GTA
General Discussion To Gateway To Airguns => The Shop => : TCups June 09, 2008, 10:49:17 PM
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Well, optimism is a sign that you don't fully understand the situation, I guess. Stayed up late last night and replaced the spring in the BAM B26 with a new Maccari spring, applied all the lubes and tars, and reassembled. Everything looked fine, but it was too late to fire last night. So this morning, first thing, I grab a few pellets and step out back. I cock the mechanism fully for the first time - very smooth, feels right. I shoulder the gun and pull the trigger -- NOTHING. The spring has engaged the trigger mechanism and is locked in place. The safety clicked off, and the trigger just pulls loosely. So now what?!!! This, of course, it the worst possible case scenario that I haven't planned for. I have a loaded gun with a cocked spring and can't fire it. I must be off to work, and I am going to have to leave it this way till I get home. And even then, I am going to have to work on a cocked and loaded gun to try to figure out what I have messed up. Any suggestions would be appreciated. Maybe it is something simple, but I can't think what. Left the gun lying on the floor with the muzzle stuck into a trap where it won't be disturbed until I figure out what to do.
tec
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Never mind, but thanks anyway all you mechanics and airgunsmiths! PeakChick figured it out. It's fixed. Thanks Stephanie.
tec
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I had something similar happen to me I don't remember if it was a new longer spring or putting spacer washers that caused it to jamb, But here is what happened the spring jambed in the piston and it wouldn't fire or release. What I ended up doing was to using a spring compressor. as a safety I took the gun apart again and the spring came out along with the piston all jambed together, I ended up with a couple of rags for hand protection and put the piston unit into my vise and turned the spring the way the coils go to tighten up the spring thus making it smaller in dia. and it came out with a lot of push but I managed to hang on to it and do not damage either to me or the gun a good pair of leather work gloves will be a help, If I didn't have a good grip on it ,it would have flew acrossed the shop . One of the first thing is to get the pellet out of the gun at least that way you wouldn't shoot yourself and deal with the jamb after. howie
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Thanks Howie
Stephanie suggested recocking and just giving the cocking leaver a good hard, sharp tug at the end of the stroke. Viola! Now it is operating smoothly. By the way, I cleaned and degreased the compression chamber after lightly honing it with 800 grit emory cloth. Reinstalled the factory seal as it looked OK and looked like a real SOB to try to remove and replace. But now the gun seems just a bit "squeaky" when I cock it -- like the back side of the piston seal is still dry. Will this change with a few firings or should I try to put some more moly paste in the tube behind the seal?
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Give it a couple shots. The squeak may clear up as the lube migrates. You might also stand the rifle butt end up for a couple hours in a warm spot to help the lube migrate a bit.
If none of those helps, then I'd tear it back down and put some silicone grease in there. you could also try a very SMALL drop of 100% silicone oil down the transfer port and half cock (don't let the sear engauge) it a few times until the squeak stops. But when you do fire it, it WILL diesel for the first couple shots.
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Assuming you have it,why not install the the Maccarri apex seal in the gun, especially if you tear it down again to apply more lube? The old seal just pops right off and no amount of lube will make it better. If you put the new seal into some hot water a little bit before installing it, it will not be too hard to push on the button on the end of the piston. Same with the old one,just let the seal and piston end soak a couple minutes in some hot water. I have arthur in my fingers and that's what i did on my RWS 320, which is the same as your gun internally. Makes it easy to install those piston seals. Adding oil and letting the gun diesel, will maybe fry the seal causing more problems, IMO.
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OK, thanks. Will try this. This is my first project gun and I am just learning. How, specifically, do you lube the compression tube and keep the lube behind the seal? I have moly paste, a black heavy tar, and a clear "velocity" tar from Maccari as well as a very small tube of high-grade silicone grease from the local hobby store.
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Hey Tommy, is that right?!?! Your the tall fella from columbia at Gene's shootout??? I'm glad Peakchick was able to get you over the "lock-up" issue with your rifle. I'd have given you my two cents on it, but the last time I did that I got 'scolded'!!! LOL's Every once in a while my old Marksman wouldn't cock correctly,...like the catch on the locking mechanism in action wouldn't seat and the barrel would spring back up. My problem I thought, was that the trigger spring sometimes won't return to the "open" position. In reality I kinda developed a 'bad habit' of leaving my finger on the safety lever of my gamo/Crosmans. I suppose sometimes I forget, because my 0035 has an automatic safty in it, I don't have to "hold" the safety. But in light of my "bad habit", when I shoot the Gamo/Crossman I always pull the safty on after each shot. You may have heard me say to Ruby "got the safty on????". It's the same thing at home too. I think I asked her that a hundred times Saturday. But I want her to get into the habit of using it, and keeping it on untill her next shot. Again, I'm happy that things are hunky-dory with your rifle. and your problem was resolved!!!!! Thomas
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T-cups, I'm no joe super tuner but here's what I have done. I put a light band of moly just behind the piston seal, and I tar the spring lightly, and moly in a couple other places . Depends on the gun. No silicone oil anywhere, ever on that type of gun with a synthetic seal. I also lightly burnish the inside of the compression tube with a very small amount of moly on a patch. I'm not sure if that's the perfect procedure but that's what I do on my guns. A guide I followed when I did mine was the "Guide To Tuning A Spring Gun(R-1)" by Tom Gaylord 's blog on Pyramids site. The R series guns and the B-20's are similar.There is always some migration of lubes in a spring piston gun. The trick is to use as little lube as possible to accomplish the job, which isn't as simple as it seems, and takes some experience to develope a feel for it.
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I put a Maccari seal in my B26. make sure you deburr the compression tube or you will damage the new seal. I didn't size mine, so it was
ReALLY tight! Measure the old seal on the piston. take it off and measure the new one on the piston. Take it down so it's about .008" LARGER than stock size. Then take off .001 at a time till its snug, medium drag; just slightly tighter than stock. BUT! Before you do that, put on some JM old school buttons! Makes the gun so smooth to cock and shoot! I put moly on the seal, NOT the front...only the surface that rides the tube, some on the piston behind the seal and a band around the buttons on the skirt of the piston. Polish spring ends and thrust washers, anything that turns with the spring. i used the stock spring and Rich made me a guide to fit it. My gun shoots CPL's @ 850 fps, super smooth shot cycle. I think it will gain speed as the seal was very tight....maybe 100,00 shots! haha, my friend said JM seals are so tough it might take a million shots! Tar the spring lightly, less on the piston end. Too much and your gun will be slow and inconsistent. Out of the box it shot 935 with CPL's, I like it alot better now. All done with hand tools, no power tools!
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Can any of you folks direct me to an exploded parts diagram or general schematic of the R9 or B26? Thanks.
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Here you go:
http://www.fortunecity.com/olympia/kickbox/377/xs-b20/xs_b20_index.html
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Lloyd:
Thanks for the reference.
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Any time buddy! The flow of info is what helps us move this sport forward. When I got my R1 in 1998/99?!?! there was very little info other than the "Beeman Protocol"! Thanks to this and other forums, I have become a competent tuner of twangers! All the info you need is out there. Here are a few sites that got a lot of info:
http://www.kermitairgunclub.com/
http://www.kermitairgunclub.com/airguntips/
http://www.airguninfo.com/index.html
The GTA library has a lot of great links too!
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Oh yeah! If you are gonna tune your gun, write out the steps before hand so you don't screw up the order of mods. Here's an example. I tuned my R1. I wanted to put Jm old school buttons on the piston (highly recommended!). Stupid me put them on AFTER I put on the new JM seal! It worked ok, but for optimum fit, I should have put the buttons on BEFORE the seal installation! That way you can test the fit of the buttons drag in the tube. Then put on the seal and size it to a little less than snug fit. keep your order straight and you won't be kicking yourself later! It's all little things. I went to a fastener shop to get stainless washers and I had an extra JM spacer from my R7 tune kit to use as a guage for the size of the washer. Guy had nothing like it. When I tuned my HW77 last week, I took the pistonn with me to ACE and got washers no problem. Mapping out procedure will save you time and GAS! LOL! Write what you wanna do, what parts you need, and call around before you take off in your buggy. Ace Hardware, auto parts stores, and specialty fastener shops will cover most everything. Home Depot has a lot of stuff too.
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Lloyd:
Yes, well, it seems the first step is to get the right size parts to start with. The B26 I have has an undersized tube compared to my R9. JM is sending a new seal.
Lesson 1. All guns that are the same aren't the same.
Step 1: buy a decent caliper
Step 2: Measure twice, buy parts once.
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Yeah...I measured the seal from my B26 and it is the same size as my stock R7 seal.