What do you mean when you say "will not mate with the receiver"? There's a couple of causes that could be the prob. Is it going on and then the barrel won't quite close? If that's the case, you'll need a Dremel and a small grindstone bit. To get the barrel to fit that way, you need to *CAREFULLY* and *slowly* grind out the little curve where the barrel lug meets the pivot pin in the receiver. Grind it straight back towards the breech, not up or down. You want to make the pivot deeper, not wider. When I say *carefully and slowly*, I mean touch the stone to both sides of the pivot just a hair and then test fit the barrel to the receiver. Do NOT grind it a few mins and then test fit it or you'll have a loose pivot and the barrel will need smithing. Slow grind, test. Over and over.
If the barrel/receiver breech gap is too large, cut a strip of coke can the width of the pivot pin and loop it around it and then close the barrel on it and trim it down. That shim will tighten the breech gap and return it to shootable condition.
The second possibility is the barrel might be closing just fine with the receiver but it's not locking. Is that one it? In that case, you'll need a flat machinist file....or a Dremel cutoff wheel if you're handy with the moto tool....and again, SLOWLY and carefully file the lower flat of the locking V on the breech end of the barrel lug. Match the angle and just take off a paper thickness and then test fit the barrel. Do that over and over til it locks.
The only other real problem you might run into with a 37A is if you pop a new barrel on and then find you can't quite cock the hammer. It will feel hard and firm like there's something blocking it and just won't quite reach the cocking "click". That's that same lower face of the locking V. Take off a paper thickness again and it'll cock and lock easy.
Those guns were built rock solid, receiver-wise....all the receivers are exactly alike and interchangeable between makes and gauges. The only probs you'll find in the series are the barrels and barrel lugs were welded by hand. The barrels were always custom fit to each gun because of that. Use the three tips above and you can mate all the barrels to your guns quickly and easily.
There's a fellow on gunbroker named Pierre in Canada. I've bought from him dozens of times. Great fellow. He always has a few 37A barrels and parts on hand.
One more thing before I let you go....the 37A and the 370 and the Cooey 84 and the Cooey 840 and the Sears Single Shot, a Ranger etc etc etc all are the same gun. They're NOT the Winnie 37, though. That's an entirely diff gun. The 37A and the 370 use different forearm lug designs to hold the forearm on so if you buy a barrel, match the one your forearm mates to....or you'll need to buy a new forearm to match the new barrel. Compare those barrels on gunbroker and you'll see what I mean.
Sorry this got long.
rich
