40 round Pmags (5.56)

[Friday]

Man...these things are tough to seat. Loaded with 40, I can't just click it in, and I can't slam it in. I have to literally push the gun down on it, like with the mag on the carpet and pushing the rifle on to it and then it will lock in.
None of my 30's act anything like this, even when maxed out.
Put 30 in the 40rd mag, and it fights you.

I get the increased spring pressure dynamic, but with just 30 they still fight back?
I have 2 of these and they both do the same thing in my PSA pistol and my M&P. Fight like hell.
Note; both of these 40 rounders have the light blue follower, only ones like that in my mag stash.
Note 2; I've never used either one of these. Will they 'get better' over time if I do?

 

[B00ger]

I have noticed that I have certain ARs that seat certain mags a bit different. Just as a check, have you tried them in any others? I have one and it always seems to click in decently.


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[Friday]

I have noticed that I have certain ARs that seat certain mags a bit different. Just as a check, have you tried them in any others? I have one and it always seems to click in decently.

I haven't tried them in any others.
Do yours have the light blue followers?

 

[B00ger]

I haven't tried them in any others.
Do yours have the light blue followers?

I can’t recall, it’s been a while. Like most, I have mainly 30 rounders, but was given a steel 40 by a friend and a 40 magpul because I was curious. Just in general know some rifles/pistols tend to be different in how they seat.


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[Friday]

I can’t recall, it’s been a while. Like most, I have mainly 30 rounders, but was given a steel 40 by a friend and a 40 magpul because I was curious. Just in general know some rifles/pistols tend to be different in how they seat.

Ok thanks B00ger. I really don't think it's a follower issue. My theory/best guess is that the increased spring tension is spreading the feed lips further apart and bucking me. Might be time to whip-out the micrometer and take some feed lip numbers between the 30 and 40.

 

[Trevillian]

I have two 40 round pmags. Each has had 400 plus rounds through. Never had one act any worse than a 30rd pmag. I've given to slapping the hell out of any mag I put in. My first rifle was weird about seating with any mag, so I slam em all home hard as I can muster.


They both sit full all the time. Just tried them both in all my rifles. No issues I found this time either.

Even the lower that hates steel cased, dry fed as much as I was willing to shuck

I gave up steel in AR's btw. But that one setups failure led me to give up steel case on general.

 

[Tim]

I have 2 of 'em. Both seat just fine when loaded to 39 rounds

 

[Derek8404]

I have one and it seats just as easily as any of my other mags even loaded up to full capacity.

 

[willpgn]

I always download Pmags, 30s and 40s (all gen2s) by 1. I’ve seen too many fall out on closed bolt reloads or closed bolt inserts (before a stage start) at matches. Not sure if this is the same for newer gen3s.

You are saying that a 40 rounder with 30 in it can’t be seated easily...no idea there...feed lips shouldn’t be expanding. 30 rounds in a 40 shouldn’t be a problem to seat. Do you have trouble with 30 rounders seating in this gun? My brother had a Spikes Tac lower that had a tight mag well but it got better over time. Is your mag catch messed up?

 

[bigfelipe]

Tough with 30rds in a 40 doesn't make sense. Something is wrong...

Do the followers drag or something? Tight magwell? Not sure what it could be but something's not right...

 

[Friday]

No trouble with either of these guns and any other mags regardless of round count. Click right in. Mag catches are working fine.
Only the 40's present issues.

I measured the back top of the mags right behind the stripper clip lines. Fully loaded. All the Pmags measured are brand new.
Pmag 40 #1- 22.55mm
Pmag 40 #2- 22.52mm
Pmag 30- 22.30mm
Alum. GI- 22.45mm

Basically, a two-tenths difference between the 40' and the 30's. That's nuthin'.

Do the followers drag or something? Tight magwell? Not sure what it could be but something's not right...

Followers seem to be just fine, magwells accept both 40's easily until you try to get the click. When I do get them locked in, they cycle the rounds with the charging handle no problem.
Yeah I'm kind of at a loss here. I'm play shooting on Sunday so I'll take them out and run them..see what happens. :shrug:

 

[Have gun-will travel]

I have 6 of them and they all work fine. I did have a hard time loading one in my Spikes tactical rifle but in all the other rifles and pistols they load just like the 30 rounders

 

[BlackGun]

The added length in the plastic mags make them bulge slightly. I have one you cannot get to seat when it’s full. I have Pmags but I don’t like Pmags. Most of mine are metal. What I don’t like about poly mags is if they are fully loaded and left in a hot truck even the thity round mags have issues with seating in the magwell.