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9/22/2017 12:11:25 AM
Posted: 8/25/2003 6:12:18 AM EDT
[Last Edit: 8/25/2003 7:04:22 AM EDT by HogSniper]
How hard is it to remove the front sight post & replace with another gas block? Is there some illustrated instructions online somewhere. I assume you must drill out the rivets, but I also have a permanent flash hider which would prevent it from sliding off muzzle end. Can the post be opened enough to get it off anyway?

Sorry if this has been covered a gazillion times, but my search didn't find anything on subject.

Appreciate any insights,
HS
Link Posted: 8/25/2003 6:27:24 AM EDT
You do not need to drill out the retaining pins that hold the front sight to the barrel. They are tapered and must be tapped out one direction with a punch and a hammer. I cannot remember off hand which direction they go. Just look at the pins and you will see one side of the pin is wider than the other side. So tap them out on the skinny end. Soak them for 15 minutes or so first with something like Rem Oil. Then tap them out. To get the sight off the barrel you might have to tap it with a rubber mallet to get it to slidem (lube it up first). I have no idea how to get it around your flash-hider unless you grind cut it off. But then you are not going to be able to install a new one either.
Link Posted: 8/25/2003 6:52:37 AM EDT
Your flash hider is gonna have to come off...if it's a postban rifle, it's either blind pinned on, or welded. Either way, it can be a pain in the ass. I ended up just having mine cut off, and the barrel recrowned. If it's welded, you can conceivably heat it up with a MAPP gas torch to where you can just unscrew it, but you're talking about temperatures over 1100 degrees to break the weld I think. If it's pinned on there, you' just gonna have to grind it off, or machine it down to even with the barrel. You can usually find someone to cut the thing off and recrown the barrel for you like I did...Compass Lake Engineering did mine, for $65 including return shipping. There are other folks who can do that, and in the end it's probably less hassle, and less chance of screwing anything up.
Link Posted: 8/25/2003 7:00:18 AM EDT
[Last Edit: 8/25/2003 7:01:28 AM EDT by HogSniper]
Sounds like more trouble than it's worth. I luv this M4 type upper & hate to mess it up. It is light & swings great. I think I will just buy another upper configured for a higher power scope later. I was concerned my front sight may interfere with the 3x9 scope I have on order. I'll just wait & see. It may work out fine as is. If it bothers me, that is just an excuse to get another upper right? :) I can put an Aimpoint or similar scope designed for the short barrel on this one. Thx
Link Posted: 8/25/2003 7:18:08 AM EDT
I spent a good 15 minutes last night trying to hammer those pins out of my front site. The problem I see is getting a stable base to put the barrel assembly on. What do you experts out there use? The other problem is you seem to need three hands; one to hold the barrel/site, one to hold the punch, and another for the sledge. I was seriously considering picking up my dremel, but wanted to check with the experts first.
Link Posted: 8/25/2003 8:36:28 AM EDT
HogSniper, I believe that you shouldn't have a problem with the sight picture w/ a 3-9X magnification scope. You might see a very faint blurred area where front sight post is at 3X, but it should shouldn't show at the higher magnification settings. The focal length of the scope at higher levels of magnification is far past the position of the front sight. It would tend to be most distracting below 3X.
Link Posted: 8/25/2003 10:11:18 AM EDT
I have a 3-9X40 mounted on a BSquare mount on my AR with the regular FSB. Looking through it, you can't see the FSB at all, even on 3x. Ghost
Link Posted: 8/25/2003 1:04:18 PM EDT
M4 guy, I use an old leather shoe to rest my barrel on. Then I set it on the floor and hold the barrel with my knee and just tap them out. Make sure you are not tapping the wrong direction. If you oil them first, use the right size punch you should be able to knock them out. Hog Sniper, why don't you just cut the top of your sighe base off if you are worried about scope use? I just milled mine off and dremeled/filed it so it looked nice. Then I painted it. I did this with it off my barrel but with some care you could easily do it while it is attached.
Link Posted: 8/26/2003 5:08:59 AM EDT
If you follow dogcatchers advice, Bushmaster has a folding frt sight that bolts around a milled frt sight. You can probably find a local machine shop who has a metal lathe and can turn down your perm attached muzzlebrake and rethread the barrel or then take it to a smith and have it recrowned if needed. Note: I would recommend against cutting off a true chrome lined barrel.
Link Posted: 8/26/2003 5:20:17 AM EDT
[Last Edit: 8/26/2003 5:25:27 AM EDT by Fenian]
First of all, you really should have one of these:[url]http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=7675[/url]. They make life so much easier for doing stuff like this. I would suggest getting another pair of hands to hold the upper while you work the punch/hammer. If you dont' have a bench block, you have to figure a way to support the barrel with something else that will provide stability but not mar the finish. Maybe a block of wood with some rags on it. Give the pins a squirt of Kroil or Liquid Wrench, then let it sit for a couple of minutes. One or two REALLY good whacks with a decent sized hammer should break the pin loose, then just use a slightly smaller punch to tap it out. (so you don't get the punch stuck lol). Some more Kroil on the barrel under the gas block should allow the thing to just slide right off...I just twisted mine a little, and then in came loose. This wasn't that difficult, but I can see that without the bench block, it could be little harder for only one person. But really, if you're only reason for doing this is the scope, don't even bother, you'll never even notice the front sight through a scope, even at 3x. Plus, you still haven't addressed the muzzle brake issue, so it sounds like the path of least resistance is to just slap the scope on there and not worry about the front sight, it won't cause a problem.
Link Posted: 8/26/2003 5:57:19 AM EDT
[Last Edit: 8/26/2003 6:01:42 AM EDT by HogSniper]
Thanks for the info guys. I realy don't want to cahnge rifle as I realy like it. I'm reassured that it will work now. In fact, I like these AR's so much, another upper is calling my name. Can't aford it, but why should that stop me? [:D] Take care, HS
Link Posted: 8/27/2003 5:13:37 AM EDT
Originally Posted By M4-guy: I spent a good 15 minutes last night trying to hammer those pins out of my front site. The problem I see is getting a stable base to put the barrel assembly on. What do you experts out there use? The other problem is you seem to need three hands; one to hold the barrel/site, one to hold the punch, and another for the sledge. I was seriously considering picking up my dremel, but wanted to check with the experts first.
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Put the sights in a vise upside down, then punch the pins out. Its easy that way.
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