GTA
All Springer/NP/PCP Air Gun Discussion General => European/Asian Air Gun Gates => German AirGun Gate => Topic started by: HPP-Mechanic on October 01, 2023, 10:40:32 AM
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This is with a new breech seal & without. No side-to-side play, Barrel just falls, as far as barrel pivot adjustment. No tight lock-up... The lock position has noticable freeplay when closed, This is an early 1982, no safety model, I inspected the ball, rotated the pin, still loose. The new breech seal does keep pressure on the barrel so the closed position is consistent, but I can still flex the barrel further closed when I compress the breech seal further. Im wondering if there is wear in the pivot bolt hole, or is it the actual ball resting place? I will investigate some more, but I thought I would ask the experts if this is a common issue with the older guns?
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Forgot to add- Old scope ran out of adjustment w/new breech seal. New scope(Hawke Vantage) was able to crank it up enough to get on target, but I have a ton of barrel droop.
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Did you read this yet? https://www.gatewaytoairguns.org/GTA/index.php?topic=167205.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=167205.0)
PM for my phone number. I have some thoughts that would take to long to type.
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I would start by replacing the pivot bolt and acorn nut. After 40 years of use and questionable lubrication (factory lubes and/or frequency), the bolt may have worn itself out of tolerance.
Also, with barrel droop, if scoping the gun, shim the rear ring to get it closer to the plane of the barrel and not the action. Scopes work and last longer when they are optically centered.
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Did you read this yet? https://www.gatewaytoairguns.org/GTA/index.php?topic=167205.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=167205.0)
PM for my phone number. I have some thoughts that would take to long to type.
Just read it, great post. Saw this too...
Replacements can also be had more locally from McMaster-Carr, part number 9595A175. I bought a pack of 25 for a little over 9 bucks. That'll last me several lifetimes.
I reckon you've gone and done now, seems your obligated to live 3 or 4 extra lifetimes!
;D ;D ;D
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I would try this first, take a new breech seal and heat it up with a hair dryer make sure it's in the correct position, theirs 2 sides to a beach seal, do this quickly, close the breech softly and let it cool, so it forms correctly the try to zero the rifle, if all else is good with the lock up? then I would check your scope! to see if it's bad? 8)
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This is with a new breech seal & without. No side-to-side play, Barrel just falls, as far as barrel pivot adjustment. No tight lock-up... The lock position has noticable freeplay when closed, This is an early 1982, no safety model, I inspected the ball, rotated the pin, still loose. The new breech seal does keep pressure on the barrel so the closed position is consistent, but I can still flex the barrel further closed when I compress the breech seal further. Im wondering if there is wear in the pivot bolt hole, or is it the actual ball resting place? I will investigate some more, but I thought I would ask the experts if this is a common issue with the older guns?
Frank,
Start by tightening the barrel pivot bolt. They way you describe the barrel just falling, means that it is too loose. Tighten to the point where the barrel will "hold" it's position when under no tension.
Then try all the other stuff if this does not work.
-Y
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The detent should hold the barrel in the lock up position as long as the pivot isn't too tight. The lockup position is set mechanically by the ball popping over a dowel pin, holding the breech step to the topside of the pin. A breech seal can only hold the lockup up off position and there'd be no play. If there's play in the lock up there's a different issue going on. Sometimes the pin wears and needs to rolled over or shifted. Sometimes crud gets in the detent ball socket, preventing the ball from fully extending. This is what I'm betting on. Usually a little exercise against the work bench and penetrating oil can free it up. Pivot bolts and holes can wear but I have over 100k shots on my first 30 and it has the original barrel and the pivot bolt was replaced once but it was really necessary.
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The detent should hold the barrel in the lock up position as long as the pivot isn't too tight. The lockup position is set mechanically by the ball popping over a dowel pin, holding the breech step to the topside of the pin. A breech seal can only hold the lockup up off position and there'd be no play. If there's play in the lock up there's a different issue going on. Sometimes the pin wears and needs to rolled over or shifted. Sometimes crud gets in the detent ball socket, preventing the ball from fully extending. This is what I'm betting on. Usually a little exercise against the work bench and penetrating oil can free it up. Pivot bolts and holes can wear but I have over 100k shots on my first 30 and it has the original barrel and the pivot bolt was replaced once but it was really necessary.
I will check the ball. I have sloppy lock-up with the breech seal removed (noticeable). With the new breech seal installed, I can still flex the barrel against the seal the same amount, but the lock-up “unlocks” easily; breech seal is wanting to help barrel open. If that makes sense.
I’m hoping the ball isn’t exposed all the way. The ball/spring are not removable?
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Frank,
If you look on the side of the barrel breech you should see a small indented stake. At least on the new ones they are...older ones might be swagged in there.
Anyway, TIGHTEN the barrel pivot bolt so the barrel no long falls. It should stay in place and not move down unless nudged.
Try the tissue test to see if any air is passing the new breech seal.
-Y
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Frank,
If you look on the side of the barrel breech you should see a small indented stake. At least on the new ones they are...older ones might be swagged in there.
Anyway, TIGHTEN the barrel pivot bolt so the barrel no long falls. It should stay in place and not move down unless nudged.
Try the tissue test to see if any air is passing the new breech seal.
-Y
Yogi, he's getting the play when it is locked, there should be no up and down play at that point even if the pivot is loose. This is what his post is about, unless I misunderstood. Now, im not saying adjusting the pivot tension isn't necessary, just that I do not believe that is his problem. JMHO
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The ball is staked in place and not serviceable. There should be zero play in the lock up with the breech seal removed. The ball basically holds the breech step on top of the pin. The pin is a 4mm dowel. I replace them when worn rather shifting them. Both methods will work but the pins are cheap enough to replace. It takes MANY thousands of rounds before the pins are an issue. Most guns will never be used enough to reach that shot count.
Without having the gun in hand it's hard to diagnose. I'm still betting on the ball not fully extending because of crud holding it back. Another possible situation is some hacker tried to service the ball and staked it too deep. As I mentioned before many people used to wrongly blame the ball detent for vertical stringing and try to service the ball detent. That's a bad idea.
Of course there's other odd ball possibilities but without having the gun in front of me I can't say.
Did this gun ever work properly for you? Did you just get it? My offer to take a call is still open.
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Frank,
If you look on the side of the barrel breech you should see a small indented stake. At least on the new ones they are...older ones might be swagged in there.
Anyway, TIGHTEN the barrel pivot bolt so the barrel no long falls. It should stay in place and not move down unless nudged.
Try the tissue test to see if any air is passing the new breech seal.
-Y
Yogi, he's getting the play when it is locked, there should be no up and down play at that point even if the pivot is loose. This is what his post is about, unless I misunderstood. Now, im not saying adjusting the pivot tension isn't necessary, just that I do not believe that is his problem. JMHO
I agree on the vertical play. But I understand he also has horizontal play. Yes, everything else mentioned is correct, but I think step#1 is to tighten the barrel bolt so the barrel stays when lifted after cocking. Then tissue test. Then ball bearing lock-up. I believe in testing changes one at a time. Just me though. :-[
-Y
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Ron,
Do you think he may have a bent cocking linkage, like one of your earlier posts?
-Y
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This is with a new breech seal & without. No side-to-side play, Barrel just falls, as far as barrel pivot adjustment. No tight lock-up... The lock position has noticable freeplay when closed, This is an early 1982, no safety model, I inspected the ball, rotated the pin, still loose. The new breech seal does keep pressure on the barrel so the closed position is consistent, but I can still flex the barrel further closed when I compress the breech seal further. Im wondering if there is wear in the pivot bolt hole, or is it the actual ball resting place? I will investigate some more, but I thought I would ask the experts if this is a common issue with the older guns?
Frank can you cock the gun and take a few pictures of the breech block, ball detent, and detent dowell/pin up close. Yes I agree you might have some built up crud in the ball detent area. And the easiest way would be to remove the barrel and work the spring loaded ball detent on a piece of wood/ work bench with a good spraying of non Chlorinated brake cleaner. This will also give you the opportunity to check the barrel pivot bolt for any irregularities. A picture is worth a 1000 words😉
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Ron,
Do you think he may have a bent cocking linkage, like one of your earlier posts?
-Y
The R7 has an articulated cocking arm and not subject to droop from binding arms like the 95 family guns. I have seen people bend the cocking foot down on the 30s trying to minimize galling. Doesn't work btw but still wouldn't create a sloppy lock up.
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The ball is staked in place and not serviceable. There should be zero play in the lock up with the breech seal removed. The ball basically holds the breech step on top of the pin. The pin is a 4mm dowel. I replace them when worn rather shifting them. Both methods will work but the pins are cheap enough to replace. It takes MANY thousands of rounds before the pins are an issue. Most guns will never be used enough to reach that shot count.
Without having the gun in hand it's hard to diagnose. I'm still betting on the ball not fully extending because of crud holding it back. Another possible situation is some hacker tried to service the ball and staked it too deep. As I mentioned before many people used to wrongly blame the ball detent for vertical stringing and try to service the ball detent. That's a bad idea.
Of course there's other odd ball possibilities but without having the gun in front of me I can't say.
Did this gun ever work properly for you? Did you just get it? My offer to take a call is still open.
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I haven’t had a chance to look at the gun more closely, but I did take some pics of the lock-up & breech port before I had to go to work. I will try & post those pics.
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Hi Frank, on my modern HW30S (2015?) the ball protrudes about 1/8'' out of the breech block, make that a nominal 3 mm. HTH.
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Here's my 30 with a 4mm pin just laid in place
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More pictures
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Another
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The other thing that could bad is the spring under the ball, it may have lost its memory and will no longer spring back with enough tension to hold the ball in place, ???
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Another
I see some galling behind the ball on the "ledge" that rests against the receiver ... seeing the mating contact area on the receiver might help, however, I'd have to say truing the two surfaces that mate up might be beneficial even if it's not the root cause.