Ar-15 Gas block removal

[PulsatingBeaver]

I want to change the front sight base for my ar-15. Its a Hbar. I do not know how to take the origional front sight base off. And i also dont know what size of gas block i should get, i hear .750 alot. any input will help. I am doing this so i can add a scope without seeing the sights. Also i will be putting a flip up sight on it. What FUP do you guys recomend? My budget for this is around $200 but if i can get away with $150 ill be happy as hell!

[Tweaker]

Gas Block
YHM is very good quality and also less expensive than most. Get that.

The front sight is pinned in. I had a gun smith do it for cheap.

Measuring when it is off will be a solid answer. Someone more knowledgable than I could tell you now.

Be careful putting the new block on to align the gas port well or you will have problems either small or very large. Resetting zero on the flip front sight will be a bear as well, as it rotates about the barrel axis. Shoot close and leave the bolts loose until you get it set up.

Flip sights
Magpul makes a nice set for cheap. It is plastic, but it seems well made.

[M1A4ME]

First, what size scope are you using? I don't "see" the front sight base/ears on any of my rifles. Even the one with a 2.5X shotgun scope on it "hides" the front sight post/ears from the field of view. The 3X9 and 4X scopes do the same thing. The scope is so close to the sight that the sight is for all purposes invisible to your eye.

Try it before you go to the trouble of removing it.

If you do remove it you've got to remove the flash suppressor as well (to get the front sight base off the barrel.) Once you remove the front sight base you can measure the barrel diameter under the base (you may be able to do that without removing the front sight base depending on your barrel contour/type - some barrels have multiple changes in diameter and some don't so much) to see what size front sight base you need.

Those taper pins (bigger on one end of the pin than on the other end - same or the holes in the front sight base) in the front sight base can be a booger to drive out. I don't remember which way to drive them, maybe someone else here does and will add that info to this thread.

I would not put a plastic/polymer sight on the gas system of an AR15. I've read reports of problems due to the heat generated if you fire lots of rounds quickly (I'd probably never shoot that many rounds that fast but some folks do/have).

Good luck with it.

[PulsatingBeaver]

hey guys do you think that thiss will be good?
http://www.cheaperthandirt.com/ARR9394-7.html