Would a good example of an XM4 Upper be:

Colt A2 Style Upper, with MB Forge Marks, the C in a Box, and the VP in the Triangle, M4 Feed Ramps, And a 4 above the Gas Tube Clover-Leaf Hole?

I would call it a darker Grey, Nowhere near Charcoal, or Black.

A friend has it, and another friend has first dibs on it, if he doesn't want to use it.  So I get sloppy second dibs. OH Well....

ETA - I will add that the Feed Ramps ARE Anodized, and the Front Pivot Pin Hole is standard Small Pin (.250") size.

I'd say it's more likely to be originally from a Colt 6520 (Gov't Carbine), but would be a good start to building a XM4 clone.

Been my experience that 6520 uppers don't have the "4" above the clover leaf.  Also DO have M4 ramps applied after the anodizing with grinder.  I'd guess most 6520 uppers were intended for A2 rifles.

Never say never when it comes to Colt.





Unfortunately I don't know when this was built. I bought it as a complete 6520 upper off the EE a few years ago to go with a 6520 lower I bought elsewhere. There's no date stamp on the barrel and it has a peel washer behind the flash hider. I couldn't get a good picture of the feed ramps but they are anodized.








 
 
 

There are no indications that it's anything other than a factory upper. Based on the peel washer and standard size pivot hole, I'm wondering if it may be off a ban-era LE rifle. I have another 6520 upper receiver which I know is has the 4 above the gas tube hole and anodized ramps, but I'm not sure if it has any proof markings. I'll see if I can dig it out of whichever box it's stored in.

I will add that the Feed Ramps ARE Anodized, and the Front Pivot Pin Hole is standard Small Pin (.250") size.

I've had plenty of LE 6520s over the years, and only one had the "4" over the cloverleaf and factory anodized ramps.   I'm guessing XM4 or early M4 upper receiver.  

I had a 6520 that had the anodized feed ramps and the 4 on the upper receiver.  Cant remember what was on the FSB. I sold the upper receiver a few years ago, damn wish I had kept it for an XM-4 build. I cut the barrel to 14.7.  I will check the date on it.  Here is the FSB.

Pic of the upper prior to sale.

Just to close this out, here's the other upper I bought from the EE, which was also advertised as a 6520 pull.




 
 
 
 

Fantastic score on that M4 marked A2 upper!  Thanks for posting the pics too.  Those are true M4 feed-ramps on your upper versus the pre-adoption "4" marked A2 uppers, which has the shallow 700 series feed-ramps.

My XM4 upper just has a 4 above the gastube hole, they are a dark charcoal gray and are exactly the same as the ones Coctailer was selling 6+ months ago, it lacks a C mark but has proofs near the port door. I can tell you they vary in co!or to a lighter gray to a very dark charcoal/black color.....these I believe are real XM4 uppers and the M4 marked ones are Colt 6520 takeoffs but I could be wrong.

The 6520 was in production in one form/model prefix or another for about twenty-five years.  

There was an incredible amount of variation in them, both in terms of configurations and markings.  

As much as people like to call this upper or that upper an "XM4," there were simply and frankly not as many of them to support just those that have been claimed as "XM4" uppers on the EE in the last year alone.  

Essentially, an unbarreled upper, unless there is a clear provenance attached to it pretty much has to be assumed to be a commercial take-off upper, be it a 6520, an RO777, or another model.  

This does not, of course, mean that these uppers can't be used to make a good, correct, representative XM4 clone--they certainly can, and if the terms being used are "could be used for an XM4," then there is nothing wrong with that, but claiming that it "is" an XM4 upper without any clear reason for doing so does not make much sense.  

~Augee