I’m using a BCM BCG in a LMT 14.5 carbine length upper ,H2 buffer, after 1000 rounds of fire I noticed by bolt cam pin has a U shaped line of wear carved in it. I can feel the ridge with my finger nail. I replaced the cam pin with another BCM cam pin and it happened again. What is the life expectancy of the bolt cam pin and is this wear normal.
Also should I practice with one cam pin and use another new one to keep in my GO TO gun.
Thanks Steve
Good question,
I have the same thing going on with my 2 LMT cam pins. I was told by another member that it is common and just to buy some extra because eventually it would jam. I’m curious to see what answer knowledgeable people give. Or if there is a fix.
the wear is normal… some guys replace the cam pin between 3-5k as PM, as play between cam-pin and bolt hole can cause broken bolts at the bolt hole.
It is normal to see this:
(Sorry for the dog hair in the picture!)
This was polished out with a dremel sandpaper wheel and then I mag tested the pin to verify what I thought and it was cracked on both sides. I stock cam pins and while I’m cleaning I visually inspect and replace them if they appear to be getting impressed too deeply from the side loading.
That pin is side loaded when the bolt reaches is maximum travel in both front and rear directions, so it is impacted with each round fired 2 times, one on each side. I don’t know how long it would take for a cam pin to get the sharp impressions, develope a surface crack and allow the crack to propogate into the machined hole, but for the couple dollars it is not worth waiting to see. Next time you order from Grant just throw 4 in your shopping cart and put one in your range bag and the others in your storage area until needed. It takes at least a few thousand rounds to really get a good sharp impression in them, so it is not like you need to be swapping them out very often. And even with the sharp impression, it may take thousands of additional rounds to develop a crack and allow it to propogate through wall.
Thanks Larry
Your pic is right on with my cam pin wear. BTW I ordered 8 extras form BCM USA and keep a extra in my Miad.