About a year ago I bought this 1400 as a project (like I didn't have enough already).... I'm a sucker for the wood on these early Crosmans, you never know what's hiding under there.... I've already rebuilt a few 140s, so I'm familiar with what they need and like.... When I bought this gun the Ad said "nice brown patina" and I should have known what that meant....
Actually the rust wasn't that bad, mostly in front of the stock where people have a tendency to pick up the gun when it's propped in a corner.... The wood is covered by Crosman's brown finish of the time but the grain underneath looks nice.... It wouldn't hold air for long and shot weakly (under 500 fps) so I pulled it apart just to diagnose it and found the quad seal leaking and replaced it.... That gave me a gun that would hold air and shoot typical of a gun of that age....320 fps at 2 pumps, 440 at 4, 510 at 6, 550 at 8, and 580 at 10 pumps.... The trigger pull was attrocious, but at least the metal trigger group on the 1400 is adjustable for pull weight where the 140 (which has the trigger mounted directly in the wood stock) was not.... I stripped the gun completely apart to start the rebuild.... Here are the parts of interest....
Starting from the top, looking at the items circled in yellow....
The cutout in the pump tube is too far forward and if you don't pump the gun VERY slowly it doesn't take in air properly as the air has to draw into the pump along the raised channel.... This is a common problem where the velocity is low unless you wait a couple seconds at the end of each "out" stroke.... The solution is to lengthen the slot and deburr it carefully....
The pump cup is difficult to replace, and this one is quite hard.... My solution is to replace the end half of the piston with a new flat topped one grooved for an O-ring.... Easily replaceable, commonly available, and you can achieve higher pressures....
The rear of the valve only has a 1/8" hole in it.... I drill it out in stages to 5/32" to match the rest of the ports in the gun....
There is an aluminum spacer in the valve which takes up about half the volume.... This means that the pressure rises very quickly, but you will notice that you get most of the performance in the first 6 pumps.... With the "dump" style valve held closed directly by the sear, the higher the pressure the harder the trigger pull.... I will be replacing the short spring and spacer with the longer one underneath them.... The additional volume will allow more velocity at higher pump numbers with reduced trigger pull weight....
The hole in the flow-through bolt is only 0.140".... I drill it out to 5/32" to match the other ports....
The stock retaining screw in this gun wasn't all mangled by pliers, so it may never have been apart.... They are usually shredded by master craftsmen, however, so I mill two flats in the larger portion to allow the use of a wrench to remove and install....
Other than these items, everything will get a thorough cleaning, rust removal, and rebluing and then I get to tackle the stock....
Bob
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