GTA
All Springer/NP/PCP Air Gun Discussion General => Air Gun Gate => Topic started by: ijinxd on February 20, 2014, 10:40:13 AM
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Ever since I first used the scope stop hole on my Big Cat, and noticed that the metal was bent backwards, I've stopped using the scope stop hole on the top of my rifles. Do you guys use this hole? If not, how do you get your scopes to stop creeping?
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I use the 1-piece Match Mount from Hawke on my D34 .22 and the scope has never moved in well over 2000 shots. It has 4 set screws to lock it down and seems to work. I have the HM 6146.
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http://www.youtube.com/watch?v=YcIhNUa4zs8# (http://www.youtube.com/watch?v=YcIhNUa4zs8#) :)
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IMHO The most important issue with stop pin holes is stop pin fit. The Stop pin must fit tight into the pin hole in the receiver.
If you have a loose sloppy fit, the pin moves forward and backwards, hammering the pin hole into a elongated slot. If the pin doesn't fit, it's up to you to acquire or make a custom pin that has a proper fit! ;)
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So with a custom fit pin (one which leaves very little space for movement) the hole on the receiver should not bend?
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So with a custom fit pin (one which leaves very little space for movement) the hole on the receiver should not bend?
Yep, typically that is normal, but not always. I recommend taking the stop pin out of the scope ring and testing how it fits into the stop pin hole in the receiver. Or with the ring mounted snug, not tight, push and pull on the scope ring to see if it moves?
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I'll have to look for a Match mount and check the screw on my current mount then. The current price on those Match mounts is around $25 unfortunately :/. I was thinking about putting a piece of rubber inside the hole on the receiver; that way it can absorb the shock better while reducing the amount of space.
Thanks everyone!
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I've had a stop pin bend, too.
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I have an older 1 piece mount on my 1994 tx200 and it NEVER moves. I've shot thousands of pellets thru it. I believe it is a RWS mount. I also bought a BKL 1 piece mount for my other tx200 and it also stays put without stops or pins so far. (bKL cost over $50.00). I really like the BKL and they are self centering when you tighten them down.
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Thanks for all the help everyone! I called Crosman earlier and inquired about the price of a replacement compression chamber tube. Turns out they go for $15. Needless to say, I slapped on the scope stop...a $15 replacement fee isn't terrible. They should really consider surrounding the area with hardened steel...
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I have an older 1 piece mount on my 1994 tx200 and it NEVER moves. I've shot thousands of pellets thru it. I believe it is a RWS mount. I also bought a BKL 1 piece mount for my other tx200 and it also stays put without stops or pins so far. (bKL cost over $50.00). I really like the BKL and they are self centering when you tighten them down.
+1 on the BKL one piece mount. It seems to have solved the problems I was having with a wandering POI. $63 shipped to my door from Pyramid Air.
More expensive than other one piece mounts, but I like that it has 6 (six!) clamp screws, and the Clamp is all one solid chunk of metal, no 2 peice clamping action like Most mounts use....
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I'd rather just rely on the mount(s) doing all the clamping/holding. I've seen horrible messes made of those holes made for "trying to" stop scope movement...
Edit in...
Trouble with a pin and hole is the hole is always a larger dia than the pin. That means there is always just one minutely small area of contact between the two, resulting in a recoil force being able to pummel the heck out of the hole. A neat (tight/perfect) fit between pin and hole would give more surface contact, spreading that load and hopefully evening out the pummelling effect...
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I had a UTG mount with 3 clamping screws and I just drilled two more holes on a drill press and tapped it for 8x32 allen head screws, real easy being it was aluminum. I now have 5 clamping screws
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I've decided to purchase the Trail NP2 so I'm going to save the cash and wait on that to come out. Anyhow, how tight do you guys screw the pin down into the scope stop hole? I'm concerned about hitting the gas piston by screwing it in too far. I own a Titan NP if that matters.
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I had the same problem with my first Gamo.
Three things (as others here): a) I've got a thicker (and stronger) pin, that naturally fits better in the hole (no matter it was already elongated); b) I've put extra screws on the mount base (from 3 to 5); c) I often check the mount base screws and keep them very tight.
It is a work team = mount base screws + stop pin
You don't have to deepen the pin because it's useless; make sure it has just entered (not trespassed) the thickness of the rifle' body surface.
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I've decided to purchase the Trail NP2 so I'm going to save the cash and wait on that to come out. Anyhow, how tight do you guys screw the pin down into the scope stop hole? I'm concerned about hitting the gas piston by screwing it in too far. I own a Titan NP if that matters.
When the stop pin, stops turning, it is tight enough! If you tighten any more you lift the scope/ring up, causing it to tilt or making it higher than your other scope ring. ;)
With the scope ring cap off, line up the stop pin shallow into hole, lock down the scope ring and now finish tightening using your allen wrench, gently turn the stop pin until it stops turning. If you tighten any more, it'll lift up the scope ring causing problems. :)
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IMHO The most important issue with stop pin holes is stop pin fit. The Stop pin must fit tight into the pin hole in the receiver.
If you have a loose sloppy fit, the pin moves forward and backwards, hammering the pin hole into a elongated slot. If the pin doesn't fit, it's up to you to acquire or make a custom pin that has a proper fit! ;)
Another issue is adequate "stop pin projection". Years ago I had a scope mounted in a two piece Beeman scope mount on the bolted on this "pot metal" scope rail of my .177 R10.........
(http://img.photobucket.com/albums/v734/wved/Airguns/Scopes_Mounts/R10scoperail-1.jpg) (http://smg.photobucket.com/user/wved/media/Airguns/Scopes_Mounts/R10scoperail-1.jpg.html)
About 3/4 way through a field target match the poi was wandering more than normal and then I noticed that the rear mount was COMPLETELY off the rail! Later that day I removed the scope and mounts to find that the stop pin didn't have adequate projection so it literally "machined" a groove through the rear on the stop pin recess. The Beeman mounts only used a split roll pin for a stop pin so it was rather easy to move it down for more engagement. Anywhoo....after that the scope mounts held just fine. LOL, I learned from experience that the adjustable RWS "C" mount I tried was practically useless for a "pot metal" scope rail!
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Ever since I first used the scope stop hole on my Big Cat, and noticed that the metal was bent backwards, I've stopped using the scope stop hole on the top of my rifles. Do you guys use this hole? If not, how do you get your scopes to stop creeping?
I also had this issue with my .177 R9 using the "normal size" stop pin found in scope mounts. One of my solutions for a Beeman scope mount was to drill and tap the hole in the mount for a socket head cap screw that was modified to fit the stop pin hole in the receiver. Here's a pic........
(http://img.photobucket.com/albums/v734/wved/Airguns/Scopes_Mounts/AlternateScopeStopPin.jpg) (http://smg.photobucket.com/user/wved/media/Airguns/Scopes_Mounts/AlternateScopeStopPin.jpg.html)
One of the good things about this stop pin is the fact that I can adjust the projection by turning with an allen wrench. The cheaper Leapers scope mounts actually have a tapped hole for their stop pin (actually a set screw) so it would be rather east to fit a modified cap screw from the under side.