View Full Version : Cam-pin wear as a contributor to bolt failure?
Does the wear of the cam-pin contribute to bolt failure at the cam-pin hole? I have noticed that cam-pins quickly wear to the point where a fingernail can catch in the wear on the side. Does this peening/wear remove metal from it in such a way as to create more slop and allow more impact/ "running start" for things and end up costing bolt life, if the cam-pin hole is to fail before the lugs in that instance?
Robb Jensen
07-03-13, 06:26
I find that it does. I put a mark on my cam pins so that their always installed in the same direction and replace them every 3K rounds or more often if they're getting really beat up before that time. I haven't broken a bolt since doing that for the last 5yrs. Since I've been shooting ARs I've broken 8 bolts.
Littlelebowski
07-03-13, 07:05
I find that it does. I put a mark on my cam pins so that their always installed in the same direction and replace them every 3K rounds or more often if they're getting really beat up before that time. I haven't broken a bolt since doing that for the last 5yrs. Since I've been shooting ARs I've broken 8 bolts.
That's pretty smart, Robb. I might need to swing by and see how you did this.
Interesting. I don't do this and have never broken a bolt. :confused:
If I'm reconfiguring a BCG and notice a ratty looking cam pin, I'll rotate it out... but never pay too much attention...
In fact... I intentionally try to keep the cam pin rotating to spread the galling evenly on both sides. :p
I started noticing some excessive wear on my BCM BCG's cam pin.
I have a new one on the way from BCM. I think its mostly from lack of lube(used to be AR illiterate). It gets greased like a pig now. :D
I started noticing some excessive wear on my BCM BCG's cam pin.
I have a new one on the way from BCM. I think its mostly from lack of lube(used to be AR illiterate). It gets greased like a pig now. :D
I used to run grease on my cam pins... I never saw that it stopped that wear. I just dry to have the whole area wet with Froglube and don't think about it anymore.
This also bares mention. I can feel wear on a normal cam-pin at around the 2-300 round mark, it catches a fingernail. I have also gotten some experience with the Rubber City Armory product. The QPQ'ed treatment seems to make the cam-pins much more wear resistant. This might be instrumental in bolt-life of that system.
Further, have you noted that cam-pins which fit tighter in a bolt result in longer bolt-life?
After reading this thread I am replacing my cam pin with 10K rounds worth of wear on it.
You can buy a chromed cam pin and not worry.
You can buy a chromed cam pin and not worry.
Has this been shown statistically to matter?
I used to run grease on my cam pins... I never saw that it stopped that wear. I just dry to have the whole area wet with Froglube and don't think about it anymore.
:( but this is super slick 0 friction super snake grease
Has this been shown statistically to matter?
I doubt it. Bolts generally last three barrels anyway.
The chromed ones I bought at Camp Perry don't gall, though. They may have been from DPMS. I bought them on Commercial Row.
If you want to consistently orient a standard cam pin you can use something like an engraving pencil and mark it with an arrow pointing toward the muzzle.
:( but this super slick 0 friction super snake grease
Grease works good there. I just got sick of having to lube with two different products.
Grease works good there. I just got sick of having to lube with two different products.
Ya I know.
My other profession is automotive. Since my work and "gun area" share the same space in my home, I figured why use more products than I have to. Grease and motor oil have been working very well for me. It's crazy smooth when I rack my carbine.
Besides a dedicated tube of Lucas red and tacky and a qt of royal purple SAE 30 will last forever! And I can use it on my truck in a pinch. What's not to like?
I don't have many rounds through my LMT enhanced carrier (+/-800 rds) but I'll be curious to see how it wears compares to my BCM BCG cam pin after a few thousand rounds.
I would say theoretically it should wear less because of the shallower track.
-Jax
Note to self: pick up some extra cam pins. Some rifles seem to be harder on cam pins than others. Why is that?
I have noticed that cam-pins quickly wear to the point where a fingernail can catch in the wear on the side.
I think you'll find that cam pin lash is the primary cause of the wear. The TDP spec for the cam pin diameter and the hole in the bolt are nearly the same. To speed production and reduce returns, most manufacturers make the hole in the bolt to big and the pin to small.
When the pin is too small and the hole to large, the unlocking force isn't lateral to rotation of the bolt and the pin rocks in the bolt hole. This leads to impact between the carrier and cam pin.
I'm not sure if the ledge that is created is a result of loss of material due to wear or if the carrier is "hammer forging" the area of cam pin that contacts the carrier to a smaller dimension.
patrick sweeney
07-03-13, 13:38
My bet is that the cam pin has been swaged, and that once the surface area moved increases to support the load, the metal movement stops.
I also don't see it as a problem. The carrier is harder than sin, it won't swage/change. the cam pin swages until it supports the load, then metal movement stops.
I toss such-ridged cam pins when they too bad simply because cam pins are cheap, and I can.
The tolerance stop is more likely a cause of bolt breakage, and the cam pin wear is just a symptom.
Doc Safari
07-03-13, 15:08
It would be nice if someone with long-term experience in this could post a pic or two of a cam pin that is in need of replacement. I never really got into logging the number of rounds or anything so it would be helpful to have a visual image of a bad pin.
It would be nice if someone with long-term experience in this could post a pic or two of a cam pin that is in need of replacement. I never really got into logging the number of rounds or anything so it would be helpful to have a visual image of a bad pin.
I would like to see this as well. I've seen a cam pin with 125 rounds that looks worse than another that has about 1000 rounds.
Ya I know.
My other profession is automotive. Since my work and "gun area" share the same space in my home, I figured why use more products than I have to. Grease and motor oil have been working very well for me. It's crazy smooth when I rack my carbine.
Besides a dedicated tube of Lucas red and tacky and a qt of royal purple SAE 30 will last forever! And I can use it on my truck in a pinch. What's not to like?
Yeah, same deal, only with the addition of 20W50 Lucas for out ludicrously balls-hot days if I need something that kinda does both.
notice the wear on a brand new BCM BCG after about 500 rnds, just been rotating it after everytime i shoot a match. does seem to have spread the wear out. but if anybody wants a cam pin will trade for 40 lbs of H322:sarcastic:I've been using EWL 30 weight, really like the fact that it stays in place on hot day's(90+) and does'nt gum up in the cold(-15 with wind chill)
I think you'll find that cam pin lash is the primary cause of the wear. The TDP spec for the cam pin diameter and the hole in the bolt are nearly the same. To speed production and reduce returns, most manufacturers make the hole in the bolt to big and the pin to small.
When the pin is too small and the hole to large, the unlocking force isn't lateral to rotation of the bolt and the pin rocks in the bolt hole. This leads to impact between the carrier and cam pin.
I'm not sure if the ledge that is created is a result of loss of material due to wear or if the carrier is "hammer forging" the area of cam pin that contacts the carrier to a smaller dimension.
I think this is the biggest culprit right here. Loose fitting pins.
I think this is the biggest culprit right here. Loose fitting pins.
My Daniel Defense BCG cam-pin was 0.001" or so (I forget, but there was a spec difference when I mic'ed it, extremely small difference) larger than the RCA cam-pin, and I could feel with my hands slightly more movement in the RCA setup, yet it delivered less wear, which is to say, no wear vs. catching my fingernail.
Okay, I'm finding tons of good info about the cam pin along with pics using the search button.
BufordTJustice
07-03-13, 23:48
I use an NiB cam pin in my LMT E-carrier and LMT std bolt. Some finish wear at the 3,700 round mark but no gouging yet. Nothing catches on my finger nail. I can't remember if I snagged it at Spikes (They're local to me) or if it's an LWRCi. I suspect it's Spikes.
The cam pin always fit virgin-tight in my LMT bolt. When I first got the pin, it wouldn't go in the bolt without grease using finger pressure alone. Greased and it slid in...haven't really thought about it since.
I dunno if I would go with HC since it has been more abrasive in texture in my experience.
This thread needs a gnarly cam pin pic...
http://i82.photobucket.com/albums/j248/87228/campin006.jpg (http://s82.photobucket.com/user/87228/media/campin006.jpg.html)
Robb Jensen
07-04-13, 07:29
My bet is that the cam pin has been swaged, and that once the surface area moved increases to support the load, the metal movement stops.
I also don't see it as a problem. The carrier is harder than sin, it won't swage/change. the cam pin swages until it supports the load, then metal movement stops.
I toss such-ridged cam pins when they too bad simply because cam pins are cheap, and I can.
The tolerance stop is more likely a cause of bolt breakage, and the cam pin wear is just a symptom.
I agree Patrick. I don't have many of them but I do find that cam pins that are nickel-boron'd or hard chrome typically last 3-4 times longer. I'd like to pick up one of those RCA (Rubber City Armory) BCGs to see how having a nitrided bolt, carrier, cam pin and firing pin all hold up together.
On my BCM BCG the cam pin measures .3105". The bore in the bolt measures .312 on the insertion side.
On my BCM BCG the cam pin measures .3105". The bore in the bolt measures .312 on the insertion side.
My RCA cam-pin measures 0.310. I did not measure the hole in the bolt because I don't trust my calipers and skill to correctly measure it to that close of a tolerance.
PA PATRIOT
07-04-13, 11:21
Been using the below in my Piston and DI guns and so far no issues what so ever.
http://www.emergingtacticalsolutions.com/images/128911272872269344802.jpeg
Reduces friction and drag of the bolt carrier.
The roller cam pin rolls as the action moves.
The roller cam pin NP3 coated and the body is
Mil-spec hard chrome plated. This allows the pin to operate without the need to lube.
This product is designed for Gas Piston guns. For use on a direct impingement AR system,
I agree Patrick. I don't have many of them but I do find that cam pins that are nickel-boron'd or hard chrome typically last 3-4 times longer. I'd like to pick up one of those RCA (Rubber City Armory) BCGs to see how having a nitrided bolt, carrier, cam pin and firing pin all hold up together.
But, is the cam pin made to be slightly softer than the carrier and bolt, allowing it (the cheaper part) to take the abuse of firing? If you change to a cam bolt having a greater hardness, then another part would have to carry that load. What does the TDP say?
Robb Jensen
07-04-13, 11:47
But, is the cam pin made to be slightly softer than the carrier and bolt, allowing it (the cheaper part) to take the abuse of firing? If you change to a cam bolt having a greater hardness, then another part would have to carry that load. What does the TDP say?
I've thought of that. Originally the cam pin was probably meant to be softer than both the bolt and carrier. "Make the cheapest part wear out first" this is 50's-60's technology...metallurgy has come a long way.
I have a RCA BCG one the way and will run the shit out of it to see if it makes any difference having the bolt, cam pin & carrier equal in hardness.
My theory which seems to be working is keeping the cam pin fit tight keeps extra movement/sloppier fit of the bolt to the carrier and barrel extension seems to promote longer bolt life. No different than changing the timing belt in your car before it breaks and you have engine failure.
I've thought of that. Originally the cam pin was probably meant to be softer than both the bolt and carrier. "Make the cheapest part wear out first" this is 50's-60's technology...metallurgy has come a long way.
I have a RCA BCG one the way and will run the shit out of it to see if it makes any difference having the bolt, cam pin & carrier equal in hardness.
My theory which seems to be working is keeping the cam pin fit tight keeps extra movement/sloppier fit of the bolt to the carrier and barrel extension seems to promote longer bolt life. No different than changing the timing belt in your car before it breaks and you have engine failure.
It will be interesting to see how your experiment works out. In the meantime I'm gonna change out my cam pin when it begins to look "ratty". I think I will stick with Colt parts if I can find them.
But, is the cam pin made to be slightly softer than the carrier and bolt, allowing it (the cheaper part) to take the abuse of firing? If you change to a cam bolt having a greater hardness, then another part would have to carry that load. What does the TDP say?
There is more than likely several material considerations in addition to hardness such as yield strength, impact resistance and wear resistance. Simply questioning the hardness is oversimplifying the relationship between parts. 41L40 alloy steel is most effective hardened to C34 and has a yield strength of 85,000 psi with moderate wear and impact resistance. 4150 alloy steel hits its prime a C63, nearly twice as hard as 41L40. Yet only has a yield strength of 48,000 psi with virtually none of the impact resistance of 41L40 although wear resistance is similar.
I've thought of that. Originally the cam pin was probably meant to be softer than both the bolt and carrier. "Make the cheapest part wear out first" this is 50's-60's technology...metallurgy has come a long way.
Given the 50's-60's design considerations were for a rifle length gas system...
I agree that is was more than likely designed to be softer. How much softer is the question. I think another question to ask is how much the wear is exacerbated by a carbine length gas system, excessively large gas ports and suppressors.
RSilvers was noodling an S2 tool steel cam pin. I'd be curious to know if they (AAC) ever prototyped one and what the results were...
"There is more than likely several material considerations in addition to hardness such as yield strength, impact resistance and wear resistance. Simply questioning the hardness is oversimplifying the relationship between parts. 41L40 alloy steel is most effective hardened to C34 and has a yield strength of 85,000 psi with moderate wear and impact resistance. 4150 alloy steel hits its prime a C63, nearly twice as hard as 41L40. Yet only has a yield strength of 48,000 psi with virtually none of the impact resistance of 41L40 although wear resistance is similar."
Exactly, and this is why I wonder what the TDP says about this particular part. It also makes me think that staying with the same company (Colt) is much safer than buying parts from others who make them from other materials-materials that might compromise other components of the carbine system.
Does anyone know the mil spec diameters and tolerance of the cam pin and hole in the bolt?
BufordTJustice
07-04-13, 14:50
I've thought of that. Originally the cam pin was probably meant to be softer than both the bolt and carrier. "Make the cheapest part wear out first" this is 50's-60's technology...metallurgy has come a long way.
I have a RCA BCG one the way and will run the shit out of it to see if it makes any difference having the bolt, cam pin & carrier equal in hardness.
My theory which seems to be working is keeping the cam pin fit tight keeps extra movement/sloppier fit of the bolt to the carrier and barrel extension seems to promote longer bolt life. No different than changing the timing belt in your car before it breaks and you have engine failure.
You rock, Robb. Thx for blowing your own money so we all can learn and benefit.
Here some of you with the more intense questions are...
http://i40.tinypic.com/2e4jfp4.jpg
http://i43.tinypic.com/3127j2f.jpg
Couple of questions:
Due to the thickness of hard chrome plating (up to .003" for wear properties), Wouldn't a cam pin have to be machined smaller than spec to allow for buildup into tolerance? Simply plating a "stock" cam pin should cause the pin to be too big for the bolt bore.
Hard chrome is around 63 Rockwell C scale. There are newer aerospace coatings that are over 90 Rockwell C scale. I believe they are currently being tested on some fire control parts for crew served weapons and yielding good results.
Nitriding (Salt Bath) is done at temperatures over 1,000 degrees F. Mil-Spec bolt carriers are heat treated at 850F degrees for one hour, then drawn at a temp of 350-375 degrees for at least one hour.
When a carrier is nitrided, the heat treat temp is breached. Would this not soften the carrier's specified hardness case depth of .010-.015"?
The carrier may be hard on the surface, but actually softened below the surface...
Couple of questions:
Due to the thickness of hard chrome plating (up to .003" for wear properties), Wouldn't a cam pin have to be machined smaller than spec to allow for buildup into tolerance? Simply plating a "stock" cam pin should cause the pin to be too big for the bolt bore.
Hard chrome is around 63 Rockwell C scale. There are newer aerospace coatings that are over 90 Rockwell C scale. I believe they are currently being tested on some fire control parts for crew served weapons and yielding good results.
Nitriding (Salt Bath) is done at temperatures over 1,000 degrees F. Mil-Spec bolt carriers are heat treated at 850F degrees for one hour, then drawn at a temp of 350-375 degrees for at least one hour.
When a carrier is nitrided, the heat treat temp is breached. Would this not soften the carrier's specified hardness case depth of .010-.015"?
The carrier may be hard on the surface, but actually softened below the surface...
I doubt most hard chrome is more than a mil . At three mils, the manufacturer would have to account for thickness.
The nitriding process could be gaseous ferritic nitrocarburizing which is done at a much lower temperature.
I doubt most hard chrome is more than a mil . At three mils, the manufacturer would have to account for thickness. Hard chrome applied for corrosion resistance is usually flash applied around .0008"-.0012" thick... Hard chrome applied for wear resistance is .0025"-.003" thick.. An application of .003" for wear resistance would actually grow a cam pin by .006".. .003" for "each" side.. I have a hard chromed BCG that has an average coating thickness of .0028". It pretty much had to be machined "small" to coat into tolerance..
The nitriding process could be gaseous ferritic nitrocarburizing which is done at a much lower temperature.
The Gas Nitriding I am familiar with is done no lower than 950 degrees F which is still above the carrier heat treat temp. It also does not yield a final surface hardness as hard as a salt-bath process (bacically "Meloniting") Do you have any info on a low temp process that I could research?
Very interesting info in this thread for sure!! Thanks for the dialogue MK18Pilot!
Have one cam pin with the contact area now mirror polished from wear, but no sign of ridges, etc. I'm assuming GTG until ridges develop. Will try to get a pic.
---sent from my PRC-104 using phonetics
Brownells already carries boron nitrided cam pins for $10 each.
http://www.brownells.com/userdocs/products/p_100009957_1.jpg
Brownells already carries boron nitrided cam pins for $10 each.
And hard chromed for $22 (http://www.brownells.com/rifle-parts/bolt-parts/bolt-hardware/bolt-pins/ar-15-m16-cam-pin-prod41508.aspx):
Here's the link to the NIB-X pin (http://www.brownells.com/rifle-parts/bolt-parts/bolt-hardware/bolt-pins/ar-15-nib-x-coated-cam-pin-prod54544.aspx) referenced earlier
Wonder if there is any downside to the hard chroming? IE: making it hard when it should be tougher/more ductile by design?
Heavy Metal
07-06-13, 22:05
I'd rather have the Boron Nitride over the Chrome if they were the same price. At $12 less, it's a no-brainer.
Boron Nitride is harder and slicker.
I'd rather have the Boron Nitride over the Chrome if they were the same price. At $12 less, it's a no-brainer.
Boron Nitride is harder and slicker.
I'm thinking for $10 I'm going to grab a couple to keep on hand. Good find, just hope the metallurgy is not an issue!
texasgunhand
07-06-13, 23:41
This thread needs a gnarly cam pin pic...
http://i82.photobucket.com/albums/j248/87228/campin006.jpg (http://s82.photobucket.com/user/87228/media/campin006.jpg.html)
I have never seen a pin like that, wow. must have a bunch of rounds on that one...
sinlessorrow
07-06-13, 23:52
I have generally found that bolts break at the lugs before they do at the cam pin hole.
I have generally found that bolts break at the lugs before they do at the cam pin hole.
It is my opinionion that they do so because of radial forces. Lower coefficient of friction would lessen radial stress, all other things being equal. QPQ offers this. I'm anxious to see Robb's impression of the RCA bcg I sold him.
sinlessorrow
07-07-13, 00:02
It is my opinionion that they do so because of radial forces. Lower coefficient of friction would lessen radial stress, all other things being equal. QPQ offers this. I'm anxious to see Robb's impression of the RCA bcg I sold him.
Even then your still talking bolt life equal to barrel life.
Even then your still talking bolt life equal to barrel life.
It depends on accuracy standards as well as the round. Further, will it fracture at 2500, or 25000? Better is better, is my point.
Three barrels to a bolt is a proven rule of thumb. After that it's a crap shoot.
Fatigue usually leads to something giving (usually a lug, then fracturing through the cam pin hole).
Three barrels to a bolt is a proven rule of thumb. After that it's a crap shoot.
Fatigue usually leads to something giving (usually a lug, then fracturing through the cam pin hole).
Bolts typically last 75-100K rounds? Why is this even an issue, then, what with KAC and LMT making such a big deal out of their "better" bolts? Might as well talk about lining a gas-key with inconel or something. :confused:
Nope, between 7,500 and 15,000 rounds a bolt.
No machine lasts forever. It can go a damn sight farther with preventative maintenance.
Most readers of this forum have absolutely no idea when their parts are due to fail by historical record. Most will never shoot out a single barrel nor change their hammer and trigger springs.
Wondering how many rounds a bolt or cam pin will take is strictly an academic exercise and OCD taking charge.
Nope, between 7,500 and 15,000 rounds a bolt.
No machine lasts forever. It can go a damn sight farther with preventative maintenance.
I don't run my stuff too hard I guess, but I expect more than 2500-5000 rounds from my barrels. More like 20-30,000 at a minimum before they lose enough accuracy for me to not have a use for them beyond making noise.
For a precision gunner we'll usually change barrels around 3,000 to 5,000 rounds depending on what you expect down range.
For belly-button to 100 yards you could go 10,000 to 20,000 rounds a barrel -- the gun still goes bang. If you're aiming at an IPSC or E-type you could be giddy happy.
You won't notice your bullets make 6 minute or bigger groups past 300 to 500 yards if you never shoot that far. You MIGHT notice if you see your bullets are key-holing at close range.
I have never seen a pin like that, wow. must have a bunch of rounds on that one...
Negative. This was my pre-M4C educated rifle, and it only had approx 800 rounds of 223 down the pipe. It was a grossly overgassed RRA mid-length upper on an improperly made Ameetec lower. It had an improperly made Ameetec carbine buffer in it. I replaced the cam pin with a BCM, and gave it a H3 buffer and BCM standard spring to calm it down. The BCM cam pin and H3 resulted in much less wear over the next 2k rounds vs the first 800. I can't say if this was due to the H3, the new cam pin, or both.
Then I sold it and bought my SR-15 :D
Negative. This was my pre-M4C educated rifle, and it only had approx 800 rounds of 223 down the pipe. It was a grossly overgassed RRA mid-length upper on an improperly made Ameetec lower. It had an improperly made Ameetec carbine buffer in it. I replaced the cam pin with a BCM, and gave it a H3 buffer and BCM standard spring to calm it down. The BCM cam pin and H3 resulted in much less wear over the next 2k rounds vs the first 800. I can't say if this was due to the H3, the new cam pin, or both.
Then I sold it and bought my SR-15 :D
With only 800 or so rounds fired on that cam pin, I would suspect improper heat treatment or none at all.
Heavy Metal
07-07-13, 12:10
Nevermind
ClearedHot
07-07-13, 12:11
Is there any appreciable difference in wear when using grease on the cam pin instead of oil?
A gunsmith friend of mine swears by wheel bearing grease.
BufordTJustice
07-07-13, 13:19
Is there any appreciable difference in wear when using grease on the cam pin instead of oil?
A gunsmith friend of mine swears by wheel bearing grease.
I actually do this. I use Aeroshell #7 grease smeared lightly on the outside of my NiB cam pin. That has to be part of the reason it has fared so well. I also smear a very thin layer on the bolt carrier bearing rails, sides of the gas key, and the bottom where the hammer rides.
BufordTJustice
07-07-13, 13:22
With only 800 or so rounds fired on that cam pin, I would suspect improper heat treatment or none at all.
Eh....you'd be shocked what an enormous gas port, weak action spring, and way-too-light buffer can accomplish. ;)
I've seen this on low round count Bushies and DPMFS's as well. Which is usually when I begin talking shit about that deputy's rifle being "as good as" a ****ing brick in another several hundred rounds. :D
Cincinnatus
05-11-14, 18:04
Hey, Robb:
Any word on how the Rubber Armory BCG and cam-pin held up?
I find that it does. I put a mark on my cam pins so that their always installed in the same direction and replace them every 3K rounds or more often if they're getting really beat up before that time. I haven't broken a bolt since doing that for the last 5yrs. Since I've been shooting ARs I've broken 8 bolts.
How I mark mine (secured in a small vice & v-block) with a small Swiss triangular file:
http://i1357.photobucket.com/albums/q759/D_A_Lutz/campinwitness_zpsdf83480c.jpg (http://s1357.photobucket.com/user/D_A_Lutz/media/campinwitness_zpsdf83480c.jpg.html)
That looks nice.
I usually just hit them in the same spot with the center punch.
It's not real pretty, but I'm sure Markm would approve.
BufordTJustice
05-18-14, 10:48
That looks nice.
I usually just hit them in the same spot with the center punch.
It's not real pretty, but I'm sure Markm would approve.
Yeah, that's what I do. Faster and easier.
However, I have found that using good moly grease or the new Redline synthetic assembly lube (4 oz grease tub) has greatly slowed cam pin wear in my LMT enhanced carrier using an NiB cam pin.
Sent from my SPH-L720T using Tapatalk
Robb Jensen
05-18-14, 14:32
Hey, Robb:
Any word on how the Rubber Armory BCG and cam-pin held up?
After coming down with chronic Lyme disease and Bartonella last year I've stopped competing/training. I've just recently started rec. shooting again. The Lyme now seems to be in remission but still have Bartonella symptoms but much less than before and I have adrenal fatigue.
BufordTJustice
05-18-14, 16:33
After coming down with chronic Lyme disease and Bartonella last year I've stopped competing/training. I've just recently started rec. shooting again. The Lyme now seems to be in remission but still have Bartonella symptoms but much less than before and I have adrenal fatigue.
Damn brother. I hope and pray your recovery is smooth from here on out.
Sent from my SPH-L720T using Tapatalk
After coming down with chronic Lyme disease and Bartonella last year I've stopped competing/training. I've just recently started rec. shooting again. The Lyme now seems to be in remission but still have Bartonella symptoms but much less than before and I have adrenal fatigue.
Man, no good! Get well soon! That's some serious drag.
Cincinnatus
05-18-14, 18:51
After coming down with chronic Lyme disease and Bartonella last year I've stopped competing/training. I've just recently started rec. shooting again. The Lyme now seems to be in remission but still have Bartonella symptoms but much less than before and I have adrenal fatigue.
Sorry you are ill. I hope things improve enough for you to live how you want.
Best regards.
Sorry you are ill. I hope things improve enough for you to live how you want.
Best regards.
Ditto from me man...
I have found H&K 416 cam pins are extremely resistant to wear. I have around 2000 rounds on one setup in particular mated with a full LMT E-BCG and I can barely see any wear at all and can't feel any with my fingernail. Time will tell if it lasts as long as the e-bolt, but so far so good.
That looks nice.
I usually just hit them in the same spot with the center punch.
It's not real pretty, but I'm sure Markm would approve.
;)
Ditto from me man...
I have found H&K 416 cam pins are extremely resistant to wear. I have around 2000 rounds on one setup in particular mated with a full LMT E-BCG and I can barely see any wear at all and can't feel any with my fingernail. Time will tell if it lasts as long as the e-bolt, but so far so good.
I bet that E carrier has a lot to do with that.
Man, no good! Get well soon! That's some serious drag.
Yeah... I thought he'd just had it with all of our crap and quit posting.
Doc Safari
05-19-14, 12:38
I think I may have asked for this in another thread years ago, but here goes:
Could someone, if possible, post a pic of a cam pin that needs to be replaced (judging by the wear)?
Heavy Metal
05-19-14, 13:26
I ruined a Craftsman Center Punch trying to put a witness mark to bias a Bushmaster Cam Pin on a friends carbine. Do you think it might be a tad too fking hard?
Yeah, that's what I do. Faster and easier.
However, I have found that using good moly grease or the new Redline synthetic assembly lube (4 oz grease tub) has greatly slowed cam pin wear in my LMT enhanced carrier using an NiB cam pin.
Sent from my SPH-L720T using Tapatalk
BufordTJustice
05-19-14, 18:15
I ruined a Craftsman Center Punch trying to put a witness mark to bias a Bushmaster Cam Pin on a friends carbine. Do you think it might be a tad too fking hard?
Holy shit. Yeah, I'm gonna stick my neck out and say that's too damn hard.
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Buford, just a spitball, but I was wondering if the round top cam pin(can not remeber manufacturer)would mitigate some of this wear?
Has anyone used this or have info on this idea to lessen the wearing action as opposed to the square head?
BufordTJustice
05-20-14, 07:44
Buford, just a spitball, but I was wondering if the round top cam pin(can not remeber manufacturer)would mitigate some of this wear?
Has anyone used this or have info on this idea to lessen the wearing action as opposed to the square head?
I think that's made by POF to alleviate the rounding of the corner in the cam pin pocket inside the upper. I am not sure that would have any effect on its relationship with the bolt.
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Guys I have some experience with the POF roller cam pins - I really like them. It basically removes the cam pin drag during feeding... It almost feels like the BCG missed picking up a round until you get used to it. So far I can't tell any side effects or unintended consequences from using the roller cam pin.
E-man, did you get the modified key or modify the existing one?
Messing with the gas key is the main reason I hesitate to try the system, plus concern over failure of the rivet, or whatever it is that is the pivot for the roller.
Modified key / roller cam kit. The roller bearing seems solid, I don't see how it could break off.
Thanks for the info. Might try it in the future, once I have nothing else to do, such as shoot, load ammo, dry fire, finish minor repairs on house...
BufordTJustice
05-20-14, 18:36
Guys I have some experience with the POF roller cam pins - I really like them. It basically removes the cam pin drag during feeding... It almost feels like the BCG missed picking up a round until you get used to it. So far I can't tell any side effects or unintended consequences from using the roller cam pin.
How many rounds on it?
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