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11/22/2017 10:05:29 PM
Posted: 10/11/2004 11:45:05 AM EST
[Last Edit: 10/11/2004 11:50:31 AM EST by Digitalpunk]
I have a Bushy flattop with an Arms 40 on it, and am swapping out the FSB for one with a bayo lug, should I get the .04 taller one? I've heard some people need them and some do not. What do you guys think?

Digital
Link Posted: 10/11/2004 11:47:23 AM EST
I do see my front sight post is at the higher elevation than the A2 upper, but I haven't felt the need to replace it.
Link Posted: 10/11/2004 11:57:55 AM EST
Get whichever one is cheaper.
It don't matter.
Link Posted: 10/11/2004 12:10:22 PM EST
They're the same price

Digital
Link Posted: 10/11/2004 12:48:13 PM EST
Call bushmaster, ask them which one is on it presently, order the same.
Personally, it's a lot of effort for a little gain if all you expect to get out of it is a bayo lug.
Link Posted: 10/11/2004 12:48:56 PM EST
Well, don't get either, since you already have one that works in your existing FSB, right?
Link Posted: 10/11/2004 1:57:22 PM EST
[Last Edit: 10/12/2004 4:36:26 AM EST by mo4040]
Speaking from personal experience, a taller front post is nice if you find yourself backing the stock one all the way out to get a proper zero. On a standard front sight assembly, you'll probably not need the taller post. However, on some aftermarket flip-up front sight assemblies, a taller post may be needed. I have a PRI front sight on one rifle and I definately needed a taller post in conjunction with my ARMS 40-L.
Link Posted: 10/11/2004 2:10:14 PM EST
I was not able to zero my rifle with the shorter sight post using the ARMS#40. I ordered the taller post from Bushmaster. Bottom line is that ARMS should include one with the #40 and save their customers the B.S.
Link Posted: 10/12/2004 5:55:17 AM EST

Originally Posted By Idah0Bound:
I was not able to zero my rifle with the shorter sight post using the ARMS#40. I ordered the taller post from Bushmaster. Bottom line is that ARMS should include one with the #40 and save their customers the B.S.



+1
I had to back out my post until it was almost all the way out.
Link Posted: 10/12/2004 6:43:44 AM EST
+1. ARMS could, at a MINIMUM, include a note with the #40 regarding the front sight height issues.
Link Posted: 10/12/2004 7:06:25 AM EST
Huh, didn't know this was a problem. My #40 seems to be fine with the fsb that came on my bushmaster superlight barrel.
Link Posted: 10/12/2004 7:15:37 AM EST
Yeah, I had to back mine out nearly all the way too.
Bushmaster sells a front sight post that is higher for this problem.

http://www.bushmaster.com/shopping/scopes/9349056-m.asp
Link Posted: 10/12/2004 7:28:17 AM EST

Originally Posted By Idah0Bound:
I was not able to zero my rifle with the shorter sight post using the ARMS#40. I ordered the taller post from Bushmaster. Bottom line is that ARMS should include one with the #40 and save their customers the B.S. Flattops should come with the taller front sight post.



+1
Link Posted: 10/12/2004 7:37:40 AM EST
I've always heard that the Colt M4 had a higher front sight base (and rear sight height), and that since the ARMS BUIS was designed for the M4 it has the higher height as well. I have a genuine Colt M4 upper that doesn't require a taller front sight post to use an ARMS 40A, so this may confirm it. I'll know for sure when I finish my M4 type upper for my MG since it will be using a Bushmaster barrel and another 40A. We're talking about .040" difference here.
Link Posted: 10/12/2004 8:54:37 AM EST
I think the taller front sight bases are labeled "H" somewhere on them. This came up a few months ago and I can't remember exactly what was said. The M4 FSB and rear sight was raised, thats why lots of BUIS sit too high for the standard FSB. It seems most manufacturers should put the raised FSB on all flattops, but I'm sure they do that.
Link Posted: 10/12/2004 9:03:35 AM EST
I'm not 100% on this one but flat top's are supposed to come with the taller front post because the removable cary handle is taller than the A2 handle and sight thus a taller front post is needed. Now with the Arms #40 it is at the A2 which needs the regular front post. You can also use a trijicon post. So... No you don't need the taller front post. One side note, there are 2 different FSB's out there "F" stands for "Flat-top" this model will come with the taller by default.
Link Posted: 10/12/2004 10:22:21 AM EST
[Last Edit: 10/12/2004 10:22:55 AM EST by Strag]

Originally Posted By Apple_Tech:
I'm not 100% on this one but flat top's are supposed to come with the taller front post because the removable cary handle is taller than the A2 handle and sight thus a taller front post is needed. Now with the Arms #40 it is at the A2 which needs the regular front post. You can also use a trijicon post. So... No you don't need the taller front post. One side note, there are 2 different FSB's out there "F" stands for "Flat-top" this model will come with the taller by default.



How do you install the ARMS #40 on an A2 handle?
Link Posted: 10/12/2004 10:23:28 AM EST

Originally Posted By fastang50:
Huh, didn't know this was a problem. My #40 seems to be fine with the fsb that came on my bushmaster superlight barrel.


When I set up my BM M4gery, I got the taller sight post to go with the #40, and ended up not needing it.
Link Posted: 10/12/2004 10:25:09 AM EST
[Last Edit: 10/12/2004 10:28:04 AM EST by Strag]
Here you go -- read this thread, and wherever it says "detachable carry handle" substitute "ARMS #40." Should provide the info you need.
Link Posted: 10/12/2004 11:41:53 AM EST
"Huh, didn't know this was a problem. My #40 seems to be fine with the fsb that came on my bushmaster superlight barrel."


+1
No problems with superlight barrell and arms #40

Brad
Link Posted: 10/12/2004 12:58:26 PM EST
I was just the opposite.
I had to lower my front site pin after installing the ARMS #40 rear.
Link Posted: 10/12/2004 1:31:58 PM EST
[Last Edit: 10/12/2004 1:32:21 PM EST by POOR_MAN]
I had to raise my front sight too, no problems now.

Link Posted: 10/12/2004 3:00:21 PM EST
Strag,

What i meant above with the Arms #40 and the A2 upper. They are at the same height for the short front post. The detachable carry handle is a slight bit taller needing the taller front post.
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