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Posted: 7/10/2015 6:24:55 AM EDT
| Isn't there someone on here that fixes the large hole (.315") uppers to reduce them to standard size (.250") ? I forget the person's name. |
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All you need is a bushing you can buy off GB for uppers.http://www.gunbroker.com/Auction/ViewItem.aspx?Item=494036141
You install it, then install your lower. You may need to twist the bushing to proper position,mark the position, remove it,then use a "super glue" or epoxy, reinstall bushing to proper position and you're good to go. |
I have the bushing you referenced. I got one at my LGS for $1, with 2 legged shipping, lol.  But I am not happy with the gap between the upper and lower that I end up with. I am considering tapping the hole, threading in a piece, and boring it to .250 for the pivot pin. Or send it to someone to do the fix.
Quoted:
All you need is a bushing you can buy off GB for uppers.http://www.gunbroker.com/Auction/ViewItem.aspx?Item=494036141 You install it, then install your lower. You may need to twist the bushing to proper position,mark the position, remove it,then use a "super glue" or epoxy, reinstall bushing to proper position and you're good to go. |
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Quoted:
I have the bushing you referenced. I got one at my LGS for $1, with 2 legged shipping, lol. But I am not happy with the gap between the upper and lower that I end up with. I am considering tapping the hole, threading in a piece, and boring it to .250 for the pivot pin. Or send it to someone to do the fix.
Quoted:
I have the bushing you referenced. I got one at my LGS for $1, with 2 legged shipping, lol. But I am not happy with the gap between the upper and lower that I end up with. I am considering tapping the hole, threading in a piece, and boring it to .250 for the pivot pin. Or send it to someone to do the fix.
Quoted:
All you need is a bushing you can buy off GB for uppers.http://www.gunbroker.com/Auction/ViewItem.aspx?Item=494036141 You install it, then install your lower. You may need to twist the bushing to proper position,mark the position, remove it,then use a "super glue" or epoxy, reinstall bushing to proper position and you're good to go. Understood, that prolly just means that your bushing is not "orientated" correctly. As I'm sure you've noticed, the bushing hole is not concentric with the outside diameter,sort of like a cam. You may be able to rotate the bushing to a better position that will pull the upper down tighter to the lower. |
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Quoted:
Understood, that prolly just means that your bushing is not "orientated" correctly. As I'm sure you've noticed, the bushing hole is not concentric with the outside diameter,sort of like a cam. You may be able to rotate the bushing to a better position that will pull the upper down tighter to the lower. Quoted:
Quoted:
I have the bushing you referenced. I got one at my LGS for $1, with 2 legged shipping, lol. But I am not happy with the gap between the upper and lower that I end up with. I am considering tapping the hole, threading in a piece, and boring it to .250 for the pivot pin. Or send it to someone to do the fix.
Quoted:
All you need is a bushing you can buy off GB for uppers.http://www.gunbroker.com/Auction/ViewItem.aspx?Item=494036141 You install it, then install your lower. You may need to twist the bushing to proper position,mark the position, remove it,then use a "super glue" or epoxy, reinstall bushing to proper position and you're good to go. Understood, that prolly just means that your bushing is not "orientated" correctly. As I'm sure you've noticed, the bushing hole is not concentric with the outside diameter,sort of like a cam. You may be able to rotate the bushing to a better position that will pull the upper down tighter to the lower. I had a devil of a time getting one right I installed on a build. |
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I have the bushing with the thinnest part to the top, which should move the pin to the highest possible position. It is insufficient to close the upper/lower gap tighter.
Quoted:
Understood, that prolly just means that your bushing is not "orientated" correctly. As I'm sure you've noticed, the bushing hole is not concentric with the outside diameter,sort of like a cam. You may be able to rotate the bushing to a better position (more meat towards the 12 o'clock position) that will pull the upper down tighter to the lower. Quoted:
Quoted:
I have the bushing you referenced. I got one at my LGS for $1, with 2 legged shipping, lol. But I am not happy with the gap between the upper and lower that I end up with. I am considering tapping the hole, threading in a piece, and boring it to .250 for the pivot pin. Or send it to someone to do the fix.
Quoted:
All you need is a bushing you can buy off GB for uppers.http://www.gunbroker.com/Auction/ViewItem.aspx?Item=494036141 You install it, then install your lower. You may need to twist the bushing to proper position,mark the position, remove it,then use a "super glue" or epoxy, reinstall bushing to proper position and you're good to go. Understood, that prolly just means that your bushing is not "orientated" correctly. As I'm sure you've noticed, the bushing hole is not concentric with the outside diameter,sort of like a cam. You may be able to rotate the bushing to a better position (more meat towards the 12 o'clock position) that will pull the upper down tighter to the lower. |
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Quoted:
I have the bushing with the thinnest part to the top, which should move the pin to the highest possible position. It is insufficient to close the upper/lower gap tighter. Quoted:
I have the bushing with the thinnest part to the top, which should move the pin to the highest possible position. It is insufficient to close the upper/lower gap tighter. Quoted:
Quoted:
I have the bushing you referenced. I got one at my LGS for $1, with 2 legged shipping, lol. But I am not happy with the gap between the upper and lower that I end up with. I am considering tapping the hole, threading in a piece, and boring it to .250 for the pivot pin. Or send it to someone to do the fix.
Quoted:
All you need is a bushing you can buy off GB for uppers.http://www.gunbroker.com/Auction/ViewItem.aspx?Item=494036141 You install it, then install your lower. You may need to twist the bushing to proper position,mark the position, remove it,then use a "super glue" or epoxy, reinstall bushing to proper position and you're good to go. Understood, that prolly just means that your bushing is not "orientated" correctly. As I'm sure you've noticed, the bushing hole is not concentric with the outside diameter,sort of like a cam. You may be able to rotate the bushing to a better position (more meat towards the 12 o'clock position) that will pull the upper down tighter to the lower. Good advice on positioning. |
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The upper I got at a gun show that forced me to make a retro build has one of these installed.
I can get some up-close pictures of the bushing if that will help anyone else get theirs installed right. Mine seems like it was pretty much press-fit in. I can't say about the upper/lower fit as I am waiting on my lower still and haven't tried it on the A2 lower that my SPR-ish build uses. I could try that this weekend if that would help though. This is the best picture I have at the moment 
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m60joe usually does the opposite work on the lower with a pinned bushing to make it milspec. it's $160 to install the bushing and $115 to have it refinished. his contact info is on his website.
http://www.M60Joe.com his clientele that usually get this service are class 3 owners with converted SP1s so they don't mind paying the fee. as far as the upper work, i'm sure he can do it and i would expect the fee to be similar. |
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Thanks, bw777. I reckon I will just have to quit being lazy and do a bit of machine work myself.
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m60joe usually does the opposite work on the lower with a pinned bushing to make it milspec. it's $160 to install the bushing and $115 to have it refinished. his contact info is on his website. http://www.M60Joe.com his clientele that usually get this service are class 3 owners with converted SP1s so they don't mind paying the fee. as far as the upper work, i'm sure he can do it and i would expect the fee to be similar. |
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I have an upper like that, but it is a small hole. The upper in question with the big hole has a FA and no cut out for an auto sear.
Quoted:
The upper I got at a gun show that forced me to make a retro build has one of these installed. I can get some up-close pictures of the bushing if that will help anyone else get theirs installed right. Mine seems like it was pretty much press-fit in. I can't say about the upper/lower fit as I am waiting on my lower still and haven't tried it on the A2 lower that my SPR-ish build uses. I could try that this weekend if that would help though. This is the best picture I have at the moment http://i70.photobucket.com/albums/i86/Squeethm/Colt%20Slick-side%20Upper%20-%20As%20Purchased%20Resized_zpsffx4wkce.jpg |
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What M1sniper said.
CDNN, Brownell's etc usually have the bushings for $2, DPMS tagged part. OP obviously has one. If going to swap the upper around on a few lowers using a bushing permanently attached I'd check it on a couple different lowers before I epoxied for best universal fitment and upper to lower clearance between a few. Otherwise possibly expect to modify rear take down pin boss on upper down the road or keep it dedicated. With a little finesse you can make the upper look like a factory small pin and will fit most anything within spec fairly decent with little gap between upper and lower. Not like the real deal stuff didn't have a little play but now days most all want very tight fitment. Personally I've never had one bad enough to effect weapon accuracy ( I can see it effecting some shooters though) and I don't permanently attach mine as it kinda defaces SP-1 upper value but in moderation even a permanent install can be removed. Upper receiver condition dictates decission for my personal use. Beater upper what difference does it make, epoxy away. Blue loc-tite also works and you can remove at later date and even romove residue. JB Weld or such isn't coming off back like talking about it. Never tried super glue but it should be versatile. OP I usually keep a few of the adapters laying around due to lack of expense and have found some fit better than others IMO due to coating thickness more than the machined part. All I've ever used are the DPMS pieces. If not permanently attached remember it's in there or keep a spare in your parts bag. In the bush and you pull the pin for various reasons if it falls out you probably won't find it. |
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OP....I'll make you an offer. If you'll measure the gap (use feeler gauges I suppose) and also measure the offset of the bushing that you have now, I'll machine you a bushing with the correct offset to close the gap.
NO CHARGE.........we'll consider it PIF. For example, your bushing should be .312+ or -, and the ID is .250+. That would have the wall thickness at .0315 if it was concentric, which it probably isn't. So.....measure the thinnest and thickest wall. Let's suppose that the thinnest wall is .025 with the thickest wall being .038, and your gap being .020 at the front, with the back being .010. That would mean that you would want a bushing with the hole offset an additional .010 to even the upper gap along its' full length. Let me know if you are interested. Stoner25 |
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I have basically done all that but still have ended up with a larger gap than I am happy with. I used loctite to retain the bushing.
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Spin it until the upper sits correctly, mark the bushing and pivot hole with a pencil/China marker and super glue the bushing in, it's free and a simple fix that does not require modding a Spotter Upper. |
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Quoted: I am considering whether the upper is worth all the bother. I may just plug the hole and bore a new hole at the correct location, and be done with it. Next option is remove the barrel and associated parts, and toss it in the parts bin to collect some dust. i know you could sell/trade it for a .250 pin upper. (maybe not a Colt, but a Fulton/Bushmaster/???, C-7 style anyway) hell, someone might trade you a Nodak for it, never know. think hard before you destroy something someone else might need. |
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Quoted:
I have the bushing with the thinnest part to the top, which should move the pin to the highest possible position. It is insufficient to close the upper/lower gap tighter. Quoted:
I have the bushing with the thinnest part to the top, which should move the pin to the highest possible position. It is insufficient to close the upper/lower gap tighter. Quoted:
Quoted:
I have the bushing you referenced. I got one at my LGS for $1, with 2 legged shipping, lol. But I am not happy with the gap between the upper and lower that I end up with. I am considering tapping the hole, threading in a piece, and boring it to .250 for the pivot pin. Or send it to someone to do the fix.
Quoted:
All you need is a bushing you can buy off GB for uppers.http://www.gunbroker.com/Auction/ViewItem.aspx?Item=494036141 You install it, then install your lower. You may need to twist the bushing to proper position,mark the position, remove it,then use a "super glue" or epoxy, reinstall bushing to proper position and you're good to go. Understood, that prolly just means that your bushing is not "orientated" correctly. As I'm sure you've noticed, the bushing hole is not concentric with the outside diameter,sort of like a cam. You may be able to rotate the bushing to a better position (more meat towards the 12 o'clock position) that will pull the upper down tighter to the lower. You want the thin part at 6 o'clock for the tightest fit, you have it 180 degrees spun in the wrong direction..... Think about it... With the thick part at 12 o'clock, it has to sit lower than if vice versa. Do you understand? Your bushing is orientated wrong just like m1sniper said. If the thick part was at 6 o'clock, it would keep the upper from fully seating where it should. |
| I bought an SP1 upper with plans to build a modern light weight KISS type rig out of it. I was going to cerakote it and epoxy the bushing in. Myabe I should just sell it for someone to use on a retro build? I'm not too into historical builds. In other words, would it be blasphemy to modify it and do a non-retro rig? |
OK, I put on my "Jethro Bodine" thinking cap.  According to the upper drawing, the pivot pin hole spec is .250" +-.001" from the parting line. This would put the edge of the pin hole .125"+-.001" from the parting line, and the center of the pin .250" from the same line. On the large pin upper, the hole is .315" putting the center of the pin .2825" from the parting line. The edge of the hole is still .125" from the parting line. This means that ideally, the offset bushing should be .00" on the thin side, and .065" on the thick side. Since it would be difficult to make the bushing with no material on the thin side, it has as little as possible on the thin side. This thin side being more than .00" means the gap will always be there, unless the pivot pin hole is plugged and bored at the proper location.
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I have the bushing with the thinnest part to the top, which should move the pin to the highest possible position. It is insufficient to close the upper/lower gap tighter. Quoted:
I have the bushing with the thinnest part to the top, which should move the pin to the highest possible position. It is insufficient to close the upper/lower gap tighter. Quoted:
You want the thin part at 6 o'clock for the tightest fit, you have it 180 degrees spun in the wrong direction..... Think about it... With the thick part at 12 o'clock, it has to sit lower than if vice versa. Do you understand? Your bushing is orientated wrong just like m1sniper said. If the thick part was at 6 o'clock, it would keep the upper from fully seating where it should. Hippy- your thinking cap is on backwards. To close the gap between the upper and lower, the pivot pin needs to move up (in the upper). The bushing needs to have the thin side up to accomplish this. |
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I bought an SP1 upper with plans to build a modern light weight KISS type rig out of it. I was going to cerakote it and epoxy the bushing in. Myabe I should just sell it for someone to use on a retro build? I'm not too into historical builds. In other words, would it be blasphemy to modify it and do a non-retro rig? It is yours.........use it however you desire. It doesn't make sense to me to say that the SP1 upper is rare, and you should sell/trade it for a Mil-soec upper, to build a non-milspec build. Using a mil-spec upper to build a non-milspec build is only going to deprive someone of a milspec upper to build a retro build.. See how twisted all that logic gets.......someone wanting an SP1 upper is going to chastise you for using it, and someone that wants a milspec upper is going to chastise you if you trade it for a milspec. Also, since the SP1 upper is a slickside, finding a 604 upper is going to be harder to come by, if you are set on building a lightweight/KISS rifle. Again........it's yours, use it however you want. |
I think I am just going to leave the bushing in as is, and live with it. It's just a Colt CH upper, nothing special. It has a Colt pencil barrel, standard FSB, Colt FA BCG, Colt 6 hole handguards. I may throw the upper assembly on a Colt LE lower, and be happy with it. 
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Hippy- your thinking cap is on backwards. To close the gap between the upper and lower, the pivot pin needs to move up (in the upper). The bushing needs to have the thin side up to accomplish this. Thin side down will make the pin sit lower in the lower and thus pull the upper down lower. 
Think about it for a minute. Just sayin' you should TRY that first and SEE if we are wrong. 
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Quoted:
Thin side down will make the pin sit lower in the lower and thus pull the upper down lower.
Think about it for a minute. Just sayin' you should TRY that first and SEE if we are wrong.
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Quoted:
Hippy- your thinking cap is on backwards. To close the gap between the upper and lower, the pivot pin needs to move up (in the upper). The bushing needs to have the thin side up to accomplish this. Thin side down will make the pin sit lower in the lower and thus pull the upper down lower.
Think about it for a minute. Just sayin' you should TRY that first and SEE if we are wrong.
Thin side down will cause the eccentric bushing to cam the upper into a higher position in relation to the lowers mating surface. The 0.250" pin will be in the same location in the lower regardless. 
I could see cause for concern if the angle between upper and lower were too great. The possibility exists for the bolt carrier to batter the lower receiver at the extension. |
| I have the same problem with an A2 upper. I have a large gap between the upper and lower, I removed the bushing re-oriented it to close up the gap and then the rear takedown pin would not go in. It looks like I have no choice but to have a large gap between upper and lower. |
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44Echo10 is absolutely correct. The bushing MUST have the center of its hole .250" from the bottom surface of the upper receiver. The center of the hole in the lower receiver is also .250" from its top surface. This closes the gap to correct specs. Bottom line is the THIN side of the bushing must be to the top of the pivot pin lug in the upper receiver.
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