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1/6/2008 5:19:42 AM EDT
Why would the rear part of these lower receivers be machined differently?

Anyone know?
1/6/2008 5:31:33 AM EDT
[#1]
They were made by different machine shops.....that's my guess
1/6/2008 5:42:29 AM EDT
[#2]

Quoted:
They were made by different machine shops.....that's my guess


Different machine shops for sure.

Just trying to find out why they would do that....whats the reason??
1/6/2008 5:49:24 AM EDT
[#3]
they are done on a cnc mill and it looks to me that the one on the right did not get finished. measure the slot on both. the operator probably had a problem and stopped the machine and then forgot that the piece was not finished. just my .02c
1/6/2008 5:55:12 AM EDT
[#4]

Quoted:
they are done on a cnc mill and it looks to me that the one on the right did not get finished. measure the slot on both. the operator probably had a problem and stopped the machine and then forgot that the piece was not finished. just my .02c


Probable, but unlikely.

Look here
1/6/2008 6:01:20 AM EDT
[#5]
Those are typical. The one on the left looks like my Mega's. The one on the left looks like an older lower I had. It is just a difference in what the shop does to machine them. Both are finished, but some shops carry the process a little further.

The top of threaded section, where the buffer tube screws in, on the one on the left again looks like Mega. The one on the right looks the the lowers I had from Spikes. I can't remember if Spikes looked like the one on the right in the channel where the selector goes through.
1/6/2008 6:46:27 AM EDT
[#6]

Quoted:
Those are typical. The one on the left looks like my Mega's. The one on the left looks like an older lower I had. It is just a difference in what the shop does to machine them. Both are finished, but some shops carry the process a little further.

The top of threaded section, where the buffer tube screws in, on the one on the left again looks like Mega. The one on the right looks the the lowers I had from Spikes. I can't remember if Spikes looked like the one on the right in the channel where the selector goes through.


A big thank you. I'm sure thats it.

Tag

Edit:  good eye, the one left is a Mega.
1/6/2008 6:54:10 AM EDT
[#7]

Quoted:

Quoted:
Those are typical. The one on the left looks like my Mega's. The one on the left looks like an older lower I had. It is just a difference in what the shop does to machine them. Both are finished, but some shops carry the process a little further.

The top of threaded section, where the buffer tube screws in, on the one on the left again looks like Mega. The one on the right looks the the lowers I had from Spikes. I can't remember if Spikes looked like the one on the right in the channel where the selector goes through.


A big thank you. I'm sure thats it.

Tag

Edit:  good eye, the one left is a Mega.

i146.photobucket.com/albums/r272/nevadasun/CTFreedom.jpg


Thought so, I love em...

Good luck with your project(s), and post pics when you are done.
1/6/2008 7:03:35 AM EDT
[#8]
My POF lowers are the same way, 416 is machined wider then the 415
1/6/2008 7:23:06 AM EDT
[#9]
The last Colt school I was the one of the Colt reps. mentioned that the rear was probably going to be seen in the future as a way of differenciating AR-15 and M-16.  The idea was that the basic garage guy could not simply drill a current receiver and fit the auto/burst sear.  

It was 2006 so I'm not 100% sure so hold off on the flammmmming if I'm wrong.  

I also love the MEGA!!!  Brian at MEGA is the bomb!
1/6/2008 7:26:51 AM EDT
[#10]
My late 90's Colt Match Target looks exactly like the one on the right.  I think it was machined like to obstruct a DIAS since late model ban Colt's didn't have the sear blocks.  I imagine current Colt Semi guns are still cut like that.
1/6/2008 7:38:23 AM EDT
[#11]
My new DPMS lower is like the one on the right. I had assumed it was to prevent the installation of a drop-in sear & FA happy switch.
1/6/2008 8:02:29 AM EDT
[#12]
neither one is machined wide enough to accept a gi auto sear
1/6/2008 8:08:04 AM EDT
[#13]
www.ar15.com/forums/topic.html?b=3&f=118&t=351771
1/6/2008 8:10:18 AM EDT
[#14]
I was going to say one may be a "high shelf", and the other could be a "low shelf" for a RDIAS.
1/6/2008 8:16:08 AM EDT
[#15]

Quoted:
neither one is machined wide enough to accept a gi auto sear


...and here I have been looking at the difference in mag-well's. I have read too many PMAG threads, lol.
1/6/2008 10:05:43 AM EDT
[#16]

Quoted:

Quoted:
neither one is machined wide enough to accept a gi auto sear


...and here I have been looking at the difference in mag-well's. I have read too many PMAG threads, lol.


I have P-mags, but on that one I'll most likely use NHMTG and Stoner Mags....your right the magwell is not as clean as the Mega
1/6/2008 10:41:23 AM EDT
[#17]

Quoted:
Those are typical. The one on the left looks like my Mega's. The one on the left looks like an older lower I had. It is just a difference in what the shop does to machine them. Both are finished, but some shops carry the process a little further.

The top of threaded section, where the buffer tube screws in, on the one on the left again looks like Mega. The one on the right looks the the lowers I had from Spikes. I can't remember if Spikes looked like the one on the right in the channel where the selector goes through.


Since we have more or less idenified this thing........ lets just say it was made for Sikes Tactical, would a CMT M4 "Type Upper" fit up and match well with this lower?

I have very succesfully built out a couple and have projects in the works, but this one throwing me a bit of a curve ..... looking for positive input.

First two builds:







The Mega receivers in Desert Tan are not built out yet ..... they have been vaccum sealed and stored away for another time ......
1/6/2008 11:41:30 AM EDT
[#18]
LAR manufactures the one with the extra meat where the selector goes through. Both of my Ameetecs (LAR machined) are like that.
1/6/2008 11:57:30 AM EDT
[#19]
I think a Spikes tactical lower would match up nicely with a CMT upper. The Spikes that I had were very nice, I just prefer Mega.

BTW your two colored Megas are nice.
1/6/2008 4:33:41 PM EDT
[#20]

Quoted:
I think a Spikes tactical lower would match up nicely with a CMT upper. The Spikes that I had were very nice, I just prefer Mega.

BTW your two colored Megas are nice.


I prefer Megas also, I'm just trying to match quality with quality.....a sincere thanks for the input.

Nevadasun
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