I was in Scheels the other day and saw 20 round PMAGs for about $14.  I only have three 20rd GI style mags (from Brownells), so I thought I would pick up a couple and try them out.  I haven't found any rule against them, so my main question is how they will perform.

I haven't made it to the range yet, and I was wondering of any of you have experience with the 20rd PMAG.  
How do they perform for you?  
Any feed issues?

I usually support the rifle with my hand under the magazine in offhand, and I notice that the PMAG has a little more curve to it.  I'm not sure how this, or the plastic construction, will effect my shooting yet...

Curved 20rd mags are not allowed,  20rd mags must be straight.

We use the 20 round PMAGs. They are legal for use. They work fine. I prefer the older metal ones, though. They usually fall free on the reload; PMAGS sometimes do not drop out.

The old 20rd PMAGS are straight and would be allowed.  Magpul doesn't make them any more.
Current production 20rd PMAGS are curved.
The rules state that, "Standard service 20-round magazines are straight, without curves."
So it's my understanding that the new curved 20rd mags would not be allowed.

Here's a link to the CMP rules... http://www.thecmp.org/Competitions/Rulebook.pdf

CMP COMPETITION RULES FOR SERVICE RIFLE AND SERVICE PISTOL
18th Edition—2014-2015
6.2.3 U.S. Rifle, Caliber 5.56 mm, M16
The rifle must be an M16A2 or M16A4 rifle issued by the U.S. Armed Forces
or a commercial rifle of the same type and caliber. M16 rifles must be
chambered for the 5.56 mm cartridge and comply with the following specific
requirements:
•
Modification to make automatic fire impossible without removing,
replacing or altering parts is allowed.
•
Metal or synthetic (polymer) magazines with standard service 20 or 30-
round box magazine dimensions must be attached during the firing of all
courses and in all positions. A 10-round magazine with the same
external dimensions as a standard service 20-round box magazine may
be used. A dummy magazine with a ramp for single shot loading may be
used if this magazine has the same external dimensions as the standard
service 20-round box magazine. Standard service 20-round magazines
are straight, without curves. Standard service 30-round magazines are
curved.

I bought flat dark earth 20 round Pmags to keep separate from other guns/sports, never even made it to a highpower match with them.   Not a single one of them fed right.  I tested 30s in them and they worked fine but dang if my HP rifle didn't like them.  

20 round GI's have never failed me. I'm sticking with what works.....

I bought a bunch of C-Products stainless steel mags (back when they were still C-products).  They have been flawless out of both my regular match rifle and my spare/reduced course rifle.

Stainless has a higher yield strength than aluminum, so they are somewhat more durable.

C-Products is now ASC.  You can find them online.

Matt

Found one in the trash. Brand new PMAG 20 at our range. They don't drop free and I had some problems feeding it.

I'm a big fan of the GI 20 rounders. tough to go wrong with the NHMTG mags, they feed a lot better than any of the C-Products various company name mags I've owned over the years.

I shot next to the USAMU at Butner. They were using them. That was all the endorsement I needed.

My straight 20rd pmags will not feed a round loaded to max c.o.a.l. , but the curved ones will .

Interesting.  I've had the exact opposite experience.  I have a bunch of NHMTG mags.  They feed fine, but at best they are 50/50 on locking the bolt to the rear in single load.  Not a big deal in offhand, but a pain in slow prone.  It also sucks when your bolt doesn't lock back during a rapid string.  It's not the end of the world, but just might be enough to screw with your cadence for the last 8 shots.  That first NM rifle was a home brew that I built myself.  I had the CMP and Army armorers look over my rifle at Camp Perry (back in 2005 or so), and they said there was nothing wrong with it.  We figured it must be bad mags, so I kept a beat up old Colt mag with aluminum follower in my stool for years just for single load.  Eventually I bought a couple different brands of mags to try, and the C-products stainless (with the orange follower) were the ones that worked the best.  That's why I recommend them to others.

I do have issues with P-mags.  They will not drop free in either my Fulton Armory or my Rock River lower.  I also noticed that rounds loaded to the full 2.260" didn't fit.  I'm not modifying a magazine (or my lower) to make it serviceable.  Mags are cheap.  If it doesn't work out of the box, ditch it and move on to something else.

Matt

Been using them for years.   Like them because of the dust cover and just tougher construction.   In comparison, my GI 20s have an average age of 20+ yrs - they were getting kind of old!

No problem dropping free in my RRA.   And yes, You can get about 0.005" longer AOL if you use GI.  That hasn't been a priority for me.

The curved rule is just stupid.  It's not 1985 any more, and such a random rule adds nothing.   I'd rather use Lancer clear 20's so you can easily see the 8 and 2 count better.  But they have a slight curve.  So while you can compete with a hot pink AR with rails, you can't have a subtle curve to the mag body.

I swore that the Marine Corps team was using them too, but then again they are not competing for Navy EIC points.  

Thanks to all for the inputs.