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Posted: 7/4/2022 12:52:26 PM EDT
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Bought a transferrable Colt AR15 SP1 that was converted and wondering what is the best option is to change to a small hole for upper swaps and such. I have a bushing kit and small push pins but remember that M60Joe was doing conversions in the past but he's retired. Is US Anodizing doing this work? It is a rollmarked 9mm lower with a mag block but I have no desire to shoot it in that configuration. Don't really know much about the bushing kits except what I'd read where once the bushings are in the correct orientation then they can be glued or pinned in place. Thanks |
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Originally Posted By cajun22: Contact Victor at US Anodizing. Gary's gun Bunker, who M60joe referred his customers to. Gary gun was what was recommended but talking with him, he says you really don't need to. He mentions it the receiver gets damage, then it would be worth it for me to do it then. So I ended up making my own thing with a KNS Quick Takedown small pin and 2 small to large pin adapters. I glued one adapter to the KNS, the other one is free float lock in place on the other side. No screw drivers needed and good lockup. |
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So get two of these and file it down to fit into the lower (instead of the upper): https://www.jsesurplus.com/coltreceiveradapteroffsetbushing.aspx  Then glue/loctite/jbweld one of them on the the KNS push button takedown pin. For this version, the balls in the KNS takedown pin holds in the other side part.  You can also used the one that has a pushbutton or hook location which is a bit longer KNS pin.  Sorry I don't have the photos with me at the moment. Another idea is like localizer11 showed in the photos.. possibly somehow weld/permanently bond the inserts into the lower. |
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Any time. Glad to help. I was at one point in time thinking of making a few of these for resale, but it just seemed too easy to make. Overall it works very well. It can be a tricky to get out since from firing it can rotate a bit, making the fit tighter. Also depending on the upper/lower fit, it can be tight. So far I've tried 8 different uppers and I was able to make it work for all of them. |
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Originally Posted By okent: I'll plan on using the bushings and see if there is a sweet spot for rotational alignment. If I can get it dialed in I'll just put some loctite in the bushing joints and call it good. I'd still use a KNS pin to prevent the one side sliding out. It is easy to find the sweet spot for one upper, but try it on a few of them just to see if it all works out the same. Going to use red loctite? |
M60joe did my conversion, although I paid him a little extra to check if everything was in spec and he missed the fact that the sear hole was out of spec (quite the contreversial post on here, I was to blame for not knowing it was out of spec apparently   ) -- Victor at US anodizing fixed the sear hole for me, runs like a champ.Anyway my opinion is its worth the small hole conversion, but the bushings do the same thing to an extent |
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Originally Posted By okent: Taymag, just to be clear, yours still requires the kns pin? The conversion didn't allow the standard retained front pin like small hole lowers? Still requires the Kns pin, I don’t love it (the kns pin situation) but I feel way better about the durability and I paid significantly less and still have the colt name, plus with the small pin I can swap uppers freely. It’s a small price to pay for a little easier use on an sp1 in my opinion |
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Originally Posted By okent: Agreed, Thanks for the info. I dont think I even read the replies before my first post but I just glanced over them, not to be repetitive but honestly if you can find someone you trust (someone on here will know) to do the work (since m60joe doesnt anymore) I would do it. I just looked back in my emails and I paid $210 in 2016, cheaper than I thought. You still need to repay to anodize which is like $400 I think and USanodizing seems to still be the go-to so there's no reputation issue there, plus you get a brand new looking lower 
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Originally Posted By okent: Taymag, just to be clear, yours still requires the kns pin? The conversion didn't allow the standard retained front pin like small hole lowers? One step in the Civvy-Bastardizing process, beyond big holes, seems to have been not including the spring/detent hole that would have held the capture detent. I have a screw-in offset adapter, and it's a pain in the ass. You have to get it just exactly right, and it tends to rotate if you shotgun the upper to clear a jam or perform any maintenance. |
Every other species kills off their stupid......we cater to them. -- spin-drift
Nobody ever called 911&said I just did something smart. -- TheFlynDutchman
Nobody ever called 911&said I just did something smart. -- TheFlynDutchman
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Originally Posted By Amish_Bill: I have the same problem. One step in the Civvy-Bastardizing process, beyond big holes, seems to have been not including the spring/detent hole that would have held the capture detent. I have a screw-in offset adapter, and it's a pain in the ass. You have to get it just exactly right, and it tends to rotate if you shotgun the upper to clear a jam or perform any maintenance. I'm not 100% sure I'm following, but did you buy a transferable SP1 without knowing the front didnt have a "regular" takedown pin/detent? I knew before I bought mine but its still a little bit of a pain, that being said with the small hole conversion its only an extra half a second removing the upper, definitely nothing to get exactly right, etc, it fits every upper almost perfect with the small hole conversion and kns pin. |
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Originally Posted By taymag: I'm not 100% sure I'm following, but did you buy a transferable SP1 without knowing the front didnt have a "regular" takedown pin/detent? I knew before I bought mine but its still a little bit of a pain, that being said with the small hole conversion its only an extra half a second removing the upper, definitely nothing to get exactly right, etc, it fits every upper almost perfect with the small hole conversion and kns pin. I'm still pissed I passed on the Bushmaster converted Bushmaster for $4k.....
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Every other species kills off their stupid......we cater to them. -- spin-drift
Nobody ever called 911&said I just did something smart. -- TheFlynDutchman
Nobody ever called 911&said I just did something smart. -- TheFlynDutchman
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Originally Posted By killingmachine123: Why not just get big hole uppers? I haven't kept up on their pricing, but since there is every flavor available, one could build those uppers for about what a guy would pay for the lower to be converted. My .02 A small hole lower gives you every upper. |
Every other species kills off their stupid......we cater to them. -- spin-drift
Nobody ever called 911&said I just did something smart. -- TheFlynDutchman
Nobody ever called 911&said I just did something smart. -- TheFlynDutchman
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Originally Posted By killingmachine123: Why not just get big hole uppers? I haven't kept up on their pricing, but since there is every flavor available, one could build those uppers for about what a guy would pay for the lower to be converted. My .02 Likely anyone who owns a SP1 has 1 large hole upper and many small hole uppers. If you have a lot of small hole uppers you don't want to convert them all to big hole. |
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Originally Posted By Ryo: Likely anyone who owns a SP1 has 1 large hole upper and many small hole uppers. If you have a lot of small hole uppers you don't want to convert them all to big hole. Originally Posted By Ryo: Originally Posted By killingmachine123: Why not just get big hole uppers? I haven't kept up on their pricing, but since there is every flavor available, one could build those uppers for about what a guy would pay for the lower to be converted. My .02 Likely anyone who owns a SP1 has 1 large hole upper and many small hole uppers. If you have a lot of small hole uppers you don't want to convert them all to big hole. I guess it's a matter of how many upper configs a guy wants to shoot and how many he already owns. Having done the adapter thing with my Sp1 in years past, I wouldn't hesitate to use one again. I'm also leery of the fact that welding on AL leaves you with something less strong than the base, unlike steel which is just as strong, if not stronger. Not an issue most likely, but it's something I think about none the less. It's also the reason I never had my SP1 lower converted. It does seem like it would make sense for some folks though. |
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Originally Posted By killingmachine123: ... Having done the adapter thing with my Sp1 in years past, I wouldn't hesitate to use one again. ... Originally Posted By killingmachine123: ... Having done the adapter thing with my Sp1 in years past, I wouldn't hesitate to use one again. ... Originally Posted By killingmachine123: ... I'm also leery of the fact that welding on AL leaves you with something less strong than the base, unlike steel which is just as strong, if not stronger. ... |
Every other species kills off their stupid......we cater to them. -- spin-drift
Nobody ever called 911&said I just did something smart. -- TheFlynDutchman
Nobody ever called 911&said I just did something smart. -- TheFlynDutchman
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Originally Posted By Amish_Bill: As I recall, M60 used to fit and time steel inserts, then locktite and pin them into the lower. No welding unless the lug was broken. Then the receiver was refinished to be pretty again. I'd like to develop a method to additionally add/retrofit the detent boss (aka "partial fence" although it could potentially be a "full fence" retrofit) to the right side of the receiver (and look original). I think one could be attached using screws and LocTite, but currently I lack the equipment to experiment with this concept. |
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Originally Posted By KitBuilder: That's correct. He machined a one-piece offset bushing, which was installed as you say. After pinning each side, an end mill was used to cut out the middle and make the outside edges flush, so you'd end up with 2 pinned/LocTited bushings. Then the receiver was refinished to be pretty again. I'd like to develop a method to additionally add/retrofit the detent boss (aka "partial fence" although it could potentially be a "full fence" retrofit) to the right side of the receiver (and look original). I think one could be attached using screws and LocTite, but currently I lack the equipment to experiment with this concept. Originally Posted By KitBuilder: Originally Posted By Amish_Bill: As I recall, M60 used to fit and time steel inserts, then locktite and pin them into the lower. No welding unless the lug was broken. Then the receiver was refinished to be pretty again. I'd like to develop a method to additionally add/retrofit the detent boss (aka "partial fence" although it could potentially be a "full fence" retrofit) to the right side of the receiver (and look original). I think one could be attached using screws and LocTite, but currently I lack the equipment to experiment with this concept. |
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I have a production machine shop and thought about welding up the spring/detent area and milling out the profile and drilling the hole for the spring and detent vs machining the spring/detent boss and then tig welding it onto the receiver. That kind of tedious work would most likely be costly at an outside shop. |
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Don't the safety detents on 1911s mount as a separate piece with little studs that go into the frame? That might be a semi-simple answer/idea for you. Drill the spring / drain holes, mill the profile and the base to leave small studs, and you only have to worry about two small holes in the receiver. |
Every other species kills off their stupid......we cater to them. -- spin-drift
Nobody ever called 911&said I just did something smart. -- TheFlynDutchman
Nobody ever called 911&said I just did something smart. -- TheFlynDutchman
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