Scraper ring on Airsporters - what does it do?

[Benelli B76]

Seen loads of the steel rings over the years. One of the problems as mentioned above was that the BSA nylon piston heads were not wet conditioned and nylon being hygroscopic they would swell up and force the metal ring and the O ring tightly against the compression chamber wall. I would always deepen the two grooves with a parting tool after skimming the OD of the piston head.

Baz

[TonyL]

A diana 28mm seal mounted to a dovetail arbour threaded onto the (shortened) spigot is the optimal efficiency tune for these... lengthens stroke by around 5 or 6mm, and the parachute seal give a much better seal and a soft landing. it literally transforms the firing cycle of the gun, and you gain 2-3 FP

Guessing the very same mod will transform the Mercury in exactly the same fashion, Jon?

[Shed tuner]

Guessing the very same mod will transform the Mercury in exactly the same fashion, Jon?

yup, but the merc is a bit more efficient to start with...

[Brad3]

yup, but the merc is a bit more efficient to start with...

I found my Mercury much better than the Airsporter. I had the Mercury first.
It was at the time of the release of the Glossy sales 2 page leaflet with a Mercury on the front showing the internals. I had to have one. (@78/79)
For the record it had the plastic head (which the advert blurb described as shock absorbing buffer) with O ring. It had an occasional lube with SM50 and accounting for countless Vermin species.
I later wanted to move upward to the Airsporter but found it a huge disappointment.
I estimated I had doubled the group size and lost a full ftlb for that Loading tap which i thought would be a step up.
Never seemed to hit anything. More pellet fussy, couldn't clean my barrel, heavier, less accurate and less powerful.
The Mercury was a great gun at that time.
Maybe I might have had a different experience if I'd had a MK2 version.
The Osprey was hopeless compared to the Mercury also.

[TonyL]

yup, but the merc is a bit more efficient to start with...

Yep, agreed.

[TonyL]

I found my Mercury much better than the Airsporter. I had the Mercury first.
It was at the time of the release of the Glossy sales 2 page leaflet with a Mercury on the front showing the internals. I had to have one. (@78/79)
For the record it had the plastic head (which the advert blurb described as shock absorbing buffer) with O ring. It had an occasional lube with SM50 and accounting for countless Vermin species.
I later wanted to move upward to the Airsporter but found it a huge disappointment.
I estimated I had doubled the group size and lost a full ftlb for that Loading tap which i thought would be a step up.
Never seemed to hit anything. More pellet fussy, couldn't clean my barrel, heavier, less accurate and less powerful.
The Mercury was a great gun at that time.
Maybe I might have had a different experience if I'd had a MK2 version.
The Osprey was hopeless compared to the Mercury also.

Absolutely. I've owned a couple of Airsporters in the past. Both were freebies but in very good condition. One a Stutzen and one had one of those horrible, slabby, blondy stocks. Neither stayed with me long. I still like the idea of the Airsporter with its concealed underlever and fine looks, but it is those shortcomings relating to the loading tap that would deter me from trying any more. And the same misgivings have also scared me off a Tracker for many years. Now, my old 1906 Lincoln Jeffries is another matter entirely....

[Brad3]

Absolutely. I've owned a couple of Airsporters in the past. Both were freebies but in very good condition. One a Stutzen and one had one of those horrible, slabby, blondy stocks. Neither stayed with me long. I still like the idea of the Airsporter with its concealed underlever and fine looks, but it is those shortcomings relating to the loading tap that would deter me from trying any more. And the same misgivings have also scared me off a Tracker for many years. Now, my old 1906 Lincoln Jeffries is another matter entirely....

I agree, and also in regard my own Lincoln absolutely.
My conclusion would be supporting the original idea of the loading tap design with all the merits it was assumed it might bring (Permenant barrel alignment, no wear of barrel pivot/ linkages etc) but only if it was done by means of a hand fitting/lapping process like the Lincoln/Improved model D.
As a mass production process it simply didn't work out as they thought.
Airsporters, Ospreys, Trackers etc could not hold a candle to Mercurys. It had to be the huge advantage of seating pellets direct into rifling as the Mercury trigger was nothing to write home about, being no better.

[TonyL]

And absolutely agree with the above too, sir.