View Full Version : POF roller cam pin?
Anyone have any experience with th POF roller cam pin? Will it fit my SR556?
I picked up a few at SHOT, I'll be taking a look at them in an upcoming review.
The roller cam pin from POF has functioned as advertised. I have not personally tried it in any other piston rifle but I have heard and read about people who have used it on an SR556 and others. I don't think you can go wrong with it if you are experiencing any upper receiver wear on your SR556 and the price is reasonable IMO. Good luck.
O
I would like to hear your review sir. I went ahead and ordered one. Also if you had time I have an idea about a way to make DI ARs function when submerged. I may not have an original idea but I might do.
Im not experiencing any wear on my second SR or any other problems for that matter just a premptive measure
Install it on your rifle and run it. If it runs, then it is a good preventative measure. I hope it works out for you like it has for others.
O
Thank you O. I think anything POF makes is dang good I just wish I could get my hands on one of their charging handles.
I'm using these in one of my Rugers and also in my PWS.
The Ruger had probably 1,500 rounds (and some pretty good cam pin wear) when I installed the POF cam pin. I've only got two or three mags through the rifle since but I don't notice any additional wear.
I had 100 rounds through the PWS and it was showing the start of cam pin wear when I swapped cam pins. I've got an additional 100 rounds through the gun (on full auto) and notice no additional wear from the initial mark made by the solid cam pin.
Granted, neither upper has many rounds downrange with the new cam pins installed but they seem to work as advertised.
SHOULD THIS ONLY BE USED ON A PISTON GUN
Awesome, how has the Ruger been working for you? I had to send my first one back and if the carrier tilt on this one gets much worse Ruger will be hearing from me again.
Cagemonkey
01-30-10, 21:04
SHOULD THIS ONLY BE USED ON A PISTON GUN
Yes. Unless you want to remove your carrier key in order to install it. Then after reassembly you can't field strip your your bolt carrier group.
Yes. Unless you want to remove your carrier key in order to install it. Then after reassembly you can't field strip your your bolt carrier group.
POF's got a new modified gas key that's cut to clear the roller cam pin.
Awesome, how has the Ruger been working for you? I had to send my first one back and if the carrier tilt on this one gets much worse Ruger will be hearing from me again.
Accurate and reliable. The one I've been shooting is actually one I bought used off gunbroker. I bought it while my first original gun was back at Ruger getting replaced for carrier tilt.
The PWS upper causes carrier tilt too. I thought their system using the long piston was supposed to change the balance point of the bolt carrier and keep the carrier from tilting. Not true...
Thomas M-4
01-30-10, 23:20
POF's got a new modified gas key that's cut to clear the roller cam pin.
OH SNAP !! I know what I am going to have to try out.
KingsideRook
01-31-10, 00:50
Not to be negative, but if cam key wear is a concern( piston rifle or not, I know people have found identical wear on DI rifles), I'd rather shell out $10 for the LWRC beveled-edge Improved cam pin than pay $70 for the POF roller cam pin AND relieved gas key, and have to restake the key. That said, I actually like the idea of the roller, just not the overall price and work involved to eliminate that kind of essentially negligible wear with the POF parts. I also would prefer not to pay the big $$ for IONBond or Failzero Bolt carriers, and the having to change out to a hard chrome key.
Cagemonkey
01-31-10, 08:24
POF's got a new modified gas key that's cut to clear the roller cam pin.
Thanks for the heads up. Have to check it out.
I've got one in my DI rifle - the roller bearing reduces the friction between the upper and cam pin when stripping rounds from the magazine... Huge little reliability upgrade in my book.
Huge little reliability upgrade in my book.
The idea behind it seems sound. Whether or not it adds anything to the overall reliability remains to be seen.
Still, I wonder why nobody thought of it years ago.
Ridge_Runner_5
01-31-10, 17:03
I still dont understand how it functions differently than a standard cam pin...
I still dont understand how it functions differently than a standard cam pin...
Instead of just a standard cam pin it is a ball bearing roller.
The idea behind it seems sound. Whether or not it adds anything to the overall reliability remains to be seen.
Still, I wonder why nobody thought of it years ago.
Wish I woulda thought of it, kinda like Seth Harness' buffer. I think I will order one of those as opposed to sending my rifle back because the second one is alot better than the first.
Thomas M-4
01-31-10, 18:55
I like the Idea of it [like how MG use rollers in the feed paw mechanism].
Do I think it would improve reliability probably not unless you consider running less lube or longer intervals between lubing up. The standard cam pin has been proven to be more than reliable for the job. I would hope that the roller cam pin would help in times of not having enough lube.
I like the Idea of it [like how MG use rollers in the feed paw mechanism].
Do I think it would improve reliability probably not unless you consider running less lube or longer intervals between lubing up. The standard cam pin has been proven to be more than reliable for the job. I would hope that the roller cam pin would help in times of not having enough lube.
Wouldn't that inherently make it more reliable? For twenty bucks I dont think better insurance can be had especially for a piston driven rifle.
As long as the riveted head doesn't come loose it should work.
As long as the riveted head doesn't come loose it should work.
Uh oh, my experiences with rivets have not been good, they seem to be ok when just holding inanimate objects. The violent action of a BCG in a piston AR hmmm....
Thomas M-4
01-31-10, 20:56
As long as the riveted head doesn't come loose it should work.
Yea that is what I would be worried about .
Imagine it would be wise to inspect it frequently and replace if you see any sign of possible trouble.
Thomas M-4
01-31-10, 21:04
Wouldn't that inherently make it more reliable? For twenty bucks I dont think better insurance can be had especially for a piston driven rifle.
I try not to get to enthusiastic over manufacturer claims. But that being said I am interested in it now that they offer a DI kit. I will have to try it gives me a good reason to pick up a MOACKS;)
I try not to get to enthusiastic over manufacturer claims. But that being said I am interested in it now that they offer a DI kit. I will have to try it gives me a good reason to pick up a MOACKS;)
Tools and guns are always a good investment
Yea that is what I would be worried about .
Imagine it would be wise to inspect it frequently and replace if you see any sign of possible trouble.
Ah the quest for piston driven AR perfection possibly continues.
I put somewhere around 800 rounds (mostly full-auto) through my PWS upper over the last couple of days. The tiny amount amount of cam pin drag that was caused by the factory GI-type cam pin appears no worse than it did before the installation of the POF cam pin. The cam pin looks unchanged, too.
Time will tell but so far so good. It seems to work like it's meant to.
I put somewhere around 800 rounds (mostly full-auto) through my PWS upper over the last couple of days. The tiny amount amount of cam pin drag that was caused by the factory GI-type cam pin appears no worse than it did before the installation of the POF cam pin. The cam pin looks unchanged, too.
Time will tell but so far so good. It seems to work like it's meant to.
Awesome, mine is slated to arrive tomorrow. I put 500 rounds of silver bear (Im cheap) thru my SR monday afternoon and the carrier tilt mark has not gotten any worse and had no malfs of any kind. Did your PWS seem to cycle any faster on FA since the addition of the POF RCP? Also did you have modify the BCG on your Ruger to get it to fit?
Did your PWS seem to cycle any faster on FA since the addition of the POF RCP? Also did you have modify the BCG on your Ruger to get it to fit?
I didn't notice any change in cyclic rate from changing the cam pin.
The POF cam pin was a drop-in fit in both the PWS and the Ruger.
I didn't notice any change in cyclic rate from changing the cam pin.
The POF cam pin was a drop-in fit in both the PWS and the Ruger.
Thank you for the info Tokarev, I know the question about cyclic rate sounded stupid, the reason I ask is because I didnt know how much friction the bearing would reduce and wether or not it would affect the weight of the buffer needed to make it function properly.
Thank you for the info Tokarev, I know the question about cyclic rate sounded stupid, the reason I ask is because I didnt know how much friction the bearing would reduce and wether or not it would affect the weight of the buffer needed to make it function properly.
Before I installed the roller cam, I only had 100 rounds through the upper. That was a 30rd mag dump, another mag using 3-4 round bursts and then 2 20rd mags on semi-auto. The cyclic rate could very well be higher due to the reduced friction but I don't think I had enough rounds fired previously to form any opinion.
Before I installed the roller cam, I only had 100 rounds through the upper. That was a 30rd mag dump, another mag using 3-4 round bursts and then 2 20rd mags on semi-auto. The cyclic rate could very well be higher due to the reduced friction but I don't think I had enough rounds fired previously to form any opinion.
Ah kind words sir, you could have eviserated me on that one. I just received my RCP and to me, having been employed by several manufacturing and fabrication shops, it appears the bearing has been swaged on. By that I mean the "rivet" is actually a machined "nipple" that the bearing fits around and then a press is used to mash the "tit" down which is an extremely strong method of attaching bearings or other fittings to their attachment point. Hopefully real soon I can run the holy crap out of my SR soon and test it fully :D
Ah kind words sir, you could have eviserated me on that one. I just received my RCP and to me, having been employed by several manufacturing and fabrication shops, it appears the bearing has been swaged on. By that I mean the "rivet" is actually a machined "nipple" that the bearing fits around and then a press is used to mash the "tit" down which is an extremely strong method of attaching bearings or other fittings to their attachment point. Hopefully real soon I can run the holy crap out of my SR soon and test it fully :D
I agree with your assessment of the "mashed tit" holding the roller in place. It should be a solid attachment and should work well since most of the force will be back and forth and not up and down.
No desire to eviscerate anyone. I'm not here to feed my ego at your expense.
I agree with your assessment of the "mashed tit" holding the roller in place. It should be a solid attachment and should work well since most of the force will be back and forth and not up and down.
No desire to eviscerate anyone. I'm not here to feed my ego and your expense.
So many are, I try to tread lightly as my experience with AR's is in its fledgling stage. Also thanks for the spelling correction:D
Let us know how it works.
Let us know how it works.
Certainly
210 rounds fired through my Ruger this weekend. The roller cam pin looks fine after the limited use.
That's about 1,000 rounds total on two POF roller cams...
I put 120 thru my SR today, and I dont remember a divot on the side of my reciever where the cam pin rides but it is sure there now. The carrier tilt mark on my buffer tube is also more pronounced. Not much of a round count so is hard to tell.
I put 120 thru my SR today, and I dont remember a divot on the side of my reciever where the cam pin rides but it is sure there now. The carrier tilt mark on my buffer tube is also more pronounced. Not much of a round count so is hard to tell.
How many rounds had been fired previously?
Keep an eye on the cam pin drag and see if it gets any worse with the change in parts. My PWS looks unchanged, as does my Ruger but both of these uppers might have reached the limit to wear before I spent my money.
I don't think the roller cam pin will do anything to change carrier tilt. If it gets bad, try one of the new PWS enhanced buffer tubes. This is a rather expensive part but should support the carrier and keep it from rocking.
How many rounds had been fired previously?
Keep an eye on the cam pin drag and see if it gets any worse with the change in parts. My PWS looks unchanged, as does my Ruger but both of these uppers might have reached the limit to wear before I spent my money.
I don't think the roller cam pin will do anything to change carrier tilt. If it gets bad, try one of the new PWS enhanced buffer tubes. This is a rather expensive part but should support the carrier and keep it from rocking.
800 - 1000 not sure exactly, the SR is boxed up and ready for pickup tomorrow (again). Im sure its not the POF part.
800 - 1000 not sure exactly, the SR is boxed up and ready for pickup tomorrow (again). Im sure its not the POF part.
Boxed up and ready for pickup? I assume you mean by Ruger? What's wrong with it?
Boxed up and ready for pickup? I assume you mean by Ruger? What's wrong with it?
I dont mind the buffer tube getting mangled its a 20 dollar fix, but the upper? I cant even take the rail off without voiding my warranty.
How bad's the cam pin wear? Worse than this? This is my SR556. The wear has progressed since but doesn't look a whole lot worse than it did here.
I need to check out the HK416 at the office and get some pics of the cam pin drag in that upper. IIRC, it's pretty deep.
http://img.photobucket.com/albums/v221/tokarev/Ruger%20SR%20556/DSCN0426.jpg
How bad's the cam pin wear? Worse than this? This is my SR556. The wear has progressed since but doesn't look a whole lot worse than it did here.
I need to check out the HK416 at the office and get some pics of the cam pin drag in that upper. IIRC, it's pretty deep.
http://img.photobucket.com/albums/v221/tokarev/Ruger%20SR%20556/DSCN0426.jpg
Every bit that bad.
I've got a non-piston Armalite M15 that looks worse than this and I've seen a number of Colt M4's that are this bad or worse, easily. This isn't a phenomenon strictly associated with Ruger or piston guns.
Most people agree that if your rifle is going to show it, it'll start early and peak at about 500 rounds. I'm unaware of this ever causing failure. Maybe one of the other members has more info.
Boxed up and ready for pickup? I assume you mean by Ruger? What's wrong with it?
Yessir by Ruger
I've got a non-piston Armalite M15 that looks worse than this and I've seen a number of Colt M4's that are this bad or worse, easily. This isn't a phenomenon strictly associated with Ruger or piston guns.
Most people agree that if your rifle is going to show it, it'll start early and peak at about 500 rounds. I'm unaware of this ever causing failure. Maybe one of the other members has more info.
Oh, I thought there was no way that it was good or normal. Again I'm not an expert by any stretch of the imagination, I just thought it was bad. Ruger is giving me my choice of something else, I wonder if I over reactted.
Oh, I thought there was no way that it was good or normal. Again I'm not an expert by any stretch of the imagination, I just thought it was bad. Ruger is giving me my choice of something else, I wonder if I over reactted.
That's good to know that Ruger will exchange the 556 for another product(s).
See if you can't get ahold of Mark Gurney. He's Ruger's product manager. Let him know that you'd like to have your gun inspected with a fine toothed comb and see what he has to say. If he agrees to get it looked at and/or replace the upper, why not give the carbine another chance?
That's good to know that Ruger will exchange the 556 for another product(s).
See if you can't get ahold of Mark Gurney. He's Ruger's product manager. Let him know that you'd like to have your gun inspected with a fine toothed comb and see what he has to say. If he agrees to get it looked at and/or replace the upper, why not give the carbine another chance?
Its very hard to say no to that, its just this is the second one I have had. I bought an AR 15 for home defense and varmint hunting, I cant kill any song dogs or scare the hell out of an intruder B4 I ground check him with my rifle at the shop. Dont get me wrong I love my other Rugers (will post a pic of my tattoo) and their customer service has been stellar, but Im just not sure.
Heavy Metal
02-08-10, 20:05
That wear looks normal.
That wear looks normal.
Should I keep it?
GLOCKMASTER
02-08-10, 20:09
I was given one today when a POF .308 was delivered to me. I'm very interested in seeing how it holds up.
Heavy Metal
02-08-10, 20:25
Should I keep it?
I would. Parts take a set on new guns and they don't always set the same. Yours looks within the realm of normal.
Shoot another thousand rounds. I bet it still looks the same.
I would. Parts take a set on new guns and they don't always set the same. Yours looks within the realm of normal.
Shoot another thousand rounds. I bet it still looks the same.
Good advice.
I would. Parts take a set on new guns and they don't always set the same. Yours looks within the realm of normal.
Shoot another thousand rounds. I bet it still looks the same.
You guys' sensibility is killin me.
Yessir by Ruger
Please check your PM's.
Please check your PM's.
Will act on that thank you.
800 - 1000 not sure exactly, the SR is boxed up and ready for pickup tomorrow (again). Im sure its not the POF part.
Did the UPS man drive off with your Ruger?
EzGoingKev
02-10-10, 14:59
I see they are selling just the roller and then a roller with a modified gas key. I can see the side of the gas key has been clearanced.
http://www.pof-usa.com/parts/rcpk1AB.jpg
If you use their gas key can you install this into a DI setup and be able to remove the roller without having to remove the gas key?
Thomas M-4
02-10-10, 15:13
I see they are selling just the roller and then a roller with a modified gas key. I can see the side of the gas key has been clearanced.
http://www.pof-usa.com/parts/rcpk1AB.jpg
If you use their gas key can you install this into a DI setup and be able to remove the roller without having to remove the gas key?
Correct
Did the UPS man drive off with your Ruger?
Yessir, he got it.
I see they are selling just the roller and then a roller with a modified gas key. I can see the side of the gas key has been clearanced.
http://www.pof-usa.com/parts/rcpk1AB.jpg
If you use their gas key can you install this into a DI setup and be able to remove the roller without having to remove the gas key?
I've never tried to file a gas key. They might be harder than woodpecker lips. But I'd think it would be an easy mod to make a small cut on your existing gas key. I don't think it would take much to clear the roller.
Heavy Metal
02-10-10, 17:36
Gas keys are soft.
They might be harder than woodpecker lips.
HAHA!
Heavy Metal
02-10-10, 17:57
Drop one onto a concrete floor sunny-side down with a Bolt Carrier attached to it and get back to me on how hard you think it is.
Well, there you go.
Why spend an additional $25 on a new gas key when it should be easy work with a small file or a Dremel? Plus no need to re-stake the bolts.
Well, there you go.
Why spend an additional $25 on a new gas key when it should be easy work with a small file or a Dremel? Plus no need to re-stake the bolts.
This was my thought. I just painted a customer sabre defence AR and the cam pin wear was really bad. After see that upper the roller looks like something Ill have to try on mine...
Anybody remember that youtube video made by the guy in Berlin? He tried to run a stock GI bolt and carrier back and forth inside an upper while pushing in against the bolt face. The bolt would drag and stall when he applied force. Granted, the feeding of rounds should really provide about zero pressure against the bolt but it did show that the cam pin does drag inside the upper during normal operation.
I've tried this same "experiment" with a standard cam pin and a roller cam pin in the gun. The roller cam pin does reduce the drag inside the upper.
This is a neat idea. As with all things; time will tell what benefit(s) it offers.
Anybody remember that youtube video made by the guy in Berlin? He tried to run a stock GI bolt and carrier back and forth inside an upper while pushing in against the bolt face. The bolt would drag and stall when he applied force. Granted, the feeding of rounds should really provide about zero pressure against the bolt but it did show that the cam pin does drag inside the upper during normal operation.
I've tried this same "experiment" with a standard cam pin and a roller cam pin in the gun. The roller cam pin does reduce the drag inside the upper.
This is a neat idea. As with all things; time will tell what benefit(s) it offers.
+ 1 good idea
Here it is. This guy really exaggerates the problem but I've seen some fairly well used M16's that are rubbed to sh!t along the inside of the upper so the potential for wear and/or malfunctions is there.
Anybody want to duplicate this test with a POF cam pin in place?
http://www.youtube.com/watch?v=6JmIQXkoog8
Yessir, he got it.
Keep us posted on what happens. If Ruger replaces your upper, I'd be curious to see how the roller cam pin works in a brand new unworn upper.
Keep us posted on what happens. If Ruger replaces your upper, I'd be curious to see how the roller cam pin works in a brand new unworn upper.
I will let you know what happens, I spoke with Mark today and asked a bunch of questions etc he was very helpful, so we will see.
I see they are selling just the roller and then a roller with a modified gas key. I can see the side of the gas key has been clearanced.
http://www.pof-usa.com/parts/rcpk1AB.jpg
If you use their gas key can you install this into a DI setup and be able to remove the roller without having to remove the gas key?
Thanks for the pic. I have been curious as to how the cut on the gas key looked.
The cam pin looks interesting... Does the roller have a small bearing on it or does it just roll on metal? Im thinking if the roller feature isnt extremely slick it would probably still drag a bit inside the upper, causing a tad bit of wear on the upper. I could be wrong though... Either way though, looks like something I might try though.
More range time yesterday with my cammed up DC-12. Total rounds now is about 1,500.
I would have fired another 150 rounds or so but my upper didn't want to cooperate. I apparently clogged the gas tube on my upper by squirting some oil in there. The oil combined with the hot gasses and carbon and turned into a hardened plaque inside the tube. I've got the action all scrubbed and running smoothly in dry fire and will try to get some additional rounds fired on Tuesday. I guess there's a reason the Soviets put those longitudinal flutes in the AK's gas tube.
Anyway, I'm not seeing anything alarming on the cam pin. The cam still looks basically new.
I don't know how much force is applied to the head of the cam pin against the receiver. However rolling contact against a relatively soft surface (the receiver) can cause fatigue failure just below the surface and the track material spalls off in flakes. Like the way a wheel bearing usually fails.
I am not predicting this but I am curious if it happens inside the receiver as round counts add up.
I don't know how much force is applied to the head of the cam pin against the receiver. However rolling contact against a relatively soft surface (the receiver) can cause fatigue failure just below the surface and the track material spalls off in flakes. Like the way a wheel bearing usually fails.
I am not predicting this but I am curious if it happens inside the receiver as round counts add up.
This will be something to watch.
I just put one into my Bushmaster/Aries bolt carrier. This coupled with Seth Harness's buffer has turned my action super smooth. I will run some rounds through it this week and start keeping a round count on the cam pin.
IPSC_GUY
SIERRA II ALPHA
I must be missing something and I haven't had my coffee yet so I am having a hard time figuring out how this is supposed to work.
The cam pin runs in a channel with two points of lateral contact in the upper receiver. How can a roller function with two points of contact 180 degrees from each other? This would be like a tire running against asphalt on the top and the bottom; it would end up skidding against both surfaces because it can only rotate in one direction at a time.
I must be missing something and I haven't had my coffee yet so I am having a hard time figuring out how this is supposed to work.
The cam pin runs in a channel with two points of lateral contact in the upper receiver. How can a roller function with two points of contact 180 degrees from each other? This would be like a tire running against asphalt on the top and the bottom; it would end up skidding against both surfaces because it can only rotate in one direction at a time.
Ahhh interesting question. The roller is not as wide as in the inside of the upper receiver (neither is a normal cam pin) so as it travels fore and aft it is not contacting both sides of the inside of the upper. The only place it positively "rolls" is the transition inside the recess as the bolt locks and unlocks, thus providing less friction.
IPSC_GUY
SIERRA II ALPHA
See, this is why I love you guys. In my lack of coffee, mind-addled state I wasn't getting it; It make sense now. I am still not convinced it is needed, or better then the current, simple method but I get it now. Thanks.
Needed? hummmmmm not sure either and if the damn thing snaps off it will really SUCK but... the action is NOTICEABLY smoother through the transition of locking and unlocking and that can't hurt at all.
Time will tell and for $20.00 I will try it.
IPSC_GUY
SIERRA II ALPHA
I've lost count but here's one of my roller cams with about 1,400 rounds on it. There's some slight wear to the finish but nothing that's not on a stock cam pin after some use.
http://img.photobucket.com/albums/v221/tokarev/PWS%20DC-12/DSCN0772.jpg
http://img.photobucket.com/albums/v221/tokarev/PWS%20DC-12/DSCN0773.jpg
Thomas M-4
02-15-10, 11:07
Tokarev are you noticing a smoother locking and unlocking ?
Tokarev are you noticing a smoother locking and unlocking ?
Not that I've really noticed.
For what it is worth, I can come up through the bottom of the mag well and stick my index finger against the bolt face. From there, I can ease the action closed against my finger and push the bolt carrier back and forth against the buffer spring. It is a little smoother in my PWS and Ruger than it is in my 6920. The 6920 still uses the GI-type cam pin.
Here's a photo of cam pin drag in my PWS. This appeared during the first 100 rounds when I still had the factory cam pin in. It hasn't progressed from this initial mark even though I'm at 1,400 or 1,500 rounds fired.
http://img.photobucket.com/albums/v221/tokarev/PWS%20DC-12/DSCN0781.jpg
Here's the same shot of cam pin drag in my Ruger. This is getting close to the 2K mark and the cam pin drag is getting ugly. I've since changed to the POF roller but haven't really fired enough since to notice any difference.
http://img.photobucket.com/albums/v221/tokarev/Ruger%20SR%20556/DSCN0783.jpg
Ok, I got out to put some rounds down range today, with the new cam pin. So I loaded up a pmag, in the rifle, rack the bolt back and let it go. My initial impression was that the bolt failed to pick up a round. You know how a bolt closing on an empty chamber sounds? That was what this was like. I slapped the bottom of the mag and find that it is fully seated. So I pull the charging handle back to do a brass check and, there was a round in the chamber... I was sure it hadn't chambered anything just because of the smoothness of how the action felt.
I ran off two hundred rounds with no fuss and no muss. So far I call it a product improvement. I will add it to my future piston build on a fresh upper to see if it does prevent wear in the cam pin notch from the get go.
By the way my Piston set up is the Aries/Shrubmaster with a Adams Arms Spring, POF Cam Pin and a Seth Harness Anti Tilt Buffer.
IPSC_GUY
SIERRA II ALPHA
meshugganator
02-26-10, 18:47
it would be good to see what wear from the original pin looks like seeing as i just (upgraded:rolleyes:)my blaster with AA piston kit and FRS buffer
Heavy Metal
02-26-10, 19:26
Not that I've really noticed.
For what it is worth, I can come up through the bottom of the mag well and stick my index finger against the bolt face. From there, I can ease the action closed against my finger and push the bolt carrier back and forth against the buffer spring. It is a little smoother in my PWS and Ruger than it is in my 6920. The 6920 still uses the GI-type cam pin.
Here's a photo of cam pin drag in my PWS. This appeared during the first 100 rounds when I still had the factory cam pin in. It hasn't progressed from this initial mark even though I'm at 1,400 or 1,500 rounds fired.
http://img.photobucket.com/albums/v221/tokarev/PWS%20DC-12/DSCN0781.jpg
Here's the same shot of cam pin drag in my Ruger. This is getting close to the 2K mark and the cam pin drag is getting ugly. I've since changed to the POF roller but haven't really fired enough since to notice any difference.
http://img.photobucket.com/albums/v221/tokarev/Ruger%20SR%20556/DSCN0783.jpg
All that wear notch says to me is that this material should have been removed by the manufacturer. It is just a short clearance that resolved itself. Parts mate.
meshugganator
02-26-10, 21:06
sweet, think ill get the pof pin
I've got an additional 400 rounds through my PWS upper. The cam pin wear has increased somewhat from the photos above. I'll try to get some photos of the progressed wear.
On another note, I have a new Ruger SR556 upper that I'm going to use with the POF roller cam. I plan on using this set-up in the VTAC Carbine 1.5 this weekend and I'll let you guys know what kind of wear I've got after the class.
oh my gawh... this things a failure waiting to happen, gentlemen. there's no wear reduction necessary at the cam pin- at least not between upper and pin. the cam pin wears away a tiny little spot and then wear stops- all on it's own. but WHEN that rivet pops off, youre skewered.
roller pins are gay. :p
im ordering one for a di set up see how it runs with my new vltor vis upper
I used a roller cam pin equipped Ruger during the recent Viking Tactics class in Phoenix. I experienced no problems during the course.
It's been established it's not held on with a rivet - the head is peened into shape. Since there is no vertical load on the pin, it wouldn't pop off anyway.
The pin head and channel are a source of friction - as the cartridge face pushes on the BCG during intial extraction, the bolt is being forced back to the closed position. The only thing that prevents it is the pin captured in the channel. Some uppers I've been issued were a machined with repetitive chatter marks from a tool head or fixture to loose to hold things firmly. Until the high points were knocked down, it was a bit stiff in function. Lots of lube helped initially.
Think about it - the few surfaces that need lubrication in a AR upper are the channel and lower rails. The channel also gets blasted by the gas tube right after unlocking, so it loses lubrication first. It's also where the head of the pin is being forced against the side of the channel due to bolt pressure.
Lube is just a friction reducing agent. If the parts are made to be more friction free, either less lube is needed, or it takes a much higher round count to get so dirty it won't cycle.
What I'd like to hear is how many rounds could be run in a dry upper before malfunction - roller pin vs GI. If it's significantly higher, why not use it?
Don't forget the AR, like any other mechanical product, had to meet a reasonable target for price to meet a competitive bid. Parts like this are what get value engineered out because the overall cost/benefit threshold was set using '50's era thinking on battlefield casualty losses. Things have changed, and now we have a much different threshold that won't accept a nominal number of losses due to stoppages. Even in Nam, it was a point to rig the cleaning rod on the handguard for immediate action use.
If it's a cost effective way to reduce friction in the AR bolt system, it's all good.
Any updates from you other guys who are using the POF cam pin?
I would like to know as well. As I said Im going to doreder one here in the next week for my SBR build...
oh my gawh... this things a failure waiting to happen, gentlemen. there's no wear reduction necessary at the cam pin- at least not between upper and pin. the cam pin wears away a tiny little spot and then wear stops- all on it's own. but WHEN that rivet pops off, youre skewered.
roller pins are gay. :p
It takes over 500 ft/lbs to force the roller off the cam pin.
It takes over 500 ft/lbs to force the roller off the cam pin.
yea, brand new. and assuming that's correct/always true.
yea, brand new.
Have you seen one fail, or do you know of a weakness in the design that would cause one to fail?
You're right, it's incorrect...the lowest number in testing was 563.
Got mine in today. Ill be testing it in my BCM 11.5" upper. This upper has only had the factory test rounds and theres NO cam pin wear as of now. Well see how this roller pin works out....
http://i39.photobucket.com/albums/e187/Hypercomp01/P1030263.jpg
Got mine in today. Ill be testing it in my BCM 11.5" upper. This upper has only had the factory test rounds and theres NO cam pin wear as of now. Well see how this roller pin works out....
Do they sell versions of the cam pin that are compatible with a standard BCG? Or does it require a modified key?
They sell a modified key. Im just gonna dremel my BCM carrier a bit. It doesnt take much to get it to fit...
Do they sell versions of the cam pin that are compatible with a standard BCG? Or does it require a modified key?
The kit includes a modified key with a relief cut.
http://img.photobucket.com/albums/v503/AR15forme/POF/IMG_81901.jpg
How's the roller cam pin working for you guys?
How's the roller cam pin working for you guys?
Sold the Ruger and got a BCM, just dont feel the need for it, currently sitting on a shelf.
How's the roller cam pin working for you guys?
I have nearly another 1000 rounds on mine and so far so good. Not one hiccup in that whole batch of rounds. The wear on the roller is pretty negligible. Where I find this thing to be the biggest advantage is super smooth feeding.
My action is noticeably smoother than just about every other AR I pick up. So much so people ask me about it. I have not put one of these into a DI gun yet but I am thinking about it...
IPSC_GUY
SIERRA II ALPHA
The wear on the roller is pretty negligible.
How's the wear inside the upper from cam pin drag?
How's the wear inside the upper from cam pin drag?
I had wear before the cam pin but since the roller it has not gotten any worse. Next time I am really cleaning the upper I will hit the wear mark with some aluminum black and see if that wears off. I am going to build another piston upper on a new receiver and I will report back on that.
So far I think these are a definite product improvement in the platform.
IPSC_GUY
SIERRA II ALPHA
It should enhance the performance and only improves on the square part that is there expected to act in a free flowing way- rolls better with wheels, put square tires on your car and see how that inproves the performance, Frank has some really great engineering concepts- out
I'm running one in an 11.5" BCM and have had no issues. It does seem to smooth the action.
I'm running one in an 11.5" BCM and have had no issues. It does seem to smooth the action.
+1, this is my set up as well....
I run rollers in ALL of my piston uppers (4-5 Adams Arms, 14.5" to 7.5", 5.56 and 300BLK) in NFA FA use and SBR/Pistols. Also do same in .308 (Sig 716 Rifle/Pistol).
No issues in any and round count (total of all) is in the 5-10k.
I generally install the POF in the upper BCG when first cleaning/lubing a new upper...
No wear seen on upper cam pin channels (but I do clean my uppers after about 500 rounds generally)
I have NOT installed (but have) a relieved gas key for a DI upper. I would use this first on a 7.5 upper (has an adjustable gas block, syrac) but even with proper gas setting, the short upper (port position) gives a violent bolt operation. The roller would likely assist that during extraction (and perhaps reduce the required gas a bit).
Just my experience
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