disco issues, a bit above my skill set

disco issues, a bit above my skill set

N2T
Joined: May 13th, 2006, 10:41 pm

March 18th, 2017, 1:57 am #1

So with the groups opening up, I removed the scope, tightened everything I could find down. And cleaned the bbl well. Then issues cropped up. The gun began to fire on closing the bolt, the bolt would not lock back, or shoot forward, close by itself and fire. I was getting weak shots that barely sent the pellet to the target etc. I removed nothing, just sprayed a bit of wd-40 down the barrel and did a half dozen passes with a brush then a few with oiled patch then wet patch. I put a drop of oil on the o-ring on the bolt probe as well. So current issues are bad groups, a bolt that closes and fires the gun by itself, "weak" shots, and the bolt not locking back. I'm a bit confused to say the least. I tightened the barrel band screws, scope rings, scope mounts, end cap, and the single screw that holds the barrel in place as well as the one that holds the breech down (single screw on top of breech), the flat head screw at the back of the breech was find and the stock screw was tightened at it had loosened as well. I'm unsure how any of this would cause such odd firing characteristics. Ideas?
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Joined: May 17th, 2004, 4:36 pm

March 18th, 2017, 2:10 am #2

Gun firing by itself indicates a bad sear engagement. I'd check the trigger group and make sure you have good sear lockup.
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N2T
Joined: May 13th, 2006, 10:41 pm

March 18th, 2017, 2:28 am #3

I haven't messed with the trigger group, honestly that's what I'm wondering, if there is some issue with lockup and the sear is letting go/slipping.
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Joined: October 11th, 2016, 2:27 pm

March 18th, 2017, 2:26 pm #4

So with the groups opening up, I removed the scope, tightened everything I could find down. And cleaned the bbl well. Then issues cropped up. The gun began to fire on closing the bolt, the bolt would not lock back, or shoot forward, close by itself and fire. I was getting weak shots that barely sent the pellet to the target etc. I removed nothing, just sprayed a bit of wd-40 down the barrel and did a half dozen passes with a brush then a few with oiled patch then wet patch. I put a drop of oil on the o-ring on the bolt probe as well. So current issues are bad groups, a bolt that closes and fires the gun by itself, "weak" shots, and the bolt not locking back. I'm a bit confused to say the least. I tightened the barrel band screws, scope rings, scope mounts, end cap, and the single screw that holds the barrel in place as well as the one that holds the breech down (single screw on top of breech), the flat head screw at the back of the breech was find and the stock screw was tightened at it had loosened as well. I'm unsure how any of this would cause such odd firing characteristics. Ideas?
When you close the bolt. There's no resistance? Either your cocking pin broke, the spring broke, or the pin became disengaged. There are diagrams, schematics online for free. You're going to have to dissasemble. Actually there's only a very small .050 Allen screw UNDERNEATH the bolt that you can't see that holds front of breech/barrel flush with transfer port. Is there ANY gap between barrel assembly breech block and air transport trigger housing block? If you need more help send me pictires by text.. email me at jamesdingle18@yahoo.com for number.
Last edited by JamesDingle777 on March 18th, 2017, 2:28 pm, edited 1 time in total.
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N2T
Joined: May 13th, 2006, 10:41 pm

March 18th, 2017, 3:20 pm #5

There is a small pin sticking up behind the breech. There is also a bit of a gap between the breech and tube. I get resistance cocking the bolt, but then it either fires on closing or shoots forward and fires itself. Not always but a fairly regular amount of times. I may just send it back to Roy and have it reworked. I'm worried I may cause more issues than I solve taking it apart, lol.
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Joined: June 2nd, 2009, 12:39 pm

March 18th, 2017, 3:29 pm #6

I had a similar problem. Turned out to be the tension balance between the 4-48 breech screw and the rear breech bolt. I disassembled and clamped down the breech to the tube and reinstalled the screw and bolt making sure both were tight and no space in between the breech and tube. That worked just fine.
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Joined: May 12th, 2001, 1:29 pm

March 18th, 2017, 3:42 pm #7

So with the groups opening up, I removed the scope, tightened everything I could find down. And cleaned the bbl well. Then issues cropped up. The gun began to fire on closing the bolt, the bolt would not lock back, or shoot forward, close by itself and fire. I was getting weak shots that barely sent the pellet to the target etc. I removed nothing, just sprayed a bit of wd-40 down the barrel and did a half dozen passes with a brush then a few with oiled patch then wet patch. I put a drop of oil on the o-ring on the bolt probe as well. So current issues are bad groups, a bolt that closes and fires the gun by itself, "weak" shots, and the bolt not locking back. I'm a bit confused to say the least. I tightened the barrel band screws, scope rings, scope mounts, end cap, and the single screw that holds the barrel in place as well as the one that holds the breech down (single screw on top of breech), the flat head screw at the back of the breech was find and the stock screw was tightened at it had loosened as well. I'm unsure how any of this would cause such odd firing characteristics. Ideas?
...have you (or someone else) ever had the action out of the stock?

The reason I ask is because the symptoms you list can be caused by failing to correctly reinstall the safety button, and removing the button is a required part of taking the action out of the stock.
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Joined: October 11th, 2016, 2:27 pm

March 18th, 2017, 4:07 pm #8

There is a small pin sticking up behind the breech. There is also a bit of a gap between the breech and tube. I get resistance cocking the bolt, but then it either fires on closing or shoots forward and fires itself. Not always but a fairly regular amount of times. I may just send it back to Roy and have it reworked. I'm worried I may cause more issues than I solve taking it apart, lol.
if you can't afford it, and you pay shipping both ways, buy rebuild kit from Magnum Air Power (Bill Baldyga) have it all sent to me and I'll rebuild it completely for free and I can guarantee I'll get your rifle shooting at least 1/2" groups at 20 yards with at least 1 pellet as long as your scope isn't broken.
Your initial issue of bad groups. How bad? Call me if you would like the offer or anything needed. 57zero-97seven-11four9
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N2T
Joined: May 13th, 2006, 10:41 pm

March 18th, 2017, 4:36 pm #9

But this isn't a stock gun and the Roy at Mountain air does a great job. I think he'll take care of me on this issue. Previously this gun was shooting sub 1" groups at 80 yards, I figured it was just really dirty, I guess something else is to blame. How bad were my bad groups? Lol from sub 1" at 80 yards to sub 3" at 50 and barely able to hold under an inch at 20. Not normal for this gun. I would take you up on the offer if I it wasn't something I was sure Roy could handle.
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N2T
Joined: May 13th, 2006, 10:41 pm

March 18th, 2017, 4:38 pm #10

...have you (or someone else) ever had the action out of the stock?

The reason I ask is because the symptoms you list can be caused by failing to correctly reinstall the safety button, and removing the button is a required part of taking the action out of the stock.
Yes, I and Roy have had the action out of the stock, gun has worked for about 5 years after that however so I'm unsure the safety is the issue. The trigger was reworked at that time and a custom brass trigger installed, along with a trigger job. I just don't think that's part of the issue at it's taken thousands of rounds and 5 years to crop up.
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