Author Topic: Failure to load problem  (Read 420 times)

Offline Bandit70

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Failure to load problem
« on: April 16, 2019, 03:05:54 PM »
Recently built 224 Valkyrie rifle that is having an issue with the gas system.  Rifle was constructed using an Aero upper and lower, Wilson Combat 6.5T 22" barrel with rifle length gas system with a diameter of .875.  Installed a Superlative Arms adjustable gas block, rifle length gas tube and am running a Failzero EXO nickle boron BCG.  I am using a rifle length buffer tube, spring and weight also.
I followed the directions on adjusting the gas block, however, I can't seem to get enough gas to push the BCG back enough to chamber the next round or lock the bolt back on an empty mag, even when the gas block is set at maximum settings.  The rifle is ejecting the spent casing at 3 o'clock. Could the weight of the buffer and spring strength also be a factor?  How would one approach to diagnose and correct the issue.  I've tried removing weight from the buffer, but have the same results.  Any help would be greatly appreciated.  Thank you.

Offline Liberator52

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Re: Failure to load problem
« Reply #1 on: April 16, 2019, 09:40:45 PM »
Factory ammo or reloads ? Check gas block alignment over barrel gas hole. If you could switch lowers, it would eliminate the buffer question. Blow through gas block and gas tube to check for machining chips etc. blocking air passage. First things to check that are easy. Keep us posted on what you find. Lib.

Offline Bandit70

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Re: Failure to load problem
« Reply #2 on: April 17, 2019, 06:55:11 PM »
I checked the gas block, gas tube and BCG.  All appeared to be correct, air flowed through easily.  The BCG looked like it had some kind of nasty grease on it, so I disassembled it, cleaned and reassembled it. I attached a different lower from a 223 carbine and the rifle ran flawlessly. I then tried the original lower, and it resorted back to not cycling.  So at this point, I would assume it's something to do with the buffer/spring combo. Can I run a carbine buffer and spring in a rifle buffer tube? I'm using the MBA1 stock that I think requires the rifle buffer tube.
I was using reloaded 88 grain ELD,  24 grains Varget, starline brass with BR4 primers as a starting load.

Offline Liberator52

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Re: Failure to load problem
« Reply #3 on: April 18, 2019, 12:13:24 AM »
Next, I would try some factory ammo , if available. How do the primers look on your reloads. Are they lite loads ? Could try the carbine buffer with the rifle length spring. Try easy things first. Last I would look at the barrel gas hole diameter. Don't give up. :)

Offline Bandit70

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Re: Failure to load problem
« Reply #4 on: April 19, 2019, 05:17:59 PM »
Tried the carbine buffer in the rifle buffer tube, it worked on first round, but wouldn't chamber the 2nd round in the magazine. I ended up ordering a jps buffer and spring assembly with some alternative weights to adjust for fine tuning.
The primers on the reloads looked fine, no distortion evident. Will pick up some factory ammo next time I'm near a sporting goods store to try as well.

Offline Liberator52

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Re: Failure to load problem
« Reply #5 on: April 19, 2019, 05:58:09 PM »
Did you use the rifle buffer spring with the carbine buffer ? I believe the rifle spring is longer, and should seat the bolt better. Interesting problem. Please keep me posted on what you find. Chuck

Offline Bandit70

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Re: Failure to load problem
« Reply #6 on: April 21, 2019, 03:57:19 PM »
Yes, I tried the rifle buffer spring with the carbine buffer, even took out 2, then 3 weights from the rifle buffer and tried that also. I think I was possibly getting BCG bounce, as it was trying to load 2 rounds at once, but have never experienced this before, so I don't know what that would be called for sure.
I will put in the JP buffer when it arrives and let you know if that helped.
I did do a ladder test, with 1 group that measured .700 including a flyer, so the rifle definitely has potential.
Thank you for all your help and I'll post what results I get from new buffer assembly.

Offline Liberator52

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Re: Failure to load problem
« Reply #7 on: April 21, 2019, 08:54:31 PM »
Wow, this is a good one. Yes, please keep us posted on your results. I'll keep scratching my head.

Offline Liberator52

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Re: Failure to load problem
« Reply #8 on: April 21, 2019, 09:07:54 PM »
Has the problem changed from short stroking to double feeding ? Am I missing something in your description ? Happy Easter ! Lib.

Offline Bandit70

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Re: Failure to load problem
« Reply #9 on: April 28, 2019, 11:06:20 AM »
Finally had time to go to the range. I installed the JP silent spring yesterday. The JP buffer is the heavier one, with 2 tungsten and 1 steel weights. I also got an additional 2 steel weights to fine tune it upon recommendations from JP staff. I loaded 1 round in the magazine and the bolt locked back on the magazine catch like it was supposed to. I then loaded 2 rounds and the rifle cycled fine, but failed to lock back on the final round. I repeated that test several times with the same results. The brass is ejecting at 5 o'clock. I'm thinking I might need to replace one tungsten weight with a steel weight, but will know more after I talk to JP to see if that will fix the issue.

Offline Hammerhead

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Re: Failure to load problem
« Reply #10 on: April 28, 2019, 07:18:17 PM »
Since it runs fine on a different lower don't count out your bolt catch. They're cheap and I've seen that possibly cure one with the same issues in the past.

Offline Bandit70

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Re: Failure to load problem
« Reply #11 on: April 28, 2019, 07:39:07 PM »
Is there anything specific I need to look for on the bolt catch, or just replace it with another one and see if that helped. Thanks.

Offline Liberator52

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Re: Failure to load problem
« Reply #12 on: April 28, 2019, 09:55:35 PM »
Do you still have the double feed problem ? Bolt catch is a good possibility for not locking back as long as it is not short stroking and not picking up the next round. You'll get it !

Offline Hammerhead

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Re: Failure to load problem
« Reply #13 on: April 29, 2019, 06:32:47 AM »
I would just replace it and go from there

Offline Bandit70

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Re: Failure to load problem
« Reply #14 on: April 29, 2019, 03:16:26 PM »
Hammerhead, the double feed issue is gone now, think it was because I took out too much mass from the original buffer trying to get it to cycle regularly.  I called JP and they said to replace the spring on the SCS system with the lighter one available in the kit.  It's on it's way now, so I'll report back after I install it.  I'll also replace the bolt catch.  Thanks.