Who has converted their (tap loading, o-ringed piston) airsporter to parachute seal ?

[Shed tuner]

Awaiting with interest... symptomatically, what's occuring ? Low power ? Bounce ?

[Hsing-ee]

Awaiting with interest... symptomatically, what's occuring ? Low power ? Bounce ?

Pete's got one (Welsh Willy did the conversion) on his Mercury Challenger and is similarly evasive....

I am going to put one of the squared off steel 'export' heads on mine, parachutes be damned...

[look no hands]

Pete's got one (Welsh Willy did the conversion) on his Mercury Challenger and is similarly evasive....

I am going to put one of the squared off steel 'export' heads on mine, parachutes be damned...

The reason I didn't reply is only Airsporter conversions where needed, UK neil actually done the head for me and the gun has a Welsh Willy tuning kit, I think the conversion is in my Mercury action? (once the Challenger or Airsporter seals are done I don't keep taking off those bloody hateful maxigrip rails to try other things) I wouldn't say it makes the gun any smoother, just gets rid of the tight O ring (if you use an Airsporter ring and not a smaller Meteor ring) and makes power pretty easily, I do have a custom seals red seal to put in as the blue Diana seals are not very supple but it's just one of those things that it's a bugger to get the spring back in with the screw on back block that almost stabs you, so I hate taking it apart when it's running OK just to try another seal, I'm getting a bit lazy in my old age, if I can't just tap out a pin or undo a bolt then it gets left until I really must have to do it.

Pete

[joffy]

I use a hw97 spring in my airsporter carbine fitted with one of Nick's top hat and guides ..... Feels much smoother than the standard setup in my mercury.

[T 20]

Awaiting with interest... symptomatically, what's occuring ? Low power ? Bounce ?

Well Jon

I've got mega slam, the power is quite low considering I've increased the stroke by 9mm and the velocity is up and down like a whore's drawers.

The slam is that bad that there is now an imprint of the transfer port on the arbor for the Diana seal, on checking the original piston head that had the same imprint.

Now I know the gun was low on power when I got it so I'm wondering if there's an inherent problem with the cylinder, I actually have a MK4 Airsporter that resists any attempt to get it's power up and I put that down to a porous breech, but I thought the S cylinder was drop forged ?

Next up I'm going to try an O ringed piston in this gun, also at + 9mm stroke using the same HW95 Spring.


And out of all the pellets I have in stock it runs at it's highest power with Napier Power Hunters.




All the best Mick

[Andy001]

I don't claim to know anything because I don't! Would the transfer port have an affect on the slam?

[El Garro]

http://s1278.photobucket.com/user/El...jjrqt.jpg.html

I've found that the cylinder can be a few different shapes and sizes which doesn't help matters.
I figured the bit of wobble from the o ring buffer and standard cross pin fit coupled with a wider parachute groove made it work
only on the ones I've done though, leaky taps and braze joints definitely don't help.

[Hsing-ee]

I use a hw97 spring in my airsporter carbine fitted with one of Nick's top hat and guides ..... Feels much smoother than the standard setup in my mercury.

What sort of power are you getting with that and did you sleeve the piston, isn't the spring alot narrower?

[Shed tuner]

Can you use the loading tap closed and decock the gun whilst holding the lever method to see / feel if you have a leak ?

If you have a load of slam, it clearly points to a leak... Also does the piston get looser at some points as you push it down by hand ?

The inconsistency is probably just a consequence of the slam.

Also, in my limited experience with leaky guns, if you do have a non piston washer leak, the gun will tend to favour lighter pellets (less pressure / leakage). If a piston washer leak, can go either way as the higher pressure can help the seal expand.

PS are you sure it's primary stroke slam, or just a huge amount of bounce, then slamming on the second fwd stroke ? Does the cycle change much with lighter or heavier pellets ?

[joffy]

What sort of power are you getting with that and did you sleeve the piston, isn't the spring alot narrower?

Mid 10s but it's a .177 springwise it's very similar to the airsporter/mercury ones ....only fitted it as I had one spare

[T 20]

Can you use the loading tap closed and decock the gun whilst holding the lever method to see / feel if you have a leak ?

If you have a load of slam, it clearly points to a leak... Also does the piston get looser at some points as you push it down by hand ?

The inconsistency is probably just a consequence of the slam.

Also, in my limited experience with leaky guns, if you do have a non piston washer leak, the gun will tend to favour lighter pellets (less pressure / leakage). If a piston washer leak, can go either way as the higher pressure can help the seal expand.

PS are you sure it's primary stroke slam, or just a huge amount of bounce, then slamming on the second fwd stroke ? Does the cycle change much with lighter or heavier pellets ?

The loading tap is definitely leaking Jon, but I've never had a parallel tap Airsporter that didn't leak.

The cylinder is sound, I've even pushed an O ringed piston down it to get a better feel.

Rather than rebuild the gun and run more pellet tests, I've decided to get my machinist mate to machine the tap to give a positive seal --- this would be easier to do on his CNC mill.




All the best Mick