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[ARCHIVED THREAD] - Cam pin wear,,, (Page 1 of 2)

Posted: 11/9/2016 10:24:32 PM EDT

Is this normal at 200 rounds? Excuse the stink finger.....

Posted: 11/9/2016 10:30:53 PM EDT

[#1]

Looks normal to me. Just remember to put lube on it.

Posted: 11/9/2016 10:45:55 PM EDT

[#2]

Quote History

Quoted:
Looks normal to me. Just remember to put lube on it.

View Quote

Same. Looks to be fairly normal. And lube, lube, lube.

Posted: 11/9/2016 10:48:16 PM EDT

[#3]

Wouldn't say it's a problem. Mine do look better than that with more rounds on them but I'm using 15w40 semi synthetic engine oil. It costs well and stays on longer than "gun" oils.

Posted: 11/9/2016 11:15:11 PM EDT

[#4]

Looks like all my BCM and colt ones when they were new. Just keep shooting and stock up on them. They're like what a $5 part?

Posted: 11/9/2016 11:37:58 PM EDT

[#5]

Yep.....it's normal

Posted: 11/10/2016 12:15:40 AM EDT

[#6]

It is normal - because it totally depends on the machining of the carrier. I have some that after 2000 rounds still look great, and others that curl up that ridge like you see there. The cam pin takes a lot of abuse. Especially in short carbine gas systems and overgassed guns.

Posted: 11/10/2016 1:18:25 AM EDT

[#7]

Some lubrication recommendations indicate grease for the cam pin. Most BCG's do fine with a good oil, but in your case if your BCG is a little rough on the cam pin, you might consider one of the appropriate Lubriplate gun greases designed for this. I forget the number designation on that particular grease. It's a white grease, and I use it on a couple of places on my AR's, even though I don't think it's always critical.

Posted: 11/10/2016 5:53:52 AM EDT

[#8]

It just looks like this phosphate finish (Parkerizing) has been worn off of the surface. That's purely cosmetic. if so. Even if a ridge is developing, that is normal wear until it gets quite deep. This is where the wear will take place. Keep it well lubed. I agree with poster above that full synthetic motor oil (heavier viscosity) is a good choice.

Posted: 11/10/2016 6:47:09 AM EDT

[#9]

If that is just finish wear, without too much noticeable gouging, then it is perfectly fine.
My main shooter rifles, one with 12k and one with 13k round count have a bit more finish wear than yours, and no issues with gouges

Posted: 11/10/2016 7:05:19 AM EDT

[#10]

The cam pin is a very high stress part. As such, it is always a good idea to have a few spares laying around.

With that said, I always grease mine with some tw25b. It wears like yours but that is perfectly normal. It wears as soon as you shoot it.

Posted: 11/10/2016 7:38:26 AM EDT

[#11]

Mine is almost completely shiny and perfectly smooth. As others have pointed out - lube, lube, and lube some more.

Posted: 11/10/2016 8:41:02 AM EDT

[#12]

The second pic almost looks like ridges are worn in it when you look close

You shouldn't be able to feel them if you drag your fingernail across it

If you can then there is likely a burr on the carrier or bolt

Eta: 1st and 3rd pic, not 2nd

Posted: 11/10/2016 10:07:04 AM EDT

[#13]

is that a gouge or surface polishing?

Posted: 11/10/2016 10:27:16 AM EDT

[#14]

Its a gouge... how should I check for the burr? Just file it down? Its a bcm carrier

Posted: 11/10/2016 10:27:20 AM EDT

[#15]

Quote History

Quoted:
The second pic almost looks like ridges are worn in it when you look close

You shouldn't be able to feel them if you drag your fingernail across it

If you can then there is likely a burr on the carrier or bolt

Eta: 1st and 3rd pic, not 2nd

View Quote

It is totally normal to be able to feel a ridge with your fingernail. It happens on many carriers/cam pins. I guess it depends on how sensitive your fingernail is. These parts wear.

Posted: 11/10/2016 10:27:38 AM EDT

[#16]

Quote History

Quoted:
Its a gouge... how should I check for the burr? Just file it down? Its a bcm carrier

View Quote

Ignore that, and shoot it.

Posted: 11/10/2016 11:52:38 AM EDT

[#17]

I use light grease on the pin. Plastilube.

You should have spares in stock, they're cheap.

Posted: 11/10/2016 12:45:05 PM EDT

[#18]

I'm thinking of ordering a complete bolt, firing pin, and cam from the art store are they're parts gtg?

Posted: 11/10/2016 12:48:38 PM EDT

[#19]

Quote History

Quoted:
I'm thinking of ordering a complete bolt, firing pin, and cam from the art store are they're parts gtg?

View Quote

Thinking you meant Arf???? Haha.

Posted: 11/10/2016 1:49:54 PM EDT

[#20]

Yep arfcom store lol damn autocorrect lol

Posted: 11/10/2016 1:53:27 PM EDT

[#21]

Quote History

Quoted:
Yep arfstore lol damn autocorrect lol

View Quote

We knew what u meant

I do not know anything about them, myself. DsArms and AIM have great bcgs, imo. Also, some Toolcraft on the EE for $100 that I saw. All solid, imo. Dont forget PSA

Edit: just saw new FN bolts on the EE for $69. Race you?.

Posted: 12/7/2016 12:46:49 AM EDT

[#22]

I use graphite moly grease the kind you buy at the auto parts store for Pre start up lube used by engine builders. This stuff is made for metal on metal applications. All seems well. I even use it on pistols.
Also, the POF roller cam pin is a nice addition.

Posted: 12/7/2016 2:57:25 AM EDT

[#23]

Yep, that's a HIGH wear part. I've had good luck with AIM's nitride BCG's (they also nitride the cam pin), as I don't see much wear there. Not sure if they're more prone to snapping later (due to hardness)... but I'll probably never send enough rounds downrange to find out (hopefully there are some long term reviews of nitride cam pins somewhere?). I also use their nitride spare bolt kit (bolt, cam pin, firing pin, and retainer pin) and keep those kits in the grips.

Posted: 12/7/2016 3:25:22 AM EDT

[#24]

Gouging of pin by Colt carrier after a couple hundred rounds.
Colt replaced the carrier under warranty.

Forget filing or stoning. Very difficult to access the area and easy to mess up the carrier.

Posted: 12/7/2016 10:29:35 AM EDT

[#25]

Surface finish wear is no big deal, but I consider eating into the base metal with that few rounds a problem.
I have had that happen a couple of times over the years, I replaced the cam pin and the replacements did not wear like that.
I wrote it off as a less than ideal heat treat, but maybe something got smoothed out.

Posted: 12/10/2016 5:17:18 AM EDT

[#26]

Ouch. Normal for a regular bcg though. Got thousands of rounds on my qpq Azimuth and can't even catch a fingernail on that area though.

Posted: 12/10/2016 9:20:14 AM EDT

[#27]

Quote History

Quoted:
Surface finish wear is no big deal, but I consider eating into the base metal with that few rounds a problem.
I have had that happen a couple of times over the years, I replaced the cam pin and the replacements did not wear like that.
I wrote it off as a less than ideal heat treat, but maybe something got smoothed out.

View Quote

Your right, it is a problem. A problem to easily dismissed as normal by many who have no experience with quality parts.

For those who think its a good idea to use grease on the cam pin, think again.

The OP's cam pin is clearly an inferior part. An out of spec carrier and/or bolt could be a contributing factor but that cam pin is junk.

Posted: 12/10/2016 9:47:00 AM EDT

[#28]

All mine are like that. I started using some Shooters Choice synthetic grease on the cam pin to see if it works better than CLP but haven't shot enough since I switched.

ETA. mine don't have any gouging in the material, just finish wear. I keep a few spares on hand in case one breaks.

Posted: 12/10/2016 10:03:55 AM EDT

[#29]

Quote History

Quoted:

Your right, it is a problem. A problem to easily dismissed as normal by many who have no experience with quality parts.

For who think its a good idea to use grease on the cam pin, think again.

The OP's cam pin is clearly an inferior part. An out of spec carrier and/or bolt could be a contributing factor but that cam pin is junk.

View Quote

I use Rigs grease on the cam pin. Never had an issue. What is there to think about?

Posted: 12/10/2016 10:24:37 AM EDT

[#30]

OP, I'd say every single one of the cam pins in my complete rifles look very similar to yours. The scrapes are NOT deep at all as I pull the carrier and completely disassemble, clean, and inspect each component every 200 rounds, especially the cam pin. On a new rifle/complete carrier I disassemble/inspect it after the first 50 rounds. It's a high stress part as others have said. All my cam pins look like yours pictured does after maybe 50 rounds. Its a result of the cam pin wearing into the bolt carrier cut-out/recess that the cam pin, "cams" in. For the most part its the bearing surfaces simply mating to each other and it is perfectly normal. Now if the gouges in your pics are actually deep enough to cut your finger running over the gouged/scratched area, yeah; then that would be a sign of a problem within only 200 rounds. IMHO, it's fine, lube it with some synthetic motor oil as previously suggested and rock on. I'm 90% sure if you replace that cam pin with a new one it will look very similar to the one in question in 50 rounds or so... I have (4) AR's, two carbines and two mid length gassed rifles. I have 2 extra cam pins for each AR in my parts bin and at least one extra firing pin, firing pin retainer pin and an extra C-158 or 9310 bolt per rifle. Being that the aforementioned parts are the highest stressed in the AR platform it makes a lot of sense to have the spares and to check that cam pin regularly. Good for you for noticing the wear OP and for asking questions/staying atop of it. I probably have 10K rounds thru the (4) said AR's and the cam pins are all fine. I've never needed to replace on yet. But I'll have the spares when that time arrives.

Posted: 12/10/2016 10:55:50 AM EDT

[#31]

Quote History

Quoted:
I use Rigs grease on the cam pin. Never had an issue. What is there to think about?

View Quote

The fact you've never had an issue using grease means nothing other than you don't understand what grease is and more importantly what it isn't.

Grease doesn't become a lubricant until it's been subjected to shear thinning/shear strain. If grease isn't used with seals and/or dust caps, the environment for it to be subject to the process necessary to convert it to the same viscosity as its base oil and become a lubricant doesn't exist.

When used on a bolt group, it doesn't stay in place and it turns into abrasive paste. It's a poor choice for lubricating anything on an AR-15 pattern firearm.

From the Birchwood Casey website:

"A thin film of RIG Universal Gun Grease will help keep your firearms rust-free. One thorough application of RIG Universal Gun Grease inside and out will protect your rifle, handgun, shotgun or muzzleloader against rust and corrosion. RIG Universal Gun Grease is a superior firearm lubricant and preservative."

Tacked on to the end, almost as an afterthought is the word lubricant.

Posted: 12/10/2016 11:46:16 AM EDT

[#32]

I'm sorry but that is not normal. Who could possibly think beyond surface abrasions is normal?

Posted: 12/10/2016 12:27:34 PM EDT

[#33]

Quoted:
Is this normal at 200 rounds? Excuse the stink finger.....
http://i.imgur.com/t1QPuyv.jpg
http://i.imgur.com/53sRAr5.jpg
http://i.imgur.com/t1QPuyv.jpg

View Quote

Yes that is perfectly normal. It is a very high wear part. 10s of 1000s PSI is coming back to cycle bolt and all that's stopping it is that cam pin. No two AR wear in the same but the same parts wear to different degree. I wouldn't exactly listen to folks here about how their AR never had the same problem. That's sort of like two people on the crapper looking at each other's toilet trying to figure out what is normal when you forget to ask why you're comparing crap in the first place?

Posted: 12/10/2016 2:16:13 PM EDT

[#34]

Assuming the cam pin is not soft, that is excessive wear on the front or rear of the pin. There are several things that can cause that. The cam slot in the carrier has 3 basic areas. Upon initial opening movement of the carrier, the first .090-.100 carrier movement does not engage the ramp of the cam slot. This is for carrier momentum. This area also insures that the bolt is full locked before the firing pin can contact the primer. If this part of the slot is too short, the carrier will slam in to the pin. There should not be any wear on the back side of the pin. Second is the ramp area of the slot that rotates the bolt. This area the carrier moves .190-.200 for full rotation. The last area of carrier movement is .050. This is where the gas ports on the side of the carrier dump off the pressure so the cam pin does not beat itself to death. If this area is too short, or the gas ports are too far forward, the pin will show excessive wear and beat itself to death. Actually, the gas ports are located such that the pressure starts to dump off before the bolt fully rotates and unlocks. Momentum takes care of the rest. Large gas ports in the barrel will contribute to this as well. A poorly designed carrier can cause you all kinds of headaches you may never figure out. Enhanced carriers move these dimensions around. I have played around with this a lot. Some things work and some don't. Increasing the length of the rotating area of the slot helps. It is like adding gear ratio to your car. There is only so much you can change . If you extend the bolt too far out of the carrier, the extractor pin can fall out. If you shorten the initial momentum movement, you will be very ammo sensitive. Craig

Posted: 12/10/2016 7:41:18 PM EDT

[#35]

Quote History

Quoted:
I'm sorry but that is not normal. Who could possibly think beyond surface abrasions is normal?

View Quote

I'd say people who actually shoot, and have experience.

Posted: 12/10/2016 9:12:10 PM EDT

[#36]

Quote History

Quoted:

I'd say people who actually shoot, and have experience.

View Quote

Boom, done! OP, below is a pic of my complete BCG with an emphasis on the Cam Pin. I took this pic this afternoon after some of the other posts saying that your Cam Pin wear wasn't normal. Well, it is... This particular BCG and Cam Pin has approximately 2500 rounds thru it. I bought this rifle complete in 2010. I've since built 3 more AR's for myself and seven to eight more for my family and friends. Each rifle of mine has about the same number of rounds thru them as I like to rotate every rifle evenly in the training/shooting schedule. And every one of the Cam Pins are worn exactly as the pic below. That is 2 complete Spikes BCG's, a complete ToolCraft BCG and an AimSurplus 9310. I have (2) other spare bolts and (2) other complete Bolt Carrier Groups that have zero wear on the bolts and no wear on the cam pins either. It is because they have yet to see a round shot thru them yet. I know that within 50 rounds of firing each bolt and Cam Pins will have similar wear in the picture below. The more you shoot the more you are going to see similar wear on engagement surfaces. Hope this helps put your mind at ease. Keep shooting and training!

Posted: 12/10/2016 9:19:56 PM EDT

[#37]

Quote History

Quoted:

I'd say people who actually shoot, and have experience.

View Quote

that's funny, especially so given you know nothing about me or my background

that is not normal by any stretch as there are beyond surface abrasions. Now run along, go play warrior for a weekend and come back when you learn a few things about your weapon

Posted: 12/10/2016 9:30:05 PM EDT

[#38]

Quote History

Quoted:
Surface finish wear is no big deal, but I consider eating into the base metal with that few rounds a problem.
I have had that happen a couple of times over the years, I replaced the cam pin and the replacements did not wear like that.
I wrote it off as a less than ideal heat treat, but maybe something got smoothed out.

View Quote

exactly but too many people here have no idea what they are talking about. OP first pic is clear, it's beyond surface finish wear and with low usage. That is a definite problem and not normal

Posted: 12/10/2016 11:14:04 PM EDT

[#39]

jmreagan,
Your pics look like normal wear. My cam pins look that that as well.
The OP pics look like gouges which I do not consider normal wear. He also states they are gouges.
I would suggest looking for burrs or excessive tool marks to explain this.

Posted: 12/11/2016 2:40:06 AM EDT

[#40]

This is about 2500-3000 rounds, mostly suppressed. If I try really really hard, I could barely feel my findernail hit the wear line on one side as it slid over it.

I get more wear on phosphated cam-pins within the first 250 rounds. They tend to gouge or "groove" as OP's did. Running them in the same carrier, so that's not a variable. Those that don't gouge, will often change profile on the front/back where the large shiny spot is on mine.The metal there is slowly shaved off and they get flat-spotted a bit. Usually in the upper-right part the cam-pin of this photo:

Posted: 12/11/2016 5:45:00 AM EDT

[#41]

My Colt 6920 has about 660 rounds and my cam pin looks just like yours.

Posted: 12/11/2016 8:32:53 AM EDT

[#42]

Quote History

Quoted:
My Colt 6920 has about 660 rounds and my cam pin looks just like yours.

View Quote

Photos?

Posted: 12/11/2016 8:53:20 AM EDT

[#43]

I've only seen one that looks like that. My brand new DPMS GII. Right out of the box it had a chunk of metal curled up on that would snag your skin like any other metal burr. I filed it off and lubed it up good with Mobil 1 and have about 200 rounds through it now with no additional wear seen.

I have one other one with a lot more rounds that has worn the finish off the pin (one of the nitride bolts/carriers I bought 3 or 4 years ago).

I like lots of lube. What the rifle doesn't need, runs out/off. Better to have more on it that it needs. And I clean/relube after every range trip.

Posted: 12/11/2016 11:50:34 AM EDT

[#44]

Quote History

Quoted:
jmreagan,
Your pics look like normal wear. My cam pins look that that as well.
The OP pics look like gouges which I do not consider normal wear. He also states they are gouges.
I would suggest looking for burrs or excessive tool marks to explain this.

View Quote

Yeah, I wasn't ever really able to zoom in too much on the OP's original pics to see exactly how deep the gouges are in his cam pin. They appear normal in his original post. I must have overlooked his re-post stating that they are in fact, deed, deep gouges. There is only one or two things going on here. A. the cam pin isn't made to the standards it should be and it's too soft. Or B. the bolt carrier itself, it's recess where the cam pin "cams", rotates, operates wasn't cut correctly and is causing the excessive and accelerated wear. Or it's a combination of both. My bet is it's an out of spec Bolt Carrier.

Posted: 12/11/2016 12:06:48 PM EDT

[#45]

OP, you got a digital Micrometer laying around??? I'd really like to see exactly how deep your cam pin gouges are. It would be very beneficial to all of us here. I bought a very nice Micrometer off of Amazon for $17 I think it was and it's "Dead on, balls accurate", as Marissa Tomei would put it.

Also OP, please take 3 or 4 nice pics of the stripped bolt carrier recess; one angle from dead top center and the rest from different angles in good lighting for us please. I'll post pics of my heaviest worn carrier and we'll compare to see if in deed your carrier is the culprit.

Posted: 12/11/2016 1:01:01 PM EDT

[#46]

Quote History

Quoted:

I'd say people who actually shoot, and have experience.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
I'm sorry but that is not normal. Who could possibly think beyond surface abrasions is normal?

I'd say people who actually shoot, and have experience.

I just cleaned an M4 clone of mine a few days ago, first time cleaning in 500 or so rounds. It is closing on 2K total, the cam pin in mine does not look anything like that (PSA PTAC ). Sure the cam pin is shiny, the wear seems to be worse on one side than the other, but there are no gouges into the metal, no raised areas. That may be OK with 10K down the pipe, but IME that is not normal.

Posted: 12/11/2016 1:04:18 PM EDT

[#47]

Quote History

Quoted:
This is about 2500-3000 rounds, mostly suppressed. If I try really really hard, I could barely feel my findernail hit the wear line on one side as it slid over it.

http://i68.tinypic.com/15oiazk.jpg

I get more wear on phosphated cam-pins within the first 250 rounds. They tend to gouge or "groove" as OP's did. Running them in the same carrier, so that's not a variable. Those that don't gouge, will often change profile on the front/back where the large shiny spot is on mine.The metal there is slowly shaved off and they get flat-spotted a bit. Usually in the upper-right part the cam-pin of this photo:
http://i66.tinypic.com/ojm0s0.jpg

View Quote

Now that looks about right.

Posted: 12/11/2016 1:09:43 PM EDT

[#48]

Quote History

Quoted:
OP, you got a digital Micrometer laying around??? I'd really like to see exactly how deep your cam pin gouges are. It would be very beneficial to all of us here. I bought a very nice Micrometer off of Amazon for $17 I think it was and it's "Dead on, balls accurate", as Marissa Tomei would put it.

Also OP, please take 3 or 4 nice pics of the stripped bolt carrier recess; one angle from dead top center and the rest from different angles in good lighting for us please. I'll post pics of my heaviest worn carrier and we'll compare to see if in deed your carrier is the culprit.

View Quote

Your killing me Smalls...

Posted: 12/11/2016 1:11:44 PM EDT

[#49]

I guess I am in the minority but your wear seems excessive to me after such a low round count. I pulled open a few of mine that have 2000+ rounds on them and no signs of grooves or indents like that

Maybe I am being mislead by the pics or the lighting - but I would say either something is digging into the pin - or the pin is soft or something.

Posted: 12/11/2016 2:37:11 PM EDT

[#50]

Quote History

Quoted:
The fact you've never had an issue using grease means nothing other than you don't understand what grease is and more importantly what it isn't.

Grease doesn't become a lubricant until it's been subjected to shear thinning/shear strain. If grease isn't used with seals and/or dust caps, the environment for it to be subject to the process necessary to convert it to the same viscosity as its base oil and become a lubricant doesn't exist.

When used on a bolt group, it doesn't stay in place and it turns into abrasive paste. It's a poor choice for lubricating anything on an AR-15 pattern firearm.

From the Birchwood Casey website:

"A thin film of RIG Universal Gun Grease will help keep your firearms rust-free. One thorough application of RIG Universal Gun Grease inside and out will protect your rifle, handgun, shotgun or muzzleloader against rust and corrosion. RIG Universal Gun Grease is a superior firearm lubricant and preservative."

Tacked on to the end, almost as an afterthought is the word lubricant.

View Quote

You're so FOS. Grease as a lubricant absolutely works just fine on a bcg or any other two surfaces sliding past one another.

It doesn't cease to be a lubricant just because it isn't used in a sealed environment.

Heavier lubricants have been shown to increase reliability in the m16 family of rifles. As to the use of grease, Ken Hackathorne among others continue to use. I'll defer to their experience.

[ARCHIVED THREAD] - Cam pin wear,,, (Page 1 of 2)

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