Win 1200 screw sheering.
I'm having problems with a Winchester 1200. It's a 12-gauge Magnum that the customer bought back in 1975. He uses it for pheasant and deer hunting. He brought it to me with the firing pin hanging out the back of the bolt body. I found the slidearm-bridge retaining screw had the head sheared off. I have replaced the screw three times, and the gun keeps coming back with the head of the screw sheared off. The customer says that it happens with both 2-3/4-inch shells and also 3-inch Magnums.
I've used Dykem blue on the screw head, and I can find no evidence that it's dragging on anything. I've noticed that the slidearm bridge is bowed away from the bottom of the bolt just enough to see daylight through there. Should I try to "unbend" it, or is this the way it was made?
Well, today I took the gun out (I got yet another screw) and fired it once. I took out the trigger group and removed the screw and checked it--no distortion or signs of stress--put it back in and shot again. I did that 4 times. The first three times the screw still looked good with no distortion or anything. The fourth time, when I took the trigger group out, the head of the screw was missing. I found it in the receiver and it looked like a clean break. It wasn't ragged or jagged, it almost looked like it was cut with a saw.
I have a 1300 Winchester in 16 gauge, and it does not have the retaining screw in the bridge, and it doesn't have a hole in it for a screw. My customer doesn't want to retire the gun, and he also doesn't really want to shell out for a different bolt and slide-arm bridge. Can you help me get this fixed and thereby get my customer to quit calling me names? I do appreciate any help you can give. Thank you in advance.
Years ago, what you're facing was a common problem, and a technician from a Winchester Authorized Service Center steered us to a solution. What's happening is the slidearm bridge is jumping up on the shoulder of the breech bolt which, in turn, pops the head off the screw. Correcting the problem calls for elongating the screw hole in the bridge with a rattail file, and using a mill file to break the leading edge of the bridge at 45 degrees. This creates a positive angle plus some drag on the bridge so it won't jump up on the breech-bolt shoulder.
On the rare occasions a gun is returned to the service center after these steps have been taken, a carbide milling cutter is used to machine a slight undercut on the shoulder of the breech bolt, creating an angled ledge to hold the slidearm bridge in place.
Fortunately, the Winchester Service Center who passed this on is still very active, so if you're concerned about tackling the job yourself, contact Nu-Line Guns at email@example.com.
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|Title Annotation:||Reader Forum; Winchester 1200's maintenance and repair|
|Date:||Nov 1, 2006|
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