Trubor Modifications

[old john]

Trubor modifications

Have any of you open shooters with a trubor done any modifications to the comp? I was wondering if I should try and improve what others at STI spent years working on. Thanks, Old John

[ErikW]

At a recent match, I asked JoJo Vidanes about his gun, which is very similar to my Open gun. He modifies the first chamber on the compensator.

Here is what he e-mailed me when I asked about the specifics of his mod:

It's not a secret, all you have to do is  get the ramp out of the first baffle by cutting it 90 degrees.  If you don't have anyone to do it, I can cut it for you for $57 w/c includes return shipping.

I have two porpoise holes in my TruBor. I like how the gun feels, but it has got some face blast with 3N38 and 115 gr bullets. I'm going to have BrianH do JoJo's mod.

[Julien Boit]

I drilled three holes in my trubor barrel, I like the way the gun feels now.

In practice I notice the blast in the visiére of my cap.

In match, I don't notice it at all, but I might take a look at this mod.

[batangueno]

My gunsmith told me not to add anymore holes in my trubor barrel. SInce the IPSC PF is at 160, the comp holes would be sufficient. Any comments? Have anybody tried the trubor without poppleholes?

THanks.

[old john]

Additional info!!

I really have been thinking of adding side holes in the first chamber of the trubor comp with the one on the left at 5/16 inch and on the right @3/16 inch to try and stabilize the left torque. What if these holes were drilled @ 30 degrees up vs. horizontal and entering the chamber at the lowest point. Has anyone gone this far and were your results positive?

I too have added two poppleholes in the barrel and like them.

Thanks for your replys, Old John

[eric nielsen]

Rather than put in side-ports, I've had really good luck taking a round file to the right-side edge of the first chamber opening. Same as what Jerry Barnhart shows on his Equipment tape, I think that's volume 10.

It took the recoil from up&right to almost straight up. And no sideports to knock me unconscious at an indoor range.

Several friends & I have used sideports in the past and we all noticed a distinct "shake" to the dot just as it starts to lift in recoil. Calling the shot isn't as clear. YMMV

PS - I love the TruBor design, I've had many screw-on comps come unscrewed...

[Flexmoney]

Several friends & I have used sideports in the past and we all noticed a distinct "shake" to the dot just as it starts to lift in recoil. Calling the shot isn't as clear. YMMV

Interesting. On first thought, you'd think the side ports would work to stabalize the gun. But, it makes sense that they would actually cause a bit a "shake".

[old john]

Thanks. Does Jerry's tape address a trubor? Old John

[Schutzenmeister]

Thanks. Does Jerry's tape address a trubor? Old John

<{POST_SNAPBACK}>

I don't believe so ... at least not directly. I believe he made his tapes before Dave Skinner came out with the TruBor.

Personally, I have 2 small blow holes on the top of my barrel just befor the comp ... I tried one of the stock STI GM guns before I ordered it and decided I wanted more muzzle control.

I am intreged on the comments about JB's enlarging of the first port on one side ... I'll have to look into that.

[eric nielsen]

Yes, the Burner tapes came before the TruBor.

Here's a photo I took a while back - shows the sharp sides on the left of the comp, the rounded & lowered sides on the right of the comp.

Click to enlarge

[Eye Cutter]

eric:

my open pistol's red dot also tracks up and to the right. what other things should i try before enlarging the chambers to straighten the dot lift?

how much do you take off the right side of the comp? and you modify all the chambers, correct?

i'm using 124gr fmj w/ 8.0gr 3n37 in a 5in. barrel

[eric nielsen]

You can experiment with different hand pressures as shown in Matt Burkett's dvd series. Also I often see a different dot-lift if I change how straight my strong-side arm is. Seems like whichever arm is bent more at the elbow, the gun is going to kick into that side more.

After one port was lowered on the right edge, I saw a difference & liked it. So I continued into all the ports over time, testing at the range several times.

As a buddy [Leo 9x25] says, the more you take out of the sides, the more muzzle flips - but more like the flip you want to see.

I prefer the up&down flip because you can tell the difference between the recoil, and trigger jerk which goes down & to the left. With up&right recoil, it all kind of looks the same.

[Jon Merricks]

Other than the 4 holes in the barrel I had my gunsmith cut the quads off the end of my S-2 and add a small hole on each side of the comp. It's now the same length as a S-1 but to me works a little better.

[Eye Cutter]

thanks eric and jon! the pistol's in its break-in stage and so far it has been running great.

batangueno and i shot a level 1 match yesterday to try out the pistol and my hand is now aching from the sharp edges of the polymer grip!

i noticed that the dot was lifting and oscillating up to the right but stays inside the cmore lens. watching our videos, the pistol recoil was very flat.

now i have to test with different grip pressures and stances first.

tyvm!

[Tom Balko]

Has anyone experimented with removing weight from the trubore by making it less of a bull barrel between the chamber and the cone? With all the push to lighten the overall weight, it seems that there is alot of mass that could be removed from that barrel by turning down the diameter of the tube. This seemed to be the place to ask if anyone else has had similar thoughts. Maybe one of the smiths can elaborate as to whether or not this mod should be attempted.

[Eye Cutter]

i saw jojo's mods for the trubor, but i think this is for his steel pistol

[Eye Cutter]

[Eye Cutter]

[TDean]

Wow, very liberal with the ol'mill. I like it!

[BrianH]

I shot Erik's super after I recut the rear port and you can feel it.

[ErikW]

I can't. Well, I've shot mostly 150 PF steel loads, one IPSC match with 7625 Major loads, more steel loads, then Corbon (Major) loads and my own Major loads in a steel match yesterday. If anything, I am tracking the dot better. And strangely enough, I don't notice the face blast I felt before, which I thought was a function of the two porpoise holes.

[BrianH]

That means you felt it!