Not sure WTF happened...Out of battery detonation

[One1Bravo]

Took my new 6XC build to the range for the first time. Lefty Impact action, TriggerTech Diamond (factory set pull weight), Altus barrel XLR Envy Chassis are the major components. I got it zeroed and starting shooting my handloads over the Magnetospeed V3. Components of the loads: Alpha brass, CCI BR4 primer, H4350, and 115gr DTAC seated .020 off the lands. My sighters for zeroing were 36grs of powder and pretty mild. Only issue was two primers that did not go off. Started chronoing at 36.5gr, 37gr, and 37.5 gr went fine. Shot two rounds of 38gr into one hole. Brass looked great. I got on target, ran my bolt forward, and just as I was starting to lock the bolt down the round went off. Scared the ever living shit out of me. Took the bolt out and inspected it and it looked fine. Action and barrel all intact with no signs of cracking. The only casualty, or so I thought, was the Triggertech Diamond. It would no longer drop the firing pin and had the very slightest slop in it. I didn't have my Fix It Sticks with me so I couldn't tear it down fully. I got home and pulled the barreled action out of the chassis. The rear screw for the trigger hanger had loosened quite a bit. Tightened it up and everything worked as it should. I've never had this happen. Any ideas about what could have caused it? Worried it may happen again and I happen to like my fingers, face, and gear.

Good piece of brass from same load:

Out of battery detonation brass:

 

[Steel head]

My guess is the trigger didn’t catch and firing pin protruding in bolt fade set off primer or it released as soon as you tried camming the bolt.

I’d really investigate your trigger to striker sear relationship.

 

[XLR308]

Pull the rear screw from the trigger hanger that you found loose and check it over very carefully for any signs of damage due to cross threading or the peaks of the threads being flat from yielding and slipping from being over tightened.
They are tiny machine screws and could be easily damaged, if you find any damage I would then carefully inspect the female threads in the action.

 

[FatBoy]

Hopefullu the screw was the culprit. If not you probably need more sear. Unload the rifle, close the bolt and smack the side of the stock with your hand and tap the handle sharply with your finger. If it drops, readjust the trigger. I have had a couple light M700s and a Timney loose the sear adjustment and fire on bolt closure.

Does the trigger have a trigger mounted safety? If so, does it still work?

 

[One1Bravo]

Hopefullu the screw was the culprit. If not you probably need more sear. Unload the rifle, close the bolt and smack the side of the stock with your hand and tap the handle sharply with your finger. If it drops, readjust the trigger. I have had a couple light M700s and a Timney loose the sear adjustment and fire on bolt closure.

Does the trigger have a trigger mounted safety? If so, does it still work?

Beat the stock and the handle pretty good and nothing happened. It does have a trigger mounted safety and it still functions as it should.

 

[Steel head]

Beat the stock and the handle pretty good and nothing happened. It does have a trigger mounted safety and it still functions as it should.

A good practice for new factory and home assembly jobs is to cycle the bolt very briskly a few times before firing.

 

[FatBoy]

You may have gotten lucky with finding the rear screw loose. I would follow XLR308s advice and inspect the screw and both sets of threads closely. If it's all good, maybe use a light thread locker on reassembly.

 

[One1Bravo]

A good practice for new factory and home assembly jobs is to cycle the bolt very briskly a few times before firing.

Yeah, I've cycled the bolt and dry fired it quite a bit prior to the first range trip. I'm not one to throw things together in a hurry and not function check but I'm definitely not perfect so I could have overlooked something.

I will pull the chassis off again and inspect the rear hanger screw to see what I find.

 

[Steel head]

Yeah, I've cycled the bolt and dry fired it quite a bit prior to the first range trip. I'm not one to throw things together in a hurry and not function check but I'm definitely not perfect so I could have overlooked something.

I will pull the chassis off again and inspect the rear hanger screw to see what I find.

Vigorously?
It does make a difference.

Certainly the rear hanger screw could cause the problem.

 

[One1Bravo]

Vigorously?
It does make a difference.

Certainly the rear hanger screw could cause the problem.

Not violently but quickly. I'll be sure to get a little rough with them in the future.

 

[AccuSol-ERN]

Given the fact its a Triggertech, sear engagement is most likely good (pre-set by the OEM). Also, I have NEVER seen a round go off from letting the firing pin forward from closing the bolt, the slow act of closing and the internal drag absorbs a LARGE portion of the firing pin impact energy.

THE PROBLEM IS: the rear trigger hanger screw was lose and, although the front was tight, it allowed the aluminum trigger hanger to flex enough letting the firing pin drop via the cocking piece riding over the trigger. The maximum load on the trigger is upon full closing on the bolt, so I don't think your "running the bolt fast" had anything to do with it...….just a coincidence of max loading at that time.

This is a drawback of trigger hanger setups. How many of you actually lock-tite those screws??? Nobody does......because you want to be able to take the trigger out and clean it or swap it for the latest trigger. I would like to see action makers put in a second layer of safety on trigger hanger actions by designing a tab/screw system on the rear of the hanger (like on the tempest action but in reverse) that allows the rear of the hanger (the most important part) to maintain its engagement/height with the firing pin cocking piece even if the front hanger screw shoots lose.

To be clear, this is not a "fault" of the action design, just something that needs to be pointed out to the kitchen table assembler. The unintended results can be VERY bad.

Just my $.02

Ern

 

[Greg Langelius *]

I always labor under the conclusion that any work I do to the rifle is intended to last for its lifespan. So dotting I's and crossing T's is an intentional act. Not to say I don't get it wrong on occasion, but the intent and follow through are meant to be there.

IMHO, 'temporary' measures aren't; and can, in fact, turn out to be the most permanent of creations. Better that they be done with permanence in mind than not.

In said instances, the permanent intentions can add a measure of effort to the task if and when revision is needed.

So what? I never do things with the idea that Oh, Dear, I'll need to be tearing this all back down someday. Do it right, then deal with what happen later; period.

Greg

 

[eastexsteve]

It sounds like a trigger issue. I had a Remington action that would do this if it was the least bit dirty.

 

[PracticalTactical]

I have a buddy with a "blue printed" rem 700 and he is now on his 3rd trigger tech trigger and still having problems.

We were at a match about a month ago and the Trigger Tech guys were there helping him...

They "said" the problem is with the relationship between the trigger pin holes and the centerline of the bolt. Apparently not all Rem 700 or 700 clone actions are the same.

The TriggerTech guys said that my buddy needs the trigger with the bolt removal lever on it and they swapped his for that one, but the problem still persists.

In my buddies case the trigger just does not catch every time, then he has to lift and close the bolt until it does, but I can see how he could have the same problem as the OP one day.

I also spoke with Patrice from Cadex about it that day and he showed me their new trigger that is both single stage and two stage... just move a pin to change from one to the other. He explained that this new trigger has features to prevent such a thing. Might be worth looking into. I do not recall what the weight range was but I thought it went fairly low.

 

[AccuSol-ERN]

PracticalTactical,

That sounds like a crazy issue. I doubt the triggers are adjusted incorrectly from the factory (especially with 3 triggers).....can your buddy be ham-fisting the install and pinching the trigger housing closed causing the sear to bind and not come up every time? I've seen this a lot with guys thinking they have the holes/pins lined up and beat it into submission...…..never knowing until the trigger comes out the housing is all narfed and causing issues.

Trigger location is pretty generous......at least as far catching...…......hard closing/travel strength and distance/timing/etc is another story.

A quick operating test is to remove the bolt so you can see the trigger sear...…..squeeze the trigger and hold it (safety off)...…...then use a punch or something to push the sear down...…..it should push and rebound with ease about 1/8".........if it doesn't that is your problem and you need to figure out why. I've seen problems range from a dumbass using heavy wheel bearing grease for trigger lube to broken internal trigger parts.

Let us know what you find out.

Ern

 

[PracticalTactical]

I wasn't there for the install but I'm confident that he was careful about it, and the reps from TriggerTech were quite familiar with the issue when we showed it to them.

They were quite specific about the dimensional variations between actions causing such problems.

They said actions with a side bolt release should not have the problem.

My take away is that you either have an action that likes a TriggerTech trigger or you don't.

My buddie threw in the towel on it and ordered a new action from Kelblys. He's been collecting Kelblys discount gift certificates at matches for 3 years now, so it wont cost him much.

 

[Changed]

This is the second time I've heard of this happening on a trigger hanger gun. I saw it in person. Hanger loosened over the course of an f-class match. In my case it was a Jewel, and the shooter caught it before an out of battery could take place.

 

[AccuSol-ERN]

Yep, I wish there was a second layer of safety with trigger hanger actions. Someday an AD is going to hurt someone.

 

[b6graham]

Wouldn't be the first time a TT diamond has dropped on bolt close and unfortunately wont be the last either

 

[AccuSol-ERN]

I am very interested in this comment. Can you give specifics on the TT diamond builds that were dropping.......actions, trigger weights, etc.

Ern

 

[b6graham]

ultimatum origin defiance

trigger weights 'within their advertised range'

 

[Deleted member 121493]

I have this issue with defiance/triggertech. Found it is eliminated (fingers crossed) by running trigger and action dry. Just a little gun oil on the bolt is enough for it to reappear. Very strange...