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All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Share Your Simple Home Projects (TRICKS-N-TIPS) => Topic started by: twh731 on December 11, 2011, 05:26:16 PM
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I have purchased a new barrel for my Benjamin NP XL1100. The original barrel rifling seems to be not as sharp as I would think it should be and I was doing a tune on the rifle anyway so thought "what the heck, while I got things in pieces". Crosman had a new barrel for less than $20 so while I was ording parts I bought one. I have the tune completed except for final reassembly. I installed the barrel shroud and the pivot sleeve and lock-up assembly. What I am having trouble with is the pin which holds the cocking arm and sling swivel onto the barrel block. I haven't tried "beating" on it but have whacked it pretty good with a pin punch and small hammer. It appears to only go in / out one way as one side is inset and flush with the barrel block and the other appears to have a dimple in it such as maybe a rivet would have. It is a pretty stout pin not some cheap rivet. Should I continue to try to force it out with a hammer or should I drill it out and then try to find someway to install it on the new barrel. If I drill it out then how would I hold the cocking arm onto the new barrel assembly? Everything was going so smoothly until this one little pin!!!! Thanks for any help. Tom
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here is a picture of the pin I'm talking about.
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I forget which AG it was but I ran into the same problem, the one I was working on had a circlip holding the pin in. The clip was hidden in the middle of the pin between the 2 halves of the cocking linkage..... luckily I found the clip before I found a BFH.
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I forget which AG it was but I ran into the same problem, the one I was working on had a circlip holding the pin in. The clip was hidden in the middle of the pin between the 2 halves of the cocking linkage..... luckily I found the clip before I found a BFH.
that is nice to know because i have a new pine for my new barrel and its totaly diferant from the original and it has a grove for a clip now i know its going to be easy install ayway and i dont have to beat on the pin........dave
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Just watch the new Barrel and be Careful for a bit there TWH.I changed the barrel on my Trail to .25 then to .177 and both barrrel's shot fine for about 15-20 shots then Misfired on the next and Broke the sear multiple times. These guns tolerances aren't the Best so I thought I'd let you know.
Some had great success with their .25 cal conversion's (and .22's),,but I had No luck.Just wanted to let you know.
Thanks
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Hi
I just examined my trail NP XL
The rivet seems to have been spun in.
The process is done in a press that has spinning anvils to set the rivet. The spinning anvils heat the metal of the rivet and smear the heads.
The process leaves a nice finish
The rivet is permanent and will have to be drilled out to remove.
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I forget which AG it was but I ran into the same problem, the one I was working on had a circlip holding the pin in. The clip was hidden in the middle of the pin between the 2 halves of the cocking linkage..... luckily I found the clip before I found a BFH.
that is nice to know because i have a new pine for my new barrel and its totaly diferant from the original and it has a grove for a clip now i know its going to be easy install ayway and i dont have to beat on the pin........dave
Negatory. Turn you gun upsidedown and i believe you will see that the combination of the Sling Mount arms and the pinched-together Cocking Link arms takes up all the room in the gap on the breech block for those items leaving no room in the middle for, nor access to, a circlip or e-ring. There is room to slip a couple of pleces of paper in there and verify that there is nothing in there. The groove IS there but is unoccupied.
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Well, I ended up drilling the punched side of the pin out and drove the pin out. No C clip and actually the pin is solid with no groove for a C clip. It went ok, but I still don't quite know how I'm going to retain the pin in the new assembly now. It did drive in with some resistance but I can't imagine that it will stay in place without some sort of help. By the way, when I got it all together (pin in place on it's own just to make sure it all works), I cocked the rifle and loaded a .22 cal pellet in the bore and watched it just slide all the way thru and onto the floor. Amazing how that happens when it's a .25 caliber bore!!!!! I ordered a .22 and evidently got a .25. No where on the barrel is the bore stamped and I didn't even think to check it. Now I'm in a quandry. It will be next week before I can get some .25 caliber pellets to try. Should I just keep the .25 and not worry about asking them to send a .22 barrel? I guess one more week can't hurt to wait and try the .25 barrel. Heck, maybe I'll like it. I hate to order several types of .25 pellets and then find out I don't like it. My Benji NP XL is the only .22 pellet rifle I have and I have a bunch of different types as I really rung it out to find which pellet it likes the best. Anybody have any thoughts on the .25 cal. Benji? Do you like it? Thanks for all the replies and any suggestions regarding the .25 cal barrel debacle are appreciated. Tom
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Hi
You might as well try the 25 out since you have it.
The traditional rivet is peened over to retain.
This is probably a two man job, one to hold the barrel and the other will use a ball peen hammer.
THis is not a smashing hit but many lighter hits.
take a steel rod a little bigger than the rivet. smooth and polish the end of the rod. the finished end of the rivet is placed on the rod which is clamped in a vice.
The round end of the hammer use used to hit the rivet.
You also can make a rivet set. It is a punch with a round cavity to the desired head size.
You then hit the rivet set with the hammer repeated ly until the rivet is set .
Dennis
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Maybe since you don't have the proper tools to reset the revit correctly, grab the phone book and call some machine shops and see how much they would charge to set one revit..
You could also grab the phone book and look up fastners to try and find a place that deals with strickly every kind of bolt, nut, screw, pin, etc and get a pin that is slightly longer or a smooth shafted bolt that has threads on the very end.. then a slim low profile type nut and thread lock it on...
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Sorry for catching this one late. The retaining pin is solid and flared on one end. What I had to do was drill into the center of the pin with a bit slightly smaller than the pin itself. Drilled in just enough to get past the flare. I then used a pin punch to carefully drive the pin out by collapsing the flare. I bought new pins to reinstall but MAY have been able to reuse the old one. Insert the new pin and make sure it is backed with something solid. Use a center punch to flare the end.
Happy Shooting!!!!
Dave
8)
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Thanks for all your great replies! I think I will visit my local Ace Hardware just to see if they have a decent rivet selection. I was raised on a farm and we had an old bar sickle mower which we had to replace blades on all the time. I am familiar with the process of riveting solid rivets. It was not as critical on a mower as it will be on the airgun but I think I can do a decent job of it. Thanks again for all your help. I hope I can get decent velocity out of the .25 cal barrel. I really liked the .22 as it hit really hard and I was getting mid to high 900's with 16 to 18 gr pellets before it started to falter after several thousand rounds. I started this project because I was suddenly getting 3" groups at 20 yards and my velocity had fallen into the mid 700's. Tom
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Hi
You probably should get the Crosman/Benj rivet. Must be a cheap part.
Do you want to get the 22 barrel?
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Although I am going to go ahead and try the .25 cal barrel I would like to get a .22 barrel since I have a HUGE selection of .22 pellets and this is the only .22 cal. pellet rifle I own. I think along with the barrel and rivet I will probably buy a couple of extra seals for future use. So yes, to answer your question, I would like a new .22 cal barrel. Do you have a source for one other than Crosman? Tom
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That pin is as said a tapered pin and some even have knurling on the sides. It swedges itself. If you order the pin I would order the cocking arm as well. That way you can change out the barrels with NO problem.
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Good idea, Whitefang
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The install will not be as bad as the uninstall of the pin and less of a chance of bending any critical part.
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I just placed an order for everything to make my Benji a switch barrel .22 / .25 cal rifle. Total cost 29.75. Crosman is replacing the .25 cal barrel which they mistakenly sent me on my last order with a .22 barrel. No charge and I guess I get to keep the .25 barrel in the bargain!!! SWEET!! So once I get everything in the order put together I will be able to switch from .25 to .22 by simply removing the stock and swapping out the barrel assembly by unscrewing the pivot bolt and the cocking lever. Unless I'm missing something I will be able to switch back and forth in about 15 - 20 minutes. This may end up being a good thing, getting the wrong barrel the first time. Now I do have a question. In the online schematics it shows a different barrel sleeve assembly for the .25 compared to the .22. Different part numbers. I will have both when I'm done but since the .22 cal sleeve installed without any problem on the .25 caliber barrel I'm just wondering why they are different part numbers in the schematics. The .22 caliber pellet just fell right thru the .25 caliber barrel with the sleeve installed and I can't see where there is any interuption in the bore with the .22 caliber sleeve installed on the .25 cal barrel. Just wondering if anyone knows what the difference is. Like I said I'm getting the appropriate one for each barrel but until I get the .25 cal one to compare it with I can't see what the difference could be. Tom
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I was thinking it only took a different barrel cap. due to the .22 vs .25 cal size wise. I think some just drilled the hole larger but by doing this I am not sure how you tighten the shroud down.
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You know, the waiting is the hardest part. I guess I'll know how this all works out in about 7 - 10 days.
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The more I think about this I am sure it needs a larger ID hole for the .25. .177 and .22 on the RWS 350 PRO COMPACK take the same muzzel brake and the .22 barrel OD is REALLY CLOSE TO THE ID OF THE BRAKE. The RWS has the OD of the barrel cap knurled to use for tightening and the XL has a hex ID to tighten the shrould down.
YES the waiting is the HARDEST!!!!
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Hi
You probably should get the Crosman/Benj rivet. Must be a cheap part.
my pin was $1.15 i just instaled my pin on the cocking linkage it was a bit of a pain. what finally ended up doing was drilling the ends slightly and the i used 2 center punches. i put one in my vice, pointed end up and the flat end resting on the center part of the vice so it could not slide down and tightend up the vice. the second punch i held on to and my daughter held the barrel with the pin installed over the punch in the vice so the punch was in the small hole i drilled on one side of the barrel and the punch i hel i put in the other small hole i drilled in the other side of the pin. then i hit the puch with the hammer a couple times. flared both sides at once done .......dave
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Yes, you will either need to drill your .177/.22 muzzle cap slightly larger, or order the .25 cal cap. I wouldnt worry about getting cap on super tight, what i do is thread in the cap as snug as you can with your hand, then grab the entire shroud and muzzle cap, and give it a little twist. The o-rings on the outside of the muzzle cap create alot of friction and will grab the inside of the shroud well, asuming you dont oil them. I drilled out my .22 because it was clipping andthis is the method i used until i found out i could use the 25 cap. Good luck man, i love my xl and im sure you will too!!
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Yeah, I ordered the .25 cal sleeve and cap already so that's no issue. Boy the tolerance on the .22 cal sleeve cap have got to be really close to the .25 bore because I can't see any obstruction thru the bore with the .22 cap installed. No matter I have the correct one on the way. Dave, I like your description of the process you used to set the rivet pin. I can just picture that in my mind, 4 hands are better than two. I don't really have a shop persay but I do have a fairly nice workbench and basic tools and a drill press. I'll give your technique a try. I only have to do it twice, once for each barrel assembly. Thanks
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took me like 30 minites once i was set up and that was using the drill press and i think a 1/16th bit
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Got into this one late, The pins can easily and securely be held in place with only a piece of packing tape on the head side after reassembly and a wipe with acetone or similar product to remove the grease residue. I have done this on .22 +.25 barrels and both have around 1500+/- rounds through them and are still holding up well. The difference with the shroud caps is that the .22 is set-up for a 1/4"allen wrench and the .25 needs a 3/8" allen to remove. The shrouds are interchangeable. While you're waiting, I would order a bushing kit and brass washers from Gene, which will help to keep all performing as expected for a long time. Good Luck! BTW, mine loves FTT"s in both calibers!
pv
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Good tip on the packing tape, Paulie. What are FTT's? My old .22 cal barrel really liked the Discovery hollow point pellets and the Gamo PBA 14.4 (believe it or not). Thanks for keeping an eye on these build threads and helping us all out. Tom
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Sorry, didn't get back to this one.... H&N Field Target Trophy pellets.
pv