02-27-2013, 04:11 PM
Just thought I would update.
I purchased the bolt from Fillar at the cost he paid. I received the bolt from UPS yesterday. Being a former fabricator, I'm used to making objects fit where most cant. Anyway, I went to my shop this morning.
Within about 30 seconds, I saw 2 problems with this bolt. First, just slightly down inside the bore for the cam pin, there was a burr sticking out just slightly. The 2nd thing I noticed was the slight, very slight egg shape of the bore.. I then took measurements of the several cam pins I have in other rifles, they all measured .3100 inches on a certified to the .0001, recently calibrated digital micrometer.
***Now for the disclaimer. If you have little to no mechanical or fabrication experience, I do not recommend you try this on your own should you run into a similar situation. I am not responsible for any ideas this may give you.***
Once I got those measurements, I then took a grease pencil and a straight edge and marked 6 places around the bore. I then took measurements from those 6 places, 4 of the 6 measured .3105, the other two measured .3090 and .3085. I then took a spare cam pin, decided to try making it fit those measurements. I discovered that while I could make the cam pin fit in the bore, it would not rotate and it would get hung up, presumablly on the burr inside the bore.
At this point, I decided the best option would be to round out the two areas that were smaller and remove the burr. I took a Dremel and a 4200 grit sanding stone bit and smoothed out the bore and removed the burr.
I then took measurements of all the same spots. I managed to get it almost perfect, can't even tell without a magnifying glass that anything was messed with. Now a standard, unmodified cam pin fits in and rotates as it should.
New measurements show that I made the bored round out to .3107. I'm sure .0002 of inch will not weak the bolt and so far it manually cycles fine in my grendel. I have not fired it due to the weather, but hopefully this weekend, I can try it out. I am confident in my work, I measured my other AR bolts, the bores for the cam pins on the other 2 are .3104 and .3109 so I'm not worried at all with it. This whole process took longer to tell than it did to make it work. Within 15 minutes, I now have a working bolt.
I do have pictures to post once my wife gets home and I can get the camera cord out of the car.
I purchased the bolt from Fillar at the cost he paid. I received the bolt from UPS yesterday. Being a former fabricator, I'm used to making objects fit where most cant. Anyway, I went to my shop this morning.
Within about 30 seconds, I saw 2 problems with this bolt. First, just slightly down inside the bore for the cam pin, there was a burr sticking out just slightly. The 2nd thing I noticed was the slight, very slight egg shape of the bore.. I then took measurements of the several cam pins I have in other rifles, they all measured .3100 inches on a certified to the .0001, recently calibrated digital micrometer.
***Now for the disclaimer. If you have little to no mechanical or fabrication experience, I do not recommend you try this on your own should you run into a similar situation. I am not responsible for any ideas this may give you.***
Once I got those measurements, I then took a grease pencil and a straight edge and marked 6 places around the bore. I then took measurements from those 6 places, 4 of the 6 measured .3105, the other two measured .3090 and .3085. I then took a spare cam pin, decided to try making it fit those measurements. I discovered that while I could make the cam pin fit in the bore, it would not rotate and it would get hung up, presumablly on the burr inside the bore.
At this point, I decided the best option would be to round out the two areas that were smaller and remove the burr. I took a Dremel and a 4200 grit sanding stone bit and smoothed out the bore and removed the burr.
I then took measurements of all the same spots. I managed to get it almost perfect, can't even tell without a magnifying glass that anything was messed with. Now a standard, unmodified cam pin fits in and rotates as it should.
New measurements show that I made the bored round out to .3107. I'm sure .0002 of inch will not weak the bolt and so far it manually cycles fine in my grendel. I have not fired it due to the weather, but hopefully this weekend, I can try it out. I am confident in my work, I measured my other AR bolts, the bores for the cam pins on the other 2 are .3104 and .3109 so I'm not worried at all with it. This whole process took longer to tell than it did to make it work. Within 15 minutes, I now have a working bolt.
I do have pictures to post once my wife gets home and I can get the camera cord out of the car.