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Posted: 10/27/2015 5:00:22 PM EDT
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My trusty S&W m&p sport was getting weak/forward ejection, so I checked the extractor spring (still strong), then pulled the weights/discs out of the buffer. To my surprise the rubber discs between the weights were disintegrating around the edges and the aft two weights were jammed in place, so only one weight was moving. So I think I found my issue.
How do you fix something like this? Do you lube the weights and discs with anything? I might have put wiped them with some lithium grease (plastic-safe) 1000 rounds ago. Short of fixing it, can I buy weights/discs or is it more normal to simply buy an all new buffer? Is the buffer a maintenance item or did I get a bad one? curiously, --edfardos |
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My trusty S&W m&p sport was getting weak/forward ejection, so I checked the extractor spring (still strong), then pulled the weights/discs out of the buffer. To my surprise the rubber discs between the weights were disintegrating around the edges and the aft two weights were jammed in place, so only one weight was moving. So I think I found my issue. How do you fix something like this? Do you lube the weights and discs with anything? I might have put wiped them with some lithium grease (plastic-safe) 1000 rounds ago. Short of fixing it, can I buy weights/discs or is it more normal to simply buy an all new buffer? Is the buffer a maintenance item or did I get a bad one? curiously, --edfardos Why are you messing with the stuff inside the buffer? I've never heard of the rubber discs disintegrating. I wouldn't be surprised if you somehow caused it. Just buy a new buffer, they're $20. |
| Carbine buffers are $10 or less brand new, get a new one and save your old one for spare parts. While your at it, get a new DamageUSA chrome silicon recoil spring for about $12, only $6 when they run them on sale, and change it too. I would also recommend a HD extractor spring for your carbine, they are just a few dollars and will help your carbine with extraction even though you might not need one now. IMHO, I consider these springs a must have upgrade to any AR-15 carbine. |
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Great info guys - thanks!
I like the idea of buying a whole new buffer and keeping the old one as a backup. I like the upgrade-while-I'm-at-it ideas too. The buffer has no designation -- I'm assuming it's an H3? I'd like to buy the right one the first time if possible. Again, this is an M&P Sport (the older one, direct impingement, 16", in 5.56). I just degreased the entire buffer assembly -- i'll try a bit of graphite to see if I can get by until the UPS man arrives. Thanks again for the great hints! --edfardos |
| The internals disintegrating would not cause your problem anyway. Even if they are coming apart, their mass is being retained in the buffer. Also, forward ejection is a symptom of stronger ejection, not weaker. What brand of ammo were you using, and was it different from what you normally use? It sounds like you are simply shooting hotter ammo, and you are worrying about some mall ninja bullshit (the ejection pattern) that doesn't really mean anything. |
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Great info guys - thanks! I like the idea of buying a whole new buffer and keeping the old one as a backup. I like the upgrade-while-I'm-at-it ideas too. The buffer has no designation -- I'm assuming it's an H3? I'd like to buy the right one the first time if possible. Again, this is an M&P Sport (the older one, direct impingement, 16", in 5.56). I just degreased the entire buffer assembly -- i'll try a bit of graphite to see if I can get by until the UPS man arrives. Thanks again for the great hints! --edfardos If the buffer has no markings then it's typically just a standard carbine buffer. The heavier ones witll be marked H , H2, and H3. |
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Great info guys - thanks! I like the idea of buying a whole new buffer and keeping the old one as a backup. I like the upgrade-while-I'm-at-it ideas too. The buffer has no designation -- I'm assuming it's an H3? I'd like to buy the right one the first time if possible. Again, this is an M&P Sport (the older one, direct impingement, 16", in 5.56). I just degreased the entire buffer assembly -- i'll try a bit of graphite to see if I can get by until the UPS man arrives. Thanks again for the great hints! --edfardos I'm curious, why would you assume it's an H3? Which is on the heavier side and no guns that I can think of come stock with it. M&P Sport comes with a carbine buffer. |
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Quoted: Why are you pulling your buffer apart and using lithium grease on it in the first place? I'm curious as to who told you that was something that should be done, or would be a good idea. "Fixing things before it breaks usually ends up breaking before you fixed it."
-dangerdan |
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"Fixing things before it breaks usually ends up breaking before you fixed it." -dangerdan Quoted:
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Why are you pulling your buffer apart and using lithium grease on it in the first place? I'm curious as to who told you that was something that should be done, or would be a good idea. "Fixing things before it breaks usually ends up breaking before you fixed it." -dangerdan Did you notice how diplomatic and nice I was in the way I asked? 
There is a lot of garbage posted on this board, so I was trying top figure out if there is a particular clownfish passing out bad info, or if the OP just decided it would be something cool to do. |
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Did you notice how diplomatic and nice I was in the way I asked?
There is a lot of garbage posted on this board, so I was trying top figure out if there is a particular clownfish passing out bad info, or if the OP just decided it would be something cool to do. You mean YOU Dont disassemble your buffers and make hybrid H-and-a-half buffers? OP That not enough rounds for something like a buffer or its weights to disintegrate. Out of curiosity, when you disassembled it, do you spray some sort of electrical cleaner on it thinking it would be ok for plastic? I've seen contact cleaner "eat" a porter cable battery.... Not mine. |
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Original poster doens't remember why he did it. I suspect they were not moving then. Only the forward weight was moving. The aft two weights were jammed up with the gravel of the deteriorating discs. The first disc had to be picked out with a dental pick as no amount of slamming the open buffer against the bench could extract the aft two weights and discs.
My ammo is home made, 55grain, 2800fps, always has been. The ejection has gotten closer and more forward over the last few hundred rounds, some right at my feet. They used to fly 12 feet. I suspect if the buffer doesn't stall the bcg when it's back for a long enough time, the brass doesn't fling quite right. It's just a guess tho, and the buffer had definitely failed. The buffer now has graphite dust in it, and I can hear all the weights moving and can feel the dead-blow hammer effect again. I'll know more at the range. I asked S&W for a part number, however, it sounds like I just want a "carbine buffer"? Any links/hints? MIdwayusa only lists variations of "heavy" buffers. thanks, -edfardos |
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Original poster doens't remember why he did it. I suspect they were not moving then. Only the forward weight was moving. The aft two weights were jammed up with the gravel of the deteriorating discs. The first disc had to be picked out with a dental pick as no amount of slamming the open buffer against the bench could extract the aft two weights and discs. My ammo is home made, 55grain, 2800fps, always has been. The ejection has gotten closer and more forward over the last few hundred rounds, some right at my feet. They used to fly 12 feet. I suspect if the buffer doesn't stall the bcg when it's back for a long enough time, the brass doesn't fling quite right. It's just a guess tho, and the buffer had definitely failed. The buffer now has graphite dust in it, and I can hear all the weights moving and can feel the dead-blow hammer effect again. I'll know more at the range. I asked S&W for a part number, however, it sounds like I just want a "carbine buffer"? Any links/hints? MIdwayusa only lists variations of "heavy" buffers. thanks, -edfardos http://www.midwayusa.com/product/553144/dpms-buffer-ar-15-carbine?cm_vc=ProductFinding Get the one from BCM ... http://www.bravocompanyusa.com/Carbine-Buffer-p/buffer%20carbine.htm |
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Cool - thanks for the links.
So on the ejection slowly getting weaker and more forward, the buffer/dwell is one possible cause, but should I also address the ejector and extractor? It used to be 8-12 feet at three o'clock, so something has changed. All parts are factory original, and I'd estimate 3000 rounds on them. The ejector spring seems quite strong to me. The extractor doesn't appear to be damaged nor worn, and the spring has the o-ring factory-installed. I don't know much about AR15's because it never broke down, ever (ask me about 1911's on the other hand). If there's a function-test or something I should look for, I'll check it out. If I manually eject a brass in the garage by pulling back on the charging handle as fast as I can, the brass ejects at 3 o'clock at 6-8 feet. Probably meaningless, but that's all I know. Is there a maintenance schedule for the springs in the bcg? or buffer spring? thanks again, --edfardos |
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Great info guys - thanks! I like the idea of buying a whole new buffer and keeping the old one as a backup. I like the upgrade-while-I'm-at-it ideas too. The buffer has no designation -- I'm assuming it's an H3? I'd like to buy the right one the first time if possible. Again, this is an M&P Sport (the older one, direct impingement, 16", in 5.56). I just degreased the entire buffer assembly -- i'll try a bit of graphite to see if I can get by until the UPS man arrives. Thanks again for the great hints! --edfardos Your old, disassembled buffer may be useful for parts, but don't try using it as-is, with graphite, grease or anything else inside it. It was almost certainly not made correctly to begin with, and messing with it is a poor use of your time. The buffer is not a repairable item, and the only folks who like to mess with them are those who are trying to create an odd-weight buffer. You need a regular H buffer, not some kludge of a buffer that may or may not do what you need. You may want to get a NEW standard carbine buffer to have as a backup, but get it from a reliable source. BCM's standard buffer is $11.00 and PSA's is $9.95. So you're looking at less than $35 for two new buffers, one standard and the other an H buffer. |
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Cool - thanks for the links. So on the ejection slowly getting weaker and more forward, the buffer/dwell is one possible cause, but should I also address the ejector and extractor? It used to be 8-12 feet at three o'clock, so something has changed. All parts are factory original, and I'd estimate 3000 rounds on them. The ejector spring seems quite strong to me. The extractor doesn't appear to be damaged nor worn, and the spring has the o-ring factory-installed. I don't know much about AR15's because it never broke down, ever (ask me about 1911's on the other hand). If there's a function-test or something I should look for, I'll check it out. If I manually eject a brass in the garage by pulling back on the charging handle as fast as I can, the brass ejects at 3 o'clock at 6-8 feet. Probably meaningless, but that's all I know. Is there a maintenance schedule for the springs in the bcg? or buffer spring? thanks again, --edfardos It's in your head. If it's eject and you're not having feeding issues it's perfectly fine. No maintenance schedule. Clean your gun and lube your BCG after you get a new buffer, and shoot your gun. Stop worrying. |
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OP rolls his own ammo but is blaming the buffer, and performing maintenance on a sealed item with no user serviceable parts inside.
A weapon that starts changing it's ejection pattern can very well be due to ammo. Powder getting too much humidity in it, different lot of primers, a charging bar not throwing the same as in the past. All that has to be checked and found to be exactly the same, no assumptions. Reagan said it nicely, trust but verify. Since the buffer has been tampered with there is a question about the consistency of how the ammo is being reloaded. There is also the issue of the gas port eroding and getting larger - it's been 3,000 rounds. No gun stays the same forever. |
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Reloads are always suspect when troubleshooting.
However cases should not be dropping at the shooter’s feet. Manually cycling the rounds would throw a live round further than that. It may not be common place, but it is not unheard of to have spring problems by 3K. OP you should also measure the recoil spring to make sure it is still in spec. Springs are cheap, even CS springs are relatively cheap these days. |
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Why are you pulling your buffer apart and using lithium grease on it in the first place? I'm curious as to who told you that was something that should be done, or would be a good idea. If it ain't broke... I swear OCD people and guns lead to more headaches.... |
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Quoted: Did you notice how diplomatic and nice I was in the way I asked? There is a lot of garbage posted on this board, so I was trying top figure out if there is a particular clownfish passing out bad info, or if the OP just decided it would be something cool to do. Quoted: Quoted: Quoted: Why are you pulling your buffer apart and using lithium grease on it in the first place? I'm curious as to who told you that was something that should be done, or would be a good idea. "Fixing things before it breaks usually ends up breaking before you fixed it." -dangerdan Did you notice how diplomatic and nice I was in the way I asked? There is a lot of garbage posted on this board, so I was trying top figure out if there is a particular clownfish passing out bad info, or if the OP just decided it would be something cool to do.  OP stop dicking with your buffer. Replace with a new H and just clean your BCG and barrel once in a while.
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And then what? Most of the time someone posts an incorrect opinion, you get a half dozen people agreeing and calling opposition to the incorrect opinion idiotic or stupid. I swear we should have an AR15 aptitude test to be able to reply to tech questions! One guy said the sight radius was reduced because I put my Eotech towards the rear of the upper
OP stop dicking with your buffer. Replace with a new H and just clean your BCG and barrel once in a while. Quoted:
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Why are you pulling your buffer apart and using lithium grease on it in the first place? I'm curious as to who told you that was something that should be done, or would be a good idea. "Fixing things before it breaks usually ends up breaking before you fixed it." -dangerdan Did you notice how diplomatic and nice I was in the way I asked?
There is a lot of garbage posted on this board, so I was trying top figure out if there is a particular clownfish passing out bad info, or if the OP just decided it would be something cool to do.
OP stop dicking with your buffer. Replace with a new H and just clean your BCG and barrel once in a while. Great idea....this would eliminate people facebook stalking in the tech sections as well. 
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Great idea....this would eliminate people facebook stalking in the tech sections as well. Why are you pulling your buffer apart and using lithium grease on it in the first place? I'm curious as to who told you that was something that should be done, or would be a good idea. "Fixing things before it breaks usually ends up breaking before you fixed it." -dangerdan Did you notice how diplomatic and nice I was in the way I asked? There is a lot of garbage posted on this board, so I was trying top figure out if there is a particular clownfish passing out bad info, or if the OP just decided it would be something cool to do. OP stop dicking with your buffer. Replace with a new H and just clean your BCG and barrel once in a while. Great idea....this would eliminate people facebook stalking in the tech sections as well. |
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And then what? Most of the time someone posts an incorrect opinion, you get a half dozen people agreeing and calling opposition to the incorrect opinion idiotic or stupid. I swear we should have an AR15 aptitude test to be able to reply to tech questions! One guy said the sight radius was reduced because I put my Eotech towards the rear of the upper
OP stop dicking with your buffer. Replace with a new H and just clean your BCG and barrel once in a while. Quoted:
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Why are you pulling your buffer apart and using lithium grease on it in the first place? I'm curious as to who told you that was something that should be done, or would be a good idea. "Fixing things before it breaks usually ends up breaking before you fixed it." -dangerdan Did you notice how diplomatic and nice I was in the way I asked?
There is a lot of garbage posted on this board, so I was trying top figure out if there is a particular clownfish passing out bad info, or if the OP just decided it would be something cool to do.
OP stop dicking with your buffer. Replace with a new H and just clean your BCG and barrel once in a while. Right on ! 
On the semi-tech note, weak ejection is definitely not caused by a bad buffer but only way to prove to yourself is stick another one in there, or give it one of the magic blue pills
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OP here. You guys are killing me :)
AR15 parts are so cheap it's almost not worth the time to analyze the problem -- which isn't exactly a real problem to begin with since it still functions. I ended up going to Brownells since I couldn't find ejector springs at the fine sites which you recommended. Since I'm at 3K rounds, It's cheap and easy to replace all the action springs along with the new buffer. Brownells.com descriptions: Carbine Buffer Carbine Buffer spring AR-15 Extractor Spring (CS) AR-15 Ejector Spring 3-pack $32 shipped - not bad. These things are much cheaper than pistol parts. Thanks a billion for all the hints and being gentle with a non-AR15-technical person. --edfardos (OP) |
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