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Posted: 10/13/2009 2:52:58 PM EDT
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I was cleaning and testing out my 16" M4 when I noticed the bolt was rather loose in the bolt carrier, but not loose enough to fall out on its own weight. Curious, I decided to swap bolts from my 24" AR to see if its just a loose carrier. I found the 24" AR bolt to be a tight fit, so I measured the gas rings from the 16" (I should have done this first) and mic'd them at 0.500-0.503". According to my notes, the gas rings should measure greater than 0.503" in diameter. The 16" M4 has only 3700 rounds through it, is this kind of early to wear out the gas rings? |
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Take the carrier with the bolt, extend the bolt without removing the bolt key, or firing pin. With the bolt extended place it downwards on a table. If the bolt withdrwaws into the carrier, replace the rings. If the bolt stays extended, your rings still have life. |
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Thanks for the link to the 23P TM. I had that before but I never understood why I didn't check it. I have this AR15 binder with about 300 pg of notes and printouts. In my notes, I wrote down "gas ring OD > 0.503" for some reason. I must have gotten that from Tweak or someone else here, but I measured those rings and one was at 0.503", the others were 0.500 or 0.490" The new rings were easily 0.530" or so. |
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I had a ring bind up the works at the range, here's what it looked like.
http://i165.photobucket.com/albums/u42/jmsstnr/AR15bolt.jpg |
My rifle fails the carrier weight test, but not the bolt under it own weight test. The rifle is a 5.45 upper from S&W, guess this baby eats rings faster than my 5.56 upper, I only have 1050rnds through the 5.45 upper But actually the russian ammo, comes in 1080rnd cans, so I'll just replace the rings every new can I bust open
Oh well, cheap parts to replace..... |
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I'm surprised that no one has mentioned McFarland gas rings. See http://www.midwayusa.com/viewproduct/?productnumber=163933 They seem to wear better than standard rings and don't present the chance that the gaps in the rings might line up. Wish they'd be offered to fit 308 bolts, too, since they work just fine on my AR's. Quoted: I was cleaning and testing out my 16" M4 when I noticed the bolt was rather loose in the bolt carrier, but not loose enough to fall out on its own weight. Curious, I decided to swap bolts from my 24" AR to see if its just a loose carrier. I found the 24" AR bolt to be a tight fit, so I measured the gas rings from the 16" (I should have done this first) and mic'd them at 0.500-0.503". According to my notes, the gas rings should measure greater than 0.503" in diameter. The 16" M4 has only 3700 rounds through it, is this kind of early to wear out the gas rings? |
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Quoted: wow, never seen a ring bind up like that. Would it be possible to run the rifle on two, or would the remaining two be to loose to seal the gas off? I have seen a rifle run with only 2 gas rings; however, who knows how long it would have continued to cycle properly after we discovered that one was missing. This is exactly why I keep a spare bolt stored on the rifle in the grip, along with a spare set of rings. They're cheap and light enough that you should have a few sets on hand for each rifle. |
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Quoted:
I'm surprised that no one has mentioned McFarland gas rings. See http://www.midwayusa.com/viewproduct/?productnumber=163933 They seem to wear better than standard rings and don't present the chance that the gaps in the rings might line up. Wish they'd be offered to fit 308 bolts, too, since they work just fine on my AR's. Quoted:
I was cleaning and testing out my 16" M4 when I noticed the bolt was rather loose in the bolt carrier, but not loose enough to fall out on its own weight. Curious, I decided to swap bolts from my 24" AR to see if its just a loose carrier. I found the 24" AR bolt to be a tight fit, so I measured the gas rings from the 16" (I should have done this first) and mic'd them at 0.500-0.503". According to my notes, the gas rings should measure greater than 0.503" in diameter. The 16" M4 has only 3700 rounds through it, is this kind of early to wear out the gas rings? I bought 2 extra McFarland 1 piece rings, to replace mine when they finally go. I would love to put a back up bolt in the MIAD grip, but I haven't found a good back-up 5.45 bolt. |
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Quoted:
They seem to wear better than standard rings and don't present the chance that the gaps in the rings might line up. Wish they'd be offered to fit 308 bolts, too, since they work just fine on my AR's. The ring end gap wives tale rears its ugly head again. If your rifle is otherwise functioning properly, your rifle will cycle perfectly with the end gaps lined up. The only time there is a gap is when the bolt has been removed from the carrier. Quoted:
I was cleaning and testing out my 16" M4 when I noticed the bolt was rather loose in the bolt carrier, but not loose enough to fall out on its own weight. Curious, I decided to swap bolts from my 24" AR to see if its just a loose carrier. I found the 24" AR bolt to be a tight fit, so I measured the gas rings from the 16" (I should have done this first) and mic'd them at 0.500-0.503". According to my notes, the gas rings should measure greater than 0.503" in diameter. The 16" M4 has only 3700 rounds through it, is this kind of early to wear out the gas rings? I didn't know an M4 (R0920) was manufactured with a sixteen inch barrel. I would love to see pictures of it. How did you get your hands on a post May select fire machinegun? Take the BCG out of your rifle. Fully extend the bolt and stand the BCG on the table bolt down. If the BCG does not collapse on itself, your rings are fine. With proper cleaning and lubrication, your rings will last a long time unless you have an aftermarket carrier that was not finished and chromed properly. |
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I'm not the only one that refers to it as a 16" M4: From AIM: DD-BHF Daniel Defense 16" M4 Profile Hammer Forged Chrome Lined Barrel
Item#DD-BHF New Daniel Defense 16" M4 Profile Cold Hammer Forged Chrome Lined Barrel. Features 4150 MP Tested Steel Construction. 1:7 Twist. 1/2x28mm Muzzle Thread. |
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Quoted:
Quoted:
wow, never seen a ring bind up like that. Would it be possible to run the rifle on two, or would the remaining two be to loose to seal the gas off? I have seen a rifle run with only 2 gas rings; however, who knows how long it would have continued to cycle properly after we discovered that one was missing. This is exactly why I keep a spare bolt stored on the rifle in the grip, along with a spare set of rings. They're cheap and light enough that you should have a few sets on hand for each rifle. That's one of the reasons for the weight test. If one of your rings fail, the other two should handle the job for a while. Has any one, had or know why gas rings would fail @ 500 rounds???? When i was at 300 it would colapse halfway, at 500 all the way. I replaced them with Colt rings, and will see what happens. FYI was a new rifle, RRA Entry Tactical. |
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Quoted:
Quoted:
Quoted:
wow, never seen a ring bind up like that. Would it be possible to run the rifle on two, or would the remaining two be to loose to seal the gas off? I have seen a rifle run with only 2 gas rings; however, who knows how long it would have continued to cycle properly after we discovered that one was missing. This is exactly why I keep a spare bolt stored on the rifle in the grip, along with a spare set of rings. They're cheap and light enough that you should have a few sets on hand for each rifle. That's one of the reasons for the weight test. If one of your rings fail, the other two should handle the job for a while. Has any one, had or know why gas rings would fail @ 500 rounds???? When i was at 300 it would colapse halfway, at 500 all the way. I replaced them with Colt rings, and will see what happens. FYI was a new rifle, RRA Entry Tactical. i got a young man bolt carrier in my yhm carbine with app. 450 rds on her after cleaning the bolt ,did the bolt test it collapsed too ok what is app. ring life of the carbine ? back in the day before the carbine out rings lived to 2500 rds before r&r whats this one??? |
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My bolt would not do this when brand new, with 0 rounds through it. It has never had a malfunction. Quoted:
Take the carrier with the bolt, extend the bolt without removing the bolt key, or firing pin. With the bolt extended place it downwards on a table. If the bolt withdrwaws into the carrier, replace the rings. If the bolt stays extended, your rings still have life. |
| I broke a ring at a 3gun match last month and put a McFarland in. This was my 3gun match rifle that ate everything wolf, brown bear you name it. With the McFarland I started having short stroke issues and the recoil pulse felt weak with the cheap steel case stuff. Today I put a set of standard 3 rings in and it eats everything and felt normal. I've got 2 sets of McFarland new in the package that will be trashed now. |
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I've read the entire thread and have a question as a somewhat new AR owner.
How do you replace the rings? I have a few sets of the McFarland that came from Brownell's yesterday and want to replace the damaged set on my SBR bolt. Getting the old ones off isn't an issue, but do you just expand the new ones and force them on? Is there a preferred technique? Thanks. |
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Quoted: I've read the entire thread and have a question as a somewhat new AR owner. How do you replace the rings? I have a few sets of the McFarland that came from Brownell's yesterday and want to replace the damaged set on my SBR bolt. Getting the old ones off isn't an issue, but do you just expand the new ones and force them on? Is there a preferred technique? Thanks. It's been a while since I installed them but if I recall, it's a matter of getting one end of the coil into the slot the original rings were in and then working your way around the McFarland coil a bit at a time until the other end pops in too. |
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