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Page AR-15 » AR-15 / M-16 Retro Forum
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Posted: 10/14/2016 7:40:44 PM EDT
My HYDRA-MATIC build is in the final stretch to completion. I now have the properly marked fire control parts, GM buffer and a perfectly "in spec" (minus the Capt Crunch cut) front have of the lower receiver. The Hydra half with my 80% lower will be going to braceman in the near future. Than the upper, slip ring and lower will all be re anodized. The only thing beyond this would be a HRA build but I feel that would be almost impossible.


Link Posted: 10/14/2016 8:32:19 PM EDT
[#1]
How can you tell that the buffer is a Hydromatic?
Link Posted: 10/14/2016 9:09:13 PM EDT
[#2]
Good question sir. The rear flat of the buffer has a indentation in the middle, rough circular cuts and flats are cut on both parts of the buffer. I'll post close up pictures soon comparing the GM to a Colt. Now it's spooky movie time with the kids.
Link Posted: 10/14/2016 10:03:26 PM EDT
[#3]
Thats going to be an awesome one
Link Posted: 10/14/2016 10:46:14 PM EDT
[#4]
What color anodize are you going to do?
Link Posted: 10/14/2016 11:58:58 PM EDT
[#5]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
What color anodize are you going to do?
View Quote


I'm going to let US Anodizing decide. I've exchanged emails and pictures with Victor as well. Both the upper and partial GM lower I have still bear the original finish and match perfectly yet are rather worn around the edges. It's almost like a satin black yet very, very smooth unlike his Colt "early grey" or "pre ban grey". It's a toss up between the Type III "new black" or the Xtremcoat" satin black and I'm going to let him decide based on the original finish. To answer M16Indiana's question regarding GM buffers here is a comparison between a GM and a Colt buffer. In the first picture the GM is on the right and the Colt is on the left. You can see the divot on the middle of the GM and the circular machine marks around the divot on the GM. GM manufactured 39 parts "in house" vs the 77 parts they purchased from "outside" so I'm going to have to start adding them up to see how close I'm getting.


GM buffers also , from the two I have seen not including mine have an additional flat cut into the middle area inline with the cut on the end of the buffer and it's very rough. The GM is on the bottom in this picture.

Link Posted: 10/15/2016 12:56:26 AM EDT
[#6]
Were the Hydramatic lowers 6061 or 7075?
Link Posted: 10/15/2016 1:29:43 AM EDT
[#7]
Cool, my first M16A1 was a hydromatic
Link Posted: 10/15/2016 9:04:22 AM EDT
[#8]
Awesome! Dream build for me for sure. Still hoping to find a nice front half like that, any particular source?
Link Posted: 10/15/2016 9:36:43 AM EDT
[#9]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Awesome! Dream build for me for sure. Still hoping to find a nice front half like that, any particular source?
View Quote


No particular source.........just speaking to the right person at the right time. Ti answer "backbencher's" question, GM production started in 68 and were made from 7075.
Link Posted: 10/15/2016 12:42:16 PM EDT
[#10]
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Quoted:
What color anodize are you going to do?
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I would vote against anodizing based on my past experience.  Since you are going to have the magwell welded to the back half of an 80% lower, the weld will show.   Also, if you have it anodized, they will sandblast the lower.  When they did that to mine, it caused some pitting which really ticked me off.  Braceman advised against having it anodized and I should have taken his advice!  I have done two others since and used Norrells and they turned out great.  
Link Posted: 10/15/2016 12:56:26 PM EDT
[#11]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


I would vote against anodizing based on my past experience.  Since you are going to have the magwell welded to the back half of an 80% lower, the weld will show.   Also, if you have it anodized, they will sandblast the lower.  When they did that to mine, it caused some pitting which really ticked me off.  Braceman advised against having it anodized and I should have taken his advice!  I have done two others since and used Norrells and they turned out great.  
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Quoted:
Quoted:
What color anodize are you going to do?


I would vote against anodizing based on my past experience.  Since you are going to have the magwell welded to the back half of an 80% lower, the weld will show.   Also, if you have it anodized, they will sandblast the lower.  When they did that to mine, it caused some pitting which really ticked me off.  Braceman advised against having it anodized and I should have taken his advice!  I have done two others since and used Norrells and they turned out great.  


Was it a GM part or a Colt part that acquired pitting as a result of the blasting process?  I have had a few things done at US anodizing including a square forge 604 upper and it came out fine.  Did you use Norrells on any GM stuff and if so what color did you use?
Link Posted: 10/15/2016 2:09:52 PM EDT
[#12]
Where are you guys finding the intact mag well sections?
Link Posted: 10/15/2016 2:46:24 PM EDT
[#13]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


Was it a GM part or a Colt part that acquired pitting as a result of the blasting process?  I have had a few things done at US anodizing including a square forge 604 upper and it came out fine.  Did you use Norrells on any GM stuff and if so what color did you use?
View Quote View All Quotes
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
What color anodize are you going to do?


I would vote against anodizing based on my past experience.  Since you are going to have the magwell welded to the back half of an 80% lower, the weld will show.   Also, if you have it anodized, they will sandblast the lower.  When they did that to mine, it caused some pitting which really ticked me off.  Braceman advised against having it anodized and I should have taken his advice!  I have done two others since and used Norrells and they turned out great.  


Was it a GM part or a Colt part that acquired pitting as a result of the blasting process?  I have had a few things done at US anodizing including a square forge 604 upper and it came out fine.  Did you use Norrells on any GM stuff and if so what color did you use?


My first was a Colt XM16E1, m.My second was a Colt M16A1, and my third was an H&R.    If you are going to have it welded by Braceman, you make want to seek his advice on anodizing. The weld would likely show up.
Link Posted: 10/15/2016 2:48:49 PM EDT
[#14]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Where are you guys finding the intact mag well sections?
View Quote



I got mine from GunBroker, but they are getting very hard to find and pricy!
Link Posted: 10/15/2016 3:51:38 PM EDT
[#15]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


My first was a Colt XM16E1, m.My second was a Colt M16A1, and my third was an H&R.    If you are going to have it welded by Braceman, you make want to seek his advice on anodizing. The weld would likely show up.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
Quoted:
What color anodize are you going to do?


I would vote against anodizing based on my past experience.  Since you are going to have the magwell welded to the back half of an 80% lower, the weld will show.   Also, if you have it anodized, they will sandblast the lower.  When they did that to mine, it caused some pitting which really ticked me off.  Braceman advised against having it anodized and I should have taken his advice!  I have done two others since and used Norrells and they turned out great.  


Was it a GM part or a Colt part that acquired pitting as a result of the blasting process?  I have had a few things done at US anodizing including a square forge 604 upper and it came out fine.  Did you use Norrells on any GM stuff and if so what color did you use?


My first was a Colt XM16E1, m.My second was a Colt M16A1, and my third was an H&R.    If you are going to have it welded by Braceman, you make want to seek his advice on anodizing. The weld would likely show up.


I will heed your advice sir!
Link Posted: 10/15/2016 4:45:02 PM EDT
[#16]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


I'm going to let US Anodizing decide. I've exchanged emails and pictures with Victor as well. Both the upper and partial GM lower I have still bear the original finish and match perfectly yet are rather worn around the edges. It's almost like a satin black yet very, very smooth unlike his Colt "early grey" or "pre ban grey". It's a toss up between the Type III "new black" or the Xtremcoat" satin black and I'm going to let him decide based on the original finish. To answer M16Indiana's question regarding GM buffers here is a comparison between a GM and a Colt buffer. In the first picture the GM is on the right and the Colt is on the left. You can see the divot on the middle of the GM and the circular machine marks around the divot on the GM. GM manufactured 39 parts "in house" vs the 77 parts they purchased from "outside" so I'm going to have to start adding them up to see how close I'm getting.
http://img.photobucket.com/albums/v633/tazaroo/GM%20Buffer%20001_zpsyv7xbmhz.jpg

GM buffers also , from the two I have seen not including mine have an additional flat cut into the middle area inline with the cut on the end of the buffer and it's very rough. The GM is on the bottom in this picture.
http://img.photobucket.com/albums/v633/tazaroo/GM%20Buffer%20002_zpstvjssdi8.jpg
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
What color anodize are you going to do?


I'm going to let US Anodizing decide. I've exchanged emails and pictures with Victor as well. Both the upper and partial GM lower I have still bear the original finish and match perfectly yet are rather worn around the edges. It's almost like a satin black yet very, very smooth unlike his Colt "early grey" or "pre ban grey". It's a toss up between the Type III "new black" or the Xtremcoat" satin black and I'm going to let him decide based on the original finish. To answer M16Indiana's question regarding GM buffers here is a comparison between a GM and a Colt buffer. In the first picture the GM is on the right and the Colt is on the left. You can see the divot on the middle of the GM and the circular machine marks around the divot on the GM. GM manufactured 39 parts "in house" vs the 77 parts they purchased from "outside" so I'm going to have to start adding them up to see how close I'm getting.
http://img.photobucket.com/albums/v633/tazaroo/GM%20Buffer%20001_zpsyv7xbmhz.jpg

GM buffers also , from the two I have seen not including mine have an additional flat cut into the middle area inline with the cut on the end of the buffer and it's very rough. The GM is on the bottom in this picture.
http://img.photobucket.com/albums/v633/tazaroo/GM%20Buffer%20002_zpstvjssdi8.jpg


Cool, thanks.  It looks like I have one in my parts box - I'll add it to my GM stash.  It looks just like yours with the flats on the side and the wine colored pad, but my end divot is not as deep as yours.
Link Posted: 10/15/2016 5:31:11 PM EDT
[#17]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


Cool, thanks.  It looks like I have one in my parts box - I'll add it to my GM stash.  It looks just like yours with the flats on the side and the wine colored pad, but my end divot is not as deep as yours.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
What color anodize are you going to do?


I'm going to let US Anodizing decide. I've exchanged emails and pictures with Victor as well. Both the upper and partial GM lower I have still bear the original finish and match perfectly yet are rather worn around the edges. It's almost like a satin black yet very, very smooth unlike his Colt "early grey" or "pre ban grey". It's a toss up between the Type III "new black" or the Xtremcoat" satin black and I'm going to let him decide based on the original finish. To answer M16Indiana's question regarding GM buffers here is a comparison between a GM and a Colt buffer. In the first picture the GM is on the right and the Colt is on the left. You can see the divot on the middle of the GM and the circular machine marks around the divot on the GM. GM manufactured 39 parts "in house" vs the 77 parts they purchased from "outside" so I'm going to have to start adding them up to see how close I'm getting.
http://img.photobucket.com/albums/v633/tazaroo/GM%20Buffer%20001_zpsyv7xbmhz.jpg

GM buffers also , from the two I have seen not including mine have an additional flat cut into the middle area inline with the cut on the end of the buffer and it's very rough. The GM is on the bottom in this picture.
http://img.photobucket.com/albums/v633/tazaroo/GM%20Buffer%20002_zpstvjssdi8.jpg


Cool, thanks.  It looks like I have one in my parts box - I'll add it to my GM stash.  It looks just like yours with the flats on the side and the wine colored pad, but my end divot is not as deep as yours.


Nothing like an undiscovered find in the old parts box!!
Link Posted: 10/16/2016 2:11:11 AM EDT
[#18]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


Nothing like an undiscovered find in the old parts box!!
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
Quoted:
What color anodize are you going to do?


I'm going to let US Anodizing decide. I've exchanged emails and pictures with Victor as well. Both the upper and partial GM lower I have still bear the original finish and match perfectly yet are rather worn around the edges. It's almost like a satin black yet very, very smooth unlike his Colt "early grey" or "pre ban grey". It's a toss up between the Type III "new black" or the Xtremcoat" satin black and I'm going to let him decide based on the original finish. To answer M16Indiana's question regarding GM buffers here is a comparison between a GM and a Colt buffer. In the first picture the GM is on the right and the Colt is on the left. You can see the divot on the middle of the GM and the circular machine marks around the divot on the GM. GM manufactured 39 parts "in house" vs the 77 parts they purchased from "outside" so I'm going to have to start adding them up to see how close I'm getting.
http://img.photobucket.com/albums/v633/tazaroo/GM%20Buffer%20001_zpsyv7xbmhz.jpg

GM buffers also , from the two I have seen not including mine have an additional flat cut into the middle area inline with the cut on the end of the buffer and it's very rough. The GM is on the bottom in this picture.
http://img.photobucket.com/albums/v633/tazaroo/GM%20Buffer%20002_zpstvjssdi8.jpg


Thought I was going to have to look for one too, but I found a GM in my stash also.  Thanks for the heads-up on what a GM buffer looks like!

Cool, thanks.  It looks like I have one in my parts box - I'll add it to my GM stash.  It looks just like yours with the flats on the side and the wine colored pad, but my end divot is not as deep as yours.


Nothing like an undiscovered find in the old parts box!!

Link Posted: 10/16/2016 3:58:25 AM EDT
[#19]
Very cool. Never knew there were GM specific made buffers.  Learn something new all the time in here! Going to be a real one of a kind build when done. Congrats on acquiring the very cool parts!
Link Posted: 10/16/2016 8:28:28 AM EDT
[#20]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Very cool. Never knew there were GM specific made buffers.  Learn something new all the time in here! Going to be a real one of a kind build when done. Congrats on acquiring the very cool parts!
View Quote


GM manufactured in house 39 parts for the rifle and purchased 77 parts. The body of the buffer was made in house but the internal buffer weights and buffer bumper were outsourced.
Link Posted: 10/16/2016 11:08:42 AM EDT
[#21]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


GM manufactured in house 39 parts for the rifle and purchased 77 parts. The body of the buffer was made in house but the internal buffer weights and buffer bumper were outsourced.
View Quote View All Quotes
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Very cool. Never knew there were GM specific made buffers.  Learn something new all the time in here! Going to be a real one of a kind build when done. Congrats on acquiring the very cool parts!


GM manufactured in house 39 parts for the rifle and purchased 77 parts. The body of the buffer was made in house but the internal buffer weights and buffer bumper were outsourced.


Very cool!
Link Posted: 10/18/2016 11:29:19 PM EDT
[#22]
Nice receiver chunk.  

Where did you get the buffer?  Can you tell us how you got it and how you know it is GM made?

ETA:  I don't remember, have you posted pictures of your upper?

Quoted:
My HYDRA-MATIC build is in the final stretch to completion. I now have the properly marked fire control parts, GM buffer and a perfectly "in spec" (minus the Capt Crunch cut) front have of the lower receiver. The Hydra half with my 80% lower will be going to braceman in the near future. Than the upper, slip ring and lower will all be re anodized. The only thing beyond this would be a HRA build but I feel that would be almost impossible.

http://img.photobucket.com/albums/v633/tazaroo/GM%20lower%20parts%20001_zpsthgil89i.jpg
http://img.photobucket.com/albums/v633/tazaroo/GM%20lower%20parts%20002_zpsfytsx1lt.jpg
View Quote

Link Posted: 10/19/2016 12:40:35 PM EDT
[#23]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Nice receiver chunk.  

Where did you get the buffer?  Can you tell us how you got it and how you know it is GM made?

ETA:  I don't remember, have you posted pictures of your upper?


View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Nice receiver chunk.  

Where did you get the buffer?  Can you tell us how you got it and how you know it is GM made?

ETA:  I don't remember, have you posted pictures of your upper?

Quoted:
My HYDRA-MATIC build is in the final stretch to completion. I now have the properly marked fire control parts, GM buffer and a perfectly "in spec" (minus the Capt Crunch cut) front have of the lower receiver. The Hydra half with my 80% lower will be going to braceman in the near future. Than the upper, slip ring and lower will all be re anodized. The only thing beyond this would be a HRA build but I feel that would be almost impossible.

http://img.photobucket.com/albums/v633/tazaroo/GM%20lower%20parts%20001_zpsthgil89i.jpg
http://img.photobucket.com/albums/v633/tazaroo/GM%20lower%20parts%20002_zpsfytsx1lt.jpg



I described a few entries above how to tell if it's a GM. I haven't posted pictures of the upper yet but I will when the build is done. I have to keep the suspense building.
Link Posted: 10/20/2016 1:53:11 AM EDT
[#24]
I looked through the tacked GM / H&R thread and see MrM1A1's buffer, are there other examples?  I didn't realize this was considered a GM trait.  (dimple on front, double flats)  I've seen the double flat buffers before but thought it was just an "old vs new" thing.  Is there any corroborating evidence that these are (all) GM buffers?  

Discussion ForumsJump to Quoted PostQuote History
Quoted:


I described a few entries above how to tell if it's a GM. I haven't posted pictures of the upper yet but I will when the build is done. I have to keep the suspense building.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Nice receiver chunk.  

Where did you get the buffer?  Can you tell us how you got it and how you know it is GM made?

ETA:  I don't remember, have you posted pictures of your upper?

Quoted:
My HYDRA-MATIC build is in the final stretch to completion. I now have the properly marked fire control parts, GM buffer and a perfectly "in spec" (minus the Capt Crunch cut) front have of the lower receiver. The Hydra half with my 80% lower will be going to braceman in the near future. Than the upper, slip ring and lower will all be re anodized. The only thing beyond this would be a HRA build but I feel that would be almost impossible.

http://img.photobucket.com/albums/v633/tazaroo/GM%20lower%20parts%20001_zpsthgil89i.jpg
http://img.photobucket.com/albums/v633/tazaroo/GM%20lower%20parts%20002_zpsfytsx1lt.jpg



I described a few entries above how to tell if it's a GM. I haven't posted pictures of the upper yet but I will when the build is done. I have to keep the suspense building.

Link Posted: 10/20/2016 2:17:39 AM EDT
[#25]
Cool project!  Can't wait to see the finished rifle!
Link Posted: 10/20/2016 8:00:29 AM EDT
[#26]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I looked through the tacked GM / H&R thread and see MrM1A1's buffer, are there other examples?  I didn't realize this was considered a GM trait.  (dimple on front, double flats)  I've seen the double flat buffers before but thought it was just an "old vs new" thing.  Is there any corroborating evidence that these are (all) GM buffers?  


View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I looked through the tacked GM / H&R thread and see MrM1A1's buffer, are there other examples?  I didn't realize this was considered a GM trait.  (dimple on front, double flats)  I've seen the double flat buffers before but thought it was just an "old vs new" thing.  Is there any corroborating evidence that these are (all) GM buffers?  

Quoted:
Quoted:
Nice receiver chunk.  

Where did you get the buffer?  Can you tell us how you got it and how you know it is GM made?

ETA:  I don't remember, have you posted pictures of your upper?

Quoted:
My HYDRA-MATIC build is in the final stretch to completion. I now have the properly marked fire control parts, GM buffer and a perfectly "in spec" (minus the Capt Crunch cut) front have of the lower receiver. The Hydra half with my 80% lower will be going to braceman in the near future. Than the upper, slip ring and lower will all be re anodized. The only thing beyond this would be a HRA build but I feel that would be almost impossible.

http://img.photobucket.com/albums/v633/tazaroo/GM%20lower%20parts%20001_zpsthgil89i.jpg
http://img.photobucket.com/albums/v633/tazaroo/GM%20lower%20parts%20002_zpsfytsx1lt.jpg



I described a few entries above how to tell if it's a GM. I haven't posted pictures of the upper yet but I will when the build is done. I have to keep the suspense building.



Here is a "archived" thread from arfcom about a gentleman who scored a GM complete upper/stock set. His came with the exact same buffer and is pictured. Scroll down to the fifth picture. http://www.ar15.com/forums/t_3_123/572546_My_original_GM_Hydramatic_upper_has_arrived____Now_with_GM_BCG_____Pic_Heavy_.html
Link Posted: 10/22/2016 10:00:01 PM EDT
[#27]
I think this guy is selling what looks like new in the wrapper GM buffers on Ebay

GM buffer
Link Posted: 10/25/2016 4:13:03 PM EDT
[#28]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I think this guy is selling what looks like new in the wrapper GM buffers on Ebay

GM buffer
View Quote


Not GM. If I'm reading the package correctly they are from either January or March of 68. GM was first awarded their contract on April 19th, 1968.
Link Posted: 10/25/2016 7:27:45 PM EDT
[#29]
Ok, I just looked at the picture and it had the flat spots in the rear ring like the GM one pictured earlier.
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