Mk760 Extractor. Is it bad?

[rssc]

When i got my mk760 it ran great. However after a few hundred rounds it started malfunctioning. After doing some research it seems the extractor is a weak point on this gun so I figured I would replace it. The one in the pictures below showing signs of wear is the old one. The other is the new one (BWE) that has been swapped in. RKI'S - Does the old one look problematic to you? I can clearly see wear to the part but I'm not sure if this is the type of wear that could/would induce a malfunction.

 

[AdamsAutomatics]

I can't see why the original wouldn't work from the pictures. It appears intact. What types of malfunctions are you getting? If only failure to extract, examine some of the spent brass for signs of chamber fouling/wear. Did swapping the extractors out fix your issues?

 

[rssc]

It's been a while since I last shot the gun so my memory isn't the best on the exact nature of the malfunctions. I recall the gun jamming up with a case in the action (not in the chamber), as the gun was trying to chamber another round.

I'm going to take the gun out and shoot it again with the new extractor and a Wolf recoil spring. I will update this thread on the result, afterwards.

 

[SHURESHOT]

The extractor normally breaks the tip of the hook off.

 

[edmoore]

While the extractor is a wear item, yours looks ok. Extractor spring gets weak over time too. Scott Andrey Machine (www.samachine.com/76home.html) has a trouble shooting page still up if your interested in looking it over. Sometimes the MK 760 can get finicky with a dirty chamber or so so ammo or feeding from the mag, etc. Don't forget to clean the mag feeds lips as they get a little crusty as time wears on like everything else. Good luck and let us know how it goes and happy shooting!

 

[rssc]

Guys, thanks for all the info and suggestions..I did swap out the extractor with the one pictured above. It appears to have fixed the issue. With the old extractor, I couldn't get through a mag without multiple stoppages. With the new extractor I was able to get through 3 mags without issue.

I did speak with an mk760 RKI. After looking at the above pictures, he mention that the contact surface on the old extractor is slightly angled. He said that this can cause issues. I think this is likely what caused my issue. I just want to provide this feedback for future use by those who experience the same issue down the road and come to this great forum for help, like I did.

 

[navgunner]

I’ve personally spoken many times with Richard about his extractors so I can confidently say that his geometry was “improved”. Also, BWE used pre-hardened steel that was cut using wire EDM (electrolysis) whereas the factory extractors were stamped. God bless Richard Hoffman.

I made a batch of ~100 extractors for the S&W76 but I didn’t do any for the 760s (they’re not interchangeable). @rssc I’m glad to hear that you got the issue sorted.

 

[edmoore]

Great rssc! Glad you got her running right again! Happy Shooting!

 

[rssc]

Thanks guys! Thx for all the info and helpful suggestions. I was concerned that this would turn into a big ordeal chasing down the issue. I am relieved it was pretty easily fixed with an ejector swap.