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Posted: 3/18/2004 5:43:09 PM EDT
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Once the roll pin from a BM front sight base is removed, does the front sight easily slip off the end of the barrel? Is it really tight, wanting to scratch every inch of the remaining barrel or does it slip off easily? How does one re align the front sight base to ensure the gas port covers the port in the barrel properly? |
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Quoted: Once the roll pin from a BM front sight base is removed, does the front sight easily slip off the end of the barrel? Is it really tight, wanting to scratch every inch of the remaining barrel or does it slip off easily? How does one re align the front sight base to ensure the gas port covers the port in the barrel properly? Yes, it should slip off over the muzzle without any damage. I removed the Barrel, and front sight base from my Bushmaster heavy barrel rifle to add the free float tube, and JP Enterprises adjustable gas block. Tyrod is correct, the FSB taper pins are a bitch to get out. I used a micrometer to measure the ends of the taper pins just to set me straight on which way to drive them. Once I was sure on which way I had to pound on them, I notched a couple of 4x4 pieces of wood to hold the barrel off the bench, and then used a 1/4" drive socket and a piece of steel to set under the FSB, so that when I started pounding on the taper pin, all the pressure from the hammer blows was on the area of the FSB around the taper pins, not on the barrel. Man I had to bash on them to get them out. Once I got them out, I noticed that the barrel had a very slight step in it that allowed the FSB to come off without scratching the muzzle end. If you look real close you should see what I'm talking about. Bottom line is it should come off with out a problem once the taper pins are out. To get it back on, on a friend of mines rifle, (Since I did not put it back on my rifle), I used a punch to align the rear taper hole, and I plugged the barrel on the chamber end with some tape and paper, and blew compressed air in the muzzle while holding my finger on the FSB where the gas tube inserts to make sure the air flowed freely out of the gas hole and that it was aligned properly. Once I got the first taper pin back in, and the alignment was good, the second one went in with no problem. Oh, I only set the first taper pin in with a slightly hard tap of the hammer and drift, and then checked it, then set the second taper pin and checked again before I seated the taper pins with a couple of really good whacks on the drift. That way I could pop them out easily if the FSB was not aligned properly. This was on a rifle that I was just putting the same FSB back on to the same slots in the barrel. If you are going to change the barrel and have to drill for the taper pins, I'd send it to a gunsmith for that! Hope this helps with your question! |
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Quoted: Quoted: Once the roll pin from a BM front sight base is removed, does the front sight easily slip off the end of the barrel? Is it really tight, wanting to scratch every inch of the remaining barrel or does it slip off easily? How does one re align the front sight base to ensure the gas port covers the port in the barrel properly? I used a micrometer to measure the ends of the taper pins just to set me straight on which way to drive them. I should add, when you carefully look at the taper pins you will see that one end is slightly smaller than the other. The small end is the on that you will put the drift on to drive it out. Drive it towards the large end. Seems obvious, but I just wanted to be clear on it for your info. |
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Squirt some Kroil or Liquid Wrench on the pins and let it sit in there for 15 minutes or so before you start...the, with everything supported as well as you can, use a pretty good sized hammer, and make your first whack or two pretty strong...it should start the pins on their way, then you can switch to a smaller hammer, and sorta tap them out using less force. That's the theory, anyway. Mine came out really easily doing it like this. The gas block/sight alingment should happen automatically...there are 2 notches in the underside of the barrel that the taper pins sit in...you'll see it when you take the sight assembly off...so you just have to line those back up when you slide the sight assembly back on. You won't even be able to start the pins back in unless everything is lined up. It's pretty self explanatory, once you see it. |
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Squirt some Kroil or Liquid Wrench on the pins and let it sit in there for 15 minutes or so before you start...the, with everything supported as well as you can, use a pretty good sized hammer, and make your first whack or two pretty strong...it should start the pins on their way, then you can switch to a smaller hammer, and sorta tap them out using less force. That's the theory, anyway. No theory, it works every time. Only thing I do a little different is used an oversized pin punch for the first couple of whacks to start the pins moving, then go to the proper size pin punch to finish driving the pins out. |
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Ditto on what fenian said. I took an armorers course this past weekend and as part of it, removed the front sight base on my rifle. I have a Bushmaster upper and the taper pins were very very tight. After a lot of bashing, used some Kroil and let it sit a little. Then did some tapping on the big end of the pins, then the small, then the big...until I saw the Kroil start to wick in around the pins. Then whack on the small ends and out they came. Bushmaster taper pins are softer than Colt [:(] and all my preliminary bashing mashed the small end like a rivet, so when it did come out, I had a small ring of metal shaved off. No problem putting it back on when aligned with the original location. |
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Must be case by case, but I just floated two new Bushmaster barrels and the pins came out nice and easy (relatively speaking). Total time for barrel break down was about 10 min. Install was smooth, reversing the process in another 10 min. Here's one I did last week: [img]http://www.hunt101.com/img/126304.JPG[/img] Kroil helps. |
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Quoted: Squirt some Kroil or Liquid Wrench on the pins and let it sit in there for 15 minutes or so before you start...the, with everything supported as well as you can, use a pretty good sized hammer, and make your first whack or two pretty strong...it should start the pins on their way, then you can switch to a smaller hammer, and sorta tap them out using less force. That's the theory, anyway. Mine came out really easily doing it like this. The gas block/sight alingment should happen automatically...there are 2 notches in the underside of the barrel that the taper pins sit in...you'll see it when you take the sight assembly off...so you just have to line those back up when you slide the sight assembly back on. You won't even be able to start the pins back in unless everything is lined up. It's pretty self explanatory, once you see it. He is correct, make sure your first whack on the pins is a good one with a decent hammer. After that they will come out very easy. Restalling the pins is even easier, start both pins and tap them in evenly, tap left pin, tap right pin, tap left pin, tap right pin, you get the picture. Good luck. |
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