Jimbo76 Posted March 23 Share Posted March 23 I have a STI Tru-Bor 2011 Pistol that does not seem to want to group. This was my back up gun that I just started shooting again and it only has about 5000 rounds through the barrel. At 25 yards it will put two shots in a 2 inch group and then they start going all over the target. Mainly vertically stringing. It has a new Cmore on it and everything is tight on the optics mount. Ammo I am using is hand loaded and tested on a steel master and shoots 2 inches at 25 yards. I never really shot this gun much, but my recollection is it was not super accurate from new. The barrel and comp are clean and as new just ultrasonically cleaned. Short of changing out the barrel does anyone have anything else to try to get this thing to group. It was mentioned to me that maybe the comp needs to be reamed larger. Just wondering if anyone had this kind of problem I am running out of ideas. Thanks in advance for any replies. Link to comment Share on other sites More sharing options...
RangerTrace Posted March 23 Share Posted March 23 I had a grouping issue with my XC. They changed the barrel link and put in a new slide stop. It still doesn't shoot as tight a group as I'd like, but I also have my suspicions about the DPP. FWIW, I don't notice any issues during matches, only trying to shoot groups off a rest at 25. Link to comment Share on other sites More sharing options...
jwhittin Posted March 23 Share Posted March 23 (edited) Yes, I hadaccuracy issues with my open gun. I check the barrel lug contact and it was a little uneven, the manufacture put in a new slide stop and that fix the issue. The slide stop was worn. Edited March 23 by jwhittin Link to comment Share on other sites More sharing options...
xjwalt666 Posted March 23 Share Posted March 23 When I've had grouping issues, one of the guns the mount screws on the frame were loose enough to allow the mount to move up and down on recoil. The other time the barrel was chambered deeper than the ammo was. I stretched out the ammo from 1.110" to 1.170" and the grouping tightened up. Other than that I'd agree with the above and check the barrel link contact. Link to comment Share on other sites More sharing options...
Jimbo76 Posted March 24 Author Share Posted March 24 Thank you all for your replies, I just shot it again today and the same problem persists definitely not the optic or anything that’s loose. I do have a question, how do you check the barrel link? When it is in battery and push down on the barrel, it does not move. The only thing I noticed is that if mount the barrel in the frame with the slide stop in the link and not using the slide, it doesn’t lay flat on the frame it kind of wobbles from side to side. I thought if you don’t have the slide on the gun and the barrel is in the frame with the slide stop and you push it forward and down it is supposed to lay in that gap between the rails. Mine does not. I think this might be part of the Problem but I don’t know what to do to fix it. Link to comment Share on other sites More sharing options...
jwhittin Posted March 24 Share Posted March 24 I was talking about the contact of the slide stop on the barrel lugs. Use a marker on the lugs and manually cycle the slide several times with the gun completely assembled. You should be able to see where the slide stop contacts each lug. Contact should be roughly even on both sides and should also make contact toward the tip on the vertical portion. Link to comment Share on other sites More sharing options...
Jimbo76 Posted March 24 Author Share Posted March 24 Thank you I will try that. Link to comment Share on other sites More sharing options...
Posvar Posted April 8 Share Posted April 8 On 3/24/2024 at 2:49 PM, Jimbo76 said: Thank you I will try that. Any success? Link to comment Share on other sites More sharing options...
RangerTrace Posted April 9 Share Posted April 9 On 3/24/2024 at 12:18 PM, Jimbo76 said: Thank you all for your replies, I just shot it again today and the same problem persists definitely not the optic or anything that’s loose. I do have a question, how do you check the barrel link? When it is in battery and push down on the barrel, it does not move. The only thing I noticed is that if mount the barrel in the frame with the slide stop in the link and not using the slide, it doesn’t lay flat on the frame it kind of wobbles from side to side. I thought if you don’t have the slide on the gun and the barrel is in the frame with the slide stop and you push it forward and down it is supposed to lay in that gap between the rails. Mine does not. I think this might be part of the Problem but I don’t know what to do to fix it. IIRC, Remove the slide from the gun, put the slide stop through the barrel link and push it back into the barrel lug. The slide stop should still be able to rotate inside the link. Link to comment Share on other sites More sharing options...
jwhittin Posted April 9 Share Posted April 9 (edited) 4 hours ago, RangerTrace said: I noticed is that if mount the barrel in the frame with the slide stop in the link and not using the slide, it doesn’t lay flat on the frame it kind of wobbles from side to side. There will be some side to side movement, that is normal. The barrel ramps are about 0.365" wide while the frame ramp slot is about 0.370". When the barrel is unlocked and slide to the rear, the barrel chamber should sit flat in the chamber bed of the frame and the feed ramp will be on the base of frame ramp channel, sitting about 1/32" from the edge of the frame ramp. This allows the next round to be chambered. As the slide moves forward feeding the next round into the chamber the lower barrel lugs ride the slide stop pin to cam the barrel up into battery. As long as the barrel moves freely and chamber sits flat in the bed, that's about all you can check in this configuration. Edited April 9 by jwhittin Link to comment Share on other sites More sharing options...
jwhittin Posted April 9 Share Posted April 9 (edited) 8 hours ago, RangerTrace said: I thought if you don’t have the slide on the gun and the barrel is in the frame with the slide stop and you push it forward and down it is supposed to lay in that gap between the rails. If you move the barrel rearward (not forward) the chamber should sit flat in the frame bed. In rereading your post, you should also check the compensator to make sure bullets are not striking the inside circumference of the compensator. Visually inspect the inside surfaces of all the baffles of the comp. If the bullet is coming in contact you will see wear and possibly lines in the direction of the bullet across the inner surface of one or more baffle. You can probably see most if not 360 degrees by looking through all the ports in the comp. If there are no signs of interference, then it seems like its barrel related. Do you have calipers? If so, measure the diameter of your slide stop where you see the set of wear marks near the middle. This is the location where the barrel lower lugs contact the slide stop. Slide stop diameters are usually 0.200" but could be 0.201". Even wear as little as 0.0005" in the diameter can loosen the fitment and cause issues. Another test is to replace the slide stop with a new one. If the group improves, you know you are on the right track but you still need to check the lower lug barrel contact with the slide stop to make sure its correct as mentioned above (marking the lower lugs and manually racking the assembled gun to see the contact pattern). If you could post a clear picture of the barrel lower lugs and the barrel top lugs, that would be helpful. Edited April 9 by jwhittin Link to comment Share on other sites More sharing options...
Jimbo76 Posted April 9 Author Share Posted April 9 Hi, thank you very much for your replies. It’s been a while since I posted and I have sidelined the gun for now but there are a few good new ideas here so I will take a look at it as soon as I can. The barrel does not lay in the frame though it sits up just a little bit too high. I think this might be the problem. I do have calipers, so I will do some checking and I will post, but it probably won’t be for a few days. My closest Range is a decent drive away, so I don’t get there as often as I’d like. Link to comment Share on other sites More sharing options...
Jimbo76 Posted April 12 Author Share Posted April 12 Hello, I believe my problem is fixed. Here is what I did. First, I measured the slide stop pin, and I found Out that it was not round anymore. It was more of an egg shape At the point it contacted the link. So I installed a new Wilson combat. Slide stop that I already had. Then I took a look at the comp and it had rough edges on the inside, but I thought that was dirt. But in any case I reamed out the comp. I then clean the gun completely In the ultrasonic cleaner. I took it out and shot a couple different types of ammo through it, and it grouped as good as my other guns now. I am going to try to post to target. The dot is about 2 inches diameter and the distance is 25 yards. I shot the group by holding the gun with one arm resting on a sand bag on the table. No fancy rests or anything just supporting my one arm and shooting a gun as I would normally. I’m sure the group would be tighter if it was in a better set up. I just want to thank everyone for your input, and I am extremely happy that this thing is fixed and I can start using it again. OK it appears my photo is too big so I will post it in a follow-up message but the group that the gunshot is about minimum 1 inch to maximum of 4 inches. Good enough for a zone hit at 25 yards all day long. Link to comment Share on other sites More sharing options...
Jimbo76 Posted April 12 Author Share Posted April 12 Link to comment Share on other sites More sharing options...
Jimbo76 Posted April 12 Author Share Posted April 12 Changing the picture to black and white and shrinking it, allowed it to be small enough to post here it is. Link to comment Share on other sites More sharing options...
CocoBolo Posted April 22 Share Posted April 22 That looks like when I shoot from a rest and close one eye instead of having both eyes open. Parallex seems to get in the way or the eye dominance. My friend Tom can take the same gun and ammo on the same rest and tie all the holes together. Then there is that dot size thing, if I turn the dot down till it is barley visible man those groups get tight, but crank it up to full bloom and they spread like geese taking off after the first shot. Lol when I finally have had enough and chuck the rest to the side I shoot the best groups just free handed. I only shoot 3 shot groups, then let it cool then shoot another. When the gun is cocked press on the hood of the barrel if it moves it won't be accurate. The worst of the worst is if the barrel at the comp end is loose in the slide. What I call the ultimate test is shooting at an 8" paper plate at 50 yards, if I fire 5 shots and they all land on the plate, go to go to the Nationals. Link to comment Share on other sites More sharing options...
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