Hi all,

Following on from my recent post asking for information on my BSA Airsporter S MK1. I have now done a fair bit of research and internet searches prompted by the information and advice I was given in my first post.

I have managed to get hold of the Airgun World magazines that contain the article by Pete Evans on the strip down of an Airsporter Stutzen. While this is a very similar rifle the stock is nothing like what is on my Airsporter S MK1 and it looks like there are other differences in the various sub assemblies. Although I have found the article helpful, I have to admit that I am a little OCD with engineering issues, and although I am a competent mechanical and electrical engineer I like to know exactly how things are before I attempt to take things apart. Consequently, even slight differences confuse me a little.

I have searched on YouTube for videos, but the ones that I can find are not a lot of use to me. When people are stripping these rifles in their videos they are obscuring what I actually want to see with their bodies, or limbs. Most of them show you the rifle and explain what they are going to do and then suddenly move on to 'here it is all taken apart', completely missing out the actual strip down process. Much the same in reverse when it comes to re-assembling everything.

I have also seen a couple of articles about spring tuning kits and I like the upgrade mods like the delryn guides, top hats and slip washers etc. I can see the benefit of these items from an engineering point of view. Once again though there is a little ambiguity in the offerings from suppliers. Some of them list tuning kits for a range of BSA Air rifles, so I am not sure if they would be suitable for my specific model. Others offer a choice of spring, but being a complete novice with air rifle dynamics I am not sure which would be the best choice. In order to find out suitability I have contacted Woodfield-GCP (Welsh Willy) for advice on what would be the best kit, but after about a week and a half since contacting them, I have had no response.

So, here I am again asking for more advice after a week and a half's googling, YouTubing and magazine reading.

I have removed the complete rifle action assembly from the stock and what I can see from the outside looks in excellent condition. the trigger mechanism is greased up and there is nothing to look at that makes me think that A. the gun has had much use, and B. that it has not been stored properly. I will not attempt to strip it down any further until I have got hold of the parts I need to service it. Before I do any further work I have some questions: -

Firstly, in order to change the spring and the piston seals do I have to remove the cocking mechanism? I am assuming that this will not be necessary for just replacing the spring, but for the piston I am not so sure. I suspect that there will be something on the cocking mechanism that engages with the piston? So, can the piston assembly be removed without first removing the cocking mechanism? Bearing in mind that the gun is looking in such good condition, I would rather not disturb anything that does not require attention (that old 'if it isn't broken don't fix it' thing).

Secondly, can anyone recommend the best spring tuning kit from the suppliers out there on the internet, and how do I know it will definitely fit my rifle?

I have seen that Welsh Willy advertises a 'parachute seal', although it says 'Out of Stock'.

Over the last 45 years I have been involved with designing and drawing up mechanical and electrical assemblies for automated food production machinery. One of the most common machines is what is called a filling machine, or depositor. The 'business end' of these machines consist of rotary valves, product cylinders and pistons, with the piston being driven by either pneumatic, or electrical power. They use many stainless, steel, waukesha and delryn parts. The piston seals on these machines range from 3/4" to 4" diameter (with metric equivalents), and have the same type of lipped seal that I have now learnt is known as a 'parachute seal' in the airgun world.

I am certain that once I have the parts stripped and have accurately measured everything, I would be able to make the necessary adaptors and source 'parachute' seals to make this kind of modification myself. I have my own Myford 7 lathe and also have access to larger lathes and milling machines when I need to use them.

One of my other hobbies is classic British motorcycles and I have a few from the 1950's and 1960's. Over the years I have made many parts for them, with great success, and the occasional disaster (which you need sometimes in order to learn). I have always been keen to make parts to improve the performance and usability of the bikes, and would want to apply the same rule to my Airsporter S renovation.

I just need more information, advice and knowledge before I proceed.

Thank you in anticipation.

Kev Ev