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chp357 · New Member

Brand new to forum. I was at a garage sale last week and came across a Winchester 425 break barrel 22 cal air rifle. Not in great shape, pitting on receiver, barrel looks good and wood is pretty good. I paid 50 buck for it. It shoots but it seems to lack velocity. I did hit a target at 40 feet but it seems weak. Made in 1970. I'm gun savvy but have little experience with air rifles. I assume there are seals of some sort that may wear out or get dry. Can I put oil in the barrel to see if that helps? Are there disassembly instructions or a video somewhere that could help me and what about parts availability? Any assistance or advise would be greatly appreciated. Thanks for your time. I have no information on the gun except the man who owned it passed away and the wife is selling all his stuff.

Slavia · Moderator

The Winchester 425 is a German Diana Model 25. Here's how I found that out:
http://www.pyramydair.com/blog/2012/11/diana-25-air-rifle-part-1/
http://www.pyramydair.com/blog/2012/11/diana-25-air-rifle-part-2/
http://www.pyramydair.com/blog/2012/11/diana-25-air-rifle-part-3/
http://www.pyramydair.com/blog/2012/12/diana-25-air-rifle-part-4/

Normally it's a bad idea to throw oil in the compression area of a spring gun, because it can diesel. This one is an exception, because it is relatively low powered and has a leather piston seal. Assuming the seal is still intact, a few drops in the transfer port might improve velocity. Here's how I learned that one:
http://www.network54.com/Forum/184474/thread/1453051529/last-1453409907/A+little+Diana+25+(basic)
http://www.pyramydair.com/s/a/RWS_Diana_Piston_Fits_RWS_Diana_25_25DS_Air_Rifles/5056

In one of those links they talk about the "tissue paper" test. That's nothing more than laying a small piece of tissue paper over the breech area to check for a leaking breech seal. If it leaks the tissue paper will move.

Here is a schematic:
https://www.gunspares.co.uk/products/24372/25/

As you do your search for more information, be aware that You have the .22 rifled version, not the .177 smoothbore.

chp357 · New Member

Thank you very much for the response. I appreciate it. I'll have a look at all the links you sent. By the way, the rear sight is broken, might you know where I may be able to find one? Thanks again.

robert w · Senior Member

that rifle should be about 550 -650 fps I belive.when lubed and cleaned up were a nice shooting rifle. id put a few drops of oil in the chamber and move barrel about 1/3 way cocked then add a few more drops then set it in a corner for 2 or 3 days n let seal soften up.and on leather seals I use about 3 drops every 4 months to keep it soft