When I read this thread and Old Fuff's pm two days ago, I put the norinco in the safe and strapped on the Glock 30. I would have replied sooner folks but the children have been under the weather and my computer time had to be used for work only. My thanks to everyone for their input!
Tuner said, to Gary:
First let's be sure that it really is a long link.
Hold the barrel in front of you horizontally and swing the link back and forth from vertical to about 25 degrees toward the muzzle. If .200 diameter pin were through the link...would the pin touch or nearly touch the lower lug at any point from the forward curve all the way to vertical...or would the link hold the pin away from the lug at all points?
Also...If the pin were through the link, would it fit the radius formed by the feet at the back of the lower lug AND touch the underside of the lug at the same time? OR...Would the pin contact the back curve closer to the
tips of the feet?
and
a correct link should [allow the pin to ?] lightly touch the lower lug just as it swings around the forward curve and bear on the bottom of the lug as the barrel goes to battery. (Link about one degree PAST vertical) Vertical lockup is properly achieved by the slidestop pin bearing upward on the bottom of the lug.
I performed this test with both the original norinco slide stop pin and the aftermarket CMC pin. Both results were the same. If you put pressure on the pin by trying to hold it close to the barrel lug, it would ride the lug EXCEPT while swinging around the forward curve. If you applied pressure to the pin as though you were trying to keep it away from the lug it would never touch the lug during the movement.
Tuner said:
The damage is due to the barrel not getting fully unlocked from the slide in time...or not falling far enough to let the slide get past it without crashing the lugs. When the slide is rearward .250 inch from battery position, there should be a minimum of .010 inch between the top of the barrel and the underside of the slide.
No fair pushing on the hood to get the clearance...It has to fall.
When I perform this test I don't think that I am getting quite .010" of clearance. I can see where the front corner of the slide has been scraping across the barrel hood.
From the looks of the lower lug, it doesn't appear to be the specs between frame and lug...maybe the link is a little long or short. With the slidestop pin through the link, with the link vertical and the pin settled into the radius of the feet...The pin should touch the lower lug...or at the very most, it shouldn't be held off of it by more than a thousandth or two. If the pin is held off of the link very much, it won't let the barrel go to bed, and the slide will hit the lugs.
Check the link by laying the barrel in the frame and inserting the slidestop pin through it...but leave the slidestop arm hanging down. Push the barrel down and back firmly and see if the pin will swing freely or get into a bind. Check also to see if the barrel sits into the bed's radius.
When I lay the barrel in the frame and insert the slidestop through the link, leaving the slide stop arm hanging down, and push the barrel down and back, the barrel does "go to bed". However, the pin **does not swing freely** when the barrel is in seat in the bed's radius. It can be moved of course, but will stay in whatever position you move it to while the barrel is in the bed. I don't know if that makes a difference or not. All parts were thoroughly cleaned before I tested.
Tuner, I don't know how to follow a radius, though that didn't stop me from following your detailed instructions for modifying my Springfield Milspec's extractor, a project that turned out with excellent results! So, I am taking up Dave Sample on his very kind and generous offer of relinking the barrel and cleaning up the barrel lugs.
And Old Fuff - Thank you for your time in writing your thoughtful and informative pm to me. I am ordering Kuhnhausen’s Shop Manual Today.
Dave Sample, a Wilson #3 link and oversized pin is on it way to you, drop-shipped directly from Brownell's via Priority Mail to your Prescott, AZ address.
Part Numbers:
Link...965-142-278 ($5.25)
Pin.....080-816-156 ($5.80)
Brownell's Order #51232502
I will send the barrel along with a return postage paid Priority Mail envelope/box to you via USPS today.
Dave, you are very kind to offer your services and I am obliged to you. I understand that you are retired. I am a book dealer and if there is book, in or out-of-print, that I can get for you as way of saying thanks, please let me know. Alternatively, I could order an extra copy of Kuhnhausen's Shop Manual and sent it to someone for you as a gift.
