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+--- Thread: Failure to go into battery (/showthread.php?tid=20692)
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Failure to go into battery - ecosystem3 - 02-25-2020
I recently finished building an upper with a Monster 20 Barrel and bolt from a recent group buy. I took it to the range this weekend to test it out and it failed to go into battery on the first try. I placed one Prvi Partizan 6.5 Grendel Ammo 120 Grain Hollow Point Boat Tail into a magazine, placed the mag into the lower and released the bolt catch. It sounded like everything went well. Pulled the trigger and "click". I went to pull the BCG back and reload but it was jammed forward to the point I had to use a mallet to disengage the BCG. I tried it again and the same thing happened. I cycled the BCG without a round and everything work fine. I am able to place a round into the bolt first, I am able to move the BCG into battery but I'm unable to do so from the magazine. It's almost as if there's not enough room for the extractor to open to receive the case before it goes into battery. There are scratch marks on the extractor.
Any thoughts?
[ATTACH=CONFIG]15533[/ATTACH]
Failure to go into battery - Kswhitetails - 02-25-2020
Disassemble extractor. Of present, remove oring. Re-assemble, try again. Is still an issue, ensure your bolt is correct. Tolerance stacking is real, and almost sounds as if you’ve found some issue with it.
What bolt/barrel/bcg, etc...?
Failure to go into battery - ecosystem3 - 02-25-2020
Yes, I removed the extractor, did a quick visual inspection, reassembled and the issue persists.
MONSTER 20 Barrel
MONSTER 6.5 Grendel Mk136 BOLT
Stag arms nickel boron coated bolt assembly
Failure to go into battery - FRB6.5 - 02-25-2020
What upper and what assembly checks and methods (light check for squareness, lapping, shimming, bedding, thermo-fitting etc.) were used?
Failure to go into battery - A5BLASTER - 02-25-2020
Do not take anything apart until you make sure your chamber isn't short and your jamming.
Drop a round of ppu120 in the chamber, muzzle down bcg locked back. Make sure there is no mag in the mag well.
Hit the bolt release and let the bcg slam home then see how it acts when trying to extract the round.
Come back after doing that and update us and we can go from there on helping you figure it out.
Failure to go into battery - ecosystem3 - 02-25-2020
A5BLASTER Wrote:Do not take anything apart until you make sure your chamber isn't short and your jamming.
Drop a round of ppu120 in the chamber, muzzle down bcg locked back. Make sure there is no mag in the mag well.
Hit the bolt release and let the bcg slam home then see how it acts when trying to extract the round.
Tried this a few times. The BCG is jammed in the forward position and requires a mallet to disengage. Once disengaged, the ppu120 falls out via gravity. There is some marking on the rim of the casing but nothing on the throat or bullet.
Failure to go into battery - LR1955 - 02-25-2020
ecosystem3 Wrote:Tried this a few times. The BCG is jammed in the forward position and requires a mallet to disengage. Once disengaged, the ppu120 falls out via gravity. There is some marking on the rim of the casing but nothing on the throat or bullet.
es3:
I caution you not to mess with live rounds in this situation while your firing pin is in the bolt. You are headed for an out of battery firing and they are dangerous. If you want to drop the bolt on live rounds trying to figure this out, remove the firing pin. Or, easy enough is to make a dummy and use that until you figure this out.
First, measure the bolt face depth. I know they said it is .136 but measure it anyway. If it is .125 then you know the problem.
If your bolt face really is .136, and the bolt locks and unlocks easily without a round in the chamber, yet it doesn't when you introduce a sized case that you know is sized down to the right dimensions, your chamber is cut too short.
Easy enough to figure out. Pull a bullet from a factory load without damaging the neck, dump powder and neutralize or pop out the primer. Factory brass is sized much smaller than most sizing dies so as to fit dozens of chambers that vary in dimensions. Drop brass into chamber, release bolt and if it does not go into battery, your chamber needs to be reamed out more.
Biggest thing for me is that you take the safety steps necessary to ensure no out of battery firing while you figure this out.
LR55
Failure to go into battery - Lemonaid - 02-25-2020
My .02 cent guess is that the rounds are not popping over the extractor or only part way. Possible fix is to polish any sharp edges on the extractor.
There are some excellent threads on the forum about extractor work if that is the problem.
Failure to go into battery - ecosystem3 - 02-25-2020
LR1955 Wrote:es3:
I caution you not to mess with live rounds in this situation while your firing pin is in the bolt. You are headed for an out of battery firing and they are dangerous. If you want to drop the bolt on live rounds trying to figure this out, remove the firing pin. Or, easy enough is to make a dummy and use that until you figure this out.
First, measure the bolt face depth. I know they said it is .136 but measure it anyway. If it is .125 then you know the problem.
If your bolt face really is .136, and the bolt locks and unlocks easily without a round in the chamber, yet it doesn't when you introduce a sized case that you know is sized down to the right dimensions, your chamber is cut too short.
Easy enough to figure out. Pull a bullet from a factory load without damaging the neck, dump powder and neutralize or pop out the primer. Factory brass is sized much smaller than most sizing dies so as to fit dozens of chambers that vary in dimensions. Drop brass into chamber, release bolt and if it does not go into battery, your chamber needs to be reamed out more.
Biggest thing for me is that you take the safety steps necessary to ensure no out of battery firing while you figure this out.
LR55
Thanks for the safety tip. That's a really common sense thing to do, yet I failed to do it.
I'll measure the bolt face when I get home this evening and then order a bullet puller.
What I'm confused about is if I manually place a round into the bolt and slide the BCG forward, it goes into battery and I'm able to pull the BCG back and the round is ejected. There are no markings and the round is not jammed.
Lemonaid Wrote:My .02 cent guess is that the rounds are not popping over the extractor or only part way. Possible fix is to polish any sharp edges on the extractor.
There are some excellent threads on the forum about extractor work if that is the problem.
I'll take a look at this too.
Failure to go into battery - LR1955 - 02-25-2020
ecosystem3 Wrote:Thanks for the safety tip. That's a really common sense thing to do, yet I failed to do it.
I'll measure the bolt face when I get home this evening and then order a bullet puller.
What I'm confused about is if I manually place a round into the bolt and slide the BCG forward, it goes into battery and I'm able to pull the BCG back and the round is ejected. There are no markings and the round is not jammed.
I'll take a look at this too.
If you manually place a round into the bolt and it goes into battery, then ejects without a problem there is no need for you to look at headspace issues or the depth of your bolt face. The problem as someone already pointed out is probably your extractor not snapping over the rim completely. In fact your picture shows wear on the extractor. That is probably the problem.
LRRP52 has some posts where he goes over polishing the extractor so it works properly. You will need to run some searches to find them.
If you are going to reload, you will eventually need a bullet puller so might as well buy one now.
LR55
Failure to go into battery - CJW - 02-25-2020
Damn great point about the firing pin LR55
Failure to go into battery - VASCAR2 - 02-26-2020
Here is a thread with pictures on tuning extractors. There are several more threads and can be found using the custom google search.
http://www.65grendel.com/forum/showthread.php?9743-extractor-polishing-pictures
https://cse.google.com/cse?cx=016368947416500061353:paqd_0xcu1o&hl=en
Failure to go into battery - ecosystem3 - 02-27-2020
Thanks, Vascar2. I found that thread too which led me to this thread and video: http://www.65grendel.com/forum/showthread.php?16276-Extractor-issue&highlight=polishing+extractor. I removed the extractor and proved it wasn't catching on the rim of the case.
I also came across this thread https://blackholeweaponry.proboards.com/thread/1538/say-goodbye-extractor-separation-issues. It mentioned that a black extractor spring plunger as a possible cause due to it's stiffness (blue ones are softer). I removed the plunger/o-ring around the extractor spring and viola, it went into battery! The first few cycles was a little rough but it begin to smooth out. I loaded 6 rounds into a mag and was able to cycle and eject each round without issue. I'll take it to the range this weekend for a final test.
Being a new member on this forum, I want to thank everyone who commented and offered your help. Your comments and direction were greatly appreciated!
Now to find a blue extractor spring plunger. I read it's ok to run without one. Any thoughts on that?
Failure to go into battery - grayfox - 02-27-2020
I've heard of running without the rubber o-ring, but not without the spring itself...
don't want to sound too simple, but what about ensuring the extractor slot and roll pin are clean and ...dry-lubed, sort-of? Every break down I do for cleaning disassembles and cleans the extractor, slot and roll pin...
just a thought.
Failure to go into battery - Kswhitetails - 02-27-2020
Either the extractor claw is too thick, the claw web is too thick, the extractor channel in the bolt is too thin (or dirty) not letting the extractor open completely, or there's an issue with some other tolerance somewhere. These are my current thoughts. Good luck.
Failure to go into battery - LRRPF52 - 02-27-2020
Your extractor is grinding against the Inside Diameter of the 2 o'clock barrel extension lug, and you can clearly see the interference.
Bill Alexander said this was one of the issues he encountered when setting up production specs for .50 Beowulf and 6.5 Grendel, since we are trying to get an articulating bolt/extractor/barrel extension profile meant for the smaller case head of the 5.56 to work with a larger case head.
Things that would never show up with a 5.56 rifle even with tolerances going out of a certain range, like they do when heat-treating the extensions after the feed ramps are broached, will show up for larger case head cartridges if you don't control the processes and tolerances more closely.
In the case of the larger case head cartridges from a production standpoint, you have to make sure that the inner diameter of the barrel extension lugs does not waver on you with the heat treat outside of a very tight range. This is something the home builder can't really control and does not even have the tooling to measure.
![[Image: 1582455373?v=1]](https://imgv2-2-f.scribdassets.com/img/document/296947990/original/ee53b051ad/1582455373?v=1)
Extractor snap-over during going into battery is part of the dynamic mechanical engineering that gets overlooked in a market where people have struggled to even correctly name the static dimensional differences on Grendel bolts, chambers, etc. One of the biggest enemies to achieving smooth snap-over is the presence of the O ring around the extractor spring. There is already a buffer inside the extractor spring meant to assist consistent spring tension under full auto fire. The O ring was added as a band-aid after SOCOM was having FTExtract malfs with M4A1s and KAC QD suppressors, as well as Mk.18s running suppressed.
The AR15 should operate smoothly within the ideal cyclic rate range with a relaxed extractor, and not need an O Ring to help with extraction on guns that are out of timing/extracting early during residual case pressure/obturation in the chamber. Those issues should be addressed at the source (gas system).
Failure to go into battery - Highbrow - 02-29-2020
I had similar issues with my 6mmAR match rifle until I dehorned the extractor.
Failure to go into battery - mighty_mace - 02-29-2020
I ran into a similar situation on a valkyrie build where the stripped upper I was using was out of spec. After replacing said upper, all is well.
Failure to go into battery - NugginFutz - 02-29-2020
LR55 - I would be hesitant to cycle the action of an AR without the firing pin installed. The firing pin is what keeps the cam pin correctly oriented, and without it, the cam pin can rotate at the worst of times, creating a locked bolt condition.
ETA: Here is a link to a thread where this issue is discussed in detail due to some unfortunate who made the mistake of function checking their AR without a firing pin.
[ARCHIVED THREAD] - bolt stuck, firing pin out, need help
Failure to go into battery - LR1955 - 03-01-2020
NugginFutz Wrote:LR55 - I would be hesitant to cycle the action of an AR without the firing pin installed. The firing pin is what keeps the cam pin correctly oriented, and without it, the cam pin can rotate at the worst of times, creating a locked bolt condition.
ETA: Here is a link to a thread where this issue is discussed in detail due to some unfortunate who made the mistake of function checking their AR without a firing pin.
[ARCHIVED THREAD] - bolt stuck, firing pin out, need help
You are correct.
I did not think through it well enough. Probably because the only out of battery firings I have ever experienced have been with a Grendel and those are real eye openers when they happen.
Thank you for correcting me on this technical issue.
LR55