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Posted: 11/28/2011 3:39:10 PM EDT
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I put a H2 buffer in one of my 14.5" guns about 700 rounds ago. Today i noticed the recoil seemed more severe than usual. Made me suspect maybe my action spring needed replacement. Removed the buffer and action spring. The action spring measures just shy of 10.45" which is withen the acceptable range.
However i noticed the rubber pad on the back of the buffer is getting a nice dent in the center. its obviously impacting the rear of the buffer tube. Is this wear normal? Is it self limiting or will it continue to wear until the buffer needs replacement? I cannot say I've ever worn out a buffer. I've tried different buffer weights including carbine, H, H2 & 9mm over the years. |
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A buffer should not be forcefully impacting the back of the buffer tube/receiver extension. A buffer/action spring is good for about 12,000-rds is what we teach in armorer classes. That doesn't mean a spring will not fail sooner or go longer, it is just a general guide line. If the rifle has quite a few rounds through it, then I recommend changing out the spring.
CY6 Greg Sullivan "Sully" SLR15 Rifles TheDefensiveEdge.com (763) 712-0123 |
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Quoted:
A buffer should not be forcefully impacting the back of the buffer tube/receiver extension. A buffer/action spring is good for about 12,000-rds is what we teach in armorer classes. That doesn't mean a spring will not fail sooner or go longer, it is just a general guide line. If the rifle has quite a few rounds through it, then I recommend changing out the spring. CY6 Greg Sullivan "Sully" SLR15 Rifles TheDefensiveEdge.com (763) 712-0123 10,418 rounds through the gun. I replaced the action spring at some point with a Brownells (SS) action spring. H2 buffer. I'm starting to doubt the quality of the cheap Brownells action springs. |
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Lets start at the beginning,
A shorter carbine buffer should only be used with a telescoping stock. If used with a full fixed length receiver extension, the back of the carrier key is going to crash into the back of the receiver, ending up with a cracked lower receiver. Next, the only thing on the back of a telescoping receiver extension should be the weep hole, and as small as it is, should not be leaving any marks on the face of the buffer bumper, From here, a receiver extension/buffer spring, just like every other recoil spring, should be changed out 3K to 6K mark. Lastly, there is math to the B/C mass, spring tension, gas pressure that the is being direct back to the gas system, and the buffer weight to control the action cycle speed. If the rifle warranted that a heavy buffer be used to control the action so it does not over function/unlock too fast), then great. But in the above case, sounds like you have just added a heaver buffer for no real reason (unless you are fighting the short barrel trying to get it run, not to be so ammo sensitive *), and since you now have more reciprocating mass of the buffer, have just increased the felt recoil of the rifle for no reason. * http://www.ar15.com/forums/t_6_23/199901_10_5_Upper______and__thing_won_t_run_.html |
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Quoted:
. Next, the only thing on the back of a telescoping receiver extension should be the weep hole, and as small as it is, should not be leaving any marks on the face of the buffer bumper, Checked 7 carbines today. They all have marks to some degree from the buffer bumper impacting the rear of the receiver extension. Have not had a chance to pull the rifles out of the safes yet to check. The pics in this thread show simular damage to the buffer bumper http://www.ar15.com/forums/t_3_118/552110_I_need_some_buffer_buffer_spring_help.html |
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Funny part about calling a rifle a carbine, most people mean the top end/upper receiver of the rifle, and the buffer, spring, and barrel extension has nothing to do with that, but what type of stock is on the rifle.
The lower parts (be it calling them a carbine or telescoping stock), has all to do with the length of the receiver extension tube void. So if the the lower receiver has a telescoping stock on it, and will use the short buffer and spring. Now, the bottom/ back of the receiver extension void, should be flush/flat with just a small weep hole in the center. If the tubes where not milled flush/flat on the bottom/back of the channel, then yes, these imperfections in the tube milling will transfer to the buffer bumper over time. So on that note, pull the buffers and springs, and take a very good look at the bottom of the tube void to see if there is imperfections in the tube production millings, or if there is just debris that have not been removed through cleaning. As for cleaning up such milling imperfections if found (high areas), just too easy to make a bottom void hand cutter so the bottom/back of the receiver extension void is square and clean, so the buffer bumper does not get chewed up over time bouncing off such imperfections. But back to the excess recoil, do you really need the heaver buffer, or was this just a spur of the moment add-on for no real reason. With only 700 rounds on the recoil spring, can not see it needing a replacing yet, so was the problem being that the upper was ammo picky or over functioning, and the reason for the heaver than 62gr ammo buffer being swapped out for the standard buffer? But yes, the more reciprocating mass you add to the rifle, such as a heaver buffer, the more it will increase felt recoil. |
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