Out-of-Spec upper

AR/M4 AR Technical Discussion
1

A few months ago I purchased a flat-top T-marked upper at a gun show from a woman who claimed it was a Bushmaster upper. Has the Cardinal Forge marking above the forward assist mechanism.

I’ve been gathering parts for my .300/221 build, and just got my charging handle. I went to slide it into the slot in the receiver, no-go. The tabs on the sides of the CH are too tall and will not fit in the slot. Have tried this CH in 2 other ARs, and it fits just fine. CHs from the other ARs do not fit either.

Does anyone have the dimension specs for the slot in the receiver and/or the charging handle? I don’t know if I can get the upper replaced as I have no legit paper trail as to who machined/finished it, and Cardinal Forge is not responsible since they only make the raw forging.

I guess I can just mill the tabs down to fit this specific upper, and not worry about the anodizing being taken off - or apply a spray-on finish such as CeraKote.

Any suggestions? Thanks.

2

Get rid of the upper and buy one that is legitimate.

3

Agree with Scotty, and in the future don’t buy sketchy parts from random gun show salesmen…:wink:

4

Nothing really sketchy about it. I didn’t have the resources to verify what mfgr’s used Cardinal Forge-marked uppers, but I have another one that is virtually identical and have absolutely no issues with it. How would I have known it wasn’t in spec? Any part you buy can be out of spec no matter who it comes from and the only way to be sure is to check yourself, or trust who is selling it.

Let’s say I’m a starving student type and can’t afford another receiver. What would be the harm in modifying the charging handle until another one can be acquired? I tested the fit and function of a couple of BCGs in it and they work fine. Dust cover, forward assist also work properly.

According to this thread (http://www.ar15.com/forums/topic.html?b=3&f=12&t=486482&page=1), DS Arms, RRA, Stag, and Colt use Cardinal Forge uppers. I thought these were all reputable manufacturers?

5

try a DPMS charging handle… they’re generally a lot skinnier at the nubs, and there’s some uppers that only take 'em

6

I would take it to a smith and see what he or she say’s. It will not hurt you to ask? Next time do business with a reputable company or person. I have done the similar before just not such an expensive component.

7

You asked for advice which you got. Good luck with whatever you do. :cool:

8

Woops

9

Wonder if they were selling out of spec SI uppers… that’s the problem they were having and if I remember correctly, they had the cardinal marking.

Is it teflon coated?

When looking at it from the back, is one wall of the upper thinner than the other?

EDIT: Actually, the SI have “SI Defense” stamped on the side.

10

Make sure that a BCG will freely move in the upper (to make sure it’s in speck). If so then take a flat file and shave the “ears” on CH SLIGHTLY. File/fit, file/fit. then put it all together and run the dog piss outta it!!!

Until that day,
Darkop

11

I’m telling you, you need to replace the upper with a quality one.

Griding down the charging handle is wrong. You will end up with two out of spec parts.

12

Come on now, he will have two completely custom “fitted” parts that are the envy of all.

Seriously though, by the time you file a charging handle and fit it to the upper, you will probably find something else wrong with the upper. Maybe the centerline where the bolt carrier lives is not really centered, maybe the height of the barrel extention is too tall to reliably feed rounds from your receiver,all bad things.

Save your time and effort and just purchase a upper reciever from Bravo Company or some other good quality vendor. Then you will lower your blood preasure and actually enjoy trouble free shooting of your rifle.

13

i’ll trade you a DPMS charging handle for the one you have. no cost, and i bet it fixes it.