GTA
All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Engineering- Research & Development => Topic started by: Bob La Londe on August 24, 2014, 01:18:37 PM
-
I acquired a brand new Benjamin Trail XL .177 NP a few weeks ago. Its powerful. I sure wasn't prepared for that rifle like crack of the first few shots. Then I read up on dieseling. Interesting.
Anyway, I have decided for the short range and type of shooting I want to do iron sights (square open sights) would have been a better choice for me. I've got a baby CNC mill, a couple small lathes, a small manual mill and a couple middle weight CNC mills in my play room. Making or modifying some types of parts is no big deal. From what I have been able to find nobody is making a sight kit for this gun and many people feel its impractical or impossible.
I know. I know. If I wanted iron sights I should have bought a gun that had them. I already read that several times in my search. I didn't know I was going to want them when I bought it. I have it now, and I want to atleast try open square sights on it. I do not want to overly dissassemble the gun just yet to learn some things though. I am hoping others who have already studied one can help a little.
Front Sight:
I read that its a barrel liner in a shroud much like many other air guns. Its heavy but the out metal does have that feel. Some posts in areas I have read seem to think that because of this you can't install a front sight. I think it would be a mostly work, and less thinking about it afternoon project to make a front clamp ring sight out aluminum that slides over the barrel and clamps in place. I've seen middle weight center fire rifles with a front sight mounted this way. I've already thought through a design that would not be a significant hinderance to cocking. For the sake of this conversation lets just please assume my front sight will work.
Rear Sight:
Now obviously I could mount something on the picatinny rail where the scope is, but I never truly trusted a break barrel gun to lock up 100% consistantly over time. Also making a square site to go on it would require making the front sight taller as well. I would prefer to mount a rear sight on the chamber area of the barrel. That being said I am not 100% certain how the chamber area of the barrel is constructed. Is it solid like the chamber of a powder gun, or is it also an assembley? If its solid drilling and tapping a couple mounting holes or even cutting a small dovetail would be no big deal.
The Picatinny rail:
How is this thing mounted? Given the other dimensions of the gun it would interfer little, but it would be a constant distraction. I see a seam that appears to be filled between the rail and the frame. My first guess would be that it was soldered in place. That would make its removal (if the iron sights experiments works out) a bit more of a project requiring full dissassembley of the frame necessary to desolder it without damaging the internals.
-
I can't speak to the exact type of rifle since I've never seen one, much less coonfingered one with intent to modify. However, there's not much reason why NOT to fit a front sight to the shroud via a band of some kind. If it's strong enough to use as a cocking device, it's strong enough to keep the front sight in place. For a rear sight, you might look at affixing some kind of dove tail to the barrel above the chamber area. Of course it'd have to be able to slide between the arms that hold the barrel in place when you cock it. Take a look at Williams 22 type rear sight or you could mock up something. I replaced an old Daisy 120 rear sight with a Daisy 880 sight that I filed down to fit in place. It's a simple sight, could be made from sheet metal if you've the means to bend, temper, etc. Just a strip of steel bent into an L shape, two screws to hold it in place, one at the front in a round hole, one towards the rear in a slot that allows you to loosen the screw and swing the strip from side to side to adjust for windage. Mendoza makes a sight that fits on a 3/8" dovetail. The "one who shall not be named" sells a Chinese steel sight that fits on a dove tail, don't know if FlyingDragon carries the same or not. There are options out there, but most of them require a dove tail of some sort to fit the sight to. If you can set up some kind of dove tail, even if it requires an extension past the breech towards your eye a bit in order to work, your options increase.
-
Anybody want to offer any more information about the specific construction of this air gun?
Specifcially, do you know if the breech is a solid piece as it appears?
Do you know how the rail is attached to the frame?
-
does this help?
http://www.crosman.com/pdf/manuals/Trail%20XL%20EVP.pdf (http://www.crosman.com/pdf/manuals/Trail%20XL%20EVP.pdf)
-
does this help?
Thje exploded diagram shows the breech as a single piece indicatiing I could drill and tap (actually mill and thread mill more likely), so it is definitely some help. Unfortunately it also shows the rail and frame as a single piece even though I am sure they are two pieces bonded in some manner, probably by soldering meaning I still do not know how practical removal of the rail would be.
Yes. It is some help. Thank you.
Sorry, you are not allowed to post external links. Really? I tried to just quote the person I was responding to.
-
I have been studying on this gun for a while now. I've gotten some great resources on tuning and adjusting it, but I have not done anything. I'm still shooting it out the backdoor of the work shop, and the groups are getting smaller.
The recoil of the gun is the biggest problem, and eventually tuning will help with that. I have to say I still dislike the scope for this short range shooting. (My target is exactly 25 yards). Its slow to come on target, and the eye relief distance is way to limited. I don't think I'll ever be able to use it on running targets like I could with my 880-.177 or my Sears .22lr.
-
Amazon sells all kinds of open sights
http://www.amazon.com/Truglo-Rifle-Sight-Set-Ruger/dp/B000KKD3I6/ref=sr_1_2?s=sporting-goods&ie=UTF8&qid=undefined&sr=1-2&keywords=Truglo+rifle++rifle+sights (http://www.amazon.com/Truglo-Rifle-Sight-Set-Ruger/dp/B000KKD3I6/ref=sr_1_2?s=sporting-goods&ie=UTF8&qid=undefined&sr=1-2&keywords=Truglo+rifle++rifle+sights)
Be Well,
Gator