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TCP 738 reliability enhancements

154K views 204 replies 82 participants last post by  olfarhors 
#1 ·
Hello,

I purchased a Taurus TCP 738 .380 a couple months ago and recently made a few small refinements that help the little pistol cycle much better.

Admittedly, I’m a tried and true 1911 guy and know very well how to make a 1911 hum so I decided to try a few small improvements to the “clunky” TCP .

I broke the sharp corner of the MIM extractor claw that was digging into my ammo case bevels:



I rounded off the sharp corner on the back of the slide stop lever to remove the offending metal that interfered with ammo as it cycled from the magazine into the barrel.


I polished down all the heavy tool mark on the barrel that dragged across the slide as the slide cycled.


These three small improvements transformed a clunky little pistol into a smooth cycling kitten.

Best regards
Eric
 
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#3 ·
Now, I'll have to go back and look at my 738. Nice work Egumpher.
 
#5 ·
I went back and looked at my 738 and your first two mods will be performed on my 738 soon. Also, I think you have addressed something that has been bothering me for a while. Some folks are reporting that their Loaded Chamber Indicator (LCI) is not working, but they are experiencing no extractor issues. It may be that the extractor is holding the round slightly off the breech face thus not engaging the LCI. Your second mod to the slide release may also address some ammo feed issues that are being reported.

Taurus should probably add this mod to any 738's coming back for LCI, extractor or feed issues.

Suggest the Forum Moderator make this a stickie.
 
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#6 ·
GreenWolf70 said:
It may be that the extractor is holding the round slightly off the breech face
Hello,

Having the case not sit flush with the breech face will also promote light primer strikes because the firing pin needs to travel beyond its normal travel. This condition might contribute to the failure to fire that some TCP experience.

Rgds
Eric
 
#7 ·
Eric,
Man...I wish you had posted this a few weeks ago! I recently sent my TCP back to Florida with extractor issues and I wonder if these mods could have solved my issues (FTE spent casing and next round in magazine becoming stuck). In any event...how did you "brake" off the parts? Did you have to disassemble the extractor? Did you use a Dremel or hand files, etc? Thanks for sharing this info with us!
Ian
 
#10 ·
Well, took my 738 apart to go over it with these mods. My barrel doesn't have any machine marks on it so I didn't feel a need to polish it. I looked at the slide and it looks like the edges were broken when they put it together, but I buffed it with a small felt wheel and jeweler's rouge on the lower edge where it had been filed. Then I looked at the slide release and ran my magazines through it to see how they were mating up and decided to only knock off the top edges and leave the lower side where it contacts the mag follower alone (I wanted to leave as much contact area as possible so the slide locks back when empty) and then buffed the it with the felt wheel.

Actually, I feel pretty good about my 738, after looking at it in terms of these mods, as I realize that the gunsmith who built it spent some time with it and did a good job.
 
#13 ·
Hello again,

I was asked ever so kindly to share some more things I did to enhance the feeding/cycling reliability of my TCP.

All of the refinements shown below are 1911 refinements that reduce or minimize drag, friction or possible interference with chambering a round into battery.

I Polished the disconnector rail. Note that the TCP doesn't have a 1911 disconnector but rather this rail cocks the hammer only. It is important to make this surface as smooth as possible because not only does it drag across the hammer but it also drags across the next round in the magazine. Too much friction here can possibly pull the next round in the magazine forward and allow the feedlip of the magazine to loose control of the round.


Next I broke the sharp corners that transition the cartridge from the magazine to the breech face. The goal here is to eliminate any interference that may rob recoil spring energy and interfere with chambering ammo.


Then I polished the top of the barrel chamber to allow ammo to slide easily into the chamber:


Lastly I polished the breech face to allow the case rim to slide easily into position to allow the bullet to fully chamber. This also allows full case rim contact with the breech face so that all of the chamber pressure pushes the case back on the breech face, thus pushing the slide out of battery after the round has fired:


That's about it.....

Enjoy
Eric
 
#16 ·
GreenWolf70 said:
Well, took my 738 apart to go over it with these mods.......... Then I looked at the slide release and ran my magazines through it to see how they were mating up and decided to only knock off the top edges and leave the lower side where it contacts the mag follower alone (I wanted to leave as much contact area as possible so the slide locks back when empty) and then buffed the it with the felt wheel.
Hello,

The tell tale sign that the slide stop is a problem is brass shavings in the mag well or around the slide stop. A dirty pistol tells many tales ....look for brass shaving after your next trip to the range....hand cycling isn't the same as shooting....my particular TCP had chunks of brass around the slide stop.....

Rgds
Eric
 
#17 ·
I didn't have any brass shavings in the receiver. But I went ahead and broke the top edges of the slide stop and then buffed it. The other stuff you posted I had already performed when I dehorned the slide. Still these are good tips. Glad to see the mods made this a stickie.
 
#18 ·
Hello,

Just in case anyone was worried about rounding off the slide stop like I did. Here is a picture that shows the results. I personally think that the rounded corner is better than the factory square corner......I guess that this is obvious because I did the work ;D



Rgds
Eric
 
#19 ·
Eric, I am a bit surprised you didn't mention polishing the feed ramp which is one thing mine needed and I did it with noticeable positive results.

I will follow your advice and directions on the other enhancements.

Thanks for the info.
 
#21 ·
andylibby said:
Eric, I am a bit surprised you didn't mention polishing the feed ramp which is one thing mine needed and I did it with noticeable positive results.

I will follow your advice and directions on the other enhancements.

Thanks for the info.
Hello andylibby,

Thanks for the reminder. Yes, I did polish the feed ramp but this is one aspect of an upgrade that if over-done can ruin a pistol so I intensionally omitted it. My ramp was pretty good from the factory so it only needed minor work.

Hello Gord,

I will elaborate on what to look for in in the extractor soon.....when I get the time...

Rgsd
ERic
 
#22 ·
Gord said:
Hi,

Can you elaborate on reshaping the extractor? It's a little hard to tell what exactly you did - as I'm reading (and seeing) it, it looks to me like you beveled the bottom corner at a ~45* angle?
Hello,

First lets start with terminology so everyone is using the same terms:

Here are three basic terms: Nose, Claw and Tensioning Wall


I had an interference between my extractor nose and case bevel that wouldn't allow the case rim to sit properly inside the extractor but rather the nose hit the case.

I removed material from the extractor nose to allow the case to sit properly in the extractor and also allow the case to sit against the breechface: (Note that the loaded chamber indicator complicates this because the rim needs to push it out against the tensioning wall)



Here is a graphic showing a 1911 extractor and the small gap needed to allow the system to work properly:


I hope this helps.

Rgds
Eric
 
#24 ·
egumpher,

I get the primer shadow that you show, but my question is, is the case supposed to set tightly to the breach face?

This weapon is new to me and has been returned to the factory for failure to feed issues - all types and brands of ammunition. So when it was returned, I took it to the range for testing and still had one or two failure to feed. ( out of 40 rounds )

When I looked over the spent brass, I noticed that the cases were gouged from the extractor. On a whim, I tried to put a spent case back into the weapon, by sliding it in from the bottom, as if it were being stripped from the magazine, and noticed that it was difficult to get it under the extractor . When I did get it in, I noticed a gap between the breach face and the bottom of the case.

There have never been any failure to eject.

I'm a new shooter and new to this forum, so any help would be greatly appreciated
 
#26 ·
I had similar issues, I sent mine to Miami with a detailed list of what the weapon was doing wrong. They did an amazing job and she has not had an issue since I got her back.... Clean or dirty she performs. I even tried to limp wrist her.... She still ejected and fed everything. As someone here said, 120% reliability is what you want with a SD weapon. I trust this little Gun 150%!!!!!!!!!!!!! Let her go to Miami...She will thank you!
 
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