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Posted: 12/26/2005 7:48:03 AM EDT
Just discovered that the FSB on my Fulton Armory Classic M4 Carbine is windage adjustable. Can someone enlighten me on this? Is this a good thing? Why is it necessary? Thanks...
Link Posted: 12/26/2005 8:15:04 AM EDT
Windage adjustable? I've never seen that on a AR front sight, AR front sights should only be elevation adjustable.

Is it a good thing? Well it would allow your BUIS to be centered so you can zero using only the front sight. I don't think it's needed, nor desireable (you now have a non standard part); but if you like then don't wory about it - go and enjoy your carbine!
Link Posted: 12/26/2005 9:03:27 AM EDT
Haven't seen it before either. This is apparently what I have...

http://www.compasslake.com/adjusting_sights1.htm

It is also F marked. I'll have to ask someone at Fulton when I order my varmint upper.

Thanks...
Link Posted: 12/26/2005 9:09:51 AM EDT
Ok that I've seen. Match rifle use it so they can zero the rifle with the rear site centered (so you'll only need to adjust the rear sight for wind correction). Again not what I'd want a duty rifle, but for anything else it will do just fine.
Link Posted: 12/26/2005 9:14:00 AM EDT

That's not really windage adjustable.
Link Posted: 12/26/2005 9:20:09 AM EDT
The Army's DMRs have set screw FSBs that are adjustable for a mechanical zero. That isn't really a surprise, as they are built by the AMU. I think those classify as "duty rifles", as in "Active Duty in Global War on Terror", yes?
Link Posted: 12/26/2005 9:30:06 AM EDT

Originally Posted By warren-hpf:
I think those classify as "duty rifles", as in "Active Duty in Global War on Terror", yes?



Do you want to go through a bayonet course with one? DMRs are a 'special purpose' weapon, not a general issue. They are also intended to be used with optics

If you can loosen the screw to adjust the zero of the front sight, then dollars to donuts you can wack it hard enough to move it. Maybe it's just the engineer in me, but a friction fit doesn't seem to have the strength to prevent rotation that a double pin setup has.
Link Posted: 12/26/2005 9:44:38 AM EDT

Originally Posted By Forest:

Originally Posted By warren-hpf:
I think those classify as "duty rifles", as in "Active Duty in Global War on Terror", yes?



Do you want to go through a bayonet course with one? DMRs are a 'special purpose' weapon, not a general issue. They are also intended to be used with optics

If you can loosen the screw to adjust the zero of the front sight, then dollars to donuts you can wack it hard enough to move it. Maybe it's just the engineer in me, but a friction fit doesn't seem to have the strength to prevent rotation that a double pin setup has.


+1

Windage adjustable front sight bases are fine in range queens, but I would never want one in a rifle that will or could see more heavy-duty use. Just move the windage knob to zero the weapon and put a big, painted witness mark on the knob.
Link Posted: 12/26/2005 9:58:11 AM EDT
[Last Edit: 12/26/2005 11:24:01 AM EDT by Gunzilla]

Originally Posted By Forest:

Originally Posted By warren-hpf:
I think those classify as "duty rifles", as in "Active Duty in Global War on Terror", yes?



Do you want to go through a bayonet course with one? DMRs are a 'special purpose' weapon, not a general issue. They are also intended to be used with optics

If you can loosen the screw to adjust the zero of the front sight, then dollars to donuts you can wack it hard enough to move it. Maybe it's just the engineer in me, but a friction fit doesn't seem to have the strength to prevent rotation that a double pin setup has.



The ones I am familiar with they are not friction fit... the barrel has four plunge cut channels (two on each side) that the screws go into and face up with steel, y'ould have to whack it pretty hard to move it (something would have to break).
Link Posted: 12/26/2005 10:47:09 AM EDT

Originally Posted By Forest:

Originally Posted By warren-hpf:
I think those classify as "duty rifles", as in "Active Duty in Global War on Terror", yes?



Do you want to go through a bayonet course with one? DMRs are a 'special purpose' weapon, not a general issue. They are also intended to be used with optics

If you can loosen the screw to adjust the zero of the front sight, then dollars to donuts you can wack it hard enough to move it. Maybe it's just the engineer in me, but a friction fit doesn't seem to have the strength to prevent rotation that a double pin setup has.



Generally, the screws are adjusted once, then loctited in place. you can search in the "barrels, uppers, etc.." forum for an old discussion about set screw FSBs, where an GWOT/OIF veteran discussed the durability of his set screw FSB, which was on an M4 upper. I think an approximate quote was "Sometimes you need leverage to get those cot frames put together."

also, maybe it's the engineer in me, but you seem to not completely understand how the setup is put together. There are milled flats on the barrel that opposing set screws tightened against.
Link Posted: 12/26/2005 10:49:17 AM EDT

Originally Posted By warren-hpf:
There are milled flats on the barrel that opposing set screws tightened against.



They system I've seen doesn't use flats. It just clamps - the screw takes the place of the taper pins (except they don't go through the barrel). Nothing but friction to prevent rotation.
Link Posted: 12/26/2005 10:56:10 AM EDT

Originally Posted By Forest:

Originally Posted By warren-hpf:
There are milled flats on the barrel that opposing set screws tightened against.



They system I've seen doesn't use flats. It just clamps - the screw takes the place of the taper pins (except they don't go through the barrel). Nothing but friction to prevent rotation.



I've never seen that setup, that sounds like BS.

This is how the DMR is setup, as well as CLE, WOA/WOP, AMU rifles, USMC Rifle Team, All Guard Team, etc: www.gswagner.com/arsight/arsightmods2.html
Link Posted: 12/26/2005 11:12:38 AM EDT

Originally Posted By warren-hpf:
I've never seen that setup, that sounds like BS.


Found in the civilian world (the people Fulton sells to):

Similar unit is sold by Armalite Armalite Catalog p22
Link Posted: 12/26/2005 11:22:42 AM EDT

Originally Posted By warren-hpf:
This is how the DMR is setup, as well as CLE, WOA/WOP, AMU rifles, USMC Rifle Team, All Guard Team, etc: www.gswagner.com/arsight/arsightmods2.html



That is very simular to the setup we use... it is really quite strong.
Link Posted: 12/26/2005 11:28:45 AM EDT
I just checked fulton-armory's website, and for their NM upper they claim "Tangent opposing set screws", which would be good to go. Then I checked out that Armalite part, that looks horrible.
Link Posted: 12/26/2005 11:35:13 AM EDT
Link Posted: 12/26/2005 11:38:53 AM EDT

Originally Posted By warren-hpf:
This is how the DMR is setup, as well as CLE, WOA/WOP, AMU rifles, USMC Rifle Team, All Guard Team, etc: www.gswagner.com/arsight/arsightmods2.html



That looks like a stronger setup than the clamp on.

I haven't been able to get on Fulton's site to see what they use (just not working for me today).
Link Posted: 12/26/2005 11:45:46 AM EDT
[Last Edit: 12/26/2005 11:46:17 AM EDT by warren-hpf]

Originally Posted By Tweak:
seems kind of pointless since you can zero center wind anyway just by moving the barrel in the upper

I don't like the idea of being able to cut off the gas flow, that's harder to do when the parts are unitized



The adjustments being made are usually in the 1 MOA range or less. More than that, then re indexing the barrel would be required.

It's likely that you would see better gas performance; usually a set screw is placed on the bottom of the FSB (where the swivel is), diametrically opposite to the gas port. When the screw is tightened, the force causes a better seal between the barrel and the FSB.
Link Posted: 12/26/2005 1:01:13 PM EDT
You need an adjustable windage front sight if you have a quick change barrel system. Thats the only way to have more than one barrels BUIS sighted in correctly.
Link Posted: 12/26/2005 1:04:51 PM EDT

Originally Posted By Tweak:
seems kind of pointless since you can zero center wind anyway just by moving the barrel in the upper

I don't like the idea of being able to cut off the gas flow, that's harder to do when the parts are unitized


Since most of us have neither the tools nor the inclination to mess with barrel alignment when zeroing our rifles, an adjustable FSB makes a lot more practical sense.

The FSB movement that it takes to bring a group to center is minimal, and has no adverse effect on gas flow. One can theorize all one wants, but the proof is in the thousands of properly functioning rifles out there with a FSB slightly canted to no wind zero, including mine.
Link Posted: 12/26/2005 3:03:26 PM EDT
Link Posted: 12/27/2005 7:28:00 PM EDT
.
Link Posted: 12/28/2005 5:12:12 AM EDT

Originally Posted By Tweak:

Originally Posted By SWO_daddy:
Since most of us have neither the tools nor the inclination to mess with barrel alignment when zeroing our rifles, an adjustable FSB makes a lot more practical sense..



but you do have the tools and inclination to move the FSB?


Yes, it takes a small hex key and five seconds.
Link Posted: 12/28/2005 5:26:36 AM EDT
Link Posted: 12/28/2005 6:59:27 AM EDT

Originally Posted By Tweak:
and it only takes a small mallet and 3 seconds to do it my way


Whatever............

Let's just say that competitive shooters (for whom the adjustable FSB was designed) don't bother with your method.
Link Posted: 12/28/2005 7:27:22 AM EDT

Originally Posted By SWO_daddy:

Originally Posted By Tweak:
and it only takes a small mallet and 3 seconds to do it my way


Whatever............

Let's just say that competitive shooters (for whom the adjustable FSB was designed) don't bother with your method.



Snuff Snuff
Link Posted: 12/28/2005 7:57:28 AM EDT

Originally Posted By Tweak:
and it only takes a small mallet and 3 seconds to do it my way



Does this include taking off a float tube?
Link Posted: 12/28/2005 8:58:06 AM EDT

Originally Posted By warren-hpf:

Originally Posted By Tweak:
and it only takes a small mallet and 3 seconds to do it my way



Does this include taking off a float tube?


Dude, don't bring facts to an opinion discussion.
Link Posted: 12/28/2005 9:03:24 AM EDT

Originally Posted By warren-hpf:

Originally Posted By Tweak:
and it only takes a small mallet and 3 seconds to do it my way



Does this include taking off a float tube?



Not needed with Tweak's method.
Link Posted: 12/28/2005 9:53:59 AM EDT

Originally Posted By Forest:

Originally Posted By warren-hpf:

Originally Posted By Tweak:
and it only takes a small mallet and 3 seconds to do it my way



Does this include taking off a float tube?



Not needed with Tweak's method.



Is Tweak's method really just beating on the FSB with a mallet?
Link Posted: 12/28/2005 9:55:56 AM EDT

Originally Posted By warren-hpf:
Is Tweak's method really just beating on the FSB with a mallet?



It's the Oly Arms way!
Link Posted: 12/28/2005 10:00:57 AM EDT
[Last Edit: 12/28/2005 10:01:40 AM EDT by NevadaARshooter]
All the Armalite flat top rifles have that clamp-on railed gas block. I've never heard of one coming loose.

Do you guys really beat on your canted FSB? Are you trying to turn the barrel in the barrel extension? I think the proper way to do it is to remove the barrel and file slightly the slot in the upper where the barrel ext pin fits.
Link Posted: 12/28/2005 11:02:03 AM EDT

Originally Posted By Forest:

Originally Posted By warren-hpf:
Is Tweak's method really just beating on the FSB with a mallet?



It's the Oly Arms way!



Awesome!
Link Posted: 12/28/2005 12:34:51 PM EDT
Link Posted: 12/28/2005 12:57:17 PM EDT

Originally Posted By Tweak:

Originally Posted By Forest:
It's the Oly Arms way!



watch the BFI assembly video and read Derrick Martin's book.



No doubt, but I first heard about that trick from you when you related one of your experiences while employed at a Washington state AR manufacturer .
Link Posted: 12/28/2005 1:09:27 PM EDT
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