OlDaky Posted April 7, 2018 Report Share Posted April 7, 2018 Hey everyone, My bolt is not catching properly, when its an empty magazine. My build is a Aero M5 lower, and 18 inch upper with an aero BCG. . The gun cycles fine, but won't lock back on an empty mag. I can lock it back fine manually with no problems. I took a picture of the measurements of the spring, buffer, and the buffer tube. I read somewhere that it might be the screw that holds on the stock on that sometimes they can effect how far back the buffer can go? Anyone have any ideas? Thank you. Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted April 7, 2018 Report Share Posted April 7, 2018 What LPK did you install? Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted April 7, 2018 Report Share Posted April 7, 2018 It’s not impossible for the screw to be an issue, but you would know right away because there would be circular step marks on your buffer knob from the end of the screw. I’m going to guess that you have the wrong balt catch installed. Somebody probably mistakenly put a standard AR-15 bolt catch in your LPK. You need to find yourself a dedicated 308 V catch. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 7, 2018 Report Share Posted April 7, 2018 Take a pic of your vented screw next to your tape measure, and I'll tell you if it's the wrong (A2) screw. Go hit the intro section, and tell us about yourself. Quote Link to comment Share on other sites More sharing options...
OlDaky Posted April 7, 2018 Author Report Share Posted April 7, 2018 54 minutes ago, Robocop1051 said: It’s not impossible for the screw to be an issue, but you would know right away because there would be circular step marks on your buffer knob from the end of the screw. I’m going to guess that you have the wrong balt catch installed. Somebody probably mistakenly put a standard AR-15 bolt catch in your LPK. You need to find yourself a dedicated 308 V catch. I was able to rule out the screw pretty quickly by installing a shorter one I had. It was not the problem. But I used the CMMG - 308 AR LOWER GUNBUILDER'S LOWER PARTS KIT as seen here: https://www.brownells.com/rifle-parts/receiver-parts/parts-kits/repair-parts-kits/308-ar-lower-gunbuilder-s-lower-parts-kit-prod72275.aspx I've heard good and bad (mainly bad) things about CMMG so purhaps the one they gave me was a AR-15 one and not a a .308 one? Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 7, 2018 Report Share Posted April 7, 2018 39 minutes ago, OlDaky said: I was able to rule out the screw pretty quickly by installing a shorter one I had. It was not the problem. If you had a shorter screw, the longer screw was a problem - you don't picture the 5/8" A2 spacer for an A2 stock in your pics - which is required for an A2 stock, with that 5/8" longer vented screw. You were running an A1 system, with an A2 screw, which stopped your buffer short of 5/8" of it's travel. It does make a difference... That's the whole reason I asked you to get a pic of the screw you used, against your tape. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 7, 2018 Report Share Posted April 7, 2018 43 minutes ago, OlDaky said: I've heard good and bad (mainly bad) things about CMMG so purhaps the one they gave me was a AR-15 one and not a a .308 one? Oh, here we go. You asked the wrong guy about CMMG parts!... You will hear about this shortly... Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted April 7, 2018 Report Share Posted April 7, 2018 7 hours ago, 98Z5V said: Oh, here we go. You asked the wrong guy about CMMG parts!... You will hear about this shortly... Gawdam right!!! Every time the “unexplainable issue” arises, the four-letter word is soon to follow. I swear to God, when I’m king of the world, I’m banning CMM-fuckin-G lower parts kits. The company is run by donkeys and the parts are made by apes. I don’t want to upset you, but pull out every pin, spring and lever made by CMMG. I don’t know if it’s bad metal, poor machining, evil voodoo magic or a combination of all three. I’ve seen CMMG grip screws fuck up a build. There are a few guys here that use CMMG parts reliably. They are far from what I consider “amateur” builders. I’ve worked with them myself on occasions. To me the money saved is not worth the time needed to modify all the parts. CMMG is the worst company in the industry when it comes to aftermarket parts. Quote Link to comment Share on other sites More sharing options...
OlDaky Posted April 7, 2018 Author Report Share Posted April 7, 2018 9 hours ago, 98Z5V said: If you had a shorter screw, the longer screw was a problem - you don't picture the 5/8" A2 spacer for an A2 stock in your pics - which is required for an A2 stock, with that 5/8" longer vented screw. You were running an A1 system, with an A2 screw, which stopped your buffer short of 5/8" of it's travel. It does make a difference... That's the whole reason I asked you to get a pic of the screw you used, against your tape. Wait, there was suppose to be a spacer? My stock never came with a 5/8 A2 spacer. I'll have to take a look and see where to buy the correct spacer at. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 7, 2018 Report Share Posted April 7, 2018 ONLY.Only if you're running it at A2 length. Only if you're running it at A2 length. I've gone over this several times here, but I'll toss it in here again. Rifle recoil systems are the same. The Rifle receiver extension never changes. It doesn't matter if it's "A1" length of "A2" length - it's the exact same rifle receiver extension, buffer and spring. The A2 is longer than the A1 stock, and that's accomplished by adding a 5/8" spacer on the end of the receiver extension before sliding the stock on. You also must use a longer vented screw to retain the stock - the vented screw is 5/8" longer than the A1 vented screw. Now, hopefully all that makes sense - if it doesn't, ask away and let's get it sorted. In the mean time - can you get me a picture of your vented buttstock screw, beside the tape measure? Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 7, 2018 Report Share Posted April 7, 2018 (edited) 13 hours ago, OlDaky said: Hey everyone, My bolt is not catching properly, when its an empty magazine. My build is a Aero M5 lower, and 18 inch upper with an aero BCG. . The gun cycles fine, but won't lock back on an empty mag. I can lock it back fine manually with no problems. I took a picture of the measurements of the spring, buffer, and the buffer tube. I read somewhere that it might be the screw that holds on the stock on that sometimes they can effect how far back the buffer can go? Anyone have any ideas? Thank you. I can't tell what's going on with your buffer, either - in this pic, it looks like it's 5.5" long. 308 rifle buffers are 5.200" long. 5.56 rifle buffers (and all small frame ARs) are 5.900" long... Please clarify on your buffer length... Edited April 7, 2018 by 98Z5V Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 7, 2018 Report Share Posted April 7, 2018 There's also a ton of other questions, before we get these answers, but crawl down this rabbit hole. You said: My bolt is not catching properly, when its an empty magazine. My build is a Aero M5 lower, and 18 inch upper with an aero BCG. . The gun cycles fine, but won't lock back on an empty mag. I can lock it back fine manually with no problems. How many rounds are through it? Was it lubed, heavily, when you first shot it? I'm talking almost dripping wet with lube. What ammo are you using? You can lock it back by hand - but where does the bolt catch grab the BCG? Is it on the bolt face? It should grab the bolt face -and not the BCG body... Quote Link to comment Share on other sites More sharing options...
OlDaky Posted April 7, 2018 Author Report Share Posted April 7, 2018 4 hours ago, 98Z5V said: There's also a ton of other questions, before we get these answers, but crawl down this rabbit hole. You said: How many rounds are through it? Was it lubed, heavily, when you first shot it? I'm talking almost dripping wet with lube. What ammo are you using? You can lock it back by hand - but where does the bolt catch grab the BCG? Is it on the bolt face? It should grab the bolt face -and not the BCG body... There is only about 30 rounds through it, and it was lubed pretty heavily. I was also shooting Fiocchi 150 GR FMJ .308 and the BCG locks back at the face when I manually do it. Here are the pictures of the screws that came with the stock. (came with two) Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 7, 2018 Report Share Posted April 7, 2018 First, those are just allen bolts. You'll need a proper vented screw. Hole in the middle of it. Some people will say "it doesn't matter..." ... but it does matter. All recoil systems need to push air out, and have a "vent" when that buffer is so quickly slammed to the back of that receiver extension. So, enough on that. You need an A1 vented screw, you do not need an A2 vented screw. There's something bad wrong with that buffer. It's clear that your tape isn't at the end of it, and I need very-end-to-very-end measurements. At any rate, it really doesn't matter, because that buffer is not 308 length, and it's not AR15 length, for a rifle buffer - it's in between. It's weird as hell. Where did you get this recoil system at?... Quote Link to comment Share on other sites More sharing options...
OlDaky Posted April 7, 2018 Author Report Share Posted April 7, 2018 This is the kit that I ordered https://www.cheaperthandirt.com/product/luth-ar-ar-308-rifle-buffer-tube-assembly308-win-859819007256.do?from=Search&cx=0 and okay i'll will get the vented screw. Quote Link to comment Share on other sites More sharing options...
unforgiven Posted April 7, 2018 Report Share Posted April 7, 2018 A lot of us here will do any business with CTD since the Sandy hook debacle where they started gouging the people. In the neck with CTD. Quote Link to comment Share on other sites More sharing options...
OlDaky Posted April 7, 2018 Author Report Share Posted April 7, 2018 (edited) 5 minutes ago, unforgiven said: A lot of us here will do any business with CTD since the Sandy hook debacle where they started gouging the people. In the neck with CTD. Yah I didn't want to buy from them. Haven't since the entire sandy hook thing. But they were the only ones who could overnight my part to me and I need it for the weekend. The one I ordered from midway ran into a problem and was back ordered for 3 weeks. Edited April 7, 2018 by OlDaky Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 7, 2018 Report Share Posted April 7, 2018 And that's working out great, isn't it... Fuk CTD. Who knows what you got from CTD, man. Who knows what cheap shiit they threw in there. Luth DOES have a complete kit, so if I were you, I'd contact them and find out what length buffer they ship with their own complete kit. Keep in mind... Luth-AR is Randy Luth. He founded DPMS, and knows his shiit. 40 years ago. I'd find out what you have first, before you do anything else. Call Luth-AR. Find out what they include, and dimensions. If it comes out that you're going after CTD for a fucked up part - good luck. They got your money, and they don't give one shiit about you now. They'll be happy to charge you a hundred bucks for a used GI 30-rd aluminum mag, though, next time that BS kicks up. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 7, 2018 Report Share Posted April 7, 2018 I knew from the start of this thread, that we were trying to diagnose some seriously fucked up shiit. I now see that I was correct. Nothing against YOU, OP... but people never, ever learn, and continue to buy cheap shiit, then come here to try to figure out what the problem could possibly be?... It's aggravating, at times. Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted April 7, 2018 Report Share Posted April 7, 2018 On 3/7/2017 at 1:48 AM, Matt.Cross said: Where the idiocy comes in, is how I've failed to realize the catch is supposed to hold on the face of the BOLT, not the carrier. So I began diagnosing why my carrier wasn't/isn't traveling far enough to the rear to function properly. The short answer is that my buffer is ~1/2" too long, explaining both my short-stroking/bcg overspeed issue, and the failure to lock back on empty. Doh! This became apparent once I compared my buffer measurements with the data mrraley published quite a while ago. Brownells sent me an Armalite AR-15 buffer! It's 5.875" and should measure 5.188"! (Based on this post.) Your buffer is too long (specifically ~1/2" too long), you need to to cut it and re-drill it for the roll pin. Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted April 7, 2018 Report Share Posted April 7, 2018 I just watched about 45 mins of LuthAR stock installation videos... It looks like the stock was actually built to fit the A1, and not the extended A2. I did not see a single LuthAR installed with a 5/8" spacer. The stock "should" have come with it's own vented screw. You shouldn't have to search one out. Quote Link to comment Share on other sites More sharing options...
OlDaky Posted April 7, 2018 Author Report Share Posted April 7, 2018 1 hour ago, 98Z5V said: I knew from the start of this thread, that we were trying to diagnose some seriously fucked up shiit. I now see that I was correct. Nothing against YOU, OP... but people never, ever learn, and continue to buy cheap shiit, then come here to try to figure out what the problem could possibly be?... It's aggravating, at times. I took the buffer to my local gun shop and by chance they had another complete Luth kit there. The buffers are the same length, and we compared it with multiple different ones. They were all the same length (expect one that was 1/3rd inch longer) Quote Link to comment Share on other sites More sharing options...
OlDaky Posted April 7, 2018 Author Report Share Posted April 7, 2018 (edited) 4 minutes ago, Robocop1051 said: I just watched about 45 mins of LuthAR stock installation videos... It looks like the stock was actually built to fit the A1, and not the extended A2. I did not see a single LuthAR installed with a 5/8" spacer. The stock "should" have come with it's own vented screw. You shouldn't have to search one out. I took a double check of the box. There was no vented screw in it. I bought the stock right from luth themselves. Starting to wonder if maybe I got a returned one. The only thing in the box was the stock, and the instructions on how to install it. No vented screws, just the ones I pictured* Edited April 7, 2018 by OlDaky Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted April 7, 2018 Report Share Posted April 7, 2018 2 minutes ago, OlDaky said: I took a double check of the box. There was no vented screw in it. I bought the stock right from luth themselves. Starting to wonder if maybe I got a returned one. The only thing in the box was the stock, and the instructions on how to install it. No vented screws, just the ones I pictured* LuthAR has their own A1 stock screw. https://www.luth-ar.com/product/a1-butt-stock-screw/ Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted April 7, 2018 Report Share Posted April 7, 2018 FWIW.... I'm still calling foul on the CMMG bolt catch (as well as every other CMMG part). Quote Link to comment Share on other sites More sharing options...
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