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Thread: Seriously BCM? What do you use for FSB pins? Or: Never invade Russia in Winter.

  1. #1
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    Seriously BCM? What do you use for FSB pins? Or: Never invade Russia in Winter.

    This is not a bash on BCM. They are an amazing company and I have never had any major problems with them even now.

    But tonight I tried to take the FSB off my favorite LW upper so I could replace the magpul hand guards. I have a Jig and good punch set. I have done this on dozens if not over 100 guns for myself and friends. It really isn't hard right? And this has become my favorite upper. Like a good lover you want her to have all the nicest things. Lets get too this I thought to myself.

    So I lay the upper gently in the Jig and whisper to it how everything it going to be fine, there will just be a couple quick taps and all will be better. Just like getting a shot. No real pain...

    Oh how I was wrong. So very, very wrong...

    The rear pin was difficult. It took some lube and I had to start with a bigger punch to get it started but after some really hard smacks with the hammer but it eventually came out.

    The forward FSB pin though... Oh that pin. So I started with normal punch. Nothing. It just kept sliding off and my upper was getting mad about it. At one point she even took a nice little check out of my palm. It is worth noting that at this point the feisty little vixen is giving me the silent treatment, not that I don't deserve it. LOL

    So lets bypass the punch for a minute I think. How about my press. It is a small home made deal but should be fine for this right? Yeah. About as right as Obama on gun policy... I watch in horror as the punch I have fit in the press starts to bend.... This isn't going to work. So I pull her out of the press and decide to resort to my final devious plan.

    To to the drill Press! I will use the proper sized bit and make the top of the pin concave. This will keep the punch in there and it wont' slip out. Then I can use multiple taps to work it out... We are beyond Obama wrong here. We are into invade Russia in winter wrong at this point. I watch as the Drill bit spins on top of the Pin. As I apply more pressure it skips off and starts chattering around the pin and cewing up the FSB... I decide that I should go with a larger bit, one that won't slip or flex like that. How about a 9/32 bit? That should do it if I am careful. Solid so it won't flex. If I don't go too far down it will just create a small pocket, worst case I can follow up with the smaller bit, drill it out and replace it right?......

    Yeah.. What is dumber than invading Russia in winter? I don't know off the top of my head but this was for sure.

    Just like the last bit it flexed. Chattered around the sides and chewed up the FSB.

    So I did what any hard working type A personality go getter would do. I said **** it. Turned off my shit and came in to drink some Woodford Reserve and then ask you all what the hell I am doing wrong.

    Seriously. What the hell does BCM make these roll pins out of and use to put them in? I am assuming they mix the steel with some ground up unicorn horn and then push them in with a 1000 ton industrial press. Ideas? Suggestions?

    I am going back to my bourbon. Thanks for any advice or ridicule. I will accept both with the grace I am sure they will be given...

    Oh yeah. Here is a Picture of her. She still won't talk to me and said something about a restraining order.

    20170118_211622.jpg
    Tell my tale to those who ask. Tell it truly; the ill deeds along with the good, and let me be judged accordingly.


  2. #2
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    ****, I need a drink of Woodford and reading/seeing that.

    Yeah, the restraining order might have merit, you might also find yourself in a running for another thread, about gunsmithing and shame. I believe it to be quite a long hall. Other than the drink I got nothing to help. Maybe try a bigger hammer? All I know is that when it comes to BCM, their gasblocks and apparently FSB are famous for the fact that they don't move, which is why I haven't ventured out to replace the DD Omega on my rifle.
    "I don't collect guns anymore, I stockpile weapons for ****ing war." Chuck P.

    "Some days you eat the bacon, and other days the bacon eats you." SeriousStudent

    "Don't complain when after killing scores of women and children in a mall, a group of well armed men who train to shoot people like you in the face show up to say hello." WillBrink

  3. #3
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    Yeah I have been watching that thread. thought about posting this in it... But This is a case where I don't really think I did anything from the start to jack it up. I have done this so many times. And yeah BCM can be a bit of a pain but I have never seen one like this. I mean it deflected a brand new carbide drill bit. It bent a Punch in a press.... This pin is the spawn of Satan after he got drunk on bad vodka and had a one night stand with a steel roller.
    Tell my tale to those who ask. Tell it truly; the ill deeds along with the good, and let me be judged accordingly.


  4. #4
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    I am assuming the pins are hardened and that's why they're so hard to drill.

    You need an unforgiving surface, big punch, and big hammer. I put mine on a piece of steel plate (maybe with a relief hole for the pin, can't remember) on the concrete floor, used a 1/2" punch and a 2 lb drilling hammer. I had no issues breaking mine loose but maybe I just got lucky. You could also try some kroil and heat.

  5. #5
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    Disclaimer: it may be too late for Option #1 at this at this point...

    #1.) I have a fairly large (1/2"?) brass punch I use to start all my FSB pins. By whacking them with a softer material it prevents the end of the pin from mushrooming over and preventing it from driving through. Once the pin is flush, I switch to the correct sized punch. I reprofile the brass punch each time before I use it.

    #2.) If it is too late for the above, I'd try to drill the pin. Don't forget to use some drill/tapping oil or even motor oil to sync the heat away and keep your bit alive. Also, it might be worth looking into getting an end mill bit or take it to a machinist to have the head knocked down square or even countersunk a little before you start hammering on it again.

    If those don't work...Adco.

  6. #6
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    Quote Originally Posted by kwelz View Post
    Yeah I have been watching that thread. thought about posting this in it... But This is a case where I don't really think I did anything from the start to jack it up. I have done this so many times. And yeah BCM can be a bit of a pain but I have never seen one like this. I mean it deflected a brand new carbide drill bit. It bent a Punch in a press....
    True. Might have the makings for it though depending on how things turn out and if you end up mad maxxing the ****er.
    On a side note you mentioned change out the magpul handguards. What you changing them out for? Curious.


    Quote Originally Posted by kwelz View Post
    This pin is the spawn of Satan after he got drunk on bad vodka and had a one night stand with a steel roller.
    I may steal this line. Just so you know. Because it is ****ing hilarious!!!!
    "I don't collect guns anymore, I stockpile weapons for ****ing war." Chuck P.

    "Some days you eat the bacon, and other days the bacon eats you." SeriousStudent

    "Don't complain when after killing scores of women and children in a mall, a group of well armed men who train to shoot people like you in the face show up to say hello." WillBrink

  7. #7
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    Yep I use a huge punch and a huge hammer with the barrel on wood blocks on the garage floor. Huge punch is key.


    Sent from my iPhone using Tapatalk

  8. #8
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    Quote Originally Posted by Kain View Post
    True. Might have the makings for it though depending on how things turn out and if you end up mad maxxing the ****er.
    On a side note you mentioned change out the magpul handguards. What you changing them out for? Curious.



    I may steal this line. Just so you know. Because it is ****ing hilarious!!!!
    Timber Creek 9 inch rail. Was going to put a BCM on it but my shop has some Timber Creek rails I want to try out. The 9 inch is only 7.4lbs which is actually a tiny bit lighter than a 9 inch KMR alpha.

    20170118_221850.jpg20170118_221830.jpg
    Tell my tale to those who ask. Tell it truly; the ill deeds along with the good, and let me be judged accordingly.


  9. #9
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    Quote Originally Posted by jstalford View Post
    Yep I use a huge punch and a huge hammer with the barrel on wood blocks on the garage floor. Huge punch is key.


    Sent from my iPhone using Tapatalk
    I even tried with a 1/4 inch punch to start. That is how I started the back one and you can see in the photo that it turned out just fine.

    I went back just now and tried again. Yeah not the smartest after a couple drinks I know. But I used a 2lb sledge and a punch. That F*cker isn't moving. I am going to run to the shop tomorrow. Worst case I cut the damn thing off and put a full length rail on it. Then use this rail on the Saint I have on order.
    Tell my tale to those who ask. Tell it truly; the ill deeds along with the good, and let me be judged accordingly.


  10. #10
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    BCM is pretty well known for having tight pins. Try removing one of their barrel nuts too.

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