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9/19/2017 7:27:10 PM
Posted: 3/22/2006 10:51:45 AM EDT


Sorry for all the questions in one day, but you guys are very helpful. I have a ban compliant bushmaster that has been with me for a few years now. Based on the advice in the other thread, I am going to have it cut down to 14.5 and add a vortex to it. I have this issue though, I am looking for the best close contact weapon. COnsidering an Eotech or an aimpoint. Should I sell this rifle (or buy another) with a flattop, or will a forward (scout style) carry handle mount do a good job for optics mounting?
Link Posted: 3/22/2006 10:53:05 AM EDT
Link Posted: 3/22/2006 10:54:34 AM EDT

Originally Posted By Stickman:
You could always just drop an A3 upper onto it, then sell the A2 upper on the EE....



Doesn't he run the risk of running into Front Sight Base height issues?

Link Posted: 3/22/2006 10:56:16 AM EDT
Put an Aimpoint on the top of the A2 carry handle...
Link Posted: 3/22/2006 10:58:40 AM EDT
I want to cowitness.
Link Posted: 3/22/2006 10:58:40 AM EDT
Link Posted: 3/22/2006 11:05:12 AM EDT

Originally Posted By Stickman:

I didn't when I did the same thing to my Bushie A2....



Did you go Bushy to Bushy? Bushmaster must use the same rear sight height on there A2 and A3 upper receivers.
Link Posted: 3/22/2006 11:07:23 AM EDT
the height problem can be fixed with a $4 extra high front sight post.
Link Posted: 3/22/2006 11:18:38 AM EDT
Link Posted: 3/22/2006 12:30:54 PM EDT
markm- you know better, don't you? That extra height really doesn't make a difference.

Jason- since you are looking at cutting the barrel as well, that's two strikes against that particular upper. Not that there is anything wrong with it per se, but it isn't fitting your idea of what you want right now.

My advice would be to sell the upper on the EE and buy a new or used A3 flattop upper with a 14.5" barrel with permanently attached phantom.

You'd be done with the upper and FS issues all at once.

Link Posted: 3/22/2006 12:59:23 PM EDT

Originally Posted By JosephR:
markm- you know better, don't you? That extra height really doesn't make a difference.



I'm unclear on your assertion. On Colts the FSB is a different height on the flat top uppers. I'm somewhat anal about having rifles that Zero pretty close to Mechanical Zero.

Link Posted: 3/22/2006 1:07:16 PM EDT
[Last Edit: 3/22/2006 1:07:35 PM EDT by Forest]

Originally Posted By markm:
I'm unclear on your assertion. On Colts the FSB is a different height on the flat top uppers. I'm somewhat anal about having rifles that Zero pretty close to Mechanical Zero.



Here is a wierd data point for you Jethro:

I have two bushy barreled flattops right now (I've had up to 4) and none of them have had issues with FSB height. The top of the front sight post was never close to the top of the ears on the FSB. No matter with ARMS#40, Bushmaster Carry Handle, KAC 600M, or LaRue BUIS. Some sights are above the flat on the FSB and one was below mechanical zero level, but neither were by much.

This weekend I zero my Colt M4 barreled upper (F marked FSB) with an ARMS#40 and the top of the pin is darn close to the top of the ears. Sure it's near 'mechanical zero', but I don't care for the pin to be so near the top.

From my perspective it looks like Bushy does a better job on the sight picture and protecting the front sight post. Wierd Eh?
Link Posted: 3/22/2006 2:31:14 PM EDT
I thought Colt added a few hundredths to the height of the rear sight base when they made the flattop. They then made special "F" marked FSBs to match. Most other companies didn't bother.

Some aftermarket sight companies like ARMS followed with COLT's extra height and some didn't.

If you buy 10 different carry handles from guys in the EE, you might be able to find that a few don't measure the same but like everyone is saying, it's not enough to really matter that much.

From what I know about getting a mechanical 0 for windage, it's not something you can or would do for elevation.

My "F" marked FSB has set screws that hold it in place. I install my rear sight and set it at ZERO. I then shoot and adjust my FSB with the set screws to get the rifle to shoot dead center with the rear sights also at ZERO with no clicks in windage.

That is mechanical ZERO for windage. The purpose of that is so you can have what appears to be a canted FSB () so that you will always know that you will shoot dead center if your rear sight is centered.

I learned this the hard way by "arguing" with Steve at ADCO about my upper.

You can't really get a mechanical ZERO elevation because the adjustment is done at the front sight pin and there is no place where the front sight post is "supposed" to be. There are no markings etc. so wherever the front sight pin ends up is where the ZERO is, whether you want to call it mechanical or not.



Link Posted: 3/22/2006 2:33:18 PM EDT

Originally Posted By JosephR:
..You can't really get a mechanical ZERO elevation because the adjustment is done at the front sight pin ...



I think what Jethro meant was the base of the front sight post was level with the base of the Front sight.
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