Classic power plus

[barryeye]

Gentleman. Here in New Zealand we do not have the 12 ft-Lb legal limit for air rifles that you have in the U.K.
My question is could some old classics like a Webley MKIII, B.S.A.Airsporter and Meteor MKIs be tuned to go above the British legal limit. And if so would this affect accuracy and the “comfort” of shooting them?
Barry

[Hsing-ee]

The BSA Meteor can be modified with a longer stroke to go to about 12 ft/lbs, this was a John Bowkett modification, similarly the BSA Airsporter can be modified to give a greater swept volume and can go a bit above 12 ft/lbs in .22, maybe 14 ft/lbs, this was something John could do as well. I don't think the Webley Mk III can do more than about 11 ft/lbs whatever you do to it. The Bowkett mods are proper re-engineering jobs, not really tuning as such, and I am not sure if they are easy to replicate.

Its not really worth doing alot of work on these older guns, if you want a high power gun get an HW80 - 18 ft/lbs is easy with that.

However, a mild tune is always a good idea on a springer, and some can be made very efficient - try

http://www.airgunbbs.com/forums/showthread.php?t=115108

Some of the earlier BSA Airsporters, like the MK 2, with the conical piston, can go slightly over 12 ft/lbs if they are set up right, but taploaders are not a very efficient design. The gun which probably has the most potential is the BSA Mercury, increase the swept volume and long-stroke it and you might get 16 ft/lbs in .22.

[keith66]

I would go along with these figures, i dont have much experience with airsporters but Mk3's are not that tunable, they simply dont have enough swept volume.
The big prewar Bsa standards & Imp model D's had a great reputation for power but i have seen figures quoted on here that could be acheived or bettered by the webley mk 3. If you measure the cylinder capacity of the big prewar BSA's it is considerably bigger than the airsporter about 1" more stroke, interestingly the pistons are the same bore as the airsporter but far heavier, another similarity is the Airsporter rear block is the same thread as the early prewar rifles and will fit. I would bet theres at least one hybrid out there!

[Hsing-ee]

Would this affect accuracy and the “comfort” of shooting them?
Barry

If you de-tune rifles & fit them with weaker springs, aiming for about 550-600 fps in .177 you might find that they are much more pleasant to shoot and can give much greater accuracy. This is also 'tuning' its just not tuning for power! Obviously not a trick for your hunting guns but for backyard target shooting and plinking it is a serious option.