So my buddy and I are at the Tanner gun show in Denver a few weeks back and were looking around. I was kinda looking for a DPMS and came by one that my buddy pointed out. It was a Lo-Pro 16" and I mentioned that it did not have the ejection port cover and the dealer heard me. Right away he goes off on me and tells me how they never needed em in Nam and that you don’t need em now. I've never owned yet alone fired an AR but this just sounds like about the stupidest thing I ever heard. He made it sound like there is no need for one on a civilian owned rifle. What does the dust and dirt not blow in non-war zones? I politely told him thanks and walked away thinking, maybe I don't need the valve cover on my engine cause heck they didn’t have em in some old ships and submarines, plus with that fan blowin it ought to keep the dust from gettin all over the rockers and valve spring not to mention the rest of the engine. Heck who needs air filters it just restricts air intake. Was this guy tiring to make a sale or is there truth behind this. At any rate a little extra protection never hurt any thing.

Diesel

Sounds like he was trying to make a sale. Gee i wonder what else that upper was missing? Cam pins! Cam Pins! in my day we didnt need cam pins! especially on "civilian owned rifles". HA! Good call not buying that upper.

with a dust cover down and a mag in the rifle the chamber is pretty well seeled which goes a long long way is keeping mud and water and dirt outta the chamber. all my ar's look "pretty" but thats not what I bought them for. if I wanted a pretty gun I would have bought a rem 700 with a wood stock and custom engraving.. etc. my ar's have on simple purpose, and that is to take what ever I can through at them, and in my experience the all have (they are all bushys). the chrome lined chambers and bores are a large factor in why they are so reliable. I would never intentionally lay an ar down in th mud unless the situation dictated I had to, but the dust cover has come in handy alot when working with water.

just my .02

I can't ever remember closing the port cover on any of my ARs. But, I can see using it in the field.

I have a new DPMS stainless, fluted 16" Lo-Pro on a Bushmaster lower w/Jewell trigger and it will shoot .50 or better groups with 55 gr. Hornady V-Max bullets - all day long. Right now I have a 3X compact ACOG on it but it should shoot even better with a 10X - 12X power scope. There is no need for an ejection port cover on this varmint gun as it is not intended for combat situations. This upper has a massive receiver, very stiff and built for accuracy. It also does not have a forward assist nor a brass deflector. I, being right handed, like the lack of brass deflector as all brass ejects into a nice little pile - no brass hunting.

Edited to add picture

Added pic of my DPMS Lo-Pro 16".

DPMS makes three flat-top upper receivers.  one of them is a regular M4/M16A4 style with the forward assist and port cover.  The other two are intended for use on target guns and they have no port cover and no forward assist.

If you are building a plinker or a target gun then no, you don't need the port cover or the forward assist.  If you plan on using it for 'social' purposes then you should go for the upper with the extra features.

I know this may be the most ridiculous questions ever asked but what would happen if a round was fired and the ejection port cover was closed?  Would the force pop it open or would it jam? I only ask because I saw a picture in the newspaper of an Israeli soldier with a "ready to fire" caption and the cover was clearly shut.

The bolt cycling rewards will open the port cover before the brass is thrown clear.

It was designed to begin firing with the cover closed - it just pops open when you shoot and you shut it when you're done (at least I do - its not a bad habit to get into, especially in sandy areas).

thanks. I thought I'd ask before trying and becoming the next "you'll never believe what I saw this moron do at the range today" story.

the dealer knows what he's talking about, after all, he was probably a SEAL in the Nam.  heheh.

I duno Inferno, Why not have an upper with one on it. I meanjust because were not all law enforcement or millatary dosent mean that we need to keep the gun clean. Target gun or not I've been both at the range and out hunting and have the wind kick up and blow dirt around and out hunting walking through brush, cross streams what ever a little extra protection never hurt no body. At any rate thanks for the feed back, when it come time for myself to get one i'll go for the one with the cover. I try to take care of my guns but there are always thoes opppsies when your crossing a fence or what ever. SEAL or not before you know it they'll be telling ye you dont need scope covers and shoes!!!

Diesel

ejection port covers, you don't need no ejection port covers!  i'm joking of course.
dealers always act like they know what's best, hell i had a guy trying to sell me cheap ass mounts and rings for a $700 rifle!  now doesn't that just defeat the purpose?  i'd go with a cover cuz it looks cool and "better to have and not need.." well you get it.