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RaylanGivens

TruBor Barrel - Are these Barrel Marks from Bullets?

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I have an STI TruBor that I shoot in Open...  I have gone through many jamming problems, including sending my gun back to STI for a replacement barrel and slide...  After getting it back from STI, I added an Aftec extractor...  My jamming problems are greatly improved, yet I still do get an occasional jam where multiple bullets collide in the chamber.

 

I have noticed that the flat area on the front of my barrel ramp has what looks like marks from the front of a bullet.  I'm wondering if this could be causing my jamming problem?  I've never seen this kind of problem in either my Limited or Single Stack guns, so I'm posting this in the Open forum...  Does anyone know what causes these marks?

 

 

STI #2 TruBor Barrel Ramp Marks.jpg

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9 mm,,38 super,,coated Bullets ,,fmj,hollow point,,

I shoot 9 major in a Trubor ,,my load is 1.165. Jhp,,by precision delta..

your load may be to long ,,short,,could mags..

You see where this is going? You will have to eliminate each problem, to fix your issues.  Good luck

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The photo you provided looks like the gun should be cleaned and

thoroughly lubricated, generously before trying it again.   That alone

might solve your problem.

 

As EEH mentioned, it can be so many other things, also - I had

same problem you did and it turned out to be one of my mags

needed new springs - try to isolate it and see if the jams happen

occasionally only with one particular mag.

 

Could also be your ammo ....

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Hello: Take the front spring out of the Aftec and see if your feeding problem goes away. If not I would put a slight radius on the barrel transition to the chamber. SLIGHT radius only using a 5/16" wood dowel and 600 grit wet/dry sandpaper. Load to 1.160"- 1.170" OAL. Thanks, Eric

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If you are talking about the marks on the very bottom of the ramp then make sure that area is not contacting your mags. That section of the ramp should be to be flush with the ramp in the frame when the slide is locked back. If it isn't then it may be coming back and making contact with the mags when the gun is cycling out of battery. The contact with the mag could shift the mag and cause feed issues.

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On 7/19/2017 at 7:28 PM, Hi-Power Jack said:

The photo you provided looks like the gun should be cleaned and

thoroughly lubricated, generously before trying it again.   That alone

might solve your problem.

 

I cleaned and lubricated the gun right before I shot the match...  This Open gun gets much dirtier than any of my other guns...

 

After the match, I took the picture because the bullet marks always seem to be on the flat portion of the barrel...  The gun didn't jam at the match where I took this picture, but the bullet marks were bothering me...  I don't see them on any of my other guns, however, my other guns all use lead bullets.

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On 7/19/2017 at 7:40 PM, Aircooled6racer said:

Hello: Take the front spring out of the Aftec and see if your feeding problem goes away. If not I would put a slight radius on the barrel transition to the chamber. SLIGHT radius only using a 5/16" wood dowel and 600 grit wet/dry sandpaper. Load to 1.160"- 1.170" OAL. Thanks, Eric

 

When I first fit my Aftec, I used only a front spring...  After about 1500 rounds the gun jammed, so I moved the single rear spring to the front and added a second, new, spring to the rear...  It's run fine until the last stage jam at the last match...  I've shot several matches since adding the second spring...  Probably 2,000 rounds or so.

 

I've been loading 124gr JHP bullets to 1.165...

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On 7/20/2017 at 8:19 AM, scottlep said:

If you are talking about the marks on the very bottom of the ramp then make sure that area is not contacting your mags. That section of the ramp should be to be flush with the ramp in the frame when the slide is locked back. If it isn't then it may be coming back and making contact with the mags when the gun is cycling out of battery. The contact with the mag could shift the mag and cause feed issues.

 

Yes...  Those marks show up all the time...  even when the gun doesn't jam...  That's really what I'm questioning...  I'm not used to seeing those marks and it seems like they shouldn't be there...  They don't happen on any of my other guns.  My gun runs fine most of the time, it just seems like these marks indicate that something is out of alignment...

 

I'll check to see where the barrel ramp lines up with the ramp in the frame when the slide is locked back...  That's something I never considered...  That's a good tip, thanks!

 

 

 

 

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Here's another picture of the barrel after Tuesday night's match...  Four stages and the gun jammed during the last stage...  The barrel still looks pretty dirty for only four stages...  about 110 rounds...  Gun was clean and lubricated before the match...

 

 

TruBor Barrel Marks Close Up.jpg

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The marks below the chamber are from the nose of the bullets hitting the ramp.  Under normal conditions the bullet nose will ride up the ramp and into the chamber.  Can't really tell but probably would not hurt to polish the ramp so as to be as slick as possible.

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Hello: The shinny marks on the bottom of the feed ramp are from the magazine hitting the ramp. That is not good. You will have to take a little off of that area. Not a lot just enough so it does not touch. The bullets are hitting the ramp in a good spot. The transition area could use a nicer radius since it looks like it is removing some of the coating on the bullets. See my answer above. Thanks, Eric

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