Unobtanium Posted July 24, 2014 Share Posted July 24, 2014 I'm curious how the cam-pins fare on these in the 10K+ round range. Stranger Danger? Any pictures? I know the cam-pin is an issue on the M4 (carbine) platform, and while I have never heard of it being one on a Benelli, I am just curious about the wear patterns. Quote Link to comment Share on other sites More sharing options...
StrangerDanger Posted July 24, 2014 Share Posted July 24, 2014 I'll look to see if there is any wear marks, but I don't recall seeing any. Quote Link to comment Share on other sites More sharing options...
WrenchBender Posted July 24, 2014 Share Posted July 24, 2014 Quite a bit of difference in the pressure exerted on a 5.56mm cam pin vs the one in the Benelli Quote Link to comment Share on other sites More sharing options...
benelliwerkes Posted July 25, 2014 Share Posted July 25, 2014 (edited) Why would there be any significant pressure on the pins at all ? The firing pin transits thru the cam pin in both 5.56 / M4 to keep it longitudinally oriented, their respective bolts are locked up with the barrel at the time of ignition....after ignition, they only serve to be a fixed point to rotate the bolt for extraction and feeding the next cartridge. If there was a any tension or pressure of significance, you would think it would manifest as a fractured firing pin as it is much smaller in diameter than the cam pin, that is being held in a right angle to the firing pin orientation, for the to-and-fro bolt to dance about. It would seem to be analogous to the firing pin retaining pin in both platforms, serving only to keep the firing pin within a certain limit of longitudinal travel. Edited July 25, 2014 by benelliwerkes Quote Link to comment Share on other sites More sharing options...
Unobtanium Posted July 25, 2014 Author Share Posted July 25, 2014 Why would there be any significant pressure on the pins at all ? The firing pin transits thru the cam pin in both 5.56 / M4 to keep it longitudinally oriented, their respective bolts are locked up with the barrel at the time of ignition....after ignition, they only serve to be a fixed point to rotate the bolt for extraction and feeding the next cartridge. If there was a any tension or pressure of significance, you would think it would manifest as a fractured firing pin as it is much smaller in diameter than the cam pin, that is being held in a right angle to the firing pin orientation, for the to-and-fro bolt to dance about. It would seem to be analogous to the firing pin retaining pin in both platforms, serving only to keep the firing pin within a certain limit of longitudinal travel. This is typical wear for an M4 carbine cam-pin. Cam-pins in this platform should be changed when they are excessively worn, as they are a contributor to broken bolts (more wear = more slop = more shock) After just 340 rounds: Quote Link to comment Share on other sites More sharing options...
StrangerDanger Posted July 25, 2014 Share Posted July 25, 2014 I just looked at the pin on a 13k+ cam for the M4. The only markings on it are polishing at the 9:30 and 4:30 position if you use the little marker point as the 12 o'clock position. This polishing is from the cam contacting the bolt carrier as it reciprocates. No dimensional changes were detected from the burnishing. Quote Link to comment Share on other sites More sharing options...
Unobtanium Posted July 25, 2014 Author Share Posted July 25, 2014 I just looked at the pin on a 13k+ cam for the M4. The only markings on it are polishing at the 9:30 and 4:30 position if you use the little marker point as the 12 o'clock position. This polishing is from the cam contacting the bolt carrier as it reciprocates. No dimensional changes were detected from the burnishing. nice That is part of what I love about the Benelli M4 so much. It was engineered so well. I have yet to find a "fatal flaw" to it. Quote Link to comment Share on other sites More sharing options...
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