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  #21  
Old 04-11-2020, 01:00 PM
Gewehr43 Gewehr43 is offline
 
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Location: Denver, CO
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Originally Posted by WindLogik View Post
Unfortuneately, this is a common problem while running a 20" AR service rifle barrel on a carbine buffer system (I'm assuming you're using that). You should be running a slower powder like Varget or RE15. The gas port on a SR barrel for a FL gas system is typically in the neighborhood of .095". Best you can do is match the standard A2 buffer at 5.2 OZ. This translates to an H3 carbine buffer. Use this with a standard carbine spring (same stiffness as an A2 spring). This should fix your problem assuming you are using a proper SR load (77 grain bullet with correct powder) and your gas port is properly sized. The other thing you can do to add weight is use an M16 style bolt carrier, this will ad a bit more weight.

This issue cropped up with the switch to optics/carbine buffer systems. Companies like WOA and CLE have done a good job controlling their port diameters for SR match builds. If you have a grossly oversized port, you will be SOL. The easy button is to buy a complete upper from WOA.
You've seen as a common problem that the rubber end of a buffer has been "destroyed" in shooting it?
Or are you referring to the general issues he's having?
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  #22  
Old 04-11-2020, 01:26 PM
WindLogik WindLogik is offline
 
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Location: Washington State
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Originally Posted by Gewehr43 View Post
You've seen as a common problem that the rubber end of a buffer has been "destroyed" in shooting it?
Or are you referring to the general issues he's having?
I have not seen that. But, I'd expect that most folks would start to troubleshoot before that became an issue. I don't think that a new shooter would have any idea what the recoil should feel like. You'd really have to do it a lot to beat up that urethane. Maybe he's using some kind of crap buffer with a bumper that is cheap, who knows. When I first started tinkering with the "new" rules, I put my 20" A2 upper on a carbine lower with a standard carbine buffer. Shooting my usual 77 grain SR load, the system was so out-of-time that it was bending the rims on the cases. In otherwords, because of the lack of mass, it was extracting cases way, way too early and with way, way too much force. Matching the buffer weight to that of an A2 immediately fixed the problem. This was with a barrel having a proper port for that load, though.

Even in the A2 days, guys would piece together rifles with incorrect gas port diameters. It's something that folks generally don't know about. They slam something together and it doesn't work right. If the OP's port diameter is in the right range, there is no reason he shouldn't be able to run a typical SR load with an H3 buffer.

We tell new folks, time and time again when they start shooting HP, not to buy anything. Invariably, they run out and buy what looks like a HP kit, but literally every component is wrong. From the upper to the sling to the mat to the spotting scope to the trigger to the bullets. I just don't know why new shooters do that. This sounds like that kind of a case. If the shooter is in a local HP community, he should be asking his peers for guidance. Literally, that is one of the purposes of the distinguished program and CMP competitions.

Last edited by WindLogik; 04-11-2020 at 01:31 PM.
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  #23  
Old 04-11-2020, 04:38 PM
Gewehr43 Gewehr43 is offline
 
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Originally Posted by WindLogik View Post
I have not seen that. But, I'd expect that most folks would start to troubleshoot before that became an issue. I don't think that a new shooter would have any idea what the recoil should feel like. You'd really have to do it a lot to beat up that urethane. Maybe he's using some kind of crap buffer with a bumper that is cheap, who knows. When I first started tinkering with the "new" rules, I put my 20" A2 upper on a carbine lower with a standard carbine buffer. Shooting my usual 77 grain SR load, the system was so out-of-time that it was bending the rims on the cases. In otherwords, because of the lack of mass, it was extracting cases way, way too early and with way, way too much force. Matching the buffer weight to that of an A2 immediately fixed the problem. This was with a barrel having a proper port for that load, though.

Even in the A2 days, guys would piece together rifles with incorrect gas port diameters. It's something that folks generally don't know about. They slam something together and it doesn't work right. If the OP's port diameter is in the right range, there is no reason he shouldn't be able to run a typical SR load with an H3 buffer.

We tell new folks, time and time again when they start shooting HP, not to buy anything. Invariably, they run out and buy what looks like a HP kit, but literally every component is wrong. From the upper to the sling to the mat to the spotting scope to the trigger to the bullets. I just don't know why new shooters do that. This sounds like that kind of a case. If the shooter is in a local HP community, he should be asking his peers for guidance. Literally, that is one of the purposes of the distinguished program and CMP competitions.
Ok.... we have the same experiences.
I was wondering about the beat up buffer..... that is a new one.
That is why (my thoughts and your comments) I asked the OP about the source of the parts/build...…
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  #24  
Old 04-11-2020, 07:37 PM
Beeks Beeks is offline
 
Join Date: Sep 2014
Location: Wisconsin
Posts: 208
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Quote:
Originally Posted by WindLogik View Post

We tell new folks, time and time again when they start shooting HP, not to buy anything. Invariably, they run out and buy what looks like a HP kit, but literally every component is wrong. From the upper to the sling to the mat to the spotting scope to the trigger to the bullets. I just don't know why new shooters do that. This sounds like that kind of a case. If the shooter is in a local HP community, he should be asking his peers for guidance. Literally, that is one of the purposes of the distinguished program and CMP competitions.
There may be a little truth to this in regards to some of the components I used. I did use a M1 in competition for a number of years before starting to build this AR. I did get a lot of advice from the other shooters. They even brought the barrel back from Perry for me. They did push a fixed stock but I thought adjustable would be better for my kids.

I found my old buffer. It doesn’t have any manufacturer markings.
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  #25  
Old 04-19-2020, 09:48 AM
hebes405 hebes405 is offline
 
Join Date: Jan 2018
Location: Ohio
Posts: 922
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Quote:
Originally Posted by WindLogik View Post
Unfortuneately, this is a common problem while running a 20" AR service rifle barrel on a carbine buffer system (I'm assuming you're using that). You should be running a slower powder like Varget or RE15. The gas port on a SR barrel for a FL gas system is typically in the neighborhood of .095". Best you can do is match the standard A2 buffer at 5.2 OZ. This translates to an H3 carbine buffer. Use this with a standard carbine spring (same stiffness as an A2 spring). This should fix your problem assuming you are using a proper SR load (77 grain bullet with correct powder) and your gas port is properly sized. The other thing you can do to add weight is use an M16 style bolt carrier, this will ad a bit more weight.

This issue cropped up with the switch to optics/carbine buffer systems. Companies like WOA and CLE have done a good job controlling their port diameters for SR match builds. If you have a grossly oversized port, you will be SOL. The easy button is to buy a complete upper from WOA.
I was thinking about the exact same thing. I would add, take the advice of your local shooters and switch to a fixed stock with all correct rifle length components. However if length of pull is a concern, put on an A1 stock. That 3/4" makes a bigger difference than you would think.

Hope you get it figured out.
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