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Posted: 1/24/2014 10:58:20 AM EDT
A friend gave me an M16 BCG that he or someone used a hacksaw to cut  to a semi auto BCG.  It looks pretty bad.  Anywho I was going to take it to a machinist so the could mill it and take all the rough edges out but is there a point where you can take off too much weight by doing this?  FYI the only part that was cut was the back, the firing pin is still shrouded.  I plan to use this on an M4 type build.  I figure I'll be saving the cost of a BCG providing the machinist doesn't charge too much.

Link Posted: 1/24/2014 11:10:38 AM EDT
[#1]
OP, from what your describing, I think you may have a brand new paper weight. But this is definitely a question that needs pics of said bolt carrier to really answer it.

Decent complete BCG's are cheap right now, it would possibly cost more to try and fix. Not worth it.
Link Posted: 1/24/2014 11:11:45 AM EDT
[#2]
Quoted:
A friend gave me an M16 BCG that he or someone used a hacksaw to cut  to a semi auto BCG.  It looks pretty bad.  Anywho I was going to take it to a machinist so the could mill it and take all the rough edges out but is there a point where you can take off too much weight by doing this?  FYI the only part that was cut was the back, the firing pin is still shrouded.  I plan to use this on an M4 type build.  I figure I'll be saving the cost of a BCG providing the machinist doesn't charge too much.
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For a while, Colt was taking off the entire underside of theirs, so nothing you need to do to clean yours up will be a problem.
Link Posted: 1/24/2014 11:23:42 AM EDT
[#3]
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Quoted:

For a while, Colt was taking off the entire underside of theirs, so nothing you need to do to clean yours up will be a problem.
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Quoted:
Quoted:
A friend gave me an M16 BCG that he or someone used a hacksaw to cut  to a semi auto BCG.  It looks pretty bad.  Anywho I was going to take it to a machinist so the could mill it and take all the rough edges out but is there a point where you can take off too much weight by doing this?  FYI the only part that was cut was the back, the firing pin is still shrouded.  I plan to use this on an M4 type build.  I figure I'll be saving the cost of a BCG providing the machinist doesn't charge too much.

For a while, Colt was taking off the entire underside of theirs, so nothing you need to do to clean yours up will be a problem.


This.

OP, pics would be helpful, but If I were you, id make sure you filed down all the rough edges, and you should be good to go.
Link Posted: 1/24/2014 11:30:58 AM EDT
[#4]
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Quoted:

For a while, Colt was taking off the entire underside of theirs, so nothing you need to do to clean yours up will be a problem.
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Quoted:
Quoted:
A friend gave me an M16 BCG that he or someone used a hacksaw to cut  to a semi auto BCG.  It looks pretty bad.  Anywho I was going to take it to a machinist so the could mill it and take all the rough edges out but is there a point where you can take off too much weight by doing this?  FYI the only part that was cut was the back, the firing pin is still shrouded.  I plan to use this on an M4 type build.  I figure I'll be saving the cost of a BCG providing the machinist doesn't charge too much.

For a while, Colt was taking off the entire underside of theirs, so nothing you need to do to clean yours up will be a problem.


I have one of those Colt BCG's with the whole underside milled off in my Colt HBAR and it has always functioned flawlessly, although it sure is ugly!

Not My Pic, Random image from google.  Mine looks like the ones on the left
Link Posted: 1/24/2014 11:32:27 AM EDT
[#5]
I'm going to try and post a pic, been having problems with that.  In any event the BCG travels smoothly in an upper receiver, the rough edges are not on the outside but if I can post a picture you'll see what I mean.

If I could get mine to look like the one in the middle, then I would be o.k. with it but the question remains, does less weight cause these to cycle faster or take a beating?
Link Posted: 1/24/2014 11:46:32 AM EDT
[#6]
Less weight will cause it to unlock quicker after firing, but you'll be hard pressed to notice any difference. Like the photo shows, you can mill a lot off the bottom. I also have bolt carrier like the one on the left.

ETA: no it won't take more of a beating because of  less weight
Link Posted: 1/24/2014 11:47:05 AM EDT
[#7]
Yes, it will cycle faster.  It shouldn't beat up your gun though.  You could always add some buffer weight if you wanted to slow it back down.



Some of the 3 gun gamers use aluminum or titanium carriers specifically to save weight.

       
 
Link Posted: 1/24/2014 12:57:19 PM EDT
[#8]
I would hone it down it down by hand. You could pay a machinist to clean it up and then pay someone to parkerize it but at that point you should have just purchased a new carrier

Start with a flat file and lightly get the big stuff, then incrementally move up to 1000grit or so sandpaper. And then polish it up a bit. Obviously it is not going to have a parkerized coating, but the polishing should help with the surface hardness, and make it less prone to a fracture
Link Posted: 1/24/2014 3:48:30 PM EDT
[#9]
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Quoted:
I would hone it down it down by hand. You could pay a machinist to clean it up and then pay someone to parkerize it but at that point you should have just purchased a new carrier

Start with a flat file and lightly get the big stuff, then incrementally move up to 1000grit or so sandpaper. And then polish it up a bit. Obviously it is not going to have a parkerized coating, but the polishing should help with the surface hardness, and make it less prone to a fracture
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I wasn't going to refinish it to avoid that expense but I do have a large flat file...
Link Posted: 1/24/2014 4:27:02 PM EDT
[#10]
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Quoted:


I wasn't going to refinish it to avoid that expense but I do have a large flat file...
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Quoted:
Quoted:
I would hone it down it down by hand. You could pay a machinist to clean it up and then pay someone to parkerize it but at that point you should have just purchased a new carrier

Start with a flat file and lightly get the big stuff, then incrementally move up to 1000grit or so sandpaper. And then polish it up a bit. Obviously it is not going to have a parkerized coating, but the polishing should help with the surface hardness, and make it less prone to a fracture


I wasn't going to refinish it to avoid that expense but I do have a large flat file...


just get a small bottle of cold blue. at least that way you wont have bare metal that could rust on you.
Link Posted: 1/24/2014 5:50:26 PM EDT
[#11]
Quoted:
A friend gave me an M16 BCG that he or someone used a hacksaw to cut  to a semi auto BCG.  It looks pretty bad.  Anywho I was going to take it to a machinist so the could mill it and take all the rough edges out but is there a point where you can take off too much weight by doing this?  FYI the only part that was cut was the back, the firing pin is still shrouded.  I plan to use this on an M4 type build.  I figure I'll be saving the cost of a BCG providing the machinist doesn't charge too much.
View Quote

Pictures.
Link Posted: 1/24/2014 6:18:42 PM EDT
[#12]
O.K.  This is what it looked like before



This is what it looks like after I took a file to it.



The back part is a little deeper, I could try to level it out but do I need to?  If I do then there will be a little step but one way or the other it doesn't affect function.



I figure the back part went a little deep because Bubba didn't cut it straight across.  What do you think, serviceable?  Its going on plinker, nothing serious.
Link Posted: 1/24/2014 7:21:54 PM EDT
[#13]
If you can hand cycle it without any hangups I doubt you'll have problems using it. An easy way to smooth it up evenly would be sanding blocks.
Link Posted: 1/24/2014 10:23:34 PM EDT
[#14]
it was ugly. now its a little less ugly

should work fine plinker or not. just throw some cold blue on it at some point. even with oil on it, if it ever just sits in the safe for a whiel it will most likely start to rust.
Link Posted: 1/25/2014 3:05:11 AM EDT
[#15]
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Quoted:
it was ugly. now its a little less ugly

should work fine plinker or not. just throw some cold blue on it at some point. even with oil on it, if it ever just sits in the safe for a whiel it will most likely start to rust.
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Spot on .


Maybe tape it off an hit it with bbq paint if you want to get fancy
Link Posted: 1/25/2014 5:50:47 AM EDT
[#16]
Looks like you cleaned it up well. It should not be a problem. Check the weight with a market semi carrier. I am guessing it will be close, as long as it does. Not grind on your upper you should be good to go.
Link Posted: 1/25/2014 1:00:30 PM EDT
[#17]
Not satisfied with the way I left it, I took another go at it.



I then hit it with some flat black.



Thanks for looking.
Link Posted: 1/25/2014 1:08:54 PM EDT
[#18]
Nice job.
Link Posted: 1/25/2014 6:10:30 PM EDT
[#19]
Looks much better now.

If it's in a mid length or a rifle length I seriously doubt it will cause problems.  In a carbine length, probably won't have any problems either, to be safe you could get a heavier buffer but chances are you're just fine.
Link Posted: 1/26/2014 2:55:00 AM EDT
[#20]
Great save on that one. Nice job.

AL
Link Posted: 1/26/2014 4:26:52 AM EDT
[#21]
Looks good OP!  Just curious, but "flat black" what?  It looks good but I'm curious if it's something that is going to wear off quickly.
Link Posted: 1/26/2014 4:57:43 AM EDT
[#22]

You did a nice job cleaning it up cosmetically.  Keep your eye on it after each time shooting for a while to make sure you aren't causing damage like cracks in the carrier or scraping inside the upper.




If you need more weight, you could go with a heavier buffer.  Alternatively, if you cant spring for a new BCG ($90 -100 from AIM, Rainier, PSA), you could get a new carrier ($50) and reuse your bolt.




Anyhow, nice job cleaning that butchering up.
Link Posted: 1/26/2014 8:36:37 PM EDT
[#23]
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Quoted:
Looks good OP!  Just curious, but "flat black" what?  It looks good but I'm curious if it's something that is going to wear off quickly.
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The paint was just to see how it would look but a friend said he would Duracoat it for nothing.  I'll make sure I clean up any burrs before I run this so I don't scratch an upper.  I also plan to keep an eye on the back part where the angle is so I don't have any cracks there. Later I may just get just the carrier (good idea) and keep this as a spare.
Link Posted: 1/27/2014 5:28:11 PM EDT
[#24]
Break the sharp edges.
Link Posted: 1/27/2014 7:09:28 PM EDT
[#25]
$80 free shipping aim bcg and call it a day. Throw that in back up to back up bin.
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