Baddfed Posted July 15, 2015 Report Share Posted July 15, 2015 I have a AR 10 defender and after cleaning, I discovered that the cam pin (EA1015) could be installed with the rounded side in either the forward or rear position. I don't know which position was forward. Does anyone know if it really matters? The manual shows the cam pin with all four sides the same, however my cam pin has one rounded side. Quote Link to comment Share on other sites More sharing options...
Baddfed Posted July 15, 2015 Author Report Share Posted July 15, 2015 This is a link to a picture of it. https://armalite.com/files/2015/02/10406000-199x286.jpg Quote Link to comment Share on other sites More sharing options...
Rsquared Posted July 15, 2015 Report Share Posted July 15, 2015 (edited) Hmm. All of my cam pins are rounded on both the forward and rear facing side. When in doubt face it forward. You've got a 50/50 shot whether it's right or not. <laughs> Joking aside. Set it facing forward and then slide the carrier in your upper. Slide it back and forth a couple times and see how it feels. Oh....and welcome to the forum. Edited July 15, 2015 by Rsquared Quote Link to comment Share on other sites More sharing options...
survivalshop Posted July 15, 2015 Report Share Posted July 15, 2015 (edited) Maybe "Mrraley" knows & will speak up . I would look at the Cam path inside the Upper Receiver & see if ether end of the channel is rounded . The rounded end of the Cam pin could keep the BCG from going into full Battery in the Barrel Extension <dontknow> , but as Rsquared noted , try it both ways if you don't see anything in the Cam Channel. It could also be the way it is disassembled , the flat would make it easier to remove the Cam Pin past the Carrier Key or just a visual to index the Cam Pin for Firing Pin install . Edited July 15, 2015 by survivalshop Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted July 15, 2015 Report Share Posted July 15, 2015 Must be something new, my AR-10 cam pins are the same on both sides........... Quote Link to comment Share on other sites More sharing options...
mrraley Posted July 18, 2015 Report Share Posted July 18, 2015 That is new since I have left in 12/2013. Not sure why they would change a design that had no problems with it either. But when installing the cam pin into the bolt carrier, have the round part going forward. Quote Link to comment Share on other sites More sharing options...
Baddfed Posted July 18, 2015 Author Report Share Posted July 18, 2015 (edited) That is new since I have left in 12/2013. Not sure why they would change a design that had no problems with it either. But when installing the cam pin into the bolt carrier, have the round part going forward. That's what I finally decided to do after trying it both ways and marking the bolt in the forward position through the ejection port both ways with no difference in bolt position noted. It just seemed the right way. Haven't shot it since removing and installing the bolt. I'll post after the next trip to the range. By the way, I can tell after the first trip to the range, this gun is a shooter. Edited July 18, 2015 by Baddfed Quote Link to comment Share on other sites More sharing options...
Rsquared Posted July 19, 2015 Report Share Posted July 19, 2015 Well of course.....it's an Armalite. <laughs> Quote Link to comment Share on other sites More sharing options...
Sisco Posted July 19, 2015 Report Share Posted July 19, 2015 Well of course.....it's an Armalite. <laughs> +1 Quote Link to comment Share on other sites More sharing options...
Quentin Posted April 3, 2016 Report Share Posted April 3, 2016 (edited) My new AR-10A Defender came right out of the box with the rounded end of the cam pin forward, toward the chamber. The flat end toward the buffer/buttstock. As others said above, it just looks right this way. Think I'll scribble that in my manual because no doubt I'll forget! Edited April 3, 2016 by Quentin Quote Link to comment Share on other sites More sharing options...
mrmackc Posted April 6, 2016 Report Share Posted April 6, 2016 Don't really make any difference in functioning as long as the hole is facing forward to back and the firing pin doesn't bind. it is probably easier to insert and remove with the flat side to the rear. The ARmalite cam pin should also fit in a DPMS pattern bolt. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted April 6, 2016 Report Share Posted April 6, 2016 Wish they would give some information on this change in style for the cam pin. I had always thought the POF roller cam was a gimmick but it is starting to seem like there may be some science behind it.....or maybe they just got tired of people calling in asking why they couldn't get the cam pin out of there new rifle. If you've never tried it on a new AR-10 before the change it is a real bear till it breaks in a bit. Quote Link to comment Share on other sites More sharing options...
blue109 Posted April 6, 2016 Report Share Posted April 6, 2016 I still think the roller cam is a gimmick Quote Link to comment Share on other sites More sharing options...
planeflyer21 Posted April 6, 2016 Report Share Posted April 6, 2016 25 minutes ago, blue109 said: I still think the roller cam is a gimmick It's a gimmick until you're left at the starting line. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted April 6, 2016 Report Share Posted April 6, 2016 (edited) I have one of the Roller Cam Pins & tried it in the 16" & it worked , but I can't say it did anything that the std Cam pin wouldn't do . I installed the std Cam Pin back in there when I installed the 16" bbl. on a Tactical Machining Upper . Its a good idea for a bearing there , but to me its one more thing to fail . Saying that ,Bearings are used in several military type rifles & older battle proven designs . Not a cam Pin , but this Bearing ( M14 Bolt ) takes quite a bit of abuse from it riding in the Charging handle . M 14 Bolt. Edited April 6, 2016 by survivalshop Quote Link to comment Share on other sites More sharing options...
mrmackc Posted April 6, 2016 Report Share Posted April 6, 2016 (edited) Shop , M-14 Charging Handle?, maybe you were referring to the operating rod handle? That is okay this one time, but next time please call it by it's real name. After all it isn't off a Armalite or a DPMS or a Colt- by- Mattel. Edited April 6, 2016 by mrmackc Quote Link to comment Share on other sites More sharing options...
blue109 Posted April 6, 2016 Report Share Posted April 6, 2016 Well played :D Quote Link to comment Share on other sites More sharing options...
survivalshop Posted April 7, 2016 Report Share Posted April 7, 2016 What ever & its designation is " Operating Rod " There is a handle on it for charging the rifle though .? Quote Link to comment Share on other sites More sharing options...
mineralman55 Posted April 8, 2016 Report Share Posted April 8, 2016 In an M14 it's an "op rod", but you know that :-) There were never reports of Garands failing at the bolt/op rod interface, but for some reason John C. thought it should be "improved". The roller bearing on the M14 bolt works and works well, but I never thought the bolt on the M1 needed improvement. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted April 8, 2016 Report Share Posted April 8, 2016 34 minutes ago, mineralman55 said: In an M14 it's an "op rod", but you know that :-) There were never reports of Garands failing at the bolt/op rod interface, but for some reason John C. thought it should be "improved". The roller bearing on the M14 bolt works and works well, but I never thought the bolt on the M1 needed improvement. It may be that they used the bearing in the M14 because of full auto capability & it helped with cycling rate or they were seeing increased wear ? Quote Link to comment Share on other sites More sharing options...
mrmackc Posted April 8, 2016 Report Share Posted April 8, 2016 The "Bolt Roller" was added to the M14 bolt to reduce friction on the operating rod, this was done to increase the reliability of the rifle in full auto mode. The operating rod was shortened for the same reason, these modifications were not needed on the M1 because of the 8 round enbloc magazine capacity and semi automatic only. The 20 round magazine capacity also allowed a much higher sustained rounds per miniute fireing rate. I believe that the sustained rate of fire for the M1 was 32 rounds per minute. I have seen a higher sustained rate from experianced Marine rifleman that actually caused the barrel to turn red hot and linseed oil on the forearm smoked and dripped off in sustained fire training exercises. Quote Link to comment Share on other sites More sharing options...
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