MarineGunBuilder
The Professor!
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Warning! THIS is why we need to follow STRICT safety protocol with a new build's first shots.
- Thread starter Racer88
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Good points all. Having one go full auto on you is not a fun experience. I've seen it happen and it is scary experience, with everyone on the range diving for cover. And professional gunsmiths have no immunity... the one I witnessed was a 1911 go full auto in the hands of a gunsmith. (brand new pistol that the owner complained was occasionally doubling shots.) So while he was testing it out with single shots, the sear portion of the three-finger spring finally broke and the five left in the magazine unloaded as a string. Last round went through the brim of the gunsmiths ball-cap and into the roof of the range. Only blood loss was the cut in the forehead from the front sight.
So, if you wanna play amateur gunsmith, good on you. It absolutely is a fun hobby. Just take a step back and work your way up until the mechanism proves it is working properly.
So, if you wanna play amateur gunsmith, good on you. It absolutely is a fun hobby. Just take a step back and work your way up until the mechanism proves it is working properly.
Flatbush Harry
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Lots of firearms have floating triggers, e.g., M1 Grand, M1A, to name two. When I clean a Glock, one of my checks is of the firing pin, its free travel, and its not extending beyond the breech face. I also check the firing pin safety for correct engagement and I always check cruciform sear engagement with an armorer's back plate to ensure at least 2/3 sear engagement. These checks will identify mechanical causes of accidental/negligent discharges.
Incidentally, changing the angle of the rear of the cruciform in an attempt to lighten the trigger pull or "correct" a non-functioning trigger is extremely dangerous. In my first build (a Polymer 80 BBS kit), the cruciform was out of spec and the trigger would not release. I contacted Polymer 80 Customer Service which sent me a new trigger bar whose Cruciform was correct. I don't screw around with the Cruciform in Glocks (or Self-Builds) and always check sear engagement to avoid problems. While I know what I'm doing with Glocks (and M1s/M1As courtesy of the CMP Advanced Maintenance Class in 2015 where I was taught by pros how to do a "trigger job" on these rifles), I just don't...and your mileage won't vary on this point.
FH
PS-In the USAF a half century ago, I got to try full auto with an M-14, and of course, with an M-16A1...they are hard to control for a full mag. Now I know all USA 11Bravos and USMC 0311s will dismiss my last comment as coming from a Chair Force puke who doesn't really know which end of a rifle is the dangerous end, nevertheless, full-auto is an adventure.
Incidentally, changing the angle of the rear of the cruciform in an attempt to lighten the trigger pull or "correct" a non-functioning trigger is extremely dangerous. In my first build (a Polymer 80 BBS kit), the cruciform was out of spec and the trigger would not release. I contacted Polymer 80 Customer Service which sent me a new trigger bar whose Cruciform was correct. I don't screw around with the Cruciform in Glocks (or Self-Builds) and always check sear engagement to avoid problems. While I know what I'm doing with Glocks (and M1s/M1As courtesy of the CMP Advanced Maintenance Class in 2015 where I was taught by pros how to do a "trigger job" on these rifles), I just don't...and your mileage won't vary on this point.
FH
PS-In the USAF a half century ago, I got to try full auto with an M-14, and of course, with an M-16A1...they are hard to control for a full mag. Now I know all USA 11Bravos and USMC 0311s will dismiss my last comment as coming from a Chair Force puke who doesn't really know which end of a rifle is the dangerous end, nevertheless, full-auto is an adventure.
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Flatbush Harry
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Racer88 made some really good points here. As to problems, there's nothing inherently wrong or dangerous with a Poly80 build or Gen 3...but sloppy building and/or non-OEM parts and tolerance deviations and tolerance stacking can create problems. The biggest potential problems come from incomplete (<67%) sear engagement, sticky firing pins, and malfunctioning firing pin safety all of which can contribute to accidental discharge. If a gun fires when the shooter pressies on the slide, as Racer88 quotes someone as saying, that comes from unsafe sear engagement which can come from several potential causes.
FH
FH
Great attitude... which could save a life, even. Take it one step at a time. Enjoy the journey and education.
Jesus
It is said that we learn more from our failures than we do from our successes. I did not watch the video but have seen others of similar situations. My own slam fire experience follows...
After assembling my first AR-15 build in 5.56, and performing all of my safety checks(or so I thought), it was time to fire it for the first time.
With the bolt locked back, I inserted a mag with one round in it, pointed the muzzle down range and released the bolt using the charging handle and my firing hand. I had not checked the safety selector which was on "fire" but my hand was nowhere near the trigger. It should not have been a problem, right?!
I was shocked when it fired as soon as the bolt closed. Definitely a major malfunction.
Upon closer inspection of the lower, the pocket for the FCG has not been milled deep enough. After a couple of passes with the router, it functioned perfectly and has ever since.
I was very glad that only one round was loaded in the mag.
No matter how careful we are, we are all capable of making a simple mistake even when we think we have checked all of the safety boxes.
The one round, two round, three round method is something I have used for all of my new acquisitions for many years. One of my first was an SKS which has a higher than normal risk of slam fires if the firing pin channel is not clean enough. It takes a lot of debris to cause problems, but some neglect to disassemble the bolt for a proper cleaning before firing.
The previous owner of my SKS cleaned cosmoline from everything but the firing pin channel in the bolt and the firing pin was locked in the forward position.
Firing on full auto has it's time and place, but unless you are testing a machine gun, it is not something most will be able to compensate for if they are not expecting it.
Unless I am laying down cover fire in a combat situation, one round at a time is the best use of available ammo based upon my experience.
After assembling my first AR-15 build in 5.56, and performing all of my safety checks(or so I thought), it was time to fire it for the first time.
With the bolt locked back, I inserted a mag with one round in it, pointed the muzzle down range and released the bolt using the charging handle and my firing hand. I had not checked the safety selector which was on "fire" but my hand was nowhere near the trigger. It should not have been a problem, right?!
I was shocked when it fired as soon as the bolt closed. Definitely a major malfunction.
Upon closer inspection of the lower, the pocket for the FCG has not been milled deep enough. After a couple of passes with the router, it functioned perfectly and has ever since.
I was very glad that only one round was loaded in the mag.
No matter how careful we are, we are all capable of making a simple mistake even when we think we have checked all of the safety boxes.
The one round, two round, three round method is something I have used for all of my new acquisitions for many years. One of my first was an SKS which has a higher than normal risk of slam fires if the firing pin channel is not clean enough. It takes a lot of debris to cause problems, but some neglect to disassemble the bolt for a proper cleaning before firing.
The previous owner of my SKS cleaned cosmoline from everything but the firing pin channel in the bolt and the firing pin was locked in the forward position.
Firing on full auto has it's time and place, but unless you are testing a machine gun, it is not something most will be able to compensate for if they are not expecting it.
Unless I am laying down cover fire in a combat situation, one round at a time is the best use of available ammo based upon my experience.
Wow. Not milling deep enough on an AR-15 lower receiver can cause THAT kind of a malfunction? Im glad to say I'm still learning everyday.
Apparently, yes.
The rifle passed all function tests prior to the attempt at test firing. It did eject the round and lock back though. That is why I concentrated on the lower to find the problem.
I can only speculate that the trigger could not get into it's proper position and allowed the hammer to drop when I released the bolt. The only thing that was borderline when I checked was the depth of the FCG area of the lower. Removing a few thousanths appears to have corrected the problem and it has run perfectly since. It definitely made the trigger reset more positive in it's feel.
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And that is exactly why "switches" are so dangerous, they are disengaging parts of the gun that stop it from slamfiring!
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AmenPersonally... I've never had an interest in commie firearms. I know a lot of guys do. But they are not for me.
OK... back on track about safety...
Make sure you've got a firm grip and control the muzzle (safely down-range) when you chamber a round in ANY gun.
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Welcome to the forum, Cgm0826!
Hello! Yes... please get yourself some "snap caps" or "dummy rounds." They have many uses beyond function testing your builds. You might enjoy this post:
Product Review - Do snap-caps matter? "B's Dummy's" Review!
Gun building discussions can be quite esoteric, and we can dwell on and wax philosophic about the virtues of a baby-butt-smooth RSA channel and the differences between various generations of ejectors. By contrast it seems any conversations about snap-caps would be rather mundane. Maybe not...
www.patriotgunbuilders.com
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Thats so sad.
My Dad purchased a New Colt 1911 series 80. Firing pin stop was out of spec and ended up dropping just enough to lock pin in forward position. He fired 1st magazine fine, reloaded,dropped slide and it went full auto. He lost grip but all rounds went down range. The stop fell completely out and pin was stuck in his chest. Only a 1/4" or so, could of ended differently.
Jfyi Colt apologized for the inconvenience and repaired the pistol for free
Anything can fail
My Dad purchased a New Colt 1911 series 80. Firing pin stop was out of spec and ended up dropping just enough to lock pin in forward position. He fired 1st magazine fine, reloaded,dropped slide and it went full auto. He lost grip but all rounds went down range. The stop fell completely out and pin was stuck in his chest. Only a 1/4" or so, could of ended differently.
Jfyi Colt apologized for the inconvenience and repaired the pistol for free
Anything can fail