Cerro Forge aka KeyHole uppers?

[PoFF]

I've got my hands on a 'keyhole' mark upper recently,

I've never heard of them before, what's the general opinion about them?

Thanks

 

[eos]

I've got my hands on a 'keyhole' mark upper recently,

I've never heard of them before, what's the general opinion about them?

Thanks

My brand new Bushmaster A3 carbine has one. Can't be bad if they use them.

 

[BattleRife]

A forge takes a rectangular piece of metal and turns it into a piece of metal that has the rough shape of a part. By all internet accounts, there are only 2-3 forges producing the receiver forgings for AR-15s. They then sell those forgings to Colt, Bushmaster, Continental, Yankee Hill, Olympic, Lewis Machine, and god knows who else. The quality of the machining that is done to the forging is 99% of the quality of the part. The forging itself is almost irrelevant.

The best way to look at it is to consider Cerro Forge as a material supplier. They sold a lump of aluminum to a machinist who made a receiver out of it. Whether or not you have a good receiver depends on the machinist, NOT on Cerro Forge.

 

[PoFF]

Ok, thanks for the tip. Is there a way to know exactly what make is my reciever. It's a flattop reciever with the keyhole mark over the forward assist (forging company as it seems) and a 'M' on the front face of the upper, just above the gas tube entry
Thanks,

PoFF

 

[dangertree]

CMT/Stag had some parts go out with M4 above the gas tube, likely Cerro forge. The Colt M4 would say it, but less likely to show up as parts(?). Just M though? Different.

Does it have Top Mark Numbers? White?