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Posted: 7/27/2016 1:23:50 PM EDT
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Yes it does. The "+" can even be found on early SP1 receivers (it is on my 1968 SP1).
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They appeared only on very early forgings - might have been a witness mark for the machining process or something like that, which they later found out wasn't needed.
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I've seen them on 601/602 receivers, but was unaware that they were also on early 603/604 partial-fence receivers......thanks for the info
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What rifles are those? Interesting to see a partial fence lower with A2 uppers. I'd like to see the whole group, do you have more pics?
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gas tube insertion identifier?(since you could see the tube with the dust cover open?) View Quote View All Quotes View All Quotes Quoted:
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They appeared only on very early forgings - might have been a witness mark for the machining process or something like that, which they later found out wasn't needed. gas tube insertion identifier?(since you could see the tube with the dust cover open?) Port cover would have covered up the mark when it was open, though... |
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Quoted: Quoted: They appeared only on very early forgings - might have been a witness mark for the machining process or something like that, which they later found out wasn't needed. This is my understanding too. http://gdtseminars.com/blog/ I have one on an XM16 Demil lower too Edit: That lower requires a TO mod for a pivot pin detent weep-hole too. Whats the marking on it 602, M16? My money is on 602. Please do show us, we are short on good pics of 602s |
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Im going to say very early vintage, There is no drain hole in the spring/pin retainer tube (m16a1 improvement)
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Datum mark for GD&T Geometric Dimension and Tolerance. At least this was my assumption too. http://gdtseminars.com/blog/ I have one on an XM16 Demil lower too Edit: That lower requires a TO mod for a pivot pin detent weep-hole too. Whats the marking on it 602, M16? My money is on 602. Please do show us, we are short on good pics of 602s View Quote View All Quotes View All Quotes Quoted:
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They appeared only on very early forgings - might have been a witness mark for the machining process or something like that, which they later found out wasn't needed. This is my understanding too. http://gdtseminars.com/blog/ I have one on an XM16 Demil lower too Edit: That lower requires a TO mod for a pivot pin detent weep-hole too. Whats the marking on it 602, M16? My money is on 602. Please do show us, we are short on good pics of 602s Partial fence. It's an early XM16E1 or 604 |
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My understanding was the contract AF Colt 604's had a mix of partial fence and full fence lowers. Most of the rebuilt AF M16A2's I've worked on were either 604 partial or full fence lowers, however, I still run into 601/602 rebuilt to M16A2 configuration
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My God that is awesome. I love:
- the + symbol on a partial fence - what appears to be an acceptance stamp - the round UID or whatever it's called sticker indicating the weapon is likely still in service Please please please post more pics. Posted Via AR15.Com Mobile |
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Quoted: My God that is awesome. I love: - the + symbol on a partial fence - what appears to be an acceptance stamp - the round UID or whatever it's called sticker indicating the weapon is likely still in service Please please please post more pics. Posted Via AR15.Com Mobile View Quote You know thinking about the + last night I don't even know if the GD&T symbols were in use in the early 60s. I haven't seen an early print of the M16 even though I've searched. I know its not on the new one. I think the old symbol may have been / or // Not sure. Why did I say 602... The round IUID stickers are AF only from what I understand. Everyone else is square or rectangle, they have only been using them since about 2012-13 in the AF I believe. |
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How about a 602 spotted in the wild..... <a href="http://s1104.photobucket.com/user/cafejeeper/media/Mobile%20Uploads/image_zpsj76cvuci.jpeg.html" target="_blank">http://i1104.photobucket.com/albums/h336/cafejeeper/Mobile%20Uploads/image_zpsj76cvuci.jpeg</a> <a href="http://s1104.photobucket.com/user/cafejeeper/media/Mobile%20Uploads/image_zpsgr1zi54j.jpeg.html" target="_blank">http://i1104.photobucket.com/albums/h336/cafejeeper/Mobile%20Uploads/image_zpsgr1zi54j.jpeg</a> View Quote I like that |
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How about a pile of 602's <a href="http://s1104.photobucket.com/user/cafejeeper/media/Mobile%20Uploads/image_zpskfyecugv.jpeg.html" target="_blank">http://i1104.photobucket.com/albums/h336/cafejeeper/Mobile%20Uploads/image_zpskfyecugv.jpeg</a> View Quote Sad, very sad, they engraved the back side of the receivers "safe, semi, & auto". I've seen that on M16A1's as well. |
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wow I didn't think there were that many 602's floatin around, much less still in action! That is really someting
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RICO,
Can you share if those are still in military service or if they are being moth balled for emergency back stock or if they are headed out to be destroyed or what? Thanks |
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Sad, very sad, they engraved the back side of the receivers "safe, semi, & auto". I've seen that on M16A1's as well. View Quote View All Quotes View All Quotes Quoted:
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How about a pile of 602's <a href="http://s1104.photobucket.com/user/cafejeeper/media/Mobile%20Uploads/image_zpskfyecugv.jpeg.html" target="_blank">http://i1104.photobucket.com/albums/h336/cafejeeper/Mobile%20Uploads/image_zpskfyecugv.jpeg</a> Sad, very sad, they engraved the back side of the receivers "safe, semi, & auto". I've seen that on M16A1's as well. I think I found my next clone build inspiration. Maybe reprofile an 80% into one of these and do an arsenal rebuild complete w/ electropencil selector markings. I love that they are still in use after what like 50 years!? Best part is outside of the lower & LPK, all the other stuff is easily acquired. Posted Via AR15.Com Mobile |
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From what I understand the USAF can no longer deploy the 601/602 series of receivers due to the lack of removeable front pivot assemblies available thru the supply chain via NSN. These 602's are kept separate from deployable 604 receivered M16A2 conversions. Eventually, they'll get turned in to the supply chain for serviceable M16A2's or current issue M4 Carbines. After turn-in, it'll be up to Big AF to decide if these 602's will be returned to national stock, or removed from inventory.
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Port cover would have covered up the mark when it was open, though... View Quote View All Quotes View All Quotes Quoted:
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They appeared only on very early forgings - might have been a witness mark for the machining process or something like that, which they later found out wasn't needed. gas tube insertion identifier?(since you could see the tube with the dust cover open?) Port cover would have covered up the mark when it was open, though... true, but only when it was ALL THE WAY open, clearly, you'd be able to hold the cover in a position to verify alignment the gas tube. |
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OK, how about this...... <a href="http://s1104.photobucket.com/user/cafejeeper/media/Mobile%20Uploads/image_zps12q2yvcb.jpeg.html" target="_blank">http://i1104.photobucket.com/albums/h336/cafejeeper/Mobile%20Uploads/image_zps12q2yvcb.jpeg</a> Sad to see that this was done...... View Quote Interesting that a low serial number 602 has the type 3 as opposed to type 2 bolt catch. Thanks for posting! Do these A2 uppers have the front pivot lug recessed out to accept the non-captured type 601/602 pivot pin? |
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Yes, there is a pivot pin lug recess to accommodate the 601/602 pivot pin assembly <a href="http://s1104.photobucket.com/user/cafejeeper/media/Mobile%20Uploads/image_zpsa6rza0tl.jpeg.html" target="_blank">http://i1104.photobucket.com/albums/h336/cafejeeper/Mobile%20Uploads/image_zpsa6rza0tl.jpeg</a> View Quote Was that part of the manufacturing process or done on base depending on which type of lower it was going on? |
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<a href="http://s1104.photobucket.com/user/cafejeeper/media/Mobile%20Uploads/image_zps9jpfajy8.jpeg.html" target="_blank">http://i1104.photobucket.com/albums/h336/cafejeeper/Mobile%20Uploads/image_zps9jpfajy8.jpeg</a> Yet, even worse..... View Quote Brust. |
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From the examples I've seen, all the M16A2 upper receivers used in the USAF M16 to M16A2 conversion process were recessed at the pivot pin lug to accommodate the 601/602 lowers receiver.
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Was that part of the manufacturing process or done on base depending on which type of lower it was going on? View Quote View All Quotes View All Quotes Quoted:
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Yes, there is a pivot pin lug recess to accommodate the 601/602 pivot pin assembly <a href="http://s1104.photobucket.com/user/cafejeeper/media/Mobile%20Uploads/image_zpsa6rza0tl.jpeg.html" target="_blank">http://i1104.photobucket.com/albums/h336/cafejeeper/Mobile%20Uploads/image_zpsa6rza0tl.jpeg</a> Was that part of the manufacturing process or done on base depending on which type of lower it was going on? |
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<a href="http://s1104.photobucket.com/user/cafejeeper/media/Mobile%20Uploads/image_zps9jpfajy8.jpeg.html" target="_blank">http://i1104.photobucket.com/albums/h336/cafejeeper/Mobile%20Uploads/image_zps9jpfajy8.jpeg</a> Yet, even worse..... Brust. I'm totally gonna incorporate the electro pencil misspelling on my clone. Posted Via AR15.Com Mobile |
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From what I understand the USAF can no longer deploy the 601/602 series of receivers due to the lack of removeable front pivot assemblies available thru the supply chain via NSN. These 602's are kept separate from deployable 604 receivered M16A2 conversions. Eventually, they'll get turned in to the supply chain for serviceable M16A2's or current issue M4 Carbines. After turn-in, it'll be up to Big AF to decide if these 602's will be returned to national stock, or removed from inventory. View Quote Rico: I would like to be the first to congratulate you on breaking the 100 post barrier in less than 16 years. Nice work! |
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