Home Forums Hunting & Shooting Air Guns In need of advice... [Benji Trail NP 22. all weather]

I recently acquired a Benjamin Trail .22 NP All Weather and I'm really quite satisfied. I knew almost immediately that it would require some work so I did some research and quickly learned a little about 'tuning' - the only problem is that the bulk of the information out there currently about 'tuning' is regarding 'springers' - there just isn't much to be found in the way of tuning NPs. So I've disassembled it, cleaned it, did a 'trigger job' on it, file all of the rough contact points, smoothed the burrs, covered everything in a generous coat of dry lube spray on graphite, and reassembled it. The performance change was immediately noticeable - especially in the trigger pull & break. It now operates smoothly, like a well oiled machine.

I should also take this opportunity to mention that the only place I currently have to shoot is inside my house, down a 30 ft. hallway, so my target is rather close but the stock scope that comes with it has a 30 ft setting, so it should be manageable. As smoothly as I've gotten this thing to perform, the accuracy is still horrible - which is oh so aggravating.

So after more reading and research, I disassembled it again and flattened and reshaped the crown on the end of the barrel (using the brass screw and lapping compound method), I also drilled 4 more holes (1 between each of the pre-existing ones) in the barrel end cap to allow more gas to vent out to the shroud. The diagram of the gun I found called it an end cap, but it feels like it should be referred to as a 'shrouded muzzle break'. Again, even smoother and more of a performance gain. I can put 3 pellets in 1 hole then the shot moves on me. As soon as I think I'm good and zeroed in, the next shot is off by 3 or 4 inches - then the next one is off by 3 or 4 inches in another direction. It's hella frustrating! It's even more frustrating that I've got all this time wrapped up in this thing and can't put 5 pellets in the same hole at 30 ft - no more than 3, ever.

I'm going to take it apart again, go through it again with the file, round out the crown again, I'm contemplating adding some holes to the front face of the barrel end cap, and this time I'm planning on coating everything in some spray on white lithium grease, let that dry, then spray it again with the graphite - then put it can together and see what happens. While the graphite works great, it stinks like hell when the weapon is fired because it comes flying out of the barrel as a micro dust, and the compression piston rubs the tube after 2 days of use, so I'm guessing that means graphite doesn't stay between the metal contact points very well. I'm hoping the white lithium grease will fix both issues.

Edit: I also wanted to add that I drilled the extra holes in the 'shrouded muzzle break' after doing some silencer research - I was hoping to reduce recoil and report. I even tried packing the barrel shroud with steel wool, also drawing on basic silencer design - don't do that, it only makes it louder. Currently I'm curious as to whether drilling holes in the front face of the 'shrouded muzzle break', allowing gas to exhaust around (vented up and away, obviously) the pellet upon exit would have any further impact on recoil and/or report reduction.


So the things I've perplexed about:
1. Does white lithium grease diesel?
2. Has anyone tried the combination of white lithium grease and graphite? Does it work? Does it 'gum up'?
3. Is there anything I can do to this rifle to fix the accuracy issues I'm experiencing?
4. Is there a 'top sights' kit I can buy and install for this rifle?
5. Does anyone have any tried and true methods for reducing report and/or recoil through barrel shroud and/or muzzle break alteration?

If I don't get the accuracy issue sorted out, this thing will be up for sale - SOON!



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I'm new to air rifles but not to gunsmithing.

I'll take a shot at a few of your questions.

I can tell you that yes, lithium grease will diesel.

The best way to quiet an airgun is with an aftermarket "lead dust collector" sold by TKO and some other companies.

You may be expecting too much out of your rifle as far as accuracy. It's a lower priced plinking or hunting gun, not a high dollar match Finewerkbau. But try some different pellets if you've only been shooting one brand. You'll probably find some style and weight of pellets will shoot better than others.

Thanks - that's more info than I had when I started! I took it apart again and found some rub marks in the graphite, top of the piston against the top of the compression tube assembly, so I filed the top of the piston just enough to take the rub out of it and it's back to slip'n and slide'n. I used the spray on lithium grease & spray on graphite powder combination and after 1 detonation, it seems to be working like a champ - and the cocking is sooooo smooth and easy now.

As for expectations of my rifle, I appreciate the thought but I've experienced better accuracy out of a Daisy. After reading multiple accounts of people 'tack driving' at 20 & 30 yrds with this specific rifle - unmodified - I don't think that my expectations of being able to produce a 1/4" grouping at 30 ft (10 yrds) out of line, especially since I've done my best to optimize it's performance - and I really think I did a pretty good job. I'll be replacing the bushings and seals as soon as I can find some replacements that aren't priced out of feasibility.

Every time I've had a shot at a squirrel or rabbit, it's missed by a mile. I'm also currently using the .22 Crosman Premier Hollow Points.

Again, thanks for the excellent information about the grease dieseling and the 'lead dust collector'. You've given me a great starting point for more research.

I still need a few more days of shooting to make a verdict about the latest round of modifications - so far, I'm diggin' it.

I zero'd the scope with a bore sight which has never proven accurate, but wow, I just put 10 pellets in a single hole. I think my accuracy issues are over... I hope. It's really hard to believe that some white lithium grease was all I needed.

I'm contemplating putting a piece of surgical tubing over the end of the pneumatic piston to dampen the impact when it hits the compression piston. Anyone tried this?

The aftermarket trigger from Airguns of arizona makes a world of difference. It is easy to install and works well.

I pulled out the trigger adjustment block & screw - that thing was useless - filed all of the action surfaces flat and sharp and put it back together. I think the culprit of the 'horrible trigger' on these things that I keep reading about is that there's a casting seam that runs down the middle of every action surface! Once I cleaned all of that up, it's a nice and predictable fire every time. I've done a few trigger jobs, mostly on AR15s, and while this isn't a typical trigger setup, the logic is the same. I gotta say, all in all I'm pretty pleased with my current trigger.

I never could understand why everyone is so quick to put a drop in replacement trigger in instead of grabbing a file and gettin' happy, but I read a lot of posts from people who were perfectly content to do so - with mixed results - everything from 'this thing works great' to 'scary dangerous hair trigger'.


What I'm looking for at the moment is a place I can buy a replacement barrel shroud and barrel shroud end cap. I'd like to play/test some different modifications to these parts but not without being able to get stock replacements if the tests go horribly array.

I'm also curious about what the differences are between the Benji .22 NP all weather and the XL 1100 - if anyone knows. They look like mirror images of each other from the pics I've seen but the fps are way different - does the XL has a bigger piston for a faster throw? or a longer piston arm for a longer throw? If so, is there some place I buy the larger piston and upgrade mine? I hope to, at some point, come across a crosman parts warehouse site - but I haven't found it yet.

So many questions.... so few answers....

I just put 20 shots in a 1/16" grouping at 30 ft. so I'm finally convinced that my accuracy woes may be behind me for good. I didn't expect the last round of lube and filing to fix all of my issues, so I built a spring compressor today. I'm 'itching' to test it out so I've decided it's time to upgrade all of the seals. I haven't been too successful in finding much info or retailers on and of them. Can anyone point me in the right direction?

I could really use some assistance figuring out which upgraded seals to get: http://www.airrifleheadquarters.com/page/page/251485.htm

I wanna replace the piston seal, the seal inside the piston tube, and the breech gasket. I'd also like to get my hands on some brass washers that I can file down to be new bushings - I can't convince myself to spend 15$ for 2 washers. The only problem is that I haven't been able to find anything about what size brass washer I should buy to make some DIY bushings; anyone know? I can take the plastic ones down to the hardware store or I can order the right size online cheaper, not to mention how much easier it would be if someone knows what size I need.

Thanks ahead of time!

In case someone refers to this thread at a later point looking for info - the break bushings/washers you want for a Trail .22 NP AW are: 5/16 ID, 9/16 OD, 1/16 thick flat brass

Mods I've completed thus far:
- modified shroud cap, 16 gas exhaust ports into the shroud, 6 in the front face
- all casting seams on trigger groups filed out
- piston catch action filed flat, edges sharpened
- spring adjustment block, screw, and spring removed
- piston cylinder honed and lubed (all lube is a spray on white lithium grease with spray on dry graphite over it)
- barrel end filed flat and recrowned
- Filed and smoothed all contact points between the piston and the piston tube
- brass break bushings

I've done a complete 180 on this rifle and am so pleased with it that I might never part with it! It's truly a 'nail driver'. To my surprise, I didn't even have to rezero the scope after working on the trigger tonight even though I had to uninstall and reinstall it, it was still right on the dot.

I've read that this particular model gets more accurate the more you shoot them, especially when they aren't cleaned for years. That being said, I'm speculative as to whether or not the white lithium / graphite combination in the piston tube didn't fill in the rifling to just the perfect extent the first couple of times it was fired after lubing. As far as I can tell, thus far, the lube combination hasn't had any ill effects as of yet.

Sidenote: I wanted to post a followup now that the work is done and the issues have been resolved because it seems that a followup is missing from every thread on the web relating to the Trail .22 NP AW which makes it difficult for new owners to know what needs to be done, so I apologize if some (or all) of this is old material for the seasoned pros. Just wanted to put a roadmap out there for other newbie DIYers like myself that may come after me.


...now on to figuring out where I'm going to get some aluminum bar or disks from to make an LDC.

Thanks 24HC!

Thanks for the write up.

Thanks for the amazing write up!

I also have a Trail NP and am searching for ways to decrease its total sound output. I do notice that the Nitro Piston spring action produces the majority of the noise, not the muzzle blast.

Do you think adding cotton/soft-paper into that small volume between the shroud and the barrel will help silence the weapon? My idea is that such soft materials could help dampen the compressed gas flowing into the shroud.

BTW, did you add any "exhaust" holes at the breech end of the shroud to relieve the pressured air flow?

- Very interested!