View Full Version : Potential problem with Anderson receiver
Thus last week we were on vacation to a family reunion. As part of the gathering several of us had some range time. One of my cousins had a rifle he built on an Anderson lower. The upper was a Psa....
As he was shooting the rifle it would drop the magazine. I checked to be sure he was fully seating it and it was initially locking up-not the problem. He would fire a round and the mag would drop out. The gun fired and ejected perfectly when the mag was properly sested.
Thinking it might be a bad mag I tried several USGI Aluminum mags...it would do it with some Centers and Okays and an FN I had along. It would not do it with a few Centers, a Bushmaster or any Pmags. Thinking it could be a mag catch issue I pulled the one from my personal gun....same problem.
I'm thinking it has to be a receiver tolerance issue?
Or a marginal mag release. Might switch out with a different, vetted release and see if issue continues.
Right hand shooter, not coming in contact with release inadvertently?
Or a marginal mag release. Might switch out with a different, vetted release and see if issue continues.
Right hand shooter, not coming in contact with release inadvertently?
Yea, I did that. I had my go to rifle there, a DD v5 and I swapped in my mag release for two mags worth. Same crap. Gun did the same thing regardless of who fired it.....Out of spec. receiver is all I can think of.
bamashooter
07-27-19, 14:16
Has the problematic lower been tried with a known good upper?
Has the problematic lower been tried with a known good upper?
No. Hadn't thought of that as a potential issue....
bamashooter
07-27-19, 15:27
No. Hadn't thought of that as a potential issue....
Nor have I however, when researching this problem, I found this to be interesting: "Hence to first make sure that the upper receiver area above the top of the lower front mag well area is not protruding over the top of lower edge, and preventing you from being able to lock a mag home to begin with, then to see the amount that the bolt catch tab is protruding into the mag well as well."
"Lastly, when you fully load a mag, it fully loaded when the top round can be pushed at least 2/3 of the way down to almost allow an other round. If you are loading the mag, to the point that once the last round is loaded, that top round can not be pushed down at least 1/2 of the way of allowing another round to be added, the you putting too many rounds in the mag. Hence on mag lock up to a closed bolt, the entire round stack has to be compressed downward in the mag (against the bottom of the carrier), and if too many rounds in the mag, the stack can not compress/the mag is not going to lock home."
Hopefully, it's ok link to another forum. Here's the complete deal with photo: https://www.ar15.com/forums/AR-15/Magazines-falling-out-/66-726809/
He only loads to 28 rounds so it's not the second issue. I'll have him try another upper just to rule that out. He has a Walmart closeout Colt 6920 that he bought several years ago. This gun was going to be his "backup" to the Colt.
bamashooter
07-27-19, 15:57
Yep, I screwed up. Didn't mean to paste the second para. Got caught up in the narrative w/ the pic and lost my mind.:laugh:
Is the magazine catch screwed in far enough?
Is the magazine catch screwed in far enough?
Yup, when I swapped mine on I tensioned it the same number of turns it had in my gun which has always been flawless.
Yup, when I swapped mine on I tensioned it the same number of turns it had in my gun which has always been flawless.
Cool. I don’t mean to call your gun into question but andersons are known to be out of spec so the same number of turns on your gun may not be the same number of turns on the Anderson.
Not wanting to belabor the point, but make sure you turn it in enough that the end of the stud is just below proud on the magazine release button.
From the TM if you don't believe me:
Install magazine catch (28). Push on magazine catch button (27) using drive pin punch and turn magazine catch clockwise until threaded end of magazine catch is flush with head of magazine catch
button.
That may very well be your frien'd problem.
titsonritz
07-28-19, 15:25
Yup, when I swapped mine on I tensioned it the same number of turns it had in my gun which has always been flawless.
Take one more turn and see if that does it. I've seen a couple lowers that required an extra spin.
I'll have him take another turn on the catch, making sure it is pretty well flush and see if it makes any difference.Thanks.
cutter_spc
07-29-19, 22:30
I got in on a group buy at work a few years ago for some Anderson lowers, at about $30 I figured why not? We found that all of the lowers we received had the mag catch slot milled too shallow, no amount of turning in the mag catch button was going to help. The company who sold them to us did make it right, but how many other lowers made it out there like this? This might very well be your issue. You could measure with a depth mic or even calipers and compare to print to find out.
Sometimes that is the unintended cost of a low, low price. My neighbor friend keeps buying Anderson with good luck. I feel that if we are buying what is technically THE GUN, we ought to spend a little more for some better QC. Nothing worse than a 40 dollar part throwing a wrench into a thousand dollar build.
I got in on a group buy at work a few years ago for some Anderson lowers, at about $30 I figured why not? We found that all of the lowers we received had the mag catch slot milled too shallow, no amount of turning in the mag catch button was going to help. The company who sold them to us did make it right, but how many other lowers made it out there like this? This might very well be your issue. You could measure with a depth mic or even calipers and compare to print to find out.
Doc Safari
07-30-19, 09:26
I've handled many Anderson and PSA lowers and the amount of mag catch tension varies greatly.
cutter_spc
07-30-19, 12:41
Sometimes that is the unintended cost of a low, low price. My neighbor friend keeps buying Anderson with good luck. I feel that if we are buying what is technically THE GUN, we ought to spend a little more for some better QC. Nothing worse than a 40 dollar part throwing a wrench into a thousand dollar build.
I totally agree with you!
I only got in the buy to help 4 others make the minimum so they could get into the building game. In the end, it did work out well for all involved, but only because I checked everything out when I got mine and alerted the others. The replacement is currently serving as 9mm pistol AR and working very well, though it is "that one thing" that I wished I had not skimped on.
I totally get it, and I'm glad it worked out. Despite what I tell my neighbor, he owns horses and his last name is Anderson, so this is his brand. It doesn't matter if he has to tap out his takedown pin with a hammer and punch. It doesn't matter if his selector goes to 'safe' on an uncocked hammer. It doesn't matter if his buffer is being dinged to shit by the retainer. :rolleyes:
I totally agree with you!
I only got in the buy to help 4 others make the minimum so they could get into the building game. In the end, it did work out well for all involved, but only because I checked everything out when I got mine and alerted the others. The replacement is currently serving as 9mm pistol AR and working very well, though it is "that one thing" that I wished I had not skimped on.
The_War_Wagon
07-30-19, 14:40
I totally get it, and I'm glad it worked out. Despite what I tell my neighbor, he owns horses and his last name is Anderson, so this is his brand.
NOT to be cruel (welllll... yeah - to be cruel), but - does he have the sticker? :jester:
https://i.ibb.co/6DjV7rw/Pony.jpg
Dude, he is shameless. Carries a Remington R51, loves his 'prized' Taurus 1911 and Judge. Shit you not, I could go on and on. He has about 200 guns, bless his heart, and they're all pretty much pawn shop rejects and gun show seconds. When we shoot our AR's, he has the quintessential "parts is parts" outlook. Doesn't know LMT from DPMS. I try. Lord knows I try.....
LOL'd at the sticker
NOT to be cruel (welllll... yeah - to be cruel), but - does he have the sticker? :jester:
https://i.ibb.co/6DjV7rw/Pony.jpg
Dude, he is shameless. Carries a Remington R51, loves his 'prized' Taurus 1911 and Judge. Shit you not, I could go on and on. He has about 200 guns, bless his heart, and they're all pretty much pawn shop rejects and gun show seconds. When we shoot our AR's, he has the quintessential "parts is parts" outlook. Doesn't know LMT from DPMS. I try. Lord knows I try.....
I guess the next question I have is, how does he shoot?
I guess the next question I have is, how does he shoot?
He probably doesn’t.
He does shoot because I can hear him doing so. However, his '100y range' is only 84y according to my laser rangefinder. That says a lot right there. Reminds me of that movie Kingpin with the 15 frame bowling score.
I guess the next question I have is, how does he shoot?
He probably doesn’t.
cutter_spc
07-30-19, 18:06
Yes, his 100 yard range only being 84 yards says tons🤣
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