fell off
Printed From: Kiwi Airgunners
Category: Technical
Forum Name: Pauly's Technical Area
Forum Description: Technical information, Modifications and DIY projects are all in here
URL: www.kiwiairgunners.co.nz/forum_posts.asp?TID=367
Printed Date: 23 Apr 2024 at 11:24pm
Software Version: Web Wiz Forums 10.14 - http://www.webwizforums.com
Topic: fell off
Posted By: xyon
Subject: fell off
Date Posted: 22 Jun 2017 at 4:26pm
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I got round to reassembling the Gamo hunter I have been restoring. I had noticed that the previous owner has epoxied the scope rail on to the compression tube. It was hard to miss the globs of epoxy on the sides of the tube, which I cleaned up, but as it looked secure I left it alone. After about 5 test shots the bloody thing fell off  Question is how to repair it? 
------------- --- My favourites springer - Diana 52 PCP - FX Wildcat III |
Replies:
Posted By: Pauly5
Date Posted: 22 Jun 2017 at 6:42pm
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Does the gun have dovetails cut into it? Can't quite see. Otherwise looks like there were bolts probably tapped into the action that have sheared off. You would have to remove those from both rail and action and if the threads are still ok, you could simply replace them and use some loctite. Your biggest thing would be to watch, will be the other end of the screw/bolt extending into the compression tube, as they may obstruct the piston or spring as they move. ------------- |
Posted By: xyon
Date Posted: 22 Jun 2017 at 8:22pm
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the newer gamos have dovetails cut into the tube. But not this one. The rail has circular bumps on the bottom that are pressed down from the top. These fit into the holes in the tube. Then they must have been expanded/riveted (or possibly spot welded) from the inside, I presume using the cocking slot for access. ------------- --- My favourites springer - Diana 52 PCP - FX Wildcat III |
Posted By: Pauly5
Date Posted: 22 Jun 2017 at 9:27pm
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Interesting. What about countersinking a screw from inside and bolting down the scope trail if it clears all the internals. ------------- |
Posted By: nunga
Date Posted: 22 Jun 2017 at 10:09pm
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that rail is not mounted on the compression tube its self by the looks so it shouldnt be that hard to fix. its on the spring retaining part on the gun...the compression tube is located at the front of the rifle. you should be able to drill the holes out and tap a new thread in the part of the gun without to many problems then bolt it to the gun. just make sure the screws are not to long. it looks pretty bad to look at...but shouldnt be too hard to fix  ------------- 2nd place HP springer - WFTF World Championships 2014 |
Posted By: dvlnme
Date Posted: 25 Jun 2017 at 6:36pm
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This used be real common prob with old mauser 98 rifles n others as well ,screws used sheer off if made soft steel,fact is springer airguns lot harder on mounts than any firearm, due recoil being forward, rather than reward as with firearms,and there being less depth metal to put screws into on the tube etc Fact is it can be harder to keep a scope on springer airgun than biggest magnum firearm,modern airgun rated scopes much stronger than equivelent firearms scopes,these days i only use good airgun scopes evan on my firearms,simply coz they tougher. I used to put cap screws threaded into tube,then drill two holes in mount for cap screw heads as anchors then screw mout down as normal,never had one shoot loose, Cheers Mike
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Posted By: xyon
Date Posted: 25 Jun 2017 at 9:55pm
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I've drilled out the rail and tube with a 5mm bit and tapped the rail with a 6mm thread. I'm trying to decide how to secure the bolt to the tube. The tube is 1.7mm thick. As nunga says its behind the compression area, so a super smooth finish is not required, but the back of the piston rides over this area so can't really have anything protruding. I was thinking about drilling the tube to 6mm, and turning a bolt down to have a tiny head tapering from 6.0 to 6.3mm. Maybe file the tube to have an approx matching taper. Other idea I had was more of a quick and dirty. Tap the tube too (with the rail clamped to it) Peen a grub screw to expand the end and squash the thread. Then screw in from tube side. When expanded end of screw binds on tube it should pull the rail snug and be difficult to undo, so hopefully won't come lose. ------------- --- My favourites springer - Diana 52 PCP - FX Wildcat III |
Posted By: nunga
Date Posted: 26 Jun 2017 at 2:31pm
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you can try flat head cap screws or a button head cap screws they should do the job http://www.steelmasters.co.nz/stainless-steel-fasteners/countersunk-csk-flat-head-socket-capscrews/m6-x-10-g304-csk-socket-screw/afa.asp?idWebPage=41063&CATID=147&ID=101322&SID=932800749" rel="nofollow - http://www.steelmasters.co.nz/stainless-steel-fasteners/countersunk-csk-flat-head-socket-capscrews/m6-x-10-g304-csk-socket-screw/afa.asp?idWebPage=41063&CATID=147&ID=101322&SID=932800749 ------------- 2nd place HP springer - WFTF World Championships 2014 |
Posted By: xyon
Date Posted: 26 Jun 2017 at 5:19pm
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I'm not sure how I could use a cap screw and have it be flush with the inside of the tube, or did you mean for the head to be countersunk into the rail and have the bottom of the screw flush with the inside of the tube? ------------- --- My favourites springer - Diana 52 PCP - FX Wildcat III |
Posted By: nunga
Date Posted: 26 Jun 2017 at 5:38pm
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yep countersink the head into the rail and cut down the screw to suit. ------------- 2nd place HP springer - WFTF World Championships 2014 |
Posted By: dvlnme
Date Posted: 04 Jul 2017 at 8:18am
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Because tube so thin,you can allways if rail steel soft solder it and screw to tube tube wont get hot enuff to cause any probs wen soldered and will never come off,lot older firearms had had sights etc soldered to barrels actions etc as did many older spring airguns. Personally i would sweat together with solder n screw as well be strong perminent solution Cheers Mike
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Posted By: xyon
Date Posted: 13 Jul 2017 at 10:07pm
I hadn't thought of soldering it, that probably would have
been quite a good way to go. But I have already repaired it now. I went for
the "forged" grub screws. And from the outside.  ------------- --- My favourites springer - Diana 52 PCP - FX Wildcat III |
Posted By: xyon
Date Posted: 13 Jul 2017 at 10:24pm
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All back together with the refinished stock and a new muzzle shroud, as the original was missing. I need to refinish the shroud, as it is turned plastic and I tried to sand it to smoth it, but that just made it look worse. I'm pleased with the stock which I spent some time sanding, staining and rubbing in 5 coats of linseed oil.  ------------- --- My favourites springer - Diana 52 PCP - FX Wildcat III |
Posted By: Pauly5
Date Posted: 13 Jul 2017 at 11:30pm
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Good job. Now to enjoy shooting it. ------------- |
Posted By: nunga
Date Posted: 14 Jul 2017 at 7:32pm
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Nice work! ------------- 2nd place HP springer - WFTF World Championships 2014 |
Posted By: J-S
Date Posted: 18 Jul 2017 at 4:02pm
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LOOKS GOOD! ------------- https://www.instagram.com/js_airguns/" rel="nofollow - J S Airguns Air Arms TX200('s) Theoben Sirocco HW77 FWB 300s Webley Patriot One or two others... Current projects: Too many.. |
Posted By: xyon
Date Posted: 18 Jul 2017 at 6:28pm
Thanks guys. Got a chance to shoot it with the sunny weather. Did 5 consecutive groups, the last is the 10 shots on the top left. The 2 shots that didn't touch the others are my fault. Got 845 to 850 fps on the chrony. ------------- --- My favourites springer - Diana 52 PCP - FX Wildcat III |