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Posted: 4/14/2014 2:35:38 PM EDT
[#1]
Quoted:
are there any Bolt cam options other than roller cam for preventing receiver ware? not that i have a problem with the roller cam 3k and still running but are there any 1 pc options out there? Cam Pin wear is a non-issue. If you have a pattern develop it will typically start and stop in the first 1000 rounds on a piston rifle. I have even seen it on DI guns with a high round count (excess of 10,000) as well. |
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Posted: 4/14/2014 4:59:49 PM EDT
[#2]
Bolt spring, to help bolt head alignment. Pmags that are not overloaded, to keep the rounds easily strippable. Rounded bolt head lugs (Hk style), to easily overcome slight bolt head misalignment.
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Posted: 4/14/2014 5:22:34 PM EDT
[#3]
Quote HistoryQuoted:
Rounded bolt head lugs (Hk style), to easily overcome slight bolt head misalignment. http://srcarms.com/wordpress/?page_id=7 |
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Posted: 4/14/2014 8:22:09 PM EDT
[#4]
I was thinking about this very topic. My AA has dug a groove, but has ceased and functions fine. However... it has me thinking... since the cam pin rotates the bolt, if a groove happens in the upper, would this mean that the lugs are not as cleanly disengaging the barrel extension as quickly?... thus maybe causing more drag/wear on the bolt lugs?
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Posted: 4/15/2014 7:16:58 AM EDT
[#5]
Quote HistoryQuoted:
I was thinking about this very topic. My AA has dug a groove, but has ceased and functions fine. However... it has me thinking... since the cam pin rotates the bolt, if a groove happens in the upper, would this mean that the lugs are not as cleanly disengaging the barrel extension as quickly?... thus maybe causing more drag/wear on the bolt lugs? Yes. The rear of the bolt lugs are dragging slightly on the front of the lugs on the barrel extension in a piston rifle. The spring added to the tail of the bolt is supposed to help a little. In a DI setup, the gas is actually pushing/holding the bolt forward at the same time it pushes the carrier rearward causing everything to line up properly before retracting the bolt carrier assembly. |
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Posted: 4/15/2014 12:39:42 PM EDT
[#6]
Quote HistoryQuote HistoryQuoted:
Quoted:
Rounded bolt head lugs (Hk style), to easily overcome slight bolt head misalignment. http://srcarms.com/wordpress/?page_id=7 Pricey  . Do these things really work
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Posted: 4/16/2014 7:21:58 AM EDT
[#7]
didn't a company come out with a rounded carrier cam pin that prevents receiver ware
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Posted: 4/17/2014 3:25:46 AM EDT
[#8]
Colt now has the metal plate in the 6940/6940P rifles to prevent this. Not sure if its on any other models
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Posted: 4/17/2014 1:06:50 PM EDT
[#9]
Mine haven't worn, but how about a little dremel work on the offending part? I'm just cheap that way.
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Posted: 4/18/2014 11:33:10 AM EDT
[#10]
I don't understand the issue OP. Cam pin wear will occur in about every AR/M4/M16. It is fine and nothing to worry about. The rifle will still function it is merely cosmetic.
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Posted: 4/18/2014 11:53:25 PM EDT
[#11]
Quote HistoryQuoted:
I don't understand the issue OP. Cam pin wear will occur in about every AR/M4/M16. It is fine and nothing to worry about. The rifle will still function it is merely cosmetic. maybe cause i just don't want the accelerated ware or aluminum shavings getting in my barrel. I have personally seen the receiver ware caused by the piston upper and i have seen how a roller cam prevented it. but i personally prefer less pcs . I am looking at the improved LRCW cam but it has a $8.95 shipping charge so i am hoping to find a vender that sales it for lower cost shipping or has parts other parts i may want to by to offset the shipping cost. |
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Posted: 4/19/2014 12:03:36 AM EDT
[#12]
Quote HistoryQuoted:
maybe cause i just don't want the accelerated ware or aluminum shavings getting in my barrel. I have personally seen the receiver ware caused by the piston upper and i have seen how a roller cam prevented it. but i personally prefer less pcs . I am looking at the improved LRCW cam but it has a $8.95 shipping charge so i am hoping to find a vender that sales it for lower cost shipping or has parts other parts i may want to by to offset the shipping cost. Quote HistoryQuoted:
Quoted:
I don't understand the issue OP. Cam pin wear will occur in about every AR/M4/M16. It is fine and nothing to worry about. The rifle will still function it is merely cosmetic. maybe cause i just don't want the accelerated ware or aluminum shavings getting in my barrel. I have personally seen the receiver ware caused by the piston upper and i have seen how a roller cam prevented it. but i personally prefer less pcs . I am looking at the improved LRCW cam but it has a $8.95 shipping charge so i am hoping to find a vender that sales it for lower cost shipping or has parts other parts i may want to by to offset the shipping cost. Don't know how much they (POF roller cam) go for, but Amazon has them for $31+ free shipping. |
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Posted: 4/19/2014 3:03:22 AM EDT
[#13]
If your bolt head alignment isn't good and if your mags aren't easily strippable, you'll get that wear even with a roller cam pin. That said, if they are good, you won't get much if any wear even using the standard cam pin.
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Posted: 4/19/2014 2:40:49 PM EDT
[#14]
Quote HistoryQuoted:
maybe cause i just don't want the accelerated ware or aluminum shavings getting in my barrel. I have personally seen the receiver ware caused by the piston upper and i have seen how a roller cam prevented it. but i personally prefer less pcs . I am looking at the improved LRCW cam but it has a $8.95 shipping charge so i am hoping to find a vender that sales it for lower cost shipping or has parts other parts i may want to by to offset the shipping cost. Quote HistoryQuoted:
Quoted:
I don't understand the issue OP. Cam pin wear will occur in about every AR/M4/M16. It is fine and nothing to worry about. The rifle will still function it is merely cosmetic. maybe cause i just don't want the accelerated ware or aluminum shavings getting in my barrel. I have personally seen the receiver ware caused by the piston upper and i have seen how a roller cam prevented it. but i personally prefer less pcs . I am looking at the improved LRCW cam but it has a $8.95 shipping charge so i am hoping to find a vender that sales it for lower cost shipping or has parts other parts i may want to by to offset the shipping cost. Please show me how aluminum shavings are getting into your barrel because I don't believe you. If you clean your rifle after you shoot it even if it did occur it would be a non issue. Eventually the wear would stop at some point. I've shot M16's that are older than me and I've seen no degradation in accuracy. I am still in the mind you are fretting over cosmetics and if that's your prerogative then whatever. |
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Posted: 4/19/2014 4:44:27 PM EDT
[#15]
You are applying a moment to the BCG, skies or not - there will be wear on the receiver, bolt head and, extension lugs. It is inherit to the piston AR design. Honestly, the OP will need to accept that it's normal for these rifles or sell it because there is no way to avoid it. Look at the 6000 rnd HK on Montrala's and you will see all of the above. I was concerned about the bolt lug to receiver extension wear at first but it hasn't increased after initial break in ( a 1080 rnd case of 7N6). Not to be rude, I live with OCD. I understand.
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Posted: 5/4/2014 5:46:28 PM EDT
[#16]
As far as i know the roller cam is the best option. I've seen people replace them on a lot of riles with great success. I've heard of people throwing them on DI guns too
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Posted: 5/4/2014 6:44:54 PM EDT
[#17]
Just to be clear all ARs exibit this wear , even DI systems.
The roller cam pin may have less friction but it still wears on the upper receiver. The best fix is to remove some material off of the standard cam pin on the side facing the upper receiver. However this wear is not detrimental and will stop after a few hundred to a few thousand rounds. Go enjoy your weapons and don't worry about it |
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Posted: 5/4/2014 7:23:02 PM EDT
[#18]
If you can get an LWRC advanced cam pin. I have that plus an advanced combat bolt and an Adams arms bolt spring. Minimal wear in my ic. I also suggest removing the gas rings to reduce friction.
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Posted: 6/19/2014 8:49:07 AM EDT
[#19]
Quote HistoryQuoted:
If you can get an LWRC advanced cam pin. I have that plus an advanced combat bolt and an Adams arms bolt spring. Minimal wear in my ic. Bingo, The answer I was looking for. so is LWRC the only place that sales them? I would like to find a place that sales other generic ar15 parts to combine shipping on one order Thanks |
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Posted: 6/19/2014 12:06:11 PM EDT
[#20]
Quote HistoryQuoted:
If you can get an LWRC advanced cam pin. I have that plus an advanced combat bolt and an Adams arms bolt spring. Minimal wear in my ic. I also suggest removing the gas rings to reduce friction. Other people say to leave the rings in place as they are supposed to help keep the bolt tighter inside the carrier and keep it from being as "floppy." Regarding the bolt spring, PWS uses a spring in their system but Stacey told me it was just to make the rifle easier to put back together and wasn't anything that helped with cam pin gouge. |
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Posted: 6/19/2014 12:09:27 PM EDT
[#21]
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Posted: 6/21/2014 12:48:59 PM EDT
[#22]
Quote HistoryQuoted:
Colt now has the metal plate in the 6940/6940P rifles to prevent this. Not sure if its on any other models Wait.....my current aluminum upper isn't made of metal? 
The cam pin wears a chamfer between the clearance cut and the main race, I don't think it's anything but cosmetic. |
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Posted: 6/23/2014 4:31:59 AM EDT
[#23]
There is always this solution of adding relief cut to upper receiver:
Picture taken after roughly 6000 rounds. Visible patch of wear is only removed anodizing, I did not feel any material removed (using my Finger Sensor 1.0). |
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Posted: 6/23/2014 11:02:11 PM EDT
[#24]
AA already comes with a "relief cut" and still gouges the heck out of the receiver.
This is after only 300 rounds. It has slowed/ceased since that, but still hard to look at. The more I learn about piston AR's, the less I'm impressed with them (and have since added a DI to the stable). No matter how you slice it, a piston AR will place ALL of the recoil force on the front lugs of the barrel extension. A DI PUSHES the bolt forward. As the pressure is still FORWARD on the bolt, with the BCG starting to move backward, THEN it unlocks/turns the bolt (which is why DI's get minimal wear there). However, a piston AR just slams back (no forward pressure on the bolt, and yes, an AA bolt spring is useless as it's nowhere near the pressure of DI's gas) and rips the bolt back, causing it to twist to clear the barrel lugs and then slamming the cam pin into the cutout edge to finish aligning (completing twist) the bolt. The parts may have proven to be able to handle this, but it's NOT a proper way for a rifle action to operate. It took me a while to understand, but now I understand why people say "if you want a piston setup, get one that's been DESIGNED as one from the start". "Conversions systems" may work, but I no longer would trust my life to one. |
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Posted: 6/24/2014 8:58:29 PM EDT
[#25]
No gouging or carrier tilt in my osprey416.On an osprey system the carrier and bolt disengage the extension lugs under their own weight so theres no drag or "ripping" of the bolt lugs from the extension lugs.You can tell how much lug resistence youll get by taking off your upper and angling up see if the bolt falls away from the extension under its own weight and gravity if not you have resistance.
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Posted: 6/25/2014 3:17:01 AM EDT
[#26]
That cam pin wear occurs when the bolt is NOT in battery. Take your bolt group out and align it next to the receiver to see what I mean. That wear occurs due to misalignment between the bolt head and extension when chambering rounds.
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Posted: 6/26/2014 6:44:14 PM EDT
[#27]
Quote HistoryQuoted:
No gouging or carrier tilt in my osprey416.On an osprey system the carrier and bolt disengage the extension lugs under their own weight so theres no drag or "ripping" of the bolt lugs from the extension lugs.You can tell how much lug resistence youll get by taking off your upper and angling up see if the bolt falls away from the extension under its own weight and gravity if not you have resistance. Except slow gravity is a far cry from the force of a piston rod. In a DI AR, they oppose (bolt is pressured FORWARD, while the bcg is pressured backward). This opposite pressure extends the bolt out fully, thus the cam pin is in alignment before it ever passes the cut out. Not so with a piston, as there is no forward pressure on the bolt to fully extend it (which is why most piston AR's smack the cam pin at the edge of the cutout). Since a DI pushes the bolt forward as it turns, it does not drag on the lugs. Piston AR's cannot do this, thus there IS dragging on the lugs. Fortunately, they are built strong enough to seemingly endure it, but it is beyond what the stresses those parts were designed to endure. |
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