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AR-15 Assembly pt. II
sandwarrior
Member Posts: 5,453 ✭✭✭
For Rebel James,
I wanted clarify what the problem can be if you don't see it coming. If you leave the firing pin out, nothing holds the pivot pin in the top of the bolt carrier group. I have always known that with the firing pin missing, there would be nothing to fire the case.
However, the problem arises as you grab hold of the charging handle and yank back. The pin can push upward and spin just ever so much as to get cockeyed up in the top of the upper receiver and thus jam. You do know it's tapered, right? If it jams, and you continue to pull, it moves metal. Or, wedges itself where you have no way to get to the offending part. Without going into detail, Neal intended for the OP not make the mistake as it's a real pita to fix.
So, as the the "Duh!" I think if you retract that statement, with fair explanation from me of course, I won't be offended any more?[}:)] FWIW, I've made mistakes on what I've said here in the past, but I own up to them.
I wanted clarify what the problem can be if you don't see it coming. If you leave the firing pin out, nothing holds the pivot pin in the top of the bolt carrier group. I have always known that with the firing pin missing, there would be nothing to fire the case.
However, the problem arises as you grab hold of the charging handle and yank back. The pin can push upward and spin just ever so much as to get cockeyed up in the top of the upper receiver and thus jam. You do know it's tapered, right? If it jams, and you continue to pull, it moves metal. Or, wedges itself where you have no way to get to the offending part. Without going into detail, Neal intended for the OP not make the mistake as it's a real pita to fix.
So, as the the "Duh!" I think if you retract that statement, with fair explanation from me of course, I won't be offended any more?[}:)] FWIW, I've made mistakes on what I've said here in the past, but I own up to them.
Comments
You said :
"I've made mistakes on what I've said here in the past, but I own up to them."
Well you better own up to this mistake!
The pivot pin has nothing to do with the bolt carrier group. The pivot pin holds the upper to the lower. The cam pin is the part you should have meant.
In any case he was correct in saying bad deal if firing pin left out.[:)]
For sandwarrior
You said :
"I've made mistakes on what I've said here in the past, but I own up to them."
Well you better own up to this mistake!
The pivot pin has nothing to do with the bolt carrier group. The pivot pin holds the upper to the lower. The cam pin is the part you should have meant.
You're correct, it's the cam pin, as I called it in the last thread, not the pivot pin. Still, you do know that's the part that will cause hate and discontent if you leave out the firing pin and the previous situation is encountered.
edited for punctuation[}:)][;)]
Added:
Since I'm on a roll, the correct nomenclature for the part I have highlighted is Forward Takedown Pin. Even though it is quite convenient to 'shotgun' AR15/M16 rifles, thus 'pivot' has become a common name, both pins were made to be removed from the upper retaining boss,[}:)][;)]....[:D] so that the upper can be completely removed from the lower.
it's the cam pin... not the pivot pin. Still, you do know that's the part that will cause hate and discontent if you leave out the firing pin
sandwarrior, thank you for the info about the missing firing pin, I had no idea it could cause that much trouble.
quote:sandwarrior :
it's the cam pin... not the pivot pin. Still, you do know that's the part that will cause hate and discontent if you leave out the firing pin
sandwarrior, thank you for the info about the missing firing pin, I had no idea it could cause that much trouble.
+1
I wouldn't have known any better until it was too late, thanks for the heads up.
I have never owned an AR-15 until now. I always shot my brothers and have never been inside one much, and like now when I'm assembling my own.
Think of any other tips/tricks speak up I'm all ears.[^]
quote:sandwarrior :
it's the cam pin... not the pivot pin. Still, you do know that's the part that will cause hate and discontent if you leave out the firing pin
sandwarrior, thank you for the info about the missing firing pin, I had no idea it could cause that much trouble.
Actually, thank Neal {nmyers} as he was the one who brought it to our attention. I had seen it happen once, that I recall. But, not how it got undone. The rifle was taken in pieces to the armorer and was useable within a short time. But, not without some anguish on the part of the private who did it.
For Rebel James,
I wanted clarify what the problem can be if you don't see it coming. If you leave the firing pin out, nothing holds the pivot pin in the top of the bolt carrier group. I have always known that with the firing pin missing, there would be nothing to fire the case.
However, the problem arises as you grab hold of the charging handle and yank back. The pin can push upward and spin just ever so much as to get cockeyed up in the top of the upper receiver and thus jam. You do know it's tapered, right? If it jams, and you continue to pull, it moves metal. Or, wedges itself where you have no way to get to the offending part. Without going into detail, Neal intended for the OP not make the mistake as it's a real pita to fix.
So, as the the "Duh!" I think if you retract that statement, with fair explanation from me of course, I won't be offended any more?[}:)] FWIW, I've made mistakes on what I've said here in the past, but I own up to them.
I had that happen a few weeks back at the range. It was a PITA to correct.
Before shooting I took the BCG out of the upper - probably to wipe it down, hadn't cleaned it previously. The cotter pin drop out and I didn't notice it. WThe BCG closed, but the firing pin (with nothing to hold it in place) was left enough to the rear that the hammer strike moved it forward but not hard enough to set off the primer. Did this 2 or 3 times, no firing, and when I popped off the upper to check out from the rear dropped the firing pin.
Trying to directly pull the bolt to the rear resulted in the bolt moving just a touch with the bolt head not turning and the lugs locking in the receiver. After much fiddling of an alternating tap forward on the rear of the BCG with a cleaning rod down the barrel tapping the bolt face worked it loose. There was a rub mark inside the upper. I suspect the cam pin turned, worked up & out and the square top pressed against the round interior of the receiver.
When the BCG came out we saw the cotter pin missing and after looking found it on the ground by the bench. Very aggravating.
When the BCG came out we saw the cotter pin missing and after looking found it on the ground by the bench.A good habit to get into before installing the BCG is to slap the base of it on your palm to insure the firing pin is secured, then flick the bolt forward.
In addition to moving the bolt into position for installation you're making sure the cam pin is installed. That would be bad.
It's a quick one-two move that makes sure everything is in it's proper place before inserting the BCG into the receiver.
Agree. I "flicked" & must have canted the bolt to the left, that's when the pin dropped out. It's actually not the usual "folded over" cotter pin but a solid one with a head and a shorter split section. A plain old cotter pin probably wouldn't have dropped out - just had to have the "new & improved" part .... [V]