I have an FT version of one of these actions that I traded a customer for that I use to fit stocks to. It doesn't hold air and knew that when I traded for it but since I have it want to make it functional so I can use it for other than work. Obviously dealers but would like some feedback on those or like a list of trusted individuals who might work on it as well.
Customer tried to put a regulator in it think he messed up some o-rings doing so.
Thanks!
I bought an O-ring kit off eBay for my AA410 for $15 shipped. It doesn't specify 400, and I didn't see this seller listing one specifically for the 400 but I'll bet it'll work since this seller lists this more expensive kit for both rifles.
Air Arms O-Ring Seal Kit For S400/410 And S500/510 Caliber O-Ring Sold Separate | eBay
My kit:
Air Arms S410 & S510-SL CARBINE & XTRA FAC 5 & 10 SHOT (Including Superlite) 753070846770 | eBay
My fix-it thread. If I did it, you can for sure. I show some photos.
AA410-H Leak. Attempted a fix… | Airgun Talk | Airgun Warriors Forum
Decent disassembly video I used as a guide in conjunction with the schematics. You shouldn't have to drill anything as shown in the video, this should only pertain to newer models.
Air Arms S410 Classic - Stripdown Guide [HD] - YouTube
You still making stocks?