Black_Sheep Posted April 3, 2021 Report Share Posted April 3, 2021 On Thursday night I finally got a chance to hit the range with a .308 build that was completed over the winter, it didn’t go well. It would load and fire no problem when I cycled the charging handle, but would not pull a round from the mag. It would either go into battery on an empty chamber, or the next round would tip up from the magazine and the bolt would wedge on the side of the case. It would also fail to hold open on an empty magazine. Spent casings would eject in roughly the 4 o’clock position. I posted my tale of woe on another MSR forum and one of the members suggested that I join here, that you guys we’re really sharp on the 308 stuff and Could help me get it sorted out. After reading through several threads, it’s apparent that I’m not the only one with cycling issues. I did some minor disassembly this morning to get measurements and verify my gas port to gas block alignment, which was right on. Here are the specs for my build, if you need any more information please let me know. Aero Precision M5 upper and lower receivers Wilson Combat 16” barrel with their proprietary intermediate length 13.25” gas system. The barrel gas port measures .075” Wilson Combat .750 low profile gas block, non adjustable Wilson Combat intermediate length gas tube which engages the gas key about .75” Aero Precision NiB BCG, the gas key is tight and the fasteners are well staked The Aero Precision receiver extension is 7” deep, measured inside The Aero Precision buffer weighs 3.436 ounces and has an OAL of 2.558” The Aero Precision buffer spring has a free length of 11.375”, 24 coils (not including the flat coil on each end) and a wire diameter of.070” Careful inspection of both receivers shows no signs of abnormal wear or interference So, where do I start? Please guys, help me sort this out so I can enjoy shooting it. Thanks in advance for any suggestions you have to offer Quote Link to comment Share on other sites More sharing options...
Black_Sheep Posted April 3, 2021 Author Report Share Posted April 3, 2021 I should add that I tried several new PMags, all with the same outcome Quote Link to comment Share on other sites More sharing options...
Magwa Posted April 3, 2021 Report Share Posted April 3, 2021 Welcome to the forum please stop by the introduction page and write a bit about yourself , gas port .075 I am not the expert here but this seems small but my main question would be how much lube do you have on your new weapon? the BCG should be dripping wet these bigger AR's need to wear in and they need a lot of lube hang in there help is on the way.. Quote Link to comment Share on other sites More sharing options...
shooterrex Posted April 3, 2021 Report Share Posted April 3, 2021 I would bet your gas port is to small and your buffer to light. There are threads that have all the info you need. Quote Link to comment Share on other sites More sharing options...
Black_Sheep Posted April 3, 2021 Author Report Share Posted April 3, 2021 44 minutes ago, Magwa said: Welcome to the forum please stop by the introduction page and write a bit about yourself , gas port .075 I am not the expert here but this seems small but my main question would be how much lube do you have on your new weapon? the BCG should be dripping wet these bigger AR's need to wear in and they need a lot of lube hang in there help is on the way.. Very wet, to the point of dripping Quote Link to comment Share on other sites More sharing options...
Magwa Posted April 3, 2021 Report Share Posted April 3, 2021 well that is a good thing I am betting your gas port is way small... wait for the professors to show up.. Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted April 3, 2021 Report Share Posted April 3, 2021 Wilson Combat is notorious for an undersized gas port on early run barrels. You'll end up drilling that gas port size up. Fortunately, it's not too difficult. Quote Link to comment Share on other sites More sharing options...
dpete Posted April 3, 2021 Report Share Posted April 3, 2021 Glad you found your way over here. Take a look at this thread. Quote Link to comment Share on other sites More sharing options...
Albroswift Posted April 4, 2021 Report Share Posted April 4, 2021 (edited) 12 hours ago, Black_Sheep said: The Aero Precision receiver extension is 7” deep, measured inside The Aero Precision buffer weighs 3.436 ounces and has an OAL of 2.558” While you can make a 7 inch tube work, no way is there a combination out there that a 3.5 oz buffer will work in a 308. Edit we'll get some more specific help to you, but first place to start is 5.4 oz buffer and a ea1095 spring in a 7-11/16" tube. Edited April 4, 2021 by Albroswift Quote Link to comment Share on other sites More sharing options...
Cliff R Posted April 4, 2021 Report Share Posted April 4, 2021 (edited) "It would load and fire no problem when I cycled the charging handle, but would not pull a round from the mag. It would either go into battery on an empty chamber, or the next round would tip up from the magazine and the bolt would wedge on the side of the case. It would also fail to hold open on an empty magazine. Spent casings would eject in roughly the 4 o’clock position." Ejecting the cases but not pulling from the mag sounds under-gassed from what I've seen with this sort of thing. Before opening up the hole for sure I would wait for 98Z5V to show up. He can smell a picture of your rifle and tell you what's wrong with it from what I've seen on here. May be something as simple that the spring, buffer and tube aren't compatible with what you are doing. Adding more gas may simply be a "crutch" fix for an issue with the combination of parts being used. Always best to opt for the correct fix vs over-gassing to correct fundamental problem(s) in other areas.....IMHO...... Edited April 4, 2021 by Cliff R Quote Link to comment Share on other sites More sharing options...
edgecrusher Posted April 5, 2021 Report Share Posted April 5, 2021 Buffer is too light and traveling too fast. Gas port is most likely two sizes too small as well Quote Link to comment Share on other sites More sharing options...
Black_Sheep Posted April 5, 2021 Author Report Share Posted April 5, 2021 I ordered a heavy buffer and spring from heavy buffers.com that is designed to work with a 7” RE, but I suspect the gas port is also too small. I found another thread where a poster with a very similar WC barrel configuration opened his up to .085 per 98Z5V’s recommendation and said it solved his issues. I’m hoping 98Z5V sees this thread and chimes in. I don’t want to go too big and muck up a $300+ barrel... Quote Link to comment Share on other sites More sharing options...
DNP Posted April 5, 2021 Report Share Posted April 5, 2021 Too big can be fixed with an adjustable gas block. Can’t go bigger than the inside of the gas tube or you’re just wasting open hole. You can almost guarantee it could go up a bit. Start small if you want after the new parts come in and work up to a comfortable level. Keep in mind some breakin will need to happen before things settle out, but build a gun that eats various ammo. Unless you’re building a competition gun around one specific reload...the basic numbers you see thrown out regularly in the other threads seem to work well. Quote Link to comment Share on other sites More sharing options...
Black_Sheep Posted April 6, 2021 Author Report Share Posted April 6, 2021 WC says: We set up our gas ports to run with carbine buffer systems (3.8 ounce carbine buffer and AR10 carbine spring) Standard (non adjustable) gas blocks are recommended. If your gun is short stroking with this setup you might might have a burr in the gas port or it might need to be opened by a couple of thousandths. A good gunsmith can assist you with that. Thanks! Since it obviously won’t run as is, I’ll have to get some number drills, can anyone recommend a quality brand that is suitable for a stainless barrel? Quote Link to comment Share on other sites More sharing options...
DNP Posted April 6, 2021 Report Share Posted April 6, 2021 That’s the ticket. Open it up and put a buffer of appropriate weight in the gun A lot of companies have tried to shrink the gas ports to compensate for running a slightly lighter and “less expensive to produce” buffer and it’s caused many a rifle to function poorly. Fixing a problem that didn’t exist. Sure, the 10 pound rifle is now 1.6 ounces lighter, but they’re trying to reduce gas and play with springs to adjust the physics of firing the rifle. I’ll take the extra ounce and a half to have a gun that eats anything. Don’t know what the right bit is for you to go with, but get a wood dowel to insert in the barrel as a backer. Quote Link to comment Share on other sites More sharing options...
sagebrush Posted April 7, 2021 Report Share Posted April 7, 2021 9 hours ago, Black_Sheep said: WC says: We set up our gas ports to run with carbine buffer systems (3.8 ounce carbine buffer and AR10 carbine spring) Standard (non adjustable) gas blocks are recommended. If your gun is short stroking with this setup you might might have a burr in the gas port or it might need to be opened by a couple of thousandths. A good gunsmith can assist you with that. Thanks! Since it obviously won’t run as is, I’ll have to get some number drills, can anyone recommend a quality brand that is suitable for a stainless barrel? ace hardware usually has irwin letter bits Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 7, 2021 Report Share Posted April 7, 2021 On 4/3/2021 at 5:42 AM, Black_Sheep said: On Thursday night I finally got a chance to hit the range with a .308 build that was completed over the winter, it didn’t go well. It would load and fire no problem when I cycled the charging handle, but would not pull a round from the mag. It would either go into battery on an empty chamber, or the next round would tip up from the magazine and the bolt would wedge on the side of the case. It would also fail to hold open on an empty magazine. Spent casings would eject in roughly the 4 o’clock position. I posted my tale of woe on another MSR forum and one of the members suggested that I join here, that you guys we’re really sharp on the 308 stuff and Could help me get it sorted out. After reading through several threads, it’s apparent that I’m not the only one with cycling issues. I did some minor disassembly this morning to get measurements and verify my gas port to gas block alignment, which was right on. Here are the specs for my build, if you need any more information please let me know. Aero Precision M5 upper and lower receivers Wilson Combat 16” barrel with their proprietary intermediate length 13.25” gas system. The barrel gas port measures .075” Wilson Combat .750 low profile gas block, non adjustable Wilson Combat intermediate length gas tube which engages the gas key about .75” Aero Precision NiB BCG, the gas key is tight and the fasteners are well staked The Aero Precision receiver extension is 7” deep, measured inside The Aero Precision buffer weighs 3.436 ounces and has an OAL of 2.558” The Aero Precision buffer spring has a free length of 11.375”, 24 coils (not including the flat coil on each end) and a wire diameter of.070” Careful inspection of both receivers shows no signs of abnormal wear or interference So, where do I start? Please guys, help me sort this out so I can enjoy shooting it. Thanks in advance for any suggestions you have to offer Toss that entire recoil system, and put in the Armalite AR-10 Carbine Recoil System. It's one part number to order, and it's the easiest, cheapest way to do this. This is what you're after: https://www.armalite.com/SACItem.aspx?Item=AR10REKIT01&ReturnURL=/Armalite/Product-Category/AR10-Parts-Accessories/Lower-Receiver-Parts&Category=ac614400-ff09-4cdf-9d35-419a654e7201 That gas port diameter does need to be 0.085" for that gun to run right. Numbered Irwin bits from any old Ace Hardware will do it. Look for a #44 drill bit. Here's a reference chart for numbered bit sizes: https://littlemachineshop.com/reference/numberdrillsize.php Make sure your gas tube ends directly in the center of the cam pin cutout in the upper receiver, just like that pic that's in the link that #dpete posted above. Quote Link to comment Share on other sites More sharing options...
Black_Sheep Posted April 7, 2021 Author Report Share Posted April 7, 2021 7 hours ago, 98Z5V said: Toss that entire recoil system, and put in the Armalite AR-10 Carbine Recoil System. It's one part number to order, and it's the easiest, cheapest way to do this. This is what you're after: https://www.armalite.com/SACItem.aspx?Item=AR10REKIT01&ReturnURL=/Armalite/Product-Category/AR10-Parts-Accessories/Lower-Receiver-Parts&Category=ac614400-ff09-4cdf-9d35-419a654e7201 That gas port diameter does need to be 0.085" for that gun to run right. Numbered Irwin bits from any old Ace Hardware will do it. Look for a #44 drill bit. Here's a reference chart for numbered bit sizes: https://littlemachineshop.com/reference/numberdrillsize.php Make sure your gas tube ends directly in the center of the cam pin cutout in the upper receiver, just like that pic that's in the link that #dpete posted above. Thanks, I will follow up with a range report when the mods are done. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 8, 2021 Report Share Posted April 8, 2021 (edited) On 4/6/2021 at 11:03 AM, Black_Sheep said: WC says: We set up our gas ports to run with carbine buffer systems (3.8 ounce carbine buffer and AR10 carbine spring) Standard (non adjustable) gas blocks are recommended. If your gun is short stroking with this setup you might might have a burr in the gas port or it might need to be opened by a couple of thousandths. A good gunsmith can assist you with that. Thanks! Since it obviously won’t run as is, I’ll have to get some number drills, can anyone recommend a quality brand that is suitable for a stainless barrel? I took their comments as "interesting," to say the best. Does that mean that Wilson Combat ONLY sets up their guns to run with Carbine Recoil Systems, and they're ONLY running 3.8oz buffers in 7.000" internal depth extensions? And what does "AR-10 spring" mean to them? What AR-10 spring?... There's only ONE AR-10 spring, and that's the Armalite EA-1095 spring, period. From what you described for your spring measurements, that's not the EA-1905 spring, nowhere close... MAYBE... Wilson Combat is talking about a 3.8oz AR15 H1 Carbine Buffer, which would require a receiver extension that's 7 5/8" internal depth, because that buffer is 3.250" long, and won't work in a 7.000" deep extension. Then, and only then, they could use the Armalite EA-1905 spring. But, the H1 buffer is still too light. Needs to be the H3, at 5.4oz... So, my real question is - if they're drilling their gas ports for that recoil system... then what happens when a customer wants a Rifle Recoil System?... That's a 9 11/16" internal depth receiver extension, with a buffer that's 5.200" long, and that buffer weighs 5.4oz... So, then the gun doesn't run right, because the proper (ONLY) Rifle Recoil System fuks it up, because they're drilling the gas ports too small?... Hmmm... They need to get their mentality right. They're missing the mark here. Someone throws a Rifle Recoil System in one of their guns, and it's gonna act like it's under-gassed, due to the increased buffer weight. Hell, it IS under-gassed, for proper buffer weight... From the old days... Deep Thoughts, By Jack Handey... Edited April 8, 2021 by 98Z5V Quote Link to comment Share on other sites More sharing options...
shooterrex Posted April 8, 2021 Report Share Posted April 8, 2021 WC got the gas port right on my creedmoor barrel. I have the Armalite rifle recoil system on my rifle and it runs fine after we changed the ejector in the bolt. The bolt was not WC though. Quote Link to comment Share on other sites More sharing options...
Black_Sheep Posted April 9, 2021 Author Report Share Posted April 9, 2021 (edited) Drilled the gas port out with a #44 bit and carefully reassembled the upper. Patiently waiting for my buffer stuff to show up so I can give it another try. One of the guys that’s shooting on our Thursday night pistol league generously offered to bring in his DPMS pattern.308’s to the range so we could swap around some parts to troubleshoot any malfunctions. I’m fairly confident it’s going to work so I told Doug let’s wait and see. I also shot a pic of the key end of the gas tube, it’s slightly past center of the cam pin cut out. Please tell me it’s GTG... Edited April 9, 2021 by Black_Sheep Horrible spelling Quote Link to comment Share on other sites More sharing options...
dpete Posted April 9, 2021 Report Share Posted April 9, 2021 Mine looked like that too and it functioned perfectly, with a 5.4oz buffer, and the Armalite spring. You should be good to go like that. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 9, 2021 Report Share Posted April 9, 2021 1 hour ago, Black_Sheep said: I also shot a pic of the key end of the gas tube, it’s slightly past center of the cam pin cut out. Please tell me it’s GTG... Great, just like that. Run with scissors with that one. Quote Link to comment Share on other sites More sharing options...
Black_Sheep Posted April 11, 2021 Author Report Share Posted April 11, 2021 The heavy buffer and spring showed up in today's mail. I'll update with a range report on Thursday. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted April 11, 2021 Report Share Posted April 11, 2021 It'll run. Quote Link to comment Share on other sites More sharing options...
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