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PistolRogue 08-21-2010 03:07 PM

A Few Simple/Cheap/Free (Depending on your toolbox) TPX Mods
Well, after getting back out with the TPX a few times, I've started to get around to fixing some of its minor issues and improving on some things I felt could be better.

Before I continue, a fair warning:


Originally Posted by TippmannEmployee1
Fyi - Doing these mods to your Tpx will void the warranty from Tippmann.

-Tippmann Sales Rep

Okay? So with that out of the way...

I've been on a big kick lately about trying NOT to spend ridiculous amounts of money on my gear anymore. So these projects were all designed for maximum benefit at minimum cost, and can be duplicated easily if you have a modicum of experience with hand tools and a dremel. In one case I DID have an unfair advantage with the use of a Bridgeport vertical mill at work, but it is NOT necessary, just makes things easier and faster. Feel free to read through and then add your free/cheap mods for the TPX.

‎"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away."

- Antoine de Saint-Exupery

Rail and Finger-Groove Removal
For those that haven't seen mine or AgentSmith's TPX's before, the first steps were removing the rail and fingergrooves. While I used the Bridgeport vertical mill at work to remove the rail quickly and cleanly, anyone could do this with some time, and a dremel or assortment of files and sandpaper. The grooves were removed using a dremel with a heavy grit sanding roll, followed by gradually working at it with sandpaper from 80 grit incrementally up to 400 grit. IMO, this makes the TPX worlds better to hold and aim, as the grooves are spaced so far that even with my big hands, my pinky was stretched enough that it created a tendency to aim low.

Adding Some Leverage to the CO2 Plug
Next up, was the common problem that changing out pressurized 12 grams is, frankly, a pain in the ***... What I did was drill and tap the bottom of the plug for a 1/4"-20 threaded bolt, and found one just the right length to barely stick past the bottom of the clamshells so as not to snag in the holster. Now, this isn't a perfect solution, as if you attempt to remove the plug with a FULLY pressurized 12ie, it will almost always go straight past the "step" and either blow out the pierce seal from behind the snap ring, OR launch the 12ie like a missile. Which looks pretty cool, but isn't the safest thing. However, it works great for when you get down to the last mag or so before empty(normal use as far as I'm concerned). Something like AgentSmith's "decoder ring" will work a lot better for you (more leverage = more control) if you want to be able to remove full-pressure 12ies.

Smoothing Out Mag Changes
Another thing I found was that on fast, no-look mag changes, I'd often get the mag hung up on the edges of the magwell, and would have to look down to reorient myself and get a clean mag change. Part of this is simply a lack of familiarity and a need to retrain my muscle memory to the mag changes. But, to make things even easier on myself, I performed an operation common in real-steel competition pistols- I chamfered the bottom edges of the magwell. This was done with a small diameter sanding roll on the dremel, and then smoothed out with various grades of sandpaper. I actually plan on hitting this again and going a little more extreme on the front and rear edges (the sides are maxxed out already) but it is already a VAST improvement in speed-reloading compared to stock. And it was easy and FREE to do!

Installing a "Man's Detent"
This one is a bit more complex, and requires a 3/8"-24 tap, and the requisite drillbit (the size of which escapes me at the moment). I have always HATED the Tippmann "ball latch", or detent. It provides a lot of drag on the bolt (pass the bolt through the breech block by hand with the detent installed and you can feel the difference) and IMO, probably contributes to paint breakage with the more brittle paints. So I got frisky and decided to install an autococker ball + spring type detent. I will advise that you don't attempt this one unless mechanically inclined as alignment is pretty important- too far back and it will interfere with the ball loading into the chamber, too far forward and it will let the second ball in the mag partial-feed and possibly get clipped by the bolt. I lined up where the point of the original "ball latch" was, and used vernier calipers to score a line across the side of the block to mark the spot. I then put the block in the drill press and centered on that line, and drilled a hole. After deburring the freshly drilled hole, it was simply a matter of tapping for the detent.

After tapping, you need to align your detent. Since the TPX is not the original application, screwing it all the way in will inevitably leave the threaded portion sticking into the breech and will either prevent your bolt from coming forward or score the crap out of it over time. You need to use some loc-tite (or, I find a dab of crazy glue works just as well and secures faster), and set the detent at the proper depth. Alternatively you can use washers or o-rings to shim the detent. I used a Check-It Products rebuild-able model that has a removable cap so you can change the spring and ball without taking the whole thing out. The last thing you need to do is drill a hole in the right side clamshell to allow the end of the detent to stick out of it. My advice is to start with a small bit and gradually step up to the size bit you need, as when I went from a small bit directly to the big one, it tore up the rectangular portion on the outside of the clamshell (see area around detent in pics).

Sadly, I didn't have the camera with me at work but you can see what it looks like from the outside in the pic. Also, depending on your preferences, you can also add another detent to the other side if you utilize field paint that is extra extra small. Even though the cocker detent sticks less than half as far into the breech as the "ball latch", I have no issues even with paint smaller than .684", even if I shake the pistol really hard to attempt to dislodge the ball from the chamber.

Other Mods

Also performed but no pics:

Polished the inner bore of the breech block to 400 grit finish
Chamfered breech hole (the one the balls pass through leaving the mag)
Polished the outside of the bolt to 400 grit finish.

Before the mods I was seeing visually noticeable velocity drop by the end of the 3rd mag. After, I have witnessed no VISIBLE drop until midway through the 4th and complete gas-out at the 3rd ball or so into the 5th mag. This is with the stock barrel and VERY small paint. My only big-dollar mod planned for this pistol is a Python barrel kit so that I can do a light underbore to achieve (hopefully) better efficiency and more consistent velocity, so we'll see how things go after that. I'm also mildly considering (simply because its cheap) giving the TechT spring kit a chance. I don't believe their claims about reduced ball breakage (if anything, in a mech spool gun, a lighter spring should have the opposite result), but lighter springs COULD very well increase efficiency.

agentSmith 08-21-2010 07:30 PM

Nice writeup!

One of the major efficiency gainers, IMO, is the detent. It reduces front bolt friction and gives extra shots. The one I have does not have the tippmann detent slot in it, it's good to know this will work with it there, thanks!

I found taking the point of the triggerguard and rounding it off helps holstering.


PistolRogue 01-08-2011 03:04 AM



Originally Posted by TippmannEmployee1
Fyi - Doing these mods to your Tpx will void the warranty from Tippmann.

I almost feel honored for Tippmann themselves to reply to my thread on PBN... lol. What can I say, nothing is ever awesome until the warranty is voided...

Smiley 01-08-2011 05:19 AM

Since the warranty was already voided...

I cleaned it up a bit more. Rounded the trigger guard,shaved the lanyard loop off and extended the magazine release.

4G010H3R0 01-08-2011 03:39 PM

I still need to adjust my c02 plug but here she is so far(drill and tap a bolt in2 it as well). I think I might fill in the holes on the side 2; using 7rd mags its hard to see the balls through the holes so I really see no point in having them there.
(done off of a phone camera :-/ )

agentSmith 01-09-2011 03:30 PM

Beautiful work guys!

I'll add my own to the chorus:

One thing I thought to add, rogue. I bought a cheapo sparkplug guage:

I pinched them under the cocker detent one at a time, until I got the exact thickness that made the detent position perfect. Then I drilled a hole the right size for the detent in the guage and cut around it with tin snips to make a washer, which I pounded flat again with a hammer. This way you get all the detent you can get...


tetanus 01-10-2011 12:49 AM

Good thread, thanks for posting these up.

Susposed to get some snow tonight so hopefully i'll have the time to do these tomorrow.

Crash 02-27-2011 08:57 PM

First photo is in this thread
This was an idea I came up with a few months back when playing with a borrowed TPX and running into problems changing 12 grams. This combined with a basic dislike for either dumping them or keeping up with them made me wish I could have run it on either CA or HPA. While waiting around to get a TPX I did some thinking and started scrounging parts. I decided to follow the kiss method and go with a dummy 12 gram and mini vert cocker asa. The dummy 12 gram I had 1/8 th inch port didn't line up properly and would have caused the asa to pinch the rear rail screw so when I turned it over to Joe I asked him to move it back about a half inch to solve this problem and had him cut the hole in the rail for the asa to sit in.

Stilgar 02-28-2011 10:19 AM

Smiley: How did you extend the Mag Release?

desertT1 02-28-2011 10:56 PM


Originally Posted by Stilgar (Post 1713358)
Smiley: How did you extend the Mag Release?

That looks like a fastener on there. I'm guessing he drilled and tapped the release and screwed the bolt in.

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