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Hey everyone. This is kind of an urgent topic. I have 4 EBR’s that are about to head across the pond in a very short period of time. Short enough that we do not have the time to send them into the armor to get them fixed.
The issue that these guns are having are all the same. When you hold the trigger all the way back after firing, the hammer does not reset and rides forward with the bolt carrier. To give some background these guns are all M14’s that were originally designed to be FA.
I am thinking that the sear on these M14’s are hanging up on something in the EBR chassis which is causing the sear to not engage the hammer fast enough. My only reason for this conclusion is some slight wear on the right side of the sear. However, I have never personally seen this issue before as my only experience is with a standard M1A and not with a real M14. The sear definitely looks different than what I am used to.
At this point my idea is to take a file and stone and begin to file the sear on the right side to give it some relief. If there are any other ideas outside of (replace) im all ears.
 

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"Death From Above"
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How well do the trigger groups seat in the stock. If there is too much room between the hammer and the bolt the hammer will never reach the hooks. Could be a geometry issue. Had this problem in a loose Garand stock. I could have bedded the trigger I just bought a new stock. Not really possible in your case but check the geometry especially if the trigger acts right when it’s out of the stock.
 

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What do regulations say on such an issue? Send to armory or self repair?. How fast would they be shipped and catch up with your unit?
 

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Look inside the chassis and see if you can tell where the sear is touching and just relieve that area inside the chassis.
I've never seen this problem and I've built alot of EBR guns.
Are the trigger groups functioning as designed when out if the chassis?
 

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https://youtu.be/1Kgnh4neVaY

Go to the 23 minute point and you will find a detailed explanation of the how the rifle works in semi and full auto. I'd check the selector to make sure that nothing is pushing on the full auto tang on the right side of the sear.
 

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According to EBRbuilder (A guy who actually built government EBR's), this is not an issue and was seen in about 30% of government EBR builds.

As long as the rifle functions in live fire, it's not an issue.
https://m14forum.com/modern-m14/131044-function-test-while-sage-chasis.html

I wrote the report that you were read from Rock Island and extensive testing proved that there was not a problem. I have shot more EBRs than anyone on this planet and there is not a safety issue. The other problems that you are having could be a number of issues such as lubrication, too much tension on the crush washer and just plain SAI fitment issues. We have found that different trigger housings cause this problem due to the geometry of the rear tang which controls the angle of the triggers insertion into the stock. About 30% of the EBRs built exibited this anomoly.
Hammer not re-setting when you function the action by hand is attributed to the housing issues. When you actually live fire the weapon, there is enough force transmitted to the trigger group to reset it just fine.

Some of the smiths on this board like SEI and Ted Brown mill about 10 thousandths out of the rear of the trigger inlet on the stock to fix this, but we discussed this with sage and determined that we would rather have a very stiff trigger lockup to support the accuracy that you get when everything is good and tight.

Some of the other problems that you are discussing could be a number of other things, where in Wisconsin are you located?

Tony.
 

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Discussion Starter #8
So it looks like it might be an issue with the chassis. I grabbed a fully functioning EBR and placed the trigger assembly in the non functioning chassis and it still did not work. I took the housing from the non working firearm and placed it in the working firearm and the trigger worked just fine. After some close inspection, it looks like there is some over travel on the trigger, due to poor machining on the EBR chassis. The problem seems to be in the realm of a couple hundredths of an inch. At the beginning I had 4 deadlined guns presenting the same issue. By swapping parts out from one trigger mechanism to another (trial and error) I was able to get 3 of the 4 working. The frustrating part is I don’t know why they are working now. Honestly, its more frustrating than the guns being broken.

Still working on that last one though... ive got two days to figure it out.
 

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This is one of the faults of the M1/M14 design.

If the distance between the receiver and the rear of the trigger assembly is not perfect, the hammer is not pushed low enough for the rear hooks to engage the sear. It can happen with any receiver/stock/trigger assembly combination, not just the SAGE.

As pointed out above, live fire usually will cause the hammer to bounce low enough to engage the sear, even if the rifle fails a manual function test.
 

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I don't think that it's a fault of the M14 design, it's a fault of any metal stock design. As mentioned, the distance between the trigger group and the bolt is critical in regards to cocking the hammer properly. With a metal chassis if that dimension is larger than the design specs then the hammer isn't close enough to the bolt to be cocked properly and you can't do much to fix the issue unless you are willing to machine some metal off of the contact area between the trigger group and the chassis.
 

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"Death From Above"
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It’s pretty simple to understand. Like I said in my first post the trigger when inserted into the stock sits too far away from the actual action even though it locks up with the trigger guard. If I was going to do anything I would get out a file and remove material from the trigger where it meets the stock. Take the actions out of the stock and I bet it works fine.
Take a look at the tab on the trigger that aligns with the slot in the action as well not just the shoes. If it works when you pull the trigger I’d call it a day.
 

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It's not an acceptable solution that the firing energy will reset the hammer. This problem will present itself when clearing the rifle, when loading the first round if the op rod is cycled and if the rifle has to be manually operated due to a jam, misfeed or misfire.

The shelf height needs to be adjusted. I don't know what you do in theater, but you may want to have it looked at before you go, or don't use the weapon system at all.

This would take about 30 minutes to alter per chassis. Shoot me an email and we can discuss a field expedient method. [email protected]
 

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This problem will present itself when clearing the rifle, when loading the first round if the op rod is cycled and if the rifle has to be manually operated due to a jam, misfeed or misfire.
Under those conditions, the hammer properly resets itself on the front hooks. It doesn't reset on the rear hooks when the trigger is held back, as in a manual function check.
 

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I don't think that it's a fault of the M14 design, it's a fault of any metal stock design. As mentioned, the distance between the trigger group and the bolt is critical in regards to cocking the hammer properly. With a metal chassis if that dimension is larger than the design specs then the hammer isn't close enough to the bolt to be cocked properly and you can't do much to fix the issue unless you are willing to machine some metal off of the contact area between the trigger group and the chassis.
Can happen with a wood stock as well. Did it on one of mine. My solution was to remove wood under the rear of the TG pad. Problem solved.
 

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Can happen with a wood stock as well. Did it on one of mine. My solution was to remove wood under the rear of the TG pad. Problem solved.
I understand that, my point was that with a metal chassis you can't fix the problem with simple hand tools. With a wood stock it would be easy to take some wood off or add bedding but with metal, to fix the problem properly, you would need to do some welding and/or milling.

A quick fix on a steel chassis might include some hand filing or metal muffler tape but I'm not sure I'd feel comfortable doing that when somebody's life might depend on the rifle being 100% reliable.
 

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Discussion Starter #17
More issues.. too little too late...

So quick update on the issue... I ended up bringing 37 EBR’s on the line to fire today with 17 experiencing the above stated problem. All rifles fired without issue. After doing a functions check post firing, all 17 still exhibited the same problem. So it would seem that they do function when using live ammo but still fail a manual functions check. (Slightly worrisome in my book but, I don’t get to make those calls.)

However we did find that almost 90% of the rifles could not maintain a zero. We confirmed the issue using multiple shooters all of whom are certified squad designated marksman or snipers. We were using M118 ammo in all of the rifles. The best my rifle could accomplish was a 6” group at 100 yards. It was rather disappointing to be perfectly honest. These rifles had never been shot before and still could not hold a zero. I even replaced the issued Leopold Mark IV with my Vortex Razor HD GenIII and could not get any better results.

Unfortunately, we are too close to heading out the door to get any issues resolved at this point. The weapons that were not able to maintain a zero will be boxed up and placed in storage to collect dust for the rest of the deployment including mine. Rather sad about that. I was pretty excited to take it.
 

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The best my rifle could accomplish was a 6” group at 100 yards...These rifles had never been shot before and still could not hold a zero.
...sounds like something is wrong with how those EBR's were put together, or the accuracy testing was done before they were 'settled' into the chassis. I don't how the barrel tension/barrel control screw was set on those 37 EBRs (maybe backed all the way out instead of providing some level of light tension/pressure?) - or if the SAGE op rod guide that connects the barrel to the chassis was incorrectly installed and thus 'binding' the barrel as it gets warmed up and causing a shifting zero? Others know more about the SAGE chassis set-up, but my understanding is the Rock Island Arsenal/TACOM-built US Army M14 EBR should be ~1.5” to 2.0” MOA rifles in 5-shot groups out of the box. Here's an 2018 article worth reading.

https://www.gunsandammo.com/editorial/how-the-u-s-army-builds-the-m14-ebr-ri/247604

How the U.S. Army Builds the M14 EBR-RI

Some end users faced situations where they needed to use M80 ball. The M14 EBR-RI would shoot this type of 7.62 NATO ammunition with two-MOA results (at best) at 100 yards. An SDM using M118LR would cut that group in half.

For accuracy testing, the Rock Island team pulled from an ample supply of M118LR. The recorded accuracy didn't take place until the tester observed that the rifle had begun to "like itself." These rifles quickly developed a specific wear pattern under recoil that allowed the barreled action to properly settle into the aluminum chassis. This was one reason why they highly advised against any operator or second-echelon armorer removing the chassis system from the rifle. Certain rifles settle in right away. At most, EBR testers allowed each rifle eight rounds, with an average of three to four bullets walking before stopping and revealing a group.

Only once has a rifle ever been condemned at accuracy testing. Although TACOM won't accept anything that shoots more than 1½ MOA, the average group measures .97 MOA (My note: these are only 3-shot groups, not 5-round groups). During my visit, four rifles were tested and the poorest accuracy was .76 MOA. The best rifle produced an incredible .44 MOA. I couldn't help but let my mind wander and think of the reaction at the range that would be elicited from the soldier in Afghanistan who is ultimately issued this rifle.
...one more interesting note from the article based on TACOM''s input:

MAINTENANCE

The aircraft-aluminum chassis was tight, and the rifle was configured so that the barreled action did not need to be removed from the chassis. Operator disassembly of the M14 EBR-RI was limited to cleaning of the external parts of the stock system, exposed action components and disassembly of the gas system to access the gas piston cylinder assembly. The M14 barreled action and forward rail should not be removed from the stock at the operator level. Any maintenance that required a barreled action to be removed from the stock should've be done by an armorer.)
...Anyhow, good luck on your deployment. Stay safe.

ON EDIT: Added info from EBR Supplement doc, dated 2009 - note that the manual states that properly setting and then locking-down the barrel control screw (aka barrel tension screw) on the top cover is the "most important step" to "ensure that it will meet the accuracy goals of one MOA or less." Sounds like the barrel tension screw might have been messed with, as TACOM tests those rifles to ensure it meets the 1.5 MOA (3-shot group) requirement before it can be shipped. I wonder if over-loosening or over-tightening of the barrel tension screw might be the culprit? A change in the POI as the barrel heats up is probably (or possibly) an issue without the barrel tension screw properly set. My 2cts.
 

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