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Posted: 7/7/2007 7:09:29 PM EST
OK, I've got a new upper that I think has a canted front sight. The windage is way left and almost bottomed out. I plan on another range trip to be sure I was not just having a bad day at the range since my last trip was rushed.

I have seen a few folks here recommend to "just smack it" with a rubber mallet. Can someone walk me through this method in detail, step by step?

A few questions...

How is the upper secured?

Which side do i strike?

How much force is required?

What is the risk of damage to the FSB / barrel / upper?

do you place a block under the barrel?

should the FSB be wrapped in a towel, etc. to prevent marring?

Does this really work if you only want to turn the barrel slightly in the receiver?

Am i insane for considering this as an option?
Link Posted: 7/7/2007 9:51:56 PM EST
Link Posted: 7/8/2007 3:15:22 AM EST
There is another possibility besides the dreaded canted front sight base - Too much torque used on the barrel nut. I put together two uppers, one with BM 16" and another with an Armalite 16", and had to torque the barrel nut beyond 60-75 ft-lbs to get the gas tube to go through.  Both ended up shooting way to the right and to correct the rear sight windage had to be moved way left, almost limited out.  The fix for both was to remove and reinstall the barrel, but time the receiver thread by facing it with a flat file, tiny bit at a time.  It was time consuming but well worth it .
Link Posted: 7/9/2007 3:55:11 PM EST
Thanks Guys. The closer i look, the more I realize that the FSB is definitely canted to the left just ever so slightly.

If I try the lever through the FSB method, how much should I worry about breaking the FSB? How much torque can it take?
Link Posted: 7/9/2007 4:07:27 PM EST
Please don't just twist or whack the FSB.  

There is a correct way to do it.

Send it to SAW.  They have a fixture just like the one Colt uses to install FSBs.  They will remove the pins, square up the FSB, and drill new oversized holes.  It corrects it the right way.  
Link Posted: 7/13/2007 3:34:15 PM EST
I had a upper that had a index slot that was off.  I put the upper in a receiver vice block, recorded the POA on a wall across the room, then remove barrel and file the index slot until the FSB was aligned with the centered rear sight.  One thing to check if you go this route is that the bolt lugs will still clear the barrel extension.  It is also recommended that you shim up the index slot once you have filed it so that the barrel can't turn back to the other side.
Link Posted: 7/13/2007 6:55:05 PM EST
[Last Edit: 7/13/2007 6:56:55 PM EST by TaylorWSO]

Originally Posted By AR15barrels:
I have gotten past smacking front sight bases.
Now I mount the receiver on a DPMS claw, insert a nice long lever and gently twist the front sight base until it "pops" (moves) into a more upright stance.

You can also do this by placing the complete rifle on a chair and sitting on it.
Then find a large screwdriver or other appropriate lever and place it through the front sight base.
Twist it whichever direction it needs to go.
If the rear sight is left, twist the front right and the rear will get adjusted back towards the right to correct the zero after front sight base adjustment.


I can't believe you recommended this. How many problems have you had to fix because of stupid things done to a upper and or barrel? Putting a upper in the claw and twisting the FSB puts a shitload of stress on the upper. Hell, there have been posts on here of guys fucking up the upper doing just this type of wecsog.


1) I would send it to a smith to get fixed (except Randall) or
2)replace the FSB with a small profile gas block

YMMV
Link Posted: 7/13/2007 9:51:37 PM EST
Link Posted: 7/13/2007 11:00:34 PM EST

Originally Posted By AR15barrels:

Originally Posted By TaylorWSO:

Originally Posted By AR15barrels:
I have gotten past smacking front sight bases.
Now I mount the receiver on a DPMS claw, insert a nice long lever and gently twist the front sight base until it "pops" (moves) into a more upright stance.

You can also do this by placing the complete rifle on a chair and sitting on it.
Then find a large screwdriver or other appropriate lever and place it through the front sight base.
Twist it whichever direction it needs to go.
If the rear sight is left, twist the front right and the rear will get adjusted back towards the right to correct the zero after front sight base adjustment.


I can't believe you recommended this. How many problems have you had to fix because of stupid things done to a upper and or barrel? Putting a upper in the claw and twisting the FSB puts a shitload of stress on the upper. Hell, there have been posts on here of guys fucking up the upper doing just this type of wecsog.

1) I would send it to a smith to get fixed (except Randall)


I think you missed the part where I said GENTLY.
I'm not using a breaker bar and a cheater pipe.
There's finesse and brute force and they are quite different things.

I guess you don't believe that I know the difference.
If you don't trust me, just don't send me any work, it's really that simple.
I have enough people out there that do trust me.

How many complaints have you seen about the quality of my work?


long lever=cheater bar, torquing until it "POPS", is NOT gentle no matter how you cut it. WTF pops anyways? The FSB pins breaking? If you do get the FSB to move then at least the pins have bent or the holes will be egged out do to the force. Care to explain any other possibility?

If a FSB is pinned correctly (steel on steel) with 2 pins each about 1/8" in diameter and the upper receiver/barrel have 1 index pin (steel vs aluminum) which will give when torquing it? The friction of the barrel will not hold it in place. Like I said there have been a few post on here with guys showing their uppers being ruined when the barrel spins and the index pin crushed the Aluminum.

Trying to move something with force that doesn't want to be moved is a good way to destroy a weapon  and I was surprised that a man of your stature on this site would recommend such a procedure.  

If I have a barrel that needs reworking I wouldn't hesitate to send it to you. I've seen your work, and its great. If I had a FSB that was canted I wouldn't send it to you.
Link Posted: 7/14/2007 12:38:37 AM EST
height=8
Originally Posted By mtdawg169:
height=8
Originally Posted By FedDC:
Please don't just twist or whack the FSB.  

There is a correct way to do it.

Send it to SAW.  They have a fixture just like the one Colt uses to install FSBs.  They will remove the pins, square up the FSB, and drill new oversized holes.  It corrects it the right way.  


FedDC

My gut says you're right. I have no business twisting or bashing on my new upper. So, I spoke to the dealer I bought it from and the manufacturer today. CS response has been very good so far & I'm shipping it to the Manf. next Monday. They have promised a quick turnaround to break the upper down & reinstall the barrel / rail. Hopefully they won't have to redrill anything. They will also test fire it before it leaves. It's a hassle and I hate having to ship it off, but as long as they deliver as promised, I'll be happy. The dealer offered a store credit for my shipping expenses too, so I won't really be losing anything but my time.have
Semper Fi,

Darryl
Link Posted: 7/15/2007 4:22:12 AM EST

I would send it to a smith to get fixed (except Randall) or ...
 Yeah, that Randall is a FNG with little experience and a lousy track record.  

For the slower folks here, yes, that is sarcasm.
Link Posted: 7/15/2007 10:17:05 AM EST
And Randall's reply carries the explanation for the vast majority of "canted sight base" posts. Far more often, it's NOT the sight base that's canted. It's the barrel that is slightly off line.

Notice; nine out of ten of these posts complain of a barrel that requires excessive LEFT WINDAGE to sight in. Why? Because the barrel  twisted to the left during  installation, taking the sight assy with it.

I've come to believe that the use of upper reciever clamping, rather than the original clamping of the barrel during installation has increased the incidence of these twisted barrel occurances. The one time I installed a barrel this way; I too got a left windage needed outcome. Since then, I've gone back to the old reliable  "clamp the barrel" installing. Just fired an M4 upper I did w/a clamped barrel. Needed three clicks RIGHT windage to zero.
Link Posted: 7/15/2007 12:41:59 PM EST
I have a Stag 2H Upper that came with the MI rear sight. I went to zero the sights yesterday at a 25 yard indoor range. I got it to shoot pretty good at 25 yards off the bench using just my arms for support as I had no sand bags or a rest to shoot from.(see target pic below) Dead on center and approx 1 1/2 inch low for 25 yards. My question is that I had to move my rear sight windage adjustment way to the right to center my shoots.So I am guesing that this could be my problem as well.

http://i146.photobucket.com/albums/r265/Unforgiven826/M4ZeroTargetmessured1.jpg

http://i146.photobucket.com/albums/r265/Unforgiven826/MIsight.jpg
Link Posted: 7/15/2007 1:26:56 PM EST

Originally Posted By AR15barrels:

I have "popped" several uppers back into alignment and then torn them down to inspect for index pin damage to the receiver.
I did not find the slots to be enlarged by the pin.


    I have adjusted an upper using the lever technique that AR15barrels speaks of in this thread. Maybe "pop" is what is throwing this guy off. The barrel simply shifts and you feel a bump when it happens. Leverage is applied slowly and gently increasing as you go until the barrel shifts. You don't just yank the piss out of the lever bar.

    I have also witnessed several occurences where a leather or heavy plastic hammer is used against the fsb to gain this same adjustment. The lever technique gives more control of the pressure applied in my opinion. No damage to the index pin occured using either technique.

    My barrel was 2 clicks from the right when zeroed . I could have let it be but I wanted it right. After one bump using the lever technique, the zero is now 2 clicks from mechanical zero.
Link Posted: 7/16/2007 4:14:18 AM EST

Originally Posted By GeigerTiger:

Originally Posted By mtdawg169:

Originally Posted By FedDC:
Please don't just twist or whack the FSB.  

There is a correct way to do it.

Send it to SAW.  They have a fixture just like the one Colt uses to install FSBs.  They will remove the pins, square up the FSB, and drill new oversized holes.  It corrects it the right way.  


FedDC

My gut says you're right. I have no business twisting or bashing on my new upper. So, I spoke to the dealer I bought it from and the manufacturer today. CS response has been very good so far & I'm shipping it to the Manf. next Monday. They have promised a quick turnaround to break the upper down & reinstall the barrel / rail. Hopefully they won't have to redrill anything. They will also test fire it before it leaves. It's a hassle and I hate having to ship it off, but as long as they deliver as promised, I'll be happy. The dealer offered a store credit for my shipping expenses too, so I won't really be losing anything but my time.


I have an M&P 15 that had the same rear sight problem.  Is your rifle an M&P 15?  I sent mine back to the factory too but they didn't break down the upper and correct problem.  How did you convince them to correct yours?

Semper Fi,

Darryl


GT, mine is not an M&P 15. Mine was made by Sabre Defence. I did not want to post the Manufacturer initially b/c folks tend to take  single instance and deem that a Manufacturer has a rampant problem. The cant in mine is slight and can be accounted for by adjusting the rear sight. Some reports of other brands have been so far off that the sight would bottom out and still not be zeroed. Mine is farther to the left than it should be and I would prefer it be closer to mechanical zero. If you sight down my rail, you can see a slight cant in the FSB. Sabre was very responsive when I called them last week and told me to send it back to them, no problem. They promised that it would be turned around quickly and they didn't like to let any "dust collect" on their repairs. I've always heard great things about Sabre's customer service and so far it appears to be true. I'm shipping mine off this week.
Link Posted: 7/16/2007 4:18:25 AM EST
Randall, thanks for all the input here. If I had a little more faith in my ability to finesse it, I'd give your method a shot, but I don't trust myself enough to do it. Some great information there though. Thanks for sharing your experience, as always.

Question: in the picture of your sight alignment bar, would you consider the FSB pictured to be close enough or in need of adjustment?

Thanks!

Matt
Link Posted: 7/16/2007 9:48:37 AM EST
Link Posted: 7/16/2007 9:52:59 AM EST
[Last Edit: 7/16/2007 9:57:44 AM EST by AR15barrels]
Link Posted: 7/16/2007 10:27:35 AM EST
I just called Stag Arms and they are sending me a shipping label for a UPS pickup. They also said they would have a quick turn around time.
Link Posted: 7/16/2007 11:44:15 AM EST

Originally Posted By AR15barrels:

Originally Posted By TaylorWSO:
I can't believe you recommended this.
Hell, there have been posts on here of guys fucking up the upper doing just this type of wecsog.

1) I would send it to a smith to get fixed (except Randall)



Originally Posted By TaylorWSO:
long lever=cheater bar, torquing until it "POPS", is NOT gentle no matter how you cut it. WTF pops anyways? The FSB pins breaking? If you do get the FSB to move then at least the pins have bent or the holes will be egged out do to the force. Care to explain any other possibility?

If I had a FSB that was canted I wouldn't send it to you.


I have fully explained how all of this works. Not initially, which is where my post was directed

I'm still awaiting an apology from TaylorWSO for basically calling me a WECSOG fuck-up.


All you have done is explain how great YOU are at fixing a problem when you originally recommended torque that FSB to "pop" it in place, "sitting on it" and using a "screwdriver". My initial point was, you as a highly regarded member of this sight, recommended to fix a problem with wescog with no other explanation.  An inexperienced guy could have taken this info and applied in the wrong way and fucked up their upper. After I made my post you explained it all clearly, but only after it riled you up.

If you would have given a better explanation IMO, besides a totally wescog method, I wouldn’t have put the comment in my original post. You should have put your "send it to me" line in their.  

AFA an apology, hell no, sitting on an upper then twisting the FSB with a screwdriver is a total wescog. You may not do this in your shop but you sure as shit recommended it. At least you could have reccomended it sending to a smith before the screwdriver.
Link Posted: 7/16/2007 1:02:47 PM EST
[Last Edit: 7/16/2007 1:09:22 PM EST by A_Free_Man]
I agree 100% with Randall's explanation of the problem and how he fixes it.  I've done exactly the same thing a number of times.

I've also disassembled, and shimmed on one side of a slot, where the slot was damaged by the assembler using barrel vise jaws rather than an action block, and denting the slot on one side.

Also, there is an allowable tolerance of how many clicks off the rear sight can be and still be acceptable.  Of course, if it is all the way over, it allows no additional adjustment, and that just won't do.

Gonebad's photos, I would NOT try to center the front sight.  Your's is within acceptable limits.  You have plenty of adjustment on the right if needed.  And your rifle should be dead on at 50 yds, about 1 5/8" high at 100 yds.  Just fine tune it at 100 yds and you are good to go.

Randall is far from a WECSOG'er.  The only place we differ is that I still use the old Peace River action block, but he has me talked into ordering a Claw.
Link Posted: 7/16/2007 9:10:32 PM EST
Link Posted: 7/17/2007 5:03:02 PM EST
height=8
Originally Posted By A_Free_Man:
...Also, there is an allowable tolerance of how many clicks off the rear sight can be and still be acceptable.  Of course, if it is all the way over, it allows no additional adjustment, and that just won't do.


Please don't take this the wrong way but can anyone tell me how many clicks of windage are considered "allowable tolerances?"

Semper Fi,

Darryl
Link Posted: 7/17/2007 10:48:40 PM EST
Link Posted: 7/18/2007 4:49:02 AM EST

Originally Posted By GeigerTiger:

Originally Posted By A_Free_Man:
...Also, there is an allowable tolerance of how many clicks off the rear sight can be and still be acceptable.  Of course, if it is all the way over, it allows no additional adjustment, and that just won't do.


Please don't take this the wrong way but can anyone tell me how many clicks of windage are considered "allowable tolerances?"

Semper Fi,

Darryl
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     http://www.ar15.com/forums/topic.html?b=2&f=138&t=147708
Link Posted: 7/18/2007 6:05:45 PM EST
[Last Edit: 7/18/2007 6:07:47 PM EST by GeigerTiger]
height=8
Originally Posted By Joe7:
height=8
Originally Posted By GeigerTiger:
height=8
Originally Posted By A_Free_Man:
...Also, there is an allowable tolerance of how many clicks off the rear sight can be and still be acceptable.  Of course, if it is all the way over, it allows no additional adjustment, and that just won't do.


Please don't take this the wrong way but can anyone tell me how many clicks of windage are considered "allowable tolerances?"

Semper Fi,

Darryl
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     http://www.ar15.com/forums/topic.html?b=2&f=138&t=147708


Thanks for the reply and the link Joe.  

Question - So according to the chart on the link:

------------------------------------------------------------------------------------------------
For the M4 (Carbine length gas and sight radius), using M4A1 – MIL-C-71186
Assuming a 2” group
Assuming 1 click = .68 MOA
You get the initial +/- 12 clicks
Plus the 10.3 clicks to adjust a shot that is on the width of the target (as defined in D from the table -14”W), left or right to adjust the POI to POA.

That would leave you with approximately 22.3 clicks of adjustment for zero

-------------------------------------------------------------------------------------------------

my S&W M&P 15 can have as much as 10.3 clicks of windage, either left or right, at 50 yards and still be within military spec.  Am I understanding the chart correctly?

Semper Fi,

Darryl
Link Posted: 7/18/2007 6:13:04 PM EST
[Last Edit: 7/18/2007 6:13:48 PM EST by Joe7]
It means that if your rear site is sitting centerd(in the middle) you have 22.3 clicks going left OR right total,to be within spec.
Link Posted: 7/19/2007 8:14:27 AM EST
Thanks for clearing that up Joe.

Semper Fi,

Darryl
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