Warriorone Posted August 30, 2021 Report Share Posted August 30, 2021 I recently build a 338 federal LR308 and I am struggling with getting it to cycle properly. After a great deal of adjustment to the gas block, it gotten it to fire and eject the cartridge but it will not chamber the next round. There is also significant scratching to the bullet and casing. I’ve taken a dremmel to the feed ramp to polish it but it only slightly lessened the scratches and continues not to feed. The rifle is built on and SLR B-30 receiver set with a Wilson Combat barrel, a JP Enterprises low mass 308 BCG, Superlative Arms adjustable gas block, Geisselle two stage trigger, Radian Raptor charging handle, Magpual UBR Stock with an Armaspec SRS AR10 spring and similarly high end parts. It has the most expensive components of the half dozen rifles that I’ve built and yet it simply will not work properly. I’ve attached a few videos showing what it’s doing. If anyone has some advice I’d appreciate it. IMG_3344.MOV IMG_3343.MOV IMG_3342.MOV Quote Link to comment Share on other sites More sharing options...
98Z5V Posted August 30, 2021 Report Share Posted August 30, 2021 (edited) 1 hour ago, Warriorone said: Magpual UBR Stock with an Armaspec SRS AR10 spring MagPul UBR, or UBR 2? There's a major difference. Which SRS AR-10 spring are you running from them? Got a model number? Run that gas block WIDE OPEN until this gets sorted out. Maxed out, max gas, get the gun running first. Play with the gas later, after it's running. I have the same barrel, and it never had an issue getting some .338 Fed out of the gun. That low mass BCG isn't doing you any favors. Edited August 30, 2021 by 98Z5V Quote Link to comment Share on other sites More sharing options...
Warriorone Posted August 30, 2021 Author Report Share Posted August 30, 2021 Thanks for response. I have the UBR 2 with the ARM153-308 spring. Oddly, when I go full gas it won’t cycle. In fact, the ejector seems to get jammed with the cartridge still in the chamber. I have to adjust the gas to roughly 3/4 full for it to eject the cartridge but it still won’t feed the next round. I’m using a magpul pmag so I wouldn’t think it’s the quality of the magazine but I’m considering trying a different one to see if that changes things. I thought about replacing the BCG but the idea of the rifle was to be an ultra-lite 338 so I’m trying to avoid that. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted August 30, 2021 Report Share Posted August 30, 2021 16 hours ago, Warriorone said: If anyone has some advice I’d appreciate it. Had some similar issues with my WC 338 barrel, it runs fine now. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted August 31, 2021 Report Share Posted August 31, 2021 (edited) 13 hours ago, Warriorone said: I thought about replacing the BCG but the idea of the rifle was to be an ultra-lite 338 so I’m trying to avoid that. The only thing ultra-light about making a .338 FED AR would be (1) barrel length - you got that covered with the 16", and (2) not using a UBR stock. Skimping on the recoil system (BCG weight included in that) is not going to lead to a fully operational lead-slinger, not for this caliber. EDIT - use of term "skimping on" does not mean that you didn't spend money. It's skimping on weight, that you need, in the wrong area to cut weight in... Edited August 31, 2021 by 98Z5V Quote Link to comment Share on other sites More sharing options...
98Z5V Posted August 31, 2021 Report Share Posted August 31, 2021 (edited) 13 hours ago, Warriorone said: Thanks for response. I have the UBR 2 with the ARM153-308 spring. Is the bolt carrier slamming into the ears on the lower receiver? That receiver extension built into the UBR 2 is 7 5/8" internal depth. The entire length of the recoil spring/buffer system you listed is 7.18". Is your BCG contacting your lower receiver, where the receiver extension screws into it? Edited August 31, 2021 by 98Z5V Quote Link to comment Share on other sites More sharing options...
98Z5V Posted August 31, 2021 Report Share Posted August 31, 2021 @Warriorone - time to start posting pics... As well as hit the Intro Section, and tell us about yourself. It's right here: https://forum.308ar.com/forum/22-introductions/ Quote Link to comment Share on other sites More sharing options...
Warriorone Posted August 31, 2021 Author Report Share Posted August 31, 2021 43 minutes ago, 98Z5V said: Is the bolt carrier slamming into the ears on the lower receiver? That receiver extension built into the UBR 2 is 7 5/8" internal depth. The entire length of the recoil spring/buffer system you listed is 7.18". Is your BCG contacting your lower receiver, where the receiver extension screws into it? Thanks for response. I don’t see any evidence that the BC is slamming into the ears. Re the stock depth, I had to add Armaspec spacers behind the spring but, yes, it is contacting the lower. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted August 31, 2021 Report Share Posted August 31, 2021 1 minute ago, Warriorone said: Thanks for response. I don’t see any evidence that the BC is slamming into the ears. Re the stock depth, I had to add Armaspec spacers behind the spring but, yes, it is contacting the lower. PIcs are mandatory now. Post pics of the contact, or we're wasting our time here... This will be the first step, in trying to figure out what's going on... Quote Link to comment Share on other sites More sharing options...
Warriorone Posted August 31, 2021 Author Report Share Posted August 31, 2021 I started the build with a smoke composite fixed stock but it didn’t work with relief for my thermal so I switched to the UBR 2. I’ve wondered if the BCG was too light, and I’d be inclined to think that contributes to it not cycling properly but the marring on the cartridges makes me think I’m missing something else… Quote Link to comment Share on other sites More sharing options...
Warriorone Posted August 31, 2021 Author Report Share Posted August 31, 2021 IMG_3343.MOV IMG_3342.MOV IMG_3344.MOV Quote Link to comment Share on other sites More sharing options...
Warriorone Posted August 31, 2021 Author Report Share Posted August 31, 2021 Will post additional pics of internals. Appreciate your responses Quote Link to comment Share on other sites More sharing options...
98Z5V Posted August 31, 2021 Report Share Posted August 31, 2021 (edited) 35 minutes ago, Warriorone said: I started the build with a smoke composite fixed stock but it didn’t work with relief for my thermal so I switched to the UBR 2. I’ve wondered if the BCG was too light, and I’d be inclined to think that contributes to it not cycling properly but the marring on the cartridges makes me think I’m missing something else… We have no idea, because we've never seen any of the pics of the "marring on the cartridges..." You starting to smell what I'm spreading yet? Pics, man. Your videos are cool. They tell PART of the story - I picked up in the first vid, that SOMETHING STOPPED YOUR RECOIL IMPULSE, DEAD IN IT'S TRACKS. I initially thought that you had a rifle recoil buffer in a carbine receiver extension... It was that fucked up, in that vid, when it happened. You're here, looking for a resolution. WE CAN'T HELP YOU with that. Know why? You won't comply with details... It's not easy diagnosing gun-function problems over the internet - but if we're given the proper information, we NAIL IT about 90% of the time. And then some. Read this - come back after you read it... Edited August 31, 2021 by 98Z5V Quote Link to comment Share on other sites More sharing options...
98Z5V Posted August 31, 2021 Report Share Posted August 31, 2021 1 hour ago, 98Z5V said: As well as hit the Intro Section, and tell us about yourself. It's right here: https://forum.308ar.com/forum/22-introductions/ @Warriorone, start working on this part, in the meantime. Make sure that happens. Thanks in advance. Quote Link to comment Share on other sites More sharing options...
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