I ordered a bcm stripped upper receiver specifically because they advertise that the front of the receiver is smaller than mil spec for a tighter fit which I hear is a good thing. Sure enough the barrel I got from Odin works will not fit in it just by a small amount which is what I was expecting. My question is to all you guys that lap the face of the receiver. How do you do it with tight uppers like this? I imagine that this is where the few bad reviews on the barrel facing tools come from with complaints the tool doesn't fit. I do not have a lathe to make one fit or make a tool for this job so I am at a loss. I hear lots of folks that say that facing the receiver is a waste of time but I do not like to skip steps. If there is something I can do to increase accuracy I want to do it. Even if it is a waste of time, I won't be wondering if I could have done it better if I go ahead and do it. So would someone explain how to overcome this?
receiver facing
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I put together an upper with a BCM receiver a few months ago. The lapping tool fit into the receiver without any problem. It needed very little lapping, if any.
I put one of the original Faxon 16" barrels into the upper. I used blue loc tite and it was a pretty snug fit, but I didn't have to do any heating or freezing to get it in.
All in all, I was pretty impressed with the BCM receiver.
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Don't know what to tell you. I've got one data point, but that line could be extrapolated in any number of directions.
I could send you my tool, but you would pay about as much in shipping it back and forth as a new one of your own would cost.
I've used the tool on 4 or 5 receivers so far, so it's a good thing to have in the tool box. That said, the BCM receiver needed less lapping than any of the others.
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I'm gonna throw this out there as an idea I had. Those who have tried it or maybe know better, feel free to point out the flaws. I had the same concern when I bought my Mega billet upper and wanted to check square. If the tool did no t fit in the receiver, I was going to put the tool in the drill and use sand paper to reduce the size of the shaft .001 at a time until it fit snugly. Fortunately I didn't have to do it. With a lot of lube and a little coercion, the tool slid in and spun freely.
You might try lubing it up good first.
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The distractions say to lube the tool before inserting into the receiver.
It's meant to fit snugly so there isn't runout.
I also do the work in the vertical plane, so gravity doesn't bias the tool in one direction inside the carrier raceway.NRA Basic, Pistol, Rifle, Shotgun, RSO
CCW, CQM, DM, Long Range Rifle Instructor
6.5 Grendel Reloading Handbooks & chamber brushes can be found here:
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Thanks guys, I may go ahead and try the tool. I was talking to a guy that has built 3 bolt actions for me and he was telling me to find an old barrel, get rid of the alignment pin and use this as a facing tool. Process being to insert the barrel extension with a small amount of lapping compound around the shoulder on the barrel then hand tighten the barrel nut. Then turn the barrel in the upper, as the barrel starts to turn easier, hand tighten the barrel nut again. Repeat this until the face of the receiver is shiny all the way around. He said this procedure would be actually better than the tool as this would true the face to the threads on the receiver. Any thoughts?
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Never heard of doing it that way myself.
Seems the tool would be doing the same thing since all you do with the tool is take it down till the face area is all shiny, seems like it would be the same out come to me but I could be wrong.
I do know from first had experience that the tool does work, have used it on my first grendel and then my woman's and my dads, brother in laws and all three of my girls uppers.
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the only difference between the tool and the barrel version he talked about is the tool would true the face to the bolt carrier and the barrel would true the receiver to the barrel nut threads if they were different.
His thought process was that if the receiver was trued to the bolt carrier and the threads were not perfectly concentric to the upper you would still have uneven pressure on the on the barrel by the barrel nut.
I think I remember one of your posts where you talked about facing your receivers, it is a big part of why I want to do it despite others who have "never faced a receiver and every one of the ARs I have built have shot quarter sized groups at 100yds".
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I'm not understanding what your meaning it would square it to the bcg.
The tool lapps the reciver face so the face of the reciver interfaces square with the the lip of the barrel extention, and that causes the reciver, barrel and scope to be more inline with each other, makeing tighter groups.
I'm not saying in any way that the way he described to do it wouldn't work or wouldn't work better then the tool.
I'm just going off what I read about the tool and how it works and it would seem that it does the same thing as doing it with a barrel extention, the tool and the barrel extention are very similar in how they are made.
I will post a pic up of mine in a few.
Either way I'm sure it would work and do what you wanted it to accomplish.
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To be honest I said squaring to the bcg because I cant think of the correct term for the section of the upper receiver that the bcg travels back and forth in, where the tool slides down in to keep it square to the receiver.
The more I think of it and after replies to this thread I may just try get the tool and try it for now, and save his method for a future build. Parts have been coming in, and I'm getting anxious to put this thing together. The tool would be (for me) easier to find than a shot out or bad barrel at this point anyway and as long as it fits in the receiver I'll be satisfied.
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