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Posted: 10/15/2003 5:33:29 AM EDT
Does anyone know where I can find detailed instructions to replace the stock front sight assembly on an M4 barrel. I thought I saw a post awhile back but I can't find it.

Thank You
Link Posted: 10/15/2003 12:16:31 PM EDT
Do you mean remove and replace the same front sight post, or remove one and replace it with a completely different (perhaps new) part?? There is a significant difference!
Link Posted: 10/16/2003 1:31:15 AM EDT
Hard work, some heat maybe, a large brass hammer, taper pin punch, supporting the otherside so the strikes are effective, and make sure you beat the pin the correct direction, from the small side I believe.
Link Posted: 10/16/2003 3:44:21 AM EDT
[Last Edit: 10/16/2003 3:47:09 AM EDT by Wheelgunner]
Replace with "new" stock A2 front sight assembly from RRA. The origional aiming post is drilled and tapped way off to the left and almost touches the left ear. The barrel is M4 style with .750 inch diameter barrel under the assembly.
Link Posted: 10/16/2003 4:59:35 AM EDT
Russ4777, I am also thinking of replacing with the DPMS 4 Rail Aluminum Gas Block with a detachable front sight. What is your opinion?
Link Posted: 10/16/2003 5:15:21 AM EDT
I had considered a flip-up front sight on my first M4gery build, but ultimately decided against it after researching the topic on this board. The fixed front sight does not interfere with a magnified optic (ACOG) and can easily co-witness with a non-magnified dot system (Aimpoint). The thinking is that the fixed front sight is more durable and, therefore, reliable than a flip-up. The only flip-ups I have seen in use by the military thus far have been on SPR (Special Purpose Rifles - semi-sniper M16s with full scopes).
Link Posted: 10/16/2003 5:32:34 AM EDT
OK, I'll stick with the stock front sight. Should I cut it off with a cutting wheel?
Link Posted: 10/17/2003 8:00:34 AM EDT
If the front sight post recess is mislocated send the barrel back to the maker/distributor. There is chance that the gas port in the front sight base is not aligned with the gas port in the barrel. Pulling the front sight base off the barrel will probably show this since most companies do not park their barrels to spec. You will see a ring on top of the barrel near the gas port. The ring is where park solution collected in the gas port of the FSB. The ring should be centered around the gas port in the barrel. Even if the gas port is aligned send it back, don't let the bottom feeders get away with shoddy work. How is the barrel marked? Replacing a front sight base is not a simple matter. Standard pinned FSBs are not interchangeable. You, or your smith, will have to jig up the barrel and re drill/ream the taper holes. If you are going to cut off the front sight base remove it from the barrel first. Chop off the largest portion with a hacksaw/chop saw/bandsaw and then finish it off with a belt sander and repark.
Link Posted: 10/17/2003 10:41:09 PM EDT
[Last Edit: 10/17/2003 10:42:53 PM EDT by Wheelgunner]
Tweak Thanks for taking pitty upon me and responding to my question. The bottom feeders were a local shop that is now out of business. I did not notice the problems until I took it to the range much later after the purchase. I was told when I purchased the barrel that it is a Wilson stainless steel. How much of that is true I have no idea. The barrel parkerised (?) and is marked SS 5.56. When you said "will have to jig up the barrel and re drill/ream the taper holes". Does this mean you can't use a hand drill with the new sight base? "If you are going to cut off the front sight base remove it from the barrel first." Uh, I am really confused on this one. I was going to cut the base to remove it from the barrel. What does "repark" mean? Thank you for your time. Dan
Link Posted: 10/18/2003 9:54:19 AM EDT
[Last Edit: 10/19/2003 9:53:08 PM EDT by Tweak]
Originally Posted By Wheelgunner: The barrel parkerised (?) and is marked SS 5.56.
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Sounds like an OlyArms barrel. They've got a "how to spot our barrels" page at their site.
Does this mean you can't use a hand drill with the new sight base?
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Correct, you won't be able to maintain sight alignment, you'll need a jig to hold the sight in its proper radial orientation on the barrel.
Uh, I am really confused on this one. I was going to cut the base to remove it from the barrel.
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Take the FSB off the barrel before you cut the top half off, it's easier to do it that way.
What does "repark" mean?
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Re Parkerize. The barrel may be Stainless Steel (the SS stamped on the barrel) but the FSB will still be carbon steel. [speeling]
Link Posted: 10/19/2003 5:46:13 AM EDT
Tweak, Thanks for the barrel ID info at Olympic Arms. Looks like I have their SS barrel. Do you know where to purchase a jig to hold alignment of FSB? Otherwise I am thinking of throwing on a light quick tack weld that I can grind off later, to hold the FSB in place for drilling. I can put on a weld without distressing the inner part of the barrel if I do it fast enough and run nitrogen gas through the bore at the same time. According to the Oly site about their barrels the coating on the SS barrels is a black oxide finish and not parkerized. If so then I will probably use flat black paint used for BBQs, its pretty tough stuff. Dan
Link Posted: 10/19/2003 9:30:16 AM EDT
Check Armalites site. They make a clamp-on front site base. Therefore you don't need to agonize over match drilling, fixtures, etc.
Link Posted: 10/19/2003 9:51:10 PM EDT
Originally Posted By Wheelgunner: Do you know where to purchase a jig to hold alignment of FSB?
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Any decent smith with a mill should be able to install it for you.
According to the Oly site about their barrels the coating on the SS barrels is a black oxide finish and not parkerized. If so then I will probably use flat black paint used for BBQs, its pretty tough stuff.
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Yes, black oxide is the finish on Oly's SS barrels but we're talking about refinishing the front sight base after you..wait are you still planning on chopping the front sight off? Send the barrel back to Oly, they'll replace/repair it for you. They have a lifetime warranty and great customer service.
Link Posted: 10/20/2003 5:16:29 AM EDT
Thank you for the information! I never would have thought that changing the FSB would be such a pain in the ass for a garage tinkerer. I will contact Oly. Dan
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