is a post-ban, with a non-PCS bolt installed. I therefore began research about how the PCS bolt works.

It is my understanding that the PCS bolt mechanism is simply a large screw that restricts of the gas path in the bolt head, thus reducing FPS. This large screw is held in place by a smaller grub set screw. Stripping my non-PCS bolt as far as possible, it is clear that the hole for the grub screw is there, albeit not threaded. The hole for the aforementioned large screw has yet to be drilled or threaded, but there is a small countersunk area in the casting that indicates where it would be.

It would be trivial to drill the hole for the large screw, then tap both that and the set screw hole, thus converting a non-PCS bolt into a PCS bolt. However, before I go any further with this line of thought, I would like to make a request: Could someone with a PCS bolt please strip it, remove the PCS screw and set screw, take some measurements, then post them here for me?

In terms of the PCS screw: The outer diameter of the threaded portion, the diameter of the head, and the length of the threaded portion would be great.

In terms of the set screw: The outer diameter and length would be great.

Of course, the actual thread pitch of both would be even better, but I understand that that is hard to measure. A good set of pictures of both would also be appreciated.

I understand that this is asking quite a lot, but if anyone has the time to help me out, it would be much appreciated.

· Premium Member
2,311 Posts
It really doesn't matter what the actual screw is. If you measure the distance from the part you are drilling and tapping to the nozzle, then add a millimeter or 2 that's the length of the big screw, and the length of the grub screw is just from the outside of the bolt to the outer diameter of the countersunk hole. As far as thread pitch goes, tighter is better so no gas escapes but it really doesn't matter when you are using screws of that size.

Basically, you can use any screw/hole combo you want - it'll have the same effect.
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.