Problems with airguns
Posted: Sat May 31, 2008 7:31 pm
Piston JAM
-----------------
Of Late my .177 Mod 25 National seemed to be hard to load and also the discharge was very lethargic. This was so for a couple of months. Two days back i had a good opportunity to shoot a "Vermin"
bandicoot.
I loaded my old trusty National and fired and all i got was a slight pssssst sound and nothing more. I cocked and fired again this time too it was the same. When i tried to load again nothing it moved freely for 3-4 inches and then it was jammed.
I figured that something had jammed or got stuck inside.
I carefully disassembled it and found that the piston was stuck - it took me quite a few persuasive methods to finally get it out and thats where i saw the culprit.
The piston in this model of National is made of 3 parts.
1. The head - where the washer screws in
2. The Rod (which locks on the trigger) which locks into the head
3. The cover of the piston which has an opening for the cocking arm to fit in.
(my apologies for not taking pics)
Parts (1+2) & 3 are locked into place by a pin. It so happened that due to years of use this pin had come loose and was touching the surface of the cylinder thus causing friction and slowing the whole thing down.
The pin hole had gotten oval due to the long use. so i couldnt put in another pin without risking a jam again.
so
I Fit part 1 & 2 in very tightly and got it welded.
After that i had the above set welded to part 3 & had it grinded off to a smooth finish.
After this i carefully cleaned the whole Airgun. Did not have a spare washer so put in the old one. which seemed fine. Lubricated all the necessary parts and fired a few pellets after assembling it.
The results are amazing. The loading is smooth and the power seems to be back & the best i ever remember it to be.
If anyone has a similar model and can post pics of the above part (with pin) that will be nice.
Thanks
/S/
-----------------
Of Late my .177 Mod 25 National seemed to be hard to load and also the discharge was very lethargic. This was so for a couple of months. Two days back i had a good opportunity to shoot a "Vermin"
bandicoot.I loaded my old trusty National and fired and all i got was a slight pssssst sound and nothing more. I cocked and fired again this time too it was the same. When i tried to load again nothing it moved freely for 3-4 inches and then it was jammed.
I figured that something had jammed or got stuck inside.
I carefully disassembled it and found that the piston was stuck - it took me quite a few persuasive methods to finally get it out and thats where i saw the culprit.
The piston in this model of National is made of 3 parts.
1. The head - where the washer screws in
2. The Rod (which locks on the trigger) which locks into the head
3. The cover of the piston which has an opening for the cocking arm to fit in.
(my apologies for not taking pics)
Parts (1+2) & 3 are locked into place by a pin. It so happened that due to years of use this pin had come loose and was touching the surface of the cylinder thus causing friction and slowing the whole thing down.
The pin hole had gotten oval due to the long use. so i couldnt put in another pin without risking a jam again.
so
I Fit part 1 & 2 in very tightly and got it welded.
After that i had the above set welded to part 3 & had it grinded off to a smooth finish.
After this i carefully cleaned the whole Airgun. Did not have a spare washer so put in the old one. which seemed fine. Lubricated all the necessary parts and fired a few pellets after assembling it.
The results are amazing. The loading is smooth and the power seems to be back & the best i ever remember it to be.
If anyone has a similar model and can post pics of the above part (with pin) that will be nice.
Thanks
/S/