GTA
Airguns by Make and Model => Benjamin Airguns => Topic started by: jmacpolo on March 23, 2013, 08:59:11 PM
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Picked up one of these last year in .22 with the center point scope, black synthetic stock, and it was great until my son dry fired it. Now it seems to be underpowered (will not penetrate through a soda can) and very inaccurate. Did he fry something inside the gun? Is there a way to fix it? Is there someone who can fix/tune these guns?
Thank you,
John
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Try replacing the piston seal.
One dry fire usually won't cause much harm, so maybe he made a habit of it... and only admits to "once".
:o
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Where do I get a new piston seal and how difficult is it to replace?
Thanks,
John
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If it doesn't shoot thru a pop can, wow,
Does it cock any easier?
If so it maybe nitro ram failure if it cocks easier than normal.
dose the breach seal look OK?
All the parts you need can be had from crosman, They are cheap, both the breach seal and ram seal + shipping should be around 10 bucks.
Take care,
Mark
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Try breaking the barrel open and set the but of the gun on a bathroom scale. Try slowly applying pressure to the end of the barrel to cock the gun - don't cock it all the way. See how many lbs of force is takes to cock it. Should be up there in the 35 lbs. area.
If less than that, I would say your gas spring (nitro ram - or whatever you wanna call it) is no good.
I did a similar thing with my Trail NP. Ended up with it only taking about 10-12lbs of force to cock it. It was sure nice and easy to cock - but it wouldn't hold a candle to what a red ryder bb gun could do. ;D The gas spring was history. There was nothing wrong with my piston seal, or the piston itself.
When I purchased a gas spring a few months ago, it was $26 plus a few dollars for S&H.
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Doesn't the Trail NP have a nitro piston preload that requires a spring compressor fixture to disassemble and re-assemble? I thought that the NP needed one, while the XL doesn't.
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You sure would need a spring compressor to take a trail NP apart then reassemble it.
I believe all break barrels of this type need a spring compressor to get to the spring / nitro piston.
Do some checking on take-apart, there is good info on this site.
The Library has a ton of good info and doing searches on the newsgroup will come up with more info.
I'm not sure how far you would like to go into fixing, this could be a fun project, It could also be a frustrating project,
read up on the articles in the Library for starters.
Take care,
Mark
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Thank you for the replies. It does cock much easier than before. I have never opened up a air gun before I thought it could be dangerous.
Thanks again,
John
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It CAN be dangerous. Thoroughly research and absorb as much information as possible before you try to dig in. Take all precautions before doing something like this. There may even be a tutorial video on YouTube. That would give you a little better idea of how to do it. Good luck.
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Here is a very good post on how to rebuild the Trail NP. It describes how to build a cool homemade spring compressor. I've been thinking of building one of those, but I haven't had a need to take one of my spring piston rifles apart yet. That's the nice thing about all of my CO2 guns - easy to disassemble and repair or modify. The bad part is much less power.
http://www.gatewaytoairguns.org/GTA/index.php?topic=33617.0 (http://www.gatewaytoairguns.org/GTA/index.php?topic=33617.0)
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If you want to save a lot of time and maybe some money (depending on what you already have for a compressor), another option is to pick up a bar clamp. I used this one to take apart and put together my Trail NP. I did have to take the barrel off to do it, but the barrel is not hard to take off. I put my forks on the square end, and the round end on the gas spring end. The handle screws in and out, and slides on the bar. I got it at Lowes hardware for about $15. It's the 24 inch version. It's item#214888. As far as dangerous, I don't know about spring based rifles, but the Trail NP only had about 1/2-3/4 inch preload on mine, not much pressure.
(http://i1237.photobucket.com/albums/ff468/thunt5/IMG_0864.jpg)
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Here is a link to quite a good video on doing a rebuild of a Trail NP.
http://www.youtube.com/watch?v=FeQQ6S6WgHc#ws (http://www.youtube.com/watch?v=FeQQ6S6WgHc#ws)
If you do decide to disassemble you gun, I would highly recommend taking photographs as you go along. Some good close-ups of parts before they are disconnected.
The guns are simple enough - if you've done them before, but if it's your first time, it's easy to get hung up.
Good luck. :)
Well, I reckon it's not just a link. It's the actual video!
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If you want to save a lot of time and maybe some money (depending on what you already have for a compressor), another option is to pick up a bar clamp. I used this one to take apart and put together my Trail NP. I did have to take the barrel off to do it, but the barrel is not hard to take off. I put my forks on the square end, and the round end on the gas spring end. The handle screws in and out, and slides on the bar. I got it at Lowes hardware for about $15. It's the 24 inch version. It's item#214888. As far as dangerous, I don't know about spring based rifles, but the Trail NP only had about 1/2-3/4 inch preload on mine, not much pressure.
(http://i1237.photobucket.com/albums/ff468/thunt5/IMG_0864.jpg)
I wonder if it would be ok to just pull the barrel down like you are cocking it and hook the bar clamp on that way. Saves you from having to take the barrel off. Just not sure how safe it would be to do it this way..
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If you want to save a lot of time and maybe some money (depending on what you already have for a compressor), another option is to pick up a bar clamp. I used this one to take apart and put together my Trail NP. I did have to take the barrel off to do it, but the barrel is not hard to take off. I put my forks on the square end, and the round end on the gas spring end. The handle screws in and out, and slides on the bar. I got it at Lowes hardware for about $15. It's the 24 inch version. It's item#214888. As far as dangerous, I don't know about spring based rifles, but the Trail NP only had about 1/2-3/4 inch preload on mine, not much pressure.
(http://i1237.photobucket.com/albums/ff468/thunt5/IMG_0864.jpg)
I wonder if it would be ok to just pull the barrel down like you are cocking it and hook the bar clamp on that way. Saves you from having to take the barrel off. Just not sure how safe it would be to do it this way..
I think then the NP would be under pressure which would make it more difficult and dangerous to compress.
I used a similar clamp to do mine but just removed the scope and hooked the front edge of that clamp (stationary edge) to the front of the weaver block and proceeded slowly and carefully. As noted, there is not much preload in the Trail NP, maybe 1/4---1/2" +-.
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I watched the video and I don't think I am comfortable doing that kind of work on the rifle. Are there tuners for these kind of guns?
Thanks,
john
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Yes there are tuners, professionals, who will fix this problem for you. Unfortunately, three of the most highly recommended are no longer tuning (retired). Check the GTA Mall, there are tuners listed there.
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I wonder if it would be ok to just pull the barrel down like you are cocking it and hook the bar clamp on that way. Saves you from having to take the barrel off. Just not sure how safe it would be to do it this way..
Never work on a nitro or spring piston rifle with the piston cocked. That would be a good way to injure yourself or anyone in the room with you. :o Removing the barrel and then using the clamp is the best approach.
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@jmacpolo
I have used the same 24inch clamp pictured by fenixt to dismantle and reassemble my Trail NP many many times and will no doubt do so again eventually. As pointed out in this and many many threads, the gas ram in the Trail NP has only about 1/2 inch of preload on it. What that means is, once the stock, barrel, scope, and tube cover have been removed, the Compression Tube Assembly can easily sit in the clamp with a 5/8ths socket clamped up against the Back Spring Guide. Tighten the clamp slightly until the pressure on the Fixed pin is releaved, remove the Fixed pin, untighten the clamp about an inch and you then slide out the trigger assembly and have easy access to the internal components. Consult the Exploded View Parts Diagram if you don't recognize the terminology.