PSA magazines and a question of operation

[ARP]

I have an EVO 3S1, have had it a number of years. Anyone on here who has had one for any length of time, perhaps 5 years remembers the situation with obtaining mags early on....they were in short supply and expensive. And then suddenly all kinds of non brand suppliers filled a hole. So I have the original equipment 20 rounders 5 PGA and 4 PSA. I am amazed I never took note of this "problem" but the PSA mags I had to slightly modify to get them to properly work, I had to sand down that plastic protruding rectangle on the front face of the mag to get them to seat.

Today I pulled out the EVO to make sure all worked properly and one of the things I noticed was that 3 out of the 4 PSA mags will NOT seat on a closed bolt. All of the PGA mags seat on a closed bolt. My belief is that open or closed that mag should seat like the others do. to seat I am beginning to answer my own question, I WANT them to seat on the closed bolt.

I would like to give a shout out to those who are alerting on the sale of 30 round mags at Midway, about to replace the PSA mags with CZ OEM mags. On sale right now, For a quick $100 I can replace the PSA.

[Trooper894]

I have "adjusted" all of my PSA mags so that they lock in and release easily in both of my Scorpions. None of my 35rd PSA mags will lock in with the bolt forward. However not a real issue for me, because I can down load the mag by 1 round and the mag will lock in fine and I still get 34 rounds and what I consider a much more durable magazine.

[ARP]

The seating on a closed bolt thing for me comes from an AR training class I attended a few years ago. I was new to the AR platform, my gear was all new. All I had was the internet knowledge I had read. So there I was, at the class and we were working on reloading. My AR had a round in chamber, I had pulled the partial full magazine and was replacing with a full mag. I fed the mag into the well, fired off a round and the mag fell to the ground. I had no idea how that could happen without me pressing the mag release. The "instructor" came over and was helping me. I did not know about the butt slap that you needed to do on a mag to seat on a closed bolt, and the instructor did not either. All of a sudden my gear became suspect(Windham Weaponry SRC) because it was not a Noveske/BCM/Colt/DD. They(2) were struggling like mad trying to push the mag into my rifle and ultimately gave up telling me that something in my rifle was out of spec and needed to sent back to the factory for inspection. When I got home from the class I tried all of my mags with 28 rounds to see if they would seat on a closed bolt. A few I could push in and get them to lock on a closed bolt. I was perplexed.

I packed the rifle into it's box, called Windham and explained the perceived problem, got a return label and sent it off. Got a call from them a few days later asking me once more what was the problem, because they could not replicate at factory. I explained and they said when they inserted a full mag into the well and gave it a butt slap, it locked every time. What is the butt slap? The guy explained to me that it is standard operating procedure to insert a mag and slap the butt of the mag to seat and then pull down on it to be certain it is seated. None of this was explained to me by the "instructors" at my entry level AR class. They had no idea either. Paid a lot of money for that 2 day class. I confirmed the procedure via youtube and internet. To Windham's credit, they replaced my bolt carrier group and sent me to new Hexmags, just to be sure of covering all possibilities.

It was just odd that I randomly decided yesterday to try the closed bolt insert mag thing. What is the adjustment that was made to the PSA mags to make them work and lock into place on a closed bolt?

[Thunderstick]

I too modified my PSA mags by sanding and I've had no issues.    Because I run mine in competition with a limit of 30 rounds in the mag, I've never experienced the problem with seating. 

I had the issue you described with my AR.   The course of fire called for load a mag, shooting 10 rounds, and reloading.   Pulled the trigger, it fired and the mag dropped.   I was on the clock and struggled to reload it.   After my run, a couple veterans approached me to help trouble shoot and the problem was I wasn't pushing the fully loaded mag hard enough on the closed bolt.    If I locked it open, then loaded the mag I would have been fine.   In only load my AR mags with 28 rounds for competition now

[ARP]

Well after fooling around with the PSA mags, the easy fix was removing a round or 2 and they seated on the closed bolt. So now I have enough mags for life.

[ARP]

The CZ mags arrived from Midway, they have a sort of textured exterior that I like, but it appears that the feed lips are polymer/plastic. So these mags will get torture tested at the range every chance I get to see if they fail.