I have an AR zero/sight problem. Looking for the best solution.

[spankaveli]

but if you use the bushmaster front sight. it will be above the wings of the fsb. prone to snagging. better get the correct FSB

That is my main concern. I know I can get a taller FSP but that is a "quick & easy" solution but maybe not the best because, as you said, I don't want the FSP taller than the ears.

[spankaveli]

I will try to get some pics to show how the fsp sits in the fsb currently.

[Molon]

but if you use the bushmaster front sight. it will be above the wings of the fsb. prone to snagging. better get the correct FSB

There is no difference in the overall height of an "F" marked front sight base from a standard front sight base. The only difference is in the "shelf" that the post screws into.

Also, you can't just swap out a standard front sight base for an "F" marked front sight base. The front sight base and the barrel need to be drilled and reamed together in a fixture.

[Belmont31R]

I would get a correct F FSB, and consider it a lesson learned.



Bravo Co sells them, and then you need to get it installed. I think ADCO would be able to do it. http://www.adcofirearms.com/shopserv...op_.cfm?code=5

[spankaveli]

update: shot both guns today and both have the same problem and two other people shot one of them as well.

so my options seem to be:

dump teh uppers and start over
change the front sight base to an f-marked
change the front sight base to a railed gas block and get rail mount si.ghts...




You guys know anyone that makes a midlength pEncil barrel upper or just the barrel? Also, what's the easiest flattop slickside upper to acquire?

[bigfelipe]

change the front sight base to a railed gas block and get rail mount si.ghts...

That's probably your easiest fix. Get a quality one piece block and make sure to have it pinned or at least heavily dimpled and loctited if using set screws.

[C4IGrant]

That is my main concern. I know I can get a taller FSP but that is a "quick & easy" solution but maybe not the best because, as you said, I don't want the FSP taller than the ears.

Yes, but your other option is to fill the holes and re-drill for a new FSB. That is a rather expensive option on a VERY cheap barrel.



C4

[C4IGrant]

That's what I thought.

Are they really that much taller?

Yes, they really are.

This is what you need: http://www.gandrtactical.com/cgi-bin...n&key=TALL-FSP

We are seeing your problem more and more. The question I have is, why doesn't anyone realize that you cannot use an A2 FSB with a flattop?????????????



C4

[spankaveli]

Yes, they really are.

This is what you need: http://www.gandrtactical.com/cgi-bin...n&key=TALL-FSP

We are seeing your problem more and more. The question I have is, why doesn't anyone realize that you cannot use an A2 FSB with a flattop?????????????



C4

When I ordered the barrel kit from M1S there was no distinction on the which FSB would be on it.

[Quentin]

Sorry to hear about this problem, spankaveli.

Since you may go with a gas block FSB, I'm pasting in a picture of my ArmaLite gas block with their fixed front sight. It has the Bushmaster 0.040" taller post because I did the IBZ/RIBZ mod. The base of the post is flush with the upper base of the FSB and my carry handle elevation knob bottoms out 10 clicks below 6/3 (Only needed 6 but the tall sight was deep in the FSB well and I like it flush.) The taller post doesn't come anywhere near the ears of the FSB but I guess it's a whole 'nother ball game with a standard A2 FSB.