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barrel fit and accuracy?


jimbullet

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Quick question as I have an STI Edge which I had a new barrel fitted in it.

 

Since then it appears that the shots are like,

 

First shot = centre

second shot = left 2-3 inches

third = center almost one hole on the first

Fourth = Left 4 inches

 

WTF....ok so my question is just as a matter of process of elimination, is it possible to fit a barrel that its causing this? Or it has a damaged crown perhaps - or is this just maybe the shooter needing to get down and start a practice regimen following an off season.

 

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Have someone else shoot it that you know is capable of pulling the trigger straight back consistently. 

 

Same pattern = gun, not so much = you.... either way, you'll know what needs to be fixed

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I would bench it - get very solid rest - fire 12 - 15 shots at a target,

and drop the 2-3 flyers.

 

Measure the rest of it (9-12 shots) and call that my group size.

 

If it was in the vicinity of 2" at 25 yards, I'd be happy.

 

If not, I'd start the process of eliminating the ammo, the gun

and other potential problems.    :) 

 

What distance are you doing your shooting?

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doing 25 yards i get 2 flyers out of 6 shots the last weekend to the left at 3-4 inch off. I might try bench rest and see how that works. Took a moment to chrono too and its doing 185 PF - maybe too hot a load

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I agree with Jack. Use as sturdy a rest as possible. A Ransom would ideally be best, but what ever you do try to eliminate sight movement (hence barrel movement) as much as possible. Twenty-five yards is a good distance for our pistols and a 2 inch, five shot group would be great. 

 

Since the barrel is new, check the crown of the muzzle for imperfections, or even take it to your friendly neighborhood pistol smith and have it re-crowned. It's amazing how that last few thousandths can effect accuracy.  

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thats frustrating as heck, agreed with the rest, bench it, have a second shooter try it, then venture outwards to a pistol smith and see whats up. hopefully it was not fitted incorrectly and if so they stand by there work

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Where was the dot when the gun went off (not when you pulled the trigger) and you had a flier? 

 

And yes, you can test accuracy without a rest, you just have to be able to see the dot when the gun goes off and ignore "fliers" that are really trigger pull issues.  If the hole is where the dot WAS when the gun fired, the gun is accurate.

 

a flier or two in 6 is likely an ammo issue, meaning 1 or two out of six is inconsistent. If they are Consistently inconsistent ( meaning grouping in their own way to the left, it's likely a trigger pull issue.

 

having a known decent shooter shoot the gun to verify the inconsistencies will be the quickest way to confirm ammo, gun, or shooter.  Everything is a variable and it's a lot less frustrating to confirm it's you or the gun or ammo.  If it's a you issue, you'll spend a lot less time fixing it then you will chasing your tail with ammo or guns only to realize it was you.  

 

Im not saying it is you, I'm only saying that you need to confirm it isn't you before you spend the time figuring out whatever else the issue could be

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this is an edge. Im assuming there is no dot on the gun. Resting an iron sighted gun has shown me that I cant group an iron sighted gun off a rest. IDK why but its very difficult for me to do. I can always shoot a better group with an iron sighted gun free handed. Maybe thats just me though.

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Sorry, no comp or red dot on mine. Its iron sights.I could have also sworn that the sights lifted and back. Deliberately did a slow fire.

 

Ammo - handloads which I have used in the past and even prior to the barrel change was performing one shot holes - that is with my old barrel set up. Why change the barrel, had to due to my old barrel broke (but that is another story).

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22 hours ago, Shmella said:

this is an edge. Im assuming there is no dot on the gun. Resting an iron sighted gun has shown me that I cant group an iron sighted gun off a rest. IDK why but its very difficult for me to do. I can always shoot a better group with an iron sighted gun free handed. Maybe thats just me though.

You are not alone here. I sometimes feel the same as for some reason if I shoot with the gun on a table for added stability, it feels like the gun lifts inconsistently.

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You said you just had a barrel fit. This is a critical step in accuracy. I had a similar issue with a new STI 3gun Edge 9mm. After a couple matches the groups started opening up. It turned out the barrel locking lugs weren't all locking into the slide and the fit of the slide lock in the barrel link was way loose. Only one locking lug was making contact with the slide. I sent it back to STI and Dave Cupp replaced the barrel and slide lock. It's a freaking tack driver now. I took a pistol class with it in April and had no problems drilling targets at 60 yards.

 

Check the fit of the slide lock in the barrel link. See if there's a good fit in the link with only a little play and then put some Dykem layout dye on the barrel lugs and in the slide grooves. Shoot a couple mags. Look for full contact on all the barrel lugs and in the slide. Mine was only locking on the back lug and combined with a loose fitting slide lock in the barrel link it wasn't locking in the same place every time. 

 

Good luck!

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On 6/2/2017 at 3:32 AM, 72stick said:

You said you just had a barrel fit. This is a critical step in accuracy. I had a similar issue with a new STI 3gun Edge 9mm. After a couple matches the groups started opening up. It turned out the barrel locking lugs weren't all locking into the slide and the fit of the slide lock in the barrel link was way loose. Only one locking lug was making contact with the slide. I sent it back to STI and Dave Cupp replaced the barrel and slide lock. It's a freaking tack driver now. I took a pistol class with it in April and had no problems drilling targets at 60 yards.

 

Check the fit of the slide lock in the barrel link. See if there's a good fit in the link with only a little play and then put some Dykem layout dye on the barrel lugs and in the slide grooves. Shoot a couple mags. Look for full contact on all the barrel lugs and in the slide. Mine was only locking on the back lug and combined with a loose fitting slide lock in the barrel link it wasn't locking in the same place every time. 

 

Good luck!

i might try this. How do you tell if all lugs are engaging?

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On 6/2/2017 at 0:54 AM, Aircooled6racer said:

Hello: You said your old barrel broke? What caused it to break? Was the frame or slide damaged? Does the new barrel lockup correctly. Lots of things could be causing your flyers. More info would be helpful. Thanks, Eric

The barrel had a huge crack where the link (not lug) is. The gunsmith informed me that I was fortunate that the frame and slide was not affected. Cause? I dunno probaby the vertical impact surface incorrectly fit long ago. so barrel change it was.

Edited by jimbullet
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Update, stripped the gun and cleaned it. Seems to have lots of friction marks on the slide lugs particularly on the left side. not so much on the right side. Anyway I ignored this as I dont have the gunsmith skills.

 

so finally had the opportunity to go to the range and reduced my loads as well.


First up = chrono, so results are 172 PF,- looking good.

 

Tried 15 yards, benched and really slow = looking better, groups about 1 1/2 inches to the left. - but at least its tighter than before. Whether it was my over load ammo or me - its gotta be me factor, at least got my confidence back that the gun appears to be shooting relatively where it should.

 

Thanks for all your help - I truly appreciate it.

 

Still interested though on how do you know if the lugs all contacting fully between slide and barrel.

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Hello: Clean the lower lugs off really well and mark it with a marker(Sharpie). Put it back together and hand cycle it ten times or so. Take it apart and see where the marks are. Lock at your slide stop also to make sure it is not worn. Thanks, Eric

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Cool have done so and so the findings are as follows:

 

barrel - all the protruding lugs appear to be contacting the slide as the sharpie is gone on the "elevated lugs" (for the lack of my knowledge in terminology here) on the barrel. This test however also shows that the lugs on the barrel (non elevated portion) is not at all touching the slide lugs.

 

Slide- all the sharpie I have put whether those protruding and the crevice (lack of terminology on the lugs) area has been removed after hand cycling.

 

Given that the sharpie on the "lug crevices" on the barrel has not been disrupted or removed in any way, is that ok?

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On 6/3/2017 at 2:05 AM, jimbullet said:

The barrel had a huge crack where the link (not lug) is. The gunsmith informed me that I was fortunate that the frame and slide was not affected. Cause? I dunno probaby the vertical impact surface incorrectly fit long ago. so barrel change it was.

Or maybe the 185 power factor?

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8 hours ago, dmshozer1 said:

Or maybe the 185 power factor?

re: old barrel - the ammo was chrono'd at 177 PF on that older barrel but using the same ammo recipe on the new barrel shot it out at 185 PF so I did dial it down now.

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6 hours ago, jimbullet said:

re: old barrel - the ammo was chrono'd at 177 PF on that older barrel but using the same ammo recipe on the new barrel shot it out at 185 PF so I did dial it down now.

Back in the day when USPSA major power factor was 175 and to be safe for the chrono we loaded to 180 or so, there were

a lot of barrel and slide problems!

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On 6/4/2017 at 3:19 AM, jimbullet said:

Cool have done so and so the findings are as follows:

 

barrel - all the protruding lugs appear to be contacting the slide as the sharpie is gone on the "elevated lugs" (for the lack of my knowledge in terminology here) on the barrel. This test however also shows that the lugs on the barrel (non elevated portion) is not at all touching the slide lugs.

 

Slide- all the sharpie I have put whether those protruding and the crevice (lack of terminology on the lugs) area has been removed after hand cycling.

 

Given that the sharpie on the "lug crevices" on the barrel has not been disrupted or removed in any way, is that ok?

 

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