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View Full Version : Casing Deflector on CMMG Upper


Eric_Oh
07-16-2008, 12:19 AM
With the numerous threads i've been seeing here lately, it reminded me of a question i wanted to ask those of you with CMMG Uppers.

I'm not sure who makes the upper receivers for CMMG, but i noticed that on mine the deflector has a kind of lip on the front. Let me clarify... it seems that the deflector first extends laterally away from the receiver at a 90deg angle for a couple mm before it angles back.

This seems to cause brass to catch on that leading edge of the deflector and has worn down the finish of the deflector in the front.

Has anyone else noticed this?

ironcross
07-16-2008, 12:29 AM
Well as the saying goes

:useless:

DDRH
07-16-2008, 7:11 AM
Yea dude, pix would be nice. i'm still a newbie...the more pix the better...that way i can also learn the terms used... :gene:

DB2
07-16-2008, 8:21 AM
How old is the upper? It seems in the last few months, some vendors were assembling there own uppers out of CMMG parts to meet demands, since CMMG could not. My Cmmg upper has keyhole mark on it. Does yours? I'm pretty sure mine is factory assembled since I got it right before the backup. The person I bought it from, started putting his together right after that. I don't see a problem with a vendor doing that, but you might have another brand of upper receiver. The keyhole mark seems to be very common though through other manufacturers.


Pics would be nice.

The_Fonz
07-16-2008, 8:57 AM
heres a pic of my CMMG upper. The leading edge of the deflector is worn (circled), is that what you mean? I always thought that was normal. The deflector surface also has brass marks but you can barely see them in the pic. Its about two years old and works 100%.

http://i80.photobucket.com/albums/j186/The_Fonz_01/boomsticks/P1010123-1.jpg

Guntech
07-16-2008, 9:00 AM
its normal everyones deflector gets wear on it

gcvt
07-16-2008, 9:05 AM
I covered my deflector with a small piece of 'female' velcro to avoid scratches.

I'm not home right now, but I don't recall my CMMG deflector sticking out like that. I'll have a look when I get home and post pics if it's any different than you describe.

West coast
07-16-2008, 9:07 AM
That is normal on the upper, i have a Stag upper and i have same wear on it too.

Eric_Oh
07-16-2008, 11:00 AM
heres a pic of my CMMG upper. The leading edge of the deflector is worn (circled), is that what you mean? I always thought that was normal. The deflector surface also has brass marks but you can barely see them in the pic. Its about two years old and works 100%.

http://i80.photobucket.com/albums/j186/The_Fonz_01/boomsticks/P1010123-1.jpg

This is exactly what i'm talking about, but now with about 600-700 rounds through my gun, its showing more wear than is shown on this particular picture posted by Fonz. I asked this because i notice that on my buddy's RRA upper, the deflector did not extend out but rather angled back directly from the side face of the upper and thus did not exhibit any wear in the same area.

As for brass rubbing off on to the deflector, a little clp will help get most of that off, but the leading edge is actually wearing out. I think the casing rim is scraping on the corner there as its ejecting.

Guess its a common thing with these uppers. No biggie. Jsut wantd to know if i was the only one.

xrMike
07-16-2008, 12:05 PM
I covered my deflector with a small piece of 'female' velcro to avoid scratches.I am guilty of this compulsion as well, :o .

Although I don't think it would fix the OP's problem. Looks like his wear is happening forward of the deflection point where most of us get the usual brass smears.

jandmtv
07-16-2008, 12:19 PM
Its a rifle, its supposed to have wear!

gcvt
07-16-2008, 12:25 PM
Just got home and looked at my CMMG. Mine sticks out the same way.

l_Z_l
07-16-2008, 1:15 PM
do all of the CMMG uppers have that little part sticking out?

The_Fonz
07-16-2008, 2:00 PM
Unless they recently changed it, then they probably all do, but I doubt it has any effect on the functionality of the upper. I wouldn't lose any sleep over it.

munkeeboi
07-16-2008, 2:04 PM
i noticed it on both my cmmg lowers bought 2 mos apart. I'm over it. just as long as it's reliable.

Dark Water
07-16-2008, 2:31 PM
I have a CMMG and have not noticed that. I am too lazy to get up and check for sure but either way it is nothing to stress out over.

DDRH
07-22-2008, 1:38 PM
I checked my STAG recently and it looks just like your CMMG upper. the deflector comes out a bit than angles back. No big deal for me, as long as it works!

tyrist
07-22-2008, 2:12 PM
Mine looks the same I just checked.

Spitfire75
07-22-2008, 4:59 PM
I submit to you that if you do NOT get wear in that spot, something ain't right! ;)

CHS
07-23-2008, 12:41 AM
So, out of curiosity, why does anyone actually care? It's a shell deflector, it's specifically designed to take the high-speed impact of an ejected shell directly from the action of the firearm. It's going to wear, because it's doing it's job.

And to the person who posted about putting some soft velcro on that spot to absorb the impact, why not just stop firing your gun altogether? Do you realize the kind of damage that every fired round is doing to the internals of your firearm?

I'm a pretty positive person, but this thread just seems so silly to me.

domokun
07-23-2008, 12:52 AM
Just put a little CLP on the deflector and then wipe/buff it dry. It usually gets most of the markings off and keeps it looking decent if that golden color from the casing is really bugging you.

Sydwaiz
07-23-2008, 5:40 AM
If the brass didn't strike it, it wouldn't be a very effective deflector would it. FYI, I have a Colt M4 receiver in my hand that is the same.

xrMike
07-23-2008, 9:17 AM
And to the person who posted about putting some soft velcro on that spot to absorb the impact, why not just stop firing your gun altogether? Do you realize the kind of damage that every fired round is doing to the internals of your firearm?I don't do it to avoid the brass marks; I don't care about those. But that little piece of velcro has pretty much stopped the dents I used to get in my case mouths. And since I reload my brass, I do care about that.

I'm a pretty positive person, but this thread just seems so silly to me.I can't believe this is your first silly thread. There are dozens of them here every day. ;)

CHS
07-23-2008, 9:38 AM
I don't do it to avoid the brass marks; I don't care about those. But that little piece of velcro has pretty much stopped the dents I used to get in my case mouths. And since I reload my brass, I do care about that.


Ahhhh, ok, that's a very good reason then :)

Sounded like you were trying to baby your gun, not baby your brass. Baby'ing brass is definitely A-ok! :)