Just got a BSA Improved Model D .177 air rifle. This was manufactured between 1915 - 1919.
When I got it, it was not working to well. You cocked the rifle and then open the pellet port and it would sometimes fire one you! This is not what you want to happen.
I started to strip it down following a guide on Vintage BSA Air Rifle Forum It was quite easy to do the only hard part was removing the stock as the screw for this is deep down inside the stock. You access this via a small port on the butt of the stock. To get to the screw you need a really really long handled screwdriver. I didn't have one but a quick phone call to a friendly farmer got me the use of screwdriver and I got the stock off.
I stripped down the rest of the rifle completely and gave it a good clean and de-grease to get rid of all the old gunk that had accumulated over the years. During this process I saw it need a new washer so I got one from TW Chambers
Once the washer arrived and was socked in oil for 12 hours I re-assembled the rifle and it all went back together really easily until I got to re-attaching the stock. I couldn't borrow the screw driver this time so I improvised. I got my longest screwdriver and a lump hammer and smashed the handle off the screwdriver. This was now long enough to reach the screw but not enough protruded from the stock for me to get a decent grip on. Then in a blinding flash of inspiration I got my hammer drill which was big enough to take the screwdriver as a bit and it put it in. I should point out I didn't plug the drill in, just used it as a large handle. Adapt, Improvise, Overcome.
Quick test fire to check it all works OK which is did, now just need a free weekend to get out and see how it fires over an extended period.