View Full Version : How does this happen?
The upper and lower bulges doesn't quite line up. Is this the result from milling the upper or drilling the holes in the lugs? I'm just wondering if the whole upper is that much further forward will it affect reliablity.
I tried my Colt upper and lines up perfecly with this lower. Just wondering. Thanks
18406
That's perfectly normal for upper and lower receivers that weren't forged in the same foundries with matching dies. I'm not even sure why that "bulge" extends onto the upper receiver anyway. Purely a cosmetic problem, don't let it bother you.
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Thanks for this info. Couldn't find anything when I searched
So many "good enough" suppliers of parts or lack of QA/QC.
Milspec means exacting dimensions and construction. It either is or it isn't. Can't be both.
sugerwater
10-15-13, 14:58
All the machining will be in the correct location, just not in proportion to the forging. Kind of stuff that if it matters to you, has to be looked at during time of purchase. Does not hurt the rifle.
So many "good enough" suppliers of parts or lack of QA/QC.
Milspec means exacting dimensions and construction. It either is or it isn't. Can't be both.
Milspec actually means "good enough" too. It just defines a particular "good enough". All of the weapons I've handled that belong to Uncle Sam (obviously milspec, right?) have had similar cosmetic differences between upper and lower receivers.
Milspec actually means "good enough" too. It just defines a particular "good enough". All of the weapons I've handled that belong to Uncle Sam (obviously milspec, right?) have had similar cosmetic differences between upper and lower receivers.
this^^^
K.L. Davis
10-15-13, 21:38
Milspec means exacting dimensions and construction.
Untrue - "milspec" means a standard, but I think you are way overplaying it... it is just like ISO Certification, you could have a shop where your written standards and procedures say that you will:
a) Never make a part to fully comply with the supplied drawing
b) Have a QC fallout rate of over 30%
c) Consistently deliver late, and
d) Always go over the job quote by at least 20%
And if you did all of those things, every time... you would have a shitty shop, but if you provided your standards and procedures to your customers, your employees knew the company standards, you ran a safe shop, documented your poor workmanship, and complied with OSHA and EPA regulations, you could - in theory - have an ISO Certified shitty shop.
If I made barrels from the highest quality, 2.25" 4150 CVM Ordnance steel, following the the TDP print to absolute ideal tolerance, they technically can not be called "milspec" cause MIL-B-11595E calls for barstock, ordnance steel, under two inched in diameter.
Milspec, mil standard, etc, etc mean nothing in and of themselves... other than there is a standard; it is incumbent on the customer to understand what the standard really is... as I've said before, if you don't believe me try taken some toilet paper home from the BEQ and give it to HH6; see how far telling her "but it's milspec T.P. hun" gets you... big difference between issue "John Wayne asswipe" and oh so fluffy Mega Soft Angel Cloud bathroom tissue.
I can look... but I am pretty sure there not a requirement for forging details mating.. it is a cosmetic issue...
That said, I am not saying it is not important - one company I worked with for a while actually milled the little forging "bump" off of the upper receivers and radiused the top of the forging bump on the lower, so it ended before it reached the mating line between the two - and they did that solely to make their upper an lower combos look better - I like that attention to detail, but also recognize that it really means nothing as far as the function of the gun.
TunaFisherman
10-15-13, 21:40
Is the lower a blemished BCM ? My blemished lower fits a BCM upper like that. Rifle still shoots great. Normal fit n finish
Non blemished lower. Both new purchased separatly.
Thanks again. Good info.
Is the lower a blemished BCM ? My blemished lower fits a BCM upper like that. Rifle still shoots great. Normal fit n finish
Untrue - "milspec" means a standard, but I think you are way overplaying it... it is just like ISO Certification, you could have a shop where your written standards and procedures say that you will:
a) Never make a part to fully comply with the supplied drawing
b) Have a QC fallout rate of over 30%
c) Consistently deliver late, and
d) Always go over the job quote by at least 20%
And if you did all of those things, every time... you would have a shitty shop, but if you provided your standards and procedures to your customers, your employees knew the company standards, you ran a safe shop, documented your poor workmanship, and complied with OSHA and EPA regulations, you could - in theory - have an ISO Certified shitty shop.
If I made barrels from the highest quality, 2.25" 4150 CVM Ordnance steel, following the the TDP print to absolute ideal tolerance, they technically can not be called "milspec" cause MIL-B-11595E calls for barstock, ordnance steel, under two inched in diameter.
Milspec, mil standard, etc, etc mean nothing in and of themselves... other than there is a standard; it is incumbent on the customer to understand what the standard really is... as I've said before, if you don't believe me try taken some toilet paper home from the BEQ and give it to HH6; see how far telling her "but it's milspec T.P. hun" gets you... big difference between issue "John Wayne asswipe" and oh so fluffy Mega Soft Angel Cloud bathroom tissue.
I can look... but I am pretty sure there not a requirement for forging details mating.. it is a cosmetic issue...
That said, I am not saying it is not important - one company I worked with for a while actually milled the little forging "bump" off of the upper receivers and radiused the top of the forging bump on the lower, so it ended before it reached the mating line between the two - and they did that solely to make their upper an lower combos look better - I like that attention to detail, but also recognize that it really means nothing as far as the function of the gun.
I picked up a Walmart colt today just for the M4 rollmark and like my other colts or noveske rifles it is not misaligned. But I will concede to your knowledge on the subject. I also know nothing on John Wayne's toiletries. :)
K.L. Davis
10-16-13, 00:46
I picked up a Walmart colt today just for the M4 rollmark and like my other colts or noveske rifles it is not misaligned. But I will concede to your knowledge on the subject. I also know nothing on John Wayne's toiletries. :)
Just like JW, it's rough, tough and don't take shit off of no one :haha:
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