Webley Senior springs

Webley Senior springs 

John Atkins said this on the BBS in answer to a query about Senior springs (with thanks to Troubleshooter for facilitating and some of the words below are his; pics are John's):

http://www.airgunbbs.com/showthread.php?841147-Webley-Senior-Mainspring-Sizes

"It's not straightforward at all. Just as an example: ‘Senior' spring lengths varied a lot, getting shorter-and-shorter as time went by, as my photos. show, These are unused and ’new’ (apart from some being c. 85-years old!) .

These things are not made to an absolute standard size I have discovered. They are all over the place in sizes at different times and from different suppliers. 

Below are all genuine ‘Senior' mainsprings from different eras, the two shortest I purchased with another 2 dozen from Webley & Scott until the Senior pistol got fractionally less powerful until the spring combined as one with the Mk. I spring for the new Premier and the spring no longer had their own individual prefix and numbering of S8 (Senior); M7 (Mk. I) and M.7 (Premier) were all made the same size by then, as part no. ‘P1032’ common to all three pistols and producing a reduced 350 f.p.s. in the .177” Premier’s published data of the time.

The longest on the 1938 box are both pre war 1930s ‘new’ unused springs The intermediate size ones are early 1950s. The power dropped as time went past until the same size spring was used for all three Mk. I Senior and Premier. This is why people putting a later spring into a Webley Senior will never achieve the same power as if an early mainspring was sourced (virt. impossible apart from my lot!)" 

John stresses the pointlessness of trying to state exact measurements for these components from different eras and different suppliers. You need to look at and compare lots of these unused, old dealers' stock, mainsprings if available - not just one someone has taken out of a rifle! If the right replacement mainspring is put in, then you shouldn’t need to start hacking bits off.

He also asked me to include the following:

"It’s important for me to also stress that Webley's blueprints for the MK. II Target Model De Luxe show the 36-coil mainspring at 7 inches MIN. 7.25 inches MAX. after cramping 12 hours. These items would be tested to this; so you can see that even mainsprings from the same period COULD well vary in length by up to a quarter of an inch - as I’ve always maintained - and this could affect mainsprings from the different eras creating even more variations in length to springs that had also been reduced intentionally down the years.