View Full Version : Colt buffer tube not installed completely?
I recently bought a preban colt sporter lightweight. While shooting today I started to get a couple failures to go into battery. After changing mags it occurred to me it was a rifle issue. Took the rifle down and found the buffer tube detent had fallen out and was behind the sear block (thanks for the sear block colt). Looking at it compared to my 6920 it appears the buffer tube wasn't installed completely causing the detent to wear through the small amount of tube holding it in place. Am I correct with that assessment? Would simply reinstalling the buffer detent and screwing the buffer tube in some more fix my issue?
Was this a new Colt? Any signs of someone being a YouTube armorer?
I recently bought a preban colt sporter lightweight. While shooting today I started to get a couple failures to go into battery. After changing mags it occurred to me it was a rifle issue. Took the rifle down and found the buffer tube detent behind the sear block (thanks colt) had fallen out. Looking at it compared to my 6920 it appears the buffer tube wasn't installed completely causing the detent to wear through the small amount of tube holding it in place. Am I correct with that assessment? Would simply reinstalling the buffer detent and screwing the buffer tube in some more fix my issue?
Bought it from the original owner that bought it back in '91. When I asked him if he removed the buffer tube his response wen't something like "I might have to see how an adjustable stock fit". Nice, now need to clean up his mess. Should I replace the tube or just tighten it up? Any idea on where to get a buffer tube detent spring?
Kerr Lake Shooter
12-27-15, 18:37
They come in standard lower parts kits, some even come in "oops" kits designed for people that lose detents and springs.
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That buffer tube was not installed by the factory.
All sporter lightweights came with fixed stocks.
So my guess is the castle nut was not staked properly, if at all and it came loose.
It still has a fixed stock. I believe he took off the stock and buffer tube and installed an adjustable stock. When he returned the rifle back to stock he didn't install it correctly. He's a family friend which makes for greater frustration.
https://www.google.com/search?q=preban+colt+sporter+lightweight.&safe=active&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiziuCLs_3JAhUP72MKHYtZBv4Q_AUICCgC&biw=1024&bih=681
Other than no bayonet lug and the fixed stock, the Lightweight Sporter is identical to the Government Carbine, as far as the examples of both I have owned were concerned.
YMMV and Colt is not necessarily consistant in their models.Colt Sporter Lightweight is designated as a 6530 I believe. No bayonet lug, A2 stock, rollmarked Sporter Lightweight and the serial number prefix is probably SL.
https://www.ar15.com/archive/topic.html?b=3&f=118&t=281176
Someone modified that. That endplate also has a weird color to it. It almost looks black. In any case I wouldn't be blaming Colt for something that happened on something that is over 20 years old and probably been messed with.
...... He's a family friend which makes for greater frustration.
Yeah, I learned the hard way, to only "sell" to family friends.
Someone modified that. That endplate also has a weird color to it. It almost looks black. In any case I wouldn't be blaming Colt for something that happened on something that is over 20 years old and probably been messed with.
Easy now, I never said colt installed it incorrectly. I love my 6920, I explained the previous owner admitted to removing the buffer tube.
Order a new detent spring and detent. I looks like the receiver extension needs to be installed in 1 more revolution. Easy and cheap fix
He can't thread it in any more past the flange. It is a rifle tube, not a carbine tube.
Ordered a magpul armorer tool and a new detent spring. Hopefully I can get it running right again.
Is there a gap between the receiver and extension flange or buttstock? If so, it should definately be screwed in all the way. If no gap, you will need a new receiver extension.
For rifle extension, I don't think the armorer tool is needed.
Is there a gap between the receiver and extension flange or buttstock? If so, it should definately be screwed in all the way. If no gap, you will need a new receiver extension.
For rifle extension, I don't think the armorer tool is needed.
You are 100 percent correct. It would seem he tried installing the stock without removing the tube from the stock. I broke it down completely and when screwing the tube in by itself, it had a solid half turn more before bottoming out. All I need is to wait on a new detent spring and I should be good to go, no tool required besides a flat head screwdriver. Thank you M4carbine.net. Maybe if he was a member here he could have done it right the first time. Measure twice, cut once and all that....
nof555 - I'm not real clear, this has an A2 stock on it it, correct? If I'm thinking correctly, you may be hosed. The A2 rifle extension has a shoulder on it and it screws all the way into the receiver. From my point of view, it should have had a little more metal holding the detent in place. If the guy didn't tighten it correctly, you may be in luck. Take the stock off, hopefully you have an armorers wrench, it should have a fixture/cutout for the protrusion on the end of the tube, torque it down good against the shoulder. I'm not sure what size open end would work, but if all else fails a crescent. If it was left a little loose by your friend, hopefully it will move enough to get away from that ate out section.
Oops, looks like you solved it while I was messing around. Good.
titsonritz
12-28-15, 00:58
Bought it from the original owner that bought it back in '91. When I asked him if he removed the buffer tube his response wen't something like "I might have to see how an adjustable stock fit". Nice, now need to clean up his mess. Should I replace the tube or just tighten it up? Any idea on where to get a buffer tube detent spring?
If you want official Colt: AR15A4 Buffer Retainer Spring (http://www.brownells.com/rifle-parts/receiver-parts/recoil-parts/buffer-retainer-springs/ar15a4-buffer-retainer-spring-sku160308111-4890-10869.aspx) or if you don't care about that Buffer Retainer Spring
(http://www.whiteoakarmament.com/xcart/product.php?productid=17591&cat=283&page=4)
ETA: Never mind looks handled.
If you want official Colt: AR15A4 Buffer Retainer Spring (http://www.brownells.com/rifle-parts/receiver-parts/recoil-parts/buffer-retainer-springs/ar15a4-buffer-retainer-spring-sku160308111-4890-10869.aspx) or if you don't care about that Buffer Retainer Spring
(http://www.whiteoakarmament.com/xcart/product.php?productid=17591&cat=283&page=4)
Thank you very much good sir. I checked midway and all they had was dpms retainer springs (which I cringed my teeth to consider buying). Honestly, it probably doesn't matter but I'm going to go with the colt instead.
I think he will need a new lower receiver extension. But without seeing it in person, I wouldn't be sure.
Someone mentioned and end plate.
Does it have one?
I don't recall an end plate being used with a rifle tube and fixed stock, the stock sits flush against the rear of the receiver, and retains the rear takedown pin spring.
An end plate would move the tube back 1/8".
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The ding in the end of the buffer tube tells me more retard was happening than just a collapsible stock install and removal. Its like your friend couldn't figure out how to install the tube and detent in conjunction with one another.
You need a new rifle buffer tube.
No it doesn't have an end plate. The tube screws into the receiver and the stock screws into the extension. I'm still not 100 percent sure everything is going to be right, I just have to wait until I get the detent spring to see.
I think what he did was try to install the stock as one unit instead of removing the buffer tube from the stock and installing it first. Judging by the damage to the top stock screw I think he was using the screw to spin the tube into the reciever. And there is no way to get enough torque to install the tube completely doing it that way.
Have you removed and reinstalled the tube? What does it look like, inside and out, when the tube is screwed all the way in? Can you take some more pics?
It either properly covers the buffer detent or it doesn't, so it should be obvious if your RE tube is fubar or serviceable.
Have you removed and reinstalled the tube? What does it look like, inside and out, when the tube is screwed all the way in? Can you take some more pics?
It either properly covers the buffer detent or it doesn't, so it should be obvious if your RE tube is fubar or serviceable.
I believe it properly covers it, but it may be a hair short. You can see when properly tightened the dent in the tube where the detent used to sit is now on top.
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As you can see there is no gap between the shoulder of the buffer tube and lower reciever.
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That looks like it should now and should keep the buffer retainer in just fine but that nick in the tube would drive me nuts.
I believe it properly covers it, but it may be a hair short. You can see when properly tightened the dent in the tube where the detent used to sit is now on top.
Very helpful pics.
I'd say he just put it back together a half turn short, judging by where the damaged portion ended up after screwing it in all the way. Looks perfectly serviceable to me. I'd get the new detent/spring and go with that RE, no doubt.
You could hit the damaged area with some Aluma Black if it bothers you.
Slvr Surfr
01-03-16, 14:28
That last pic looks good to me. Especially since the damaged portion of the RE is now completely opposite where it used to be. That shows just how short it was when assembled by the last guy.
As said by straitR, hit the damaged portion with some Birchwood Casey Aluminum Black and it should look fine. No one will be the wiser when your upper is assembled to the lower.
I believe it properly covers it, but it may be a hair short. You can see when properly tightened the dent in the tube where the detent used to sit is now on top.
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