Jfridley Posted March 12, 2017 Report Share Posted March 12, 2017 Good afternoon all, im in need of some help/ information. I finished a 308 build a little while back and finally got the time to shoot. Unfortunately my first go at it was left with disappointment and confusion. The issue I had was short stroking and the bolt getting stuck forward. I think I have the short stroking issues solved has the buffer I was using was to long. I've replaced it with the correct buffer and anxiously awaiting to try it again. However the bolt sticking forward still exists. The problem is once I racked a round and fired I really had to force the charging handle back to eject the shell. I've seen the mortaring videos on how to release the bolt. This is not something I want to do all the time. Why is it doing this? And how do I fix it? I'm using Aero Precision upper and lower along with their nickel boron bcg and a mega arms barrel. Help me understand why this is happening. Quote Link to comment Share on other sites More sharing options...
jtallen83 Posted March 12, 2017 Report Share Posted March 12, 2017 What ammo were you using? Do you notice any machine marks in the chamber or odd pattern on the fired brass? Many times these types of issues are resolved with a little chamber polishing. Could be ammo, I have a build that sticks with Magtech ammo but runs fine with other brands of ammo. Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted March 12, 2017 Report Share Posted March 12, 2017 14 minutes ago, Jfridley said: Good afternoon all, im in need of some help/ information. I finished a 308 build a little while back and finally got the time to shoot. Unfortunately my first go at it was left with disappointment and confusion. The issue I had was short stroking and the bolt getting stuck forward. I think I have the short stroking issues solved has the buffer I was using was to long. I've replaced it with the correct buffer and anxiously awaiting to try it again. However the bolt sticking forward still exists. The problem is once I racked a round and fired I really had to force the charging handle back to eject the shell. I've seen the mortaring videos on how to release the bolt. This is not something I want to do all the time. Why is it doing this? And how do I fix it? I'm using Aero Precision upper and lower along with their nickel boron bcg and a mega arms barrel. Help me understand why this is happening. It's going to be pretty tight until it gets broken in, I recommend a light coat of oil on everything in the bolt carrier group. The rifle isn't cycling at all, IE the bolt doesn't unlock and the carrier doesn't move? You may have issues with your gas system, that would explain both short stroking and failure to cycle. Check your gas block alignment with the gas port and make sure your gas tube is correct and installed correctly. Quote Link to comment Share on other sites More sharing options...
Jfridley Posted March 12, 2017 Author Report Share Posted March 12, 2017 I never really good get a good reading on the shells due to poor ejection. Getting stuck in bcg or getting jammed at the exit door. The spent brass was typically scratched, dented or smashed because of the short stroke not being able to properly eject.. I never could the gas system set either. No matter how far I adjusted the gas it never locked back. That I believe was because the buffer was too long and not allowing the bolt to travel far enough. I'm using Hornady Superformance. I will check the gas block alignment. Quote Link to comment Share on other sites More sharing options...
unforgiven Posted March 12, 2017 Report Share Posted March 12, 2017 I had a similar problem with my M5 setup. The bolt wouldn't lock up. I also had the NiBor BCG. Then it stuck and I had to mortor it open. I think it was tolerance stacking with the coating on the BCG. One of the guys had an issue with the recoil system and change over to Armalite extension tube, spring and buffer. Tube was longer as was spring and buffer heavier. Worked fine after that. Would probably work with original parts now that its broken in. Try heavy lube and work the charging Handel to get the bolt to seat itself. Some grease on the teeth of the bolt front and back will help also. At the time I call Aero tech support and mentioned this issue to them and they were unaware anyone had this issue. I think it goes back to the NiBor bcg that needs to wear in. Grease/lube and stroke and charge it for awhile [ no ammo]. I am very happy with my M5 after this slight hiccup. Just my 2 mags. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 12, 2017 Report Share Posted March 12, 2017 Too much or inconsistent NIB BCG coating by some manufacturers . Have you checked Head Spaced this Rifle ? Quote Link to comment Share on other sites More sharing options...
Jfridley Posted March 12, 2017 Author Report Share Posted March 12, 2017 From what I can tell the headspace seems fine. However I've been wrong at least once before Quote Link to comment Share on other sites More sharing options...
98Z5V Posted March 13, 2017 Report Share Posted March 13, 2017 (edited) On 3/12/2017 at 0:25 PM, Jfridley said: I'm using Hornady Superformance. Change ammo and retest your rifle configuration, as is, before you do anything else. Read here about Superformance and gas guns: http://www.hornady.com/ammunition/superformance-in-gas-operated-firearms "Due to the longer duration of peak pressure produced by Superformance™, the post peak/declining port pressure at common carbine and mid-length gas port locations is still higher than that produced by standard propellant. This has a tendency to flood the system with a larger volume of gas, at a higher velocity, that tries to open the bolt of the gun too fast. It’s a timing issue. The cartridge case is still swollen from the application of pressure during firing while the gun is simultaneously trying to extract the cartridge case before it has had an opportunity to settle back to its original size, or more simply: the gun is still in the process or firing while it’s trying to extract the cartridge case." Edited March 13, 2017 by 98Z5V Quote Link to comment Share on other sites More sharing options...
Jfridley Posted March 13, 2017 Author Report Share Posted March 13, 2017 That's interesting thank you. I'll swap and see what happens. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 14, 2017 Report Share Posted March 14, 2017 What are the Spec's of the Barrel , length , Gas system , type of Gas Block ? May also be type of Bullet loaded in the Hornady ammo , not just the pressure of the SP Load . So as said , try mil spec Ball ammo , Fed M 80 is a good choice . On 3/12/2017 at 5:20 PM, Jfridley said: From what I can tell the headspace seems fine. However I've been wrong at least once before You need to check Head Space or have it checked by a competent Gunsmith , just to be sure . Quote Link to comment Share on other sites More sharing options...
Jfridley Posted March 14, 2017 Author Report Share Posted March 14, 2017 The barrel is a 18in mega arms 1/10 twist. Mid length, with a JP adjustable block. I was planning on having the headspace checked tomorrow. Also a fortis muzzle break. If that makes a difference. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 14, 2017 Report Share Posted March 14, 2017 With an adj. Gas Block , the Ammo or type means nothing , you can adj. for high or lower pressure ammo . The NIB Bolt or a HS issue because of it, would be the first thing to look at . I have seen tight tolerances when checking HS on some NIB coated Bolts , with some that don't pass . Sometimes working the well lubed BCG over & over again , wears them in enough to allow full function with loaded ammo . It may also be too much pressure from the SP Ammo , as was posted by 98 , just adj. the Gas Block as described in the instruction that cam with it . Quote Link to comment Share on other sites More sharing options...
98Z5V Posted March 14, 2017 Report Share Posted March 14, 2017 1 hour ago, survivalshop said: With an adj. Gas Block , the Ammo or type means nothing , you can adj. for high or lower pressure ammo . The NIB Bolt or a HS issue because of it, would be the first thing to look at . I have seen tight tolerances when checking HS on some NIB coated Bolts , with some that don't pass . Sometimes working the well lubed BCG over & over again , wears them in enough to allow full function with loaded ammo . It may also be too much pressure from the SP Ammo , as was posted by 98 , just adj. the Gas Block as described in the instruction that cam with it . I think with the Superformance ammo (powder, really), it's more about when the peak impulse happens, not how much. In the Superformance, it occurs later. It's maxing out later, just as the gas guns are trying to begin the ejection cycle. Bam, stuck case in the chamber. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 14, 2017 Report Share Posted March 14, 2017 You should still be able to adj. that or any other Gas Impulse signal with the adj. Gas Block . The issue there as with adj. for any one load is , it may not work with a milder or one loaded with a Powder that has different characteristics . It seems they went out of their way to mention Carbines & Mid-lengths , but also had to be talking about other conventional Gas systems , including Piston systems . No mention if the systems were regulated or not . Quote Link to comment Share on other sites More sharing options...
98Z5V Posted March 14, 2017 Report Share Posted March 14, 2017 (edited) 1 hour ago, survivalshop said: It seems they went out of their way to mention Carbines & Mid-lengths , but also had to be talking about other conventional Gas systems , including Piston systems . Was thinking about this earlier, specifically. I'll bet it plays hell with piston systems. Piston systems still being operated by gas, with a very short trip (the smallest, shortest gas system?). That gas goes up the gas port, directly into the "manifold" that houses the piston, and the operating rod is a direct link to the BCG. In a gas tube, at least the longer gas tubes have to "fill and pressurize" in order to move the BCG. Once that magic pressure is reached, the BCG begins its trip rearward. Not so on a piston system... Edited March 15, 2017 by 98Z5V Quote Link to comment Share on other sites More sharing options...
survivalshop Posted March 15, 2017 Report Share Posted March 15, 2017 10 hours ago, 98Z5V said: Was thinking about this earlier, specifically. I'll bet it plays hell with piston systems. Piston systems still being operated by gas, with a very short trip (the smallest, shortest gas system?). That gas goes up the gas port, directly into the "manifold" that houses the piston, and the operating rod is a direct link to the BCG. In a gas tube, at least the longer gas tubes have to "fill and pressurize" in order to move the BCG. Once that magic pressure is reached, the BCG begins its trip rearward. Not so on a piston system... Probably conventional Piston systems as in a Browning BAR , some Remington semi auto rifles , for example , with no adj. of the gas available . Those Pistons get to full stroke & all excess Gas is expelled into the atmosphere , that may be a speedy piston travel . I would think that the Superlative Piston system ( and their adj. Gas Block ), with its exhausted waste gas system , might be a good thing . Quote Link to comment Share on other sites More sharing options...
dprice38444 Posted April 13, 2017 Report Share Posted April 13, 2017 did you clean the bolt face area in the barrel before attempting to fire it. might have some dirt or a high spot/burr on an edge there.check the bolt face for burrs or marks. might have to put some valve lapping compound on the bolt lugs and manually cycle it. had that happen 1 time in my new build.so far works good. Quote Link to comment Share on other sites More sharing options...
mrmackc Posted April 14, 2017 Report Share Posted April 14, 2017 On 3/14/2017 at 6:59 PM, 98Z5V said: Was thinking about this earlier, specifically. I'll bet it plays hell with piston systems. Piston systems still being operated by gas, with a very short trip (the smallest, shortest gas system?). That gas goes up the gas port, directly into the "manifold" that houses the piston, and the operating rod is a direct link to the BCG. In a gas tube, at least the longer gas tubes have to "fill and pressurize" in order to move the BCG. Once that magic pressure is reached, the BCG begins its trip rearward. Not so on a piston system... Also in the AR system the action of the gas inside the BCG with gas rings delay the rearward motion of the bolt and takes some stress off the bolt lugs until chamber pressure drops to a safer level, so I have been told. Quote Link to comment Share on other sites More sharing options...
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