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Posted: 6/5/2026 8:59:17 PM EDT
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If you have the time, please help me verify an issue I'm having. The BCG is BCM. I bought my first A5 length buffer setup and installed it, but I think I have a problem. I bought a "blem" A5 length receiver extension, a rifle-length "M16" springco spring, and a PWS A5 size buffer, H2, but when I install it all, and push my BCG back into the tube by hand, I think it's going to far in. The carrier gas key is smacking right into the receiver. I think I've seen there should be a gap, as the BCG should bottom out and stop, and the back of the key shouldn't strike the receiver. Can you guys confirm this? I took a little video to show what I'm referring to, and you may not be able to see it clearly, but the carrier key is definitely smacking right into the receiver. I've also linked the parts I bought so you can tell me if I got something wrong. The tube is screwed in as far as it will go, I can't screw it any further because it's hitting the buffer retainer pin already. I think the "blem" tube I got must be too deep, which sucks, I was hoping to shoot this tomorrow, but I'm thinking if I shoot it like this I can damage my BCG or receiver, right? I am grateful for any insight you can provide. Here's a video of the issue. I tried to use the rumble link thingy but it doesn't work with the URL. https://rumble.com/shorts/v7avsfc Buffer Receiver extension Spring |
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I think I remember once hearing that you can put a quarter in the tube before the spring, so I tried that. That seemed to work, but something is off. Without the quarter, the buffer gas key smacks the receiver, but with one quarter installed, when I press the buffer back, there is now a gap between the carrier gas key and lower reciever that I can fit 2 QUARTERS in. How did adding only one quarter cause the buffer/bcg to bottom out 2 quarters worth? I'm no physicist, but my monkey brain says that's weird. anyway, is it safe to run with a quarter under the spring? |
I'm pretty sure it's the right one. Here's a pic, the new one is on the left. Can you confirm that it's safe to run with a quarter? I don't see any reason why it wouldn't be, but some feedback from those with more experience would be greatly appreciated.
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Looks right. I have never used quarters because of their uneven surface. I ordered some thin washers with a small bolt hole for the drain and used them a couple of times. I used them because the tubes had wide angle divot in the bottom that wasn't supposed to be there not for a spacing need. |
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Originally Posted By 2nd_citizen: If you have the time, please help me verify an issue I'm having. The BCG is BCM. I bought my first A5 length buffer setup and installed it, but I think I have a problem. I bought a "blem" A5 length receiver extension, a rifle-length "M16" springco spring, and a PWS A5 size buffer, H2, but when I install it all, and push my BCG back into the tube by hand, I think it's going to far in. The carrier gas key is smacking right into the receiver. I think I've seen there should be a gap, as the BCG should bottom out and stop, and the back of the key shouldn't strike the receiver. Can you guys confirm this? I took a little video to show what I'm referring to, and you may not be able to see it clearly, but the carrier key is definitely smacking right into the receiver. I've also linked the parts I bought so you can tell me if I got something wrong. The tube is screwed in as far as it will go, I can't screw it any further because it's hitting the buffer retainer pin already. I think the "blem" tube I got must be too deep, which sucks, I was hoping to shoot this tomorrow, but I'm thinking if I shoot it like this I can damage my BCG or receiver, right? I am grateful for any insight you can provide. Here's a video of the issue. I tried to use the rumble link thingy but it doesn't work with the URL. https://rumble.com/shorts/v7avsfc Buffer Receiver extension Spring All of these items were purchased from Primary Arms, yes? My first stop would have been with them. Yet here we are, LOL. No. The back of the key SHOULD NOT hit the receiver. Neither should the back of the gas key hit the back of the charging handle. Blem usually does NOT refer to out-of-spec dimensions. Blem usually means finish issues. You should take that up with PA. MY suspicion is that sprinco spring. How many coils. How thick is the spring material? In functioning, as I recall, the buffer doesn't normally contact the back of the buffer tube. The spring prevents that. That is another thing you should bring up with PA. |
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Originally Posted By Kobolowsky_Tires: All of these items were purchased from Primary Arms, yes? My first stop would have been with them. Yet here we are, LOL. No. The back of the key SHOULD NOT hit the receiver. Neither should the back of the gas key hit the back of the charging handle. Blem usually does NOT refer to out-of-spec dimensions. Blem usually means finish issues. You should take that up with PA. MY suspicion is that sprinco spring. How many coils. How thick is the spring material? In functioning, as I recall, the buffer doesn't normally contact the back of the buffer tube. The spring prevents that. That is another thing you should bring up with PA. The buffer bottoms out in the tube. The spring should not go to full compression and stop the buffer. |
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Originally Posted By Kobolowsky_Tires: All of these items were purchased from Primary Arms, yes? My first stop would have been with them. Yet here we are, LOL. No. The back of the key SHOULD NOT hit the receiver. Neither should the back of the gas key hit the back of the charging handle. Blem usually does NOT refer to out-of-spec dimensions. Blem usually means finish issues. You should take that up with PA. MY suspicion is that sprinco spring. How many coils. How thick is the spring material? In functioning, as I recall, the buffer doesn't normally contact the back of the buffer tube. The spring prevents that. That is another thing you should bring up with PA. All good advice, thank you. I will contact PA, but I'm going out of town to go shooting tomorrow, so I'm going to use it with a washer in it for that. If I can't return it after that I'll just pick up a new one. |
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