GTA
Airguns by Make and Model => Benjamin Airguns => Topic started by: imadunatic on March 06, 2017, 09:18:48 PM
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2 guns for the price of 1.5!! Decided since the NP2 makes so much more power in .22, and the fact that it could be affordably converted that it needed to be done, if only to say I did and be able to easily swap back and forth. The kicker is being able to swap calibers in about 5 minutes once you have gathered the necessary parts and put the sub-assemblies together. I took a few pics while I was doing it (also upgraded the trigger to the CBR and refined my brass washers slightly, they were too tight the first time I did it, so I tuned them slightly whilst I had this apart.
On to the pics:
First step is to remove the action from the stock (3 screws, 2 on the forearm, 1 to the rear of the trigger guard).
Next, remove the anti-beartrap arm and cocking lever:
(http://i.imgur.com/zaNucWK.jpg)
Next, loosen the small (I think it requires a 1/16 hex key allen wrench) set screw, and remove the pivot screw completely:
(http://i.imgur.com/9VO09by.jpg)
At this point, you should be able to pivot the entire breech assembly up and out of the compression tube assembly.
These are the parts you'll need (with prices) to complete the conversion, and while you're at it, might be a good time to do the "brass washer upgrade (http://www.gatewaytoairguns.org/GTA/index.php?topic=82134.0)" or possibly a CBR trigger (http://charliedatuna.com/NPSS%20non%20PP.htm) 8)
(http://i.imgur.com/BrV8wsQ.jpg)
The easiest way is with a vice to press the knurled pin/sling mount/lever assembly together, but this could also be done with a hammer and a solid surface if you're lacking a vice. The pin goes in fairly easily, but the best reference you have for this is the assembly you just removed from the rifle.
This is the sub assembly once you've pressed everything together:
(http://i.imgur.com/PUNw7D3.jpg?1)
You may also want to give your new barrel a good scrub with JB Bore Paste and a brass brush (do your homework here, some feel this will damage the barrel, personally, after using it on a dozen barrels, I've never had a steel barrel damaged by a brass brush, but knowledge is power, so do your homework and decide what you're comfortable with) and follow up with Balistol or Goo Gone with a wet-dry-wet-dry patch cycle to clean all the gunk out.
At this point, it's time to reassemble the breech assembly to the compression tube, put it all back in the stock and run some shot strings. For comparisons sake, I've included the last string I ran with this rifle in .177 form before tearing it down for the conversion.
(http://i.imgur.com/WEDrZzS.jpg)
(http://i.imgur.com/4KevIv1.jpg)
As you can see, going from .177 to .22 results in approximately a ~22% increase in power with approximately a 19% reduction in velocity. As we all know, there is no free lunch with springers, but if power is what you're after, the .22 definitely the way to go. Not sure how mine will spend the majority of it's days, I suppose time will sort that one out.
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thats awesome.. I bet a lot of these crosram gas rams have interchangeable front ends.
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I agree Rob. For the price and required effort, I'd definitely recommend it to anyone. Way too windy up here to try it out this week, but hoping for calmer weather this weekend and see which pellets it likes. The .177 ate up the CPHP, hoping for the same with .22!
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Thanks Kevin, Awesome pix and great data. Any trick on getting the guide pins back in the breach?
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Thanks Kevin, Awesome pix and great data. Any trick on getting the guide pins back in the breach?
I just used a vice on mine, it self aligns on the smooth end. Did you re-use the old one? I think they may be a "one and done" pin due to the interference fit, but I'm not positive. If you don't have a vice, I think setting the breech on a stable surface that won't mar it (piece of wood maybe) and using a hammer would also work.
As far as the anti-beartrap spring/roll pin, I just tapped that in with a hammer. They require a very deliberate tap to get started, then they can be adjusted fairly easily. That pin could definitely be re-used if needed.
Are you converting, repairing or just playing?
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Kevin,
I have just tuned my NP with the requisite piston seal, breach washers ( I'm trying steel this time) and trigger (NP2). When I had it apart I noticed how easy it would be to convert to .22 and wondered if there were any special presses or other tools needed for the task. So I'm just playing for now and will probably order a whole guns worth of parts and build a new "hybrid" .22 .
Thanks for the tips!
As far as my tune goes, I'm very happy with the sub .500 groups @ 10m with various types of pellets, working on my technique should tighten that up even more.
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Nice write up, Kevin!
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Excellent Post ....Kevin ! Best Wishes - Tom
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So does the barrel assembly not come with cocking linkage attached?
I am thinking about converting my Vantage NP in .177 to .22, and have been looking at the parts list determining what I need and thought I'd only need to order the new barrel to be able to swap the .177 and .22 back and forth. Seems like the linkage is a different part though? That's worrisome to me, because even with a solid punch and a hammer, I could NOT get that pin out.
Might be worth it to get a sling mount in though!
Cool write-up.
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So does the barrel assembly not come with cocking linkage attached?
I am thinking about converting my Vantage NP in .177 to .22, and have been looking at the parts list determining what I need and thought I'd only need to order the new barrel to be able to swap the .177 and .22 back and forth. Seems like the linkage is a different part though? That's worrisome to me, because even with a solid punch and a hammer, I could NOT get that pin out.
Might be worth it to get a sling mount in though!
Cool write-up.
Did you try punching from both sides? I believe one side is made wider than the other
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So does the barrel assembly not come with cocking linkage attached?
I am thinking about converting my Vantage NP in .177 to .22, and have been looking at the parts list determining what I need and thought I'd only need to order the new barrel to be able to swap the .177 and .22 back and forth. Seems like the linkage is a different part though? That's worrisome to me, because even with a solid punch and a hammer, I could NOT get that pin out.
Might be worth it to get a sling mount in though!
Cool write-up.
It does not come with anything assembled. That third picture is basically how it comes from Crosman. I ordered all the parts so I have sub assemblies for either caliber and can swap them out in ~20 min or so. If you wanted a permanent swap you could certainly save a few bucks. The only thing I'm not sure about is if that splined pin is a one and done and must be replaced every time or if you can reuse it. Personally, for the extra $15 I'd probably just buy all the parts and then you know it will work.
Good luck either way.
Kevin
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So does the barrel assembly not come with cocking linkage attached?
I am thinking about converting my Vantage NP in .177 to .22, and have been looking at the parts list determining what I need and thought I'd only need to order the new barrel to be able to swap the .177 and .22 back and forth. Seems like the linkage is a different part though? That's worrisome to me, because even with a solid punch and a hammer, I could NOT get that pin out.
Might be worth it to get a sling mount in though!
Cool write-up.
It does not come with anything assembled. That third picture is basically how it comes from Crosman. I ordered all the parts so I have sub assemblies for either caliber and can swap them out in ~20 min or so. If you wanted a permanent swap you could certainly save a few bucks. The only thing I'm not sure about is if that splined pin is a one and done and must be replaced every time or if you can reuse it. Personally, for the extra $15 I'd probably just buy all the parts and then you know it will work.
Good luck either way.
Kevin
Thanks!
Yeah I was thinking how nice it would be to have a fully functional .22 and .177 barrel to make it interchangeable. I have one of those Beeman RS2 dual calibers, but I hardly ever do a quick change since it requires a new zero, so having to disassemble more of the rifle to change the barrel isn't a huge deal to me.
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Yeah I was thinking how nice it would be to have a fully functional .22 and .177 barrel to make it interchangeable. I have one of those Beeman RS2 dual calibers, but I hardly ever do a quick change since it requires a new zero, so having to disassemble more of the rifle to change the barrel isn't a huge deal to me.
KJB......I have a Hatsan with two complete barrel assemblies.
One is a 25 cal. barrel for hunting and one is a 117 cal. barrel that I can do most of my target shooting with.
Best Wishes - Tom
Click the image once or twice to enlarge.
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Don't mean to get off topic but nice rig, Tom. If you got the extra barrel from Hatsan, how are they as far as ordering parts?