Advice on stripping a mk1 Airsporter

[CapitalBee]

Good evening folks. I'm in the process of stripping down an early mk1 Airsporter for a neighbour (it could be a bit of a forlorn hope, we'll see though). I'm now aware the trigger block and fixing is different from the later marks as I have the block off and I'm left with a hollow stud and friction washer holding the spring in tension. Can anyone advise the best method for removing the spring (and piston)?

[Airsporter1st]

As I recall, the trigger block and threaded portion are separate items, joined together by a hollow bolt and a kind of star washer which is supposed to lock everything together so that you unscrew the whole thing as one piece. It seems that yours has not.

You need now to find a way to unscrew the threaded portion and I can't remember whether that has any means of gripping it. Even if it does it is going to be hard to restrain the spring without a proper spring compressor. I am thinking that a centre punch gently tapped may turn the threaded portion out to a point where you can grip it with e.g. water pump pliers and a piece of rubber or leather to protect the thread. Once you can, it will be a matter of using a spring compressor or other restraint whilst you unscrew it fully.

Hopefully someone else who has had recent experience will be along shortly to either confirm or deny my thinking.

P.S. you could try screwing the trigger block back on with some threadlocker, leave it to go off then unscrew the whole thing?

[ggggr]

Good evening folks. I'm in the process of stripping down an early mk1 Airsporter for a neighbour (it could be a bit of a forlorn hope, we'll see though). I'm now aware the trigger block and fixing is different from the later marks as I have the block off and I'm left with a hollow stud and friction washer holding the spring in tension. Can anyone advise the best method for removing the spring (and piston)?

I had this on a mk2 hybrid gun. From memory I think I drilled a couple of holes in the back block cup (N116) https://www.gunspares.co.uk/products/24688/Mk6/ , then filed them until I could get a screwdriver in. I know yours is not a Mk6, but this is the best view of the back block cup. Unfortunately the serrations an the back block cup and trigger block had badly worn and I thought it easier and cheaper to get a 2nd hand set up than buy new parts that might not cure the problem. I had managed to get mine back together with the old set up with a weak mainspring. If your bits are not badly worn, a new lockwasher might cure it for in future.

[Airsporter1st]

I had this on a mk2 hybrid gun. From memory I think I drilled a couple of holes in the back block cup (N116) https://www.gunspares.co.uk/products/24688/Mk6/ , then filed them until I could get a screwdriver in. I know yours is not a Mk6, but this is the best view of the back block cup. Unfortunately the serrations an the back block cup and trigger block had badly worn and I thought it easier and cheaper to get a 2nd hand set up than buy new parts that might not cure the problem. I had managed to get mine back together with the old set up with a weak mainspring. If your bits are not badly worn, a new lockwasher might cure it for in future.

This picture gives a much better idea of what you are dealing with. My suggestion to use a centre punch on the N116 component to tap it around is probably inferior to Guy's idea of drilling a couple of holes in it. Once you have done the latter, you can improvise a peg spanner.

If and when you get it out, you need to reassemble such that the trigger block is properly aligned when it is all screwed fully together (that's the whole point of this construction - to allow proper alignment). If the serrations are worn, which may be the case with yours - hence it not coming off in one piece, then you can use a heavy duty threadlocker when re-assembling. You can get the alignment right without the spring/piston installed. Once the threadlock has gone off, you can then reassemble the gun and it should come apart again all in one piece in future.