asi/gamo mc supermatch target rifle help please.

[wadcutter]

I only went and picked up one of these really neat rifles knowing they are almost non repairable (by most airgun bodgers) but I got it anyway,they have a complex air system that is prone to failure with seals and all that stuff this rifle is in very good nick but is more dead than alive,i have done some research and these have been mentioned before on the bbs and I know that people have re engineered them and used different seals and all sorts of things,right before I get the butchers knife out and rip its guts out to see what makes it tick is there anybody out there who knows how to repair these dam things, I know even gamo wont touch one with a barge pole, its a pity they are supposed to be really good when working,any help appreciated thanks.

[Nikkormat]

I don't know anything about these Gamos, apart from what I've read on here, but I guess if anyone can help it would be Lawrie Amatruda, whose profile is here.

Good luck with it, they look nice rifles, and I am sure it will be fun when it's sorted.

Matt

edit to add: Looking at this thread, it might also be worth messaging gedfinn 2 and asking about his experiences.

[u.k.neil]

I did one of these for a feature in Airgunner magazine and I think it was published sometime in 2015. There are two types of main piston seal. They are both for 30mm diameter compression tubes, but one has a 22mm internal diameter and the other has a 24mm internal diameter and they are not interchangeable. These seals are very rare, if not now impossible to source, as are the firing valves and seals. They are fairly simple to strip, but as I have said, getting hold of spares will be your main problem.


Neil

[gedfinn 2]

I only went and picked up one of these really neat rifles knowing they are almost non repairable (by most airgun bodgers) but I got it anyway,they have a complex air system that is prone to failure with seals and all that stuff this rifle is in very good nick but is more dead than alive,i have done some research and these have been mentioned before on the bbs and I know that people have re engineered them and used different seals and all sorts of things,right before I get the butchers knife out and rip its guts out to see what makes it tick is there anybody out there who knows how to repair these dam things, I know even gamo wont touch one with a barge pole, its a pity they are supposed to be really good when working,any help appreciated thanks.

Why not try the BBS archives ? just a search, A number of threads & Pics.
Ged.

http://www.airgunbbs.com/showthread....hlight=gedfinn

[Phil Russell]

Neil did indeed do a strip, reseal and rebuild of these rifles in Airgunner, but it was the April (strip) and May (rebuild) 2016 editions. He got new seals from Knibbs so it may be worth a phone call to them.

If you get stuck for copies of his articles I will sort out a copy for you if you give me a couple of days. Just let me know.

Cheers, Phil

[u.k.neil]

Neil did indeed do a strip, reseal and rebuild of these rifles in Airgunner, but it was the April (strip) and May (rebuild) 2016 editions. He got new seals from Knibbs so it may be worth a phone call to them.

If you get stuck for copies of his articles I will sort out a copy for you if you give me a couple of days. Just let me know.

Cheers, Phil

Thanks Phil, I was going from the date on the original document that I did.

Neil

[wadcutter]

phil thanks for the offer on the stripdown article by neil if you can sort it,also thanks to the other guy I am well aware of lawrie I know he does good work on guns I will see what happens with neils stripdown guide.

[Phil Russell]

Hopefully scans of Neil's guide sent to your e mail address. If they do not arrive, do not hesitate to let me know and I will try again.

Cheers, Phil

[wadcutter]

stripped the rifle using neils guide and as expected all the red plastic seals had turned to mush, provisionally they can be replaced by o rings which I did I don't think the seal under the white inner piston seal is realy neaded its just a dust seal, the rifle cocks and fires but there is hardly any compression , I have read that the main piston has a inner piston that is oil filled and is pressurised so that you cant push the inner piston in if you know what I mean,it looks a bit of a bugger to take apart to check internal seals tried to get end bit off with moderate force but looks like it needs warming up with a hot air gun ,can anybody offer more help on this done as much research as I can and this piston is the problem, thanks again to neil and the professor for their help with this.

[abellringer]

Hi, I have had one of these guns [ broken for over 15 years in my gun cupboard] and only recently bothered to have a look at it in depth. I did fix it as I have some spares from way back when and it is now fine. The basic service is, as has been said fairly straight forward, and I have used J.K spares with great results in the past, but if the inner piston system has failed, this has always been considered non repairable because you have to be able to re- pressurise it, even if you get the appropriate seals. The idea of the inner piston is to give a more consistent air pressure, with a 'secondary' push as needed, not just the usual decompressing puff as per a normal SSP. I know some years ago a friend of mine's gun had the inner piston problem and he played about with putting a spring in place of the compressed air but this was never much success and he spent lots of time on it; so eventually he used O rings to seal it and fixed it in its forward position, so giving just a normal SSP action; it seemed to work OK and he used it for a while after the mod. The only downside to this is if you try and fail the piston is probably scrapped. I have tried several times to find out how Gamo pressurised the piston and to what pressure, but no one seems to know and they won't tell anyone, maybe for safety reasons.
As has been said Laurie is always worth contacting for something like this and it would be a shame if a fairly rare target rifle was written off without at least trying all avenues.
ATVB
abellringer

[gwyn]

stripped the rifle using neils guide and as expected all the red plastic seals had turned to mush, provisionally they can be replaced by o rings which I did I don't think the seal under the white inner piston seal is realy neaded its just a dust seal, the rifle cocks and fires but there is hardly any compression , I have read that the main piston has a inner piston that is oil filled and is pressurised so that you cant push the inner piston in if you know what I mean,it looks a bit of a bugger to take apart to check internal seals tried to get end bit off with moderate force but looks like it needs warming up with a hot air gun ,can anybody offer more help on this done as much research as I can and this piston is the problem, thanks again to neil and the professor for their help with this.

Hi,we have one of these ASI Supermatch rifles at our club,they are very low powered but very accurate,superb trigger.
I just Googled Gamo Supermatch and found an article by Pilkguns about these rifles and its Daisy 126 counterpart, if you havn't already seen it it may be worth a read?
We had our club rifle repaired by ASI when they were the Gamo FWB importer years ago and i remember it was returned with the latest type piston assembly fitted,i think the gunsmith was called Peter?nice guy spoke to him several times as we sent a couple of FWB 65 and 80's and my 300 to them for servicing.I know it was a long time back but a phone enquirey??you never know.
I assume the complete piston assembly poo28?on Chambers site is the thing you could do with?£45 if they had one!!!
Don.

[Helm]

hi i picked up one last year ,,having read every article i could find....including msany bizarevideas as to the piston....its meant to absorbe any vibration from the pellett going up the barrell
it cost me £10 in materials and it is my goto gun when others start spraying peletts
to dismantel followvthe pilks gun instructions ....BUT when you undo the two allen bolts that hold the end block in ..open the lever fully as this takes strain of the bolts....
take the piston ,
get a piece of wood drill a hole the size of the piston......cut wood in half through center
wrap cloth tape round piston and clamp to that area with the wood in a vice
find a a suitable piece of metal to fit the end and unscew
take out every thing including the small piston
clean with solvent to degrease
and fill with two pack plastic metal and screw in the end piece
turn up the other way and smooth level with lip of piston
find a large o ring to fit the groove where the white plastic gos you could fit another on the front to increase compression but it doesent need o touch sides
the trigger rubbers
the front section i stamped out of the plastic you fit under a sink drainer and in the larger space two orings side by side which i then sanded on 1200 wet a dry....im in brighton if thats anyuse if you dont fancy a go
cheers ian

[wadcutter]

read that pilk guns article also and lots of others,already clamped two pieces of wood together and used a hole cutter and have some old rubber car mat cut up to grip and protect the piston,dont think I will do anything too permanent like fill it with two pack or something if I blank it off I will make some sort of removeable plug with o rings on,i will try the oil filled route and fix the seals if I can first im sure the piston is pressurised just by pumping the rifle although I have read it may have been pressurised in some sort of pressure chamber but I cant see that myself,i have read you can also use some kind of spring inside the piston as well but if its just blanked off the rifle should work but on lower power,anyway next step undo piston and see whats inside,by the way how was the power on your rifle once you fixed it?as usual thanks evertbody for your input I have taken note of whats been said will update as soon as I can get something done.

[Helm]

there is no pressure in the piston ,i think that if you restore that to original its a lot of money for no real gain also i was dubious as to the quality of the seals seeing as there over 30 years old.it does not increase pressure it is there to reduce vibration as the pellet goes up the barrell
its shooting consistently at 584 to 592 ft per second happy with that as its a target rifle
I guess you could get clever and increase the compression but you would need to measure the distance between the piston and the end ..lump of plastecine ?
but from mfemory its about 2mm so any increase would be marginal
cheers ian

[gedfinn 2]

there is no pressure in the piston ,i think that if you restore that to original its a lot of money for no real gain also i was dubious as to the quality of the seals seeing as there over 30 years old.it does not increase pressure it is there to reduce vibration as the pellet goes up the barrell
its shooting consistently at 584 to 592 ft per second happy with that as its a target rifle
I guess you could get clever and increase the compression but you would need to measure the distance between the piston and the end ..lump of plastecine ?
but from mfemory its about 2mm so any increase would be marginal
cheers ian

Hi, I have one of these & A spare uprated action,
Following the above thread for a while , It appears no one really knows !
The inner piston is there to make cocking effort easier , The piston is indeed pressurised , This is depressed
when the piston is compressed, Its action has nothing to do with vibration ?
As to pressurising ( There have been a couple of comments ? )
& No one has mentioned the exhaust valve/set up,

The basic mechanism is quite simple, The Exhaust valve is " Cocked " When the piston is withdrawn IE
prior to pumping,
The piston then pressurises the available compression area ( Including the second piston )
This compressed piston helps to maintain the pressure, Exerting extra pressure on the exhausting air when the exhaust valve is released ( Vertically )
This " Vertical " exhaust action then does not compromise recoil ( In either direction IE Backwards/Forwards )
( This same compressed piston action works on all pump ups , The Webley " Paradigm " had it & a couple of mine ) Almost giving
something for nothing !

There are a couple of possible upgrades ? ( I mentioned these a couple of years ago with little interest )
One OTT example was a " 2 Stroke " action ,
This involved fitting a one way valve,
PS, You could not physically pump 2 strokes given the diameter of the piston , The effort was far too great !
So !!!!!! What do you do , What I did was ?
I have power outputs for both of the above ( I think I gave them on the thread & Fired pellet Pics Some depicting " atomisation" ) I know I removed some or all
after little interest.
Ged.

A Pic or 2 , I have the other Pics on file somewhere , ( I have them but not on my Photobucket library )

http://s101.photobucket.com/user/ged...ml?sort=6&o=14

http://s101.photobucket.com/user/ged...l?sort=6&o=193

http://s101.photobucket.com/user/ged...l?sort=6&o=192