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XCR-L Opening Itself While Firing

522 Views 8 Replies 4 Participants Last post by  LS2Cobra
First, just to make sure, are the spring guide male part and lower receiver female part correct? Should the actuation nub look like this when the rifle is assembled?

Automotive tire Bumper Wood Automotive lighting Automotive exterior

Automotive tire Automotive design Rim Bicycle part Auto part

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Rifle is 12XXX serial number. Bought it 2nd-hand. "Competition" length upper and a 14.5" heavy barrel with pinned/welded Surefire Warcomp (dunno why the PO chose the Warcomp as the competition handguard length covers the back of the device and precludes installing a can...) Has all the ambi parts and the FAST2 stock.

I've had the rifle on a square range several times to zero different optics with no problems.

Yesterday, while on the clock at a competition, I get Bang, Bang, dead trigger. I smacked the mag and went to rack the charging handle and when I did, I almost smacked myself in the face with the operating assembly.

At some point during the cycle the rifle had opened itself and had NOT reset the trigger. It did successfully eject the empty case.

At that failure I was standing and shooting over the trunk of a prop car using the car and a large sandbag as a rest.

I put it back together and proceeded with the stage. It happened twice more during that stage - once from a similar shooting position on another car and again while kneeling and shooting from a van's dashboard.

Same thing happened while shooting prone against a barricade port at the next stage.

Was using the same ammo with which I set zero - full pressure 5.56, 62 gr. brass cased from Stand 1 Armory.

Any ideas what's could be causing this?
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NO! It's not fully engaged. In your first pic, there should be no visible hole. The tapered block should be back another 1/8" or so.....the "button" on the end of the recoil spring in your 3rd pic should be fully seated in the upper hole in your 2nd pic.

You should be able to simply press it farther back in with your thumb when you close the upper onto the lower...since you've obviously shot it successfully in the past without it popping open.

If it was brand new or assembled from parts, I'd tell you that you likely need to fit that 'button' or nub on the end of the recoil spring. RA fits them to keep the lockup tight. Looks like yours is slightly too tight or you just didn't notice that the take down tapered block wasn't seated completely.
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That's what I assumed y'all would confirm.
I will try again (and push harder) to get it to set 100% but as far as I can remember since I've had it, Picture 1 was as deep as the male component of the spring guide has set.
I guess I got lucky it hasn't popped open on me before.
If that's the case, you need to fit the nub/nipple to the upper hole in the lower receiver. You can do it with a file or grinder....I've used both for a handful of builds.
To clarify...you should just need to fit/file that very top portion of the boss (where the ridge on top is) on the nipple. I should have said that originally.
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