I'm planning to replace my current front sight with a flip-up front sight/gas block. The one things I'm not overly clear on is what is the best way to ensure that the new FSB is properly aligned with regards to the actual sights, ie - that the sight is not canted. I've read once that there is a tool that helps with this, but for the life of me I can't find where it is. I'm sure the info is on here, but with search being down......

Any help you guys can give would be greatly appreciated!

If it were me, I'd eyeball it, set the screws, take it to the range, zero it.  If the rear sight is not close to the mechanical middle, I would adjust the front sight tower slightly.

-z

Click on the Armalite link at the top.  Click on catalog (upper left corner of screen).  Click on Tools & Accessories.  About half-way down the page is the Front Sight Alignment Tool.  They really think a lot of it; they want $58 for a rod.

When I replaced my front sight base (with an Armalite fixed base FWIW), I already had my Aimpoint dot set on the original front sight post.  So, I aligned the new base so that the new sight post was on the Aimpoint dot.  I figured this would get it close enough.  At the range I only needed to make one click adjustment on the windage.  

If you use the Armalite tool, I believe you need to attache the tool to a removable carry handle.  I'm actually thinking of buying one of those because I think I just got real lucky.

Hey, if you're handy enough you might be able to make one of those rods.  

Thanks for the replies.  I figure I'll try to eyeball it alignment wise, and if I have any trouble, well then I can order the tool. I've also got an Aimpoint set up that way, so hopefully it shouldn't be a major deal.....

Thanks again!

Quoted: When I replaced my front sight base (with an Armalite fixed base FWIW), I already had my Aimpoint dot set on the original front sight post.  So, I aligned the new base so that the new sight post was on the Aimpoint dot.  I figured this would get it close enough.  At the range I only needed to make one click adjustment on the windage.

That's probably the best idea I've ever read for aligning a new front sight.

Thanks, bud.  

Alright, could some kind soul please explain to me how in the hell do you remove the taper pins from a Bushy front sight base? So far within about 12 hammer hits I've ruined THREE PUNCHES! One concave punch has been completely bent back (so the "dimple" is now practically flat) and had part of it chip off, another concave punch has been completely bent back, and an oversized flat punch has started to get a slight dimple on it, and the fucker hasn't even budges a hair!!!! According to the measuring the pin ends, the larger (by maybe a half a millimeter)  is on the left side of the FSB if looking toward the front of the barrel, and the smaller is on the right, so I'm hammering from right to left (which seems correct as well according to the blow up diagram).....do the pins always get put in the same direction, and am I going in that?

Anyone have any luck with drilling through the pins?

From my archives:

jason_h
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Joined :: March 2001
Post Number :: 411

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Removing the front sight base (FSB) is easier said than done. To do it right, you need either a steel punch that has a concave tip to fit the ends of the taper pins properly or a sturdy brass punch (at least 3/8" diameter). I perfer using a brass punch to get the pins broken loose and then tap them out the rest of the way with a smaller steel punch (note: pins are tapered so they only come out on one side). Using a flat tipped steel punch might mushroom the ends of the taper pins, resulting in haveing to get out the dremel to remove the FSB. Getting the taper pins to break loose is the most difficult part. You need to have the side of the FSB resting on a hard surface and you really need to whack that punch. Do not hold back, ideally use at a minimum, a 1 lb. hammer, heavier is even better. Going at it with a 18 lb sledge is not all that unreasonable, well maybe a little. Once the taper pins have been removed, its all gravy at that point, just slide the FSB off the front of the barrel (you may need to use rubber mallet to tap is loose). You don't need to remove the gas tube before doing this, it can be removed with the FSB as a unit.



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Posted :: 4/28/2004 1:29:55 AM


mongo001
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Post Number :: 354

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I've done so many that I can have the sight base off in about one minute. My secret is to use an oversized punch, meaning the head of the punch is bigger than the end of the taper pin. I support the FSB with two oak blocks and support the rest of the barrel so the whole setup sits relatively flat. Using the oversized punch, I give the small end of the pins one good whack (sometimes it takes two) with a hammer to get them started moving. If building a safe queen, be careful that the oversized punch does not contact the FSB, as a ding may occur. If you are careful with your punch placement, this is not an issue. Once they are loose and moving, I move to the proper sized punch and finish driving them out. Kroil or some other type of penetrating oil helps on the stubborn ones, but I just did one last night and the pins were out in about a minute. Just got to get the nerve to swing that hammer. Once you get over that, it becomes easy. Your first couple will inevitably end up with a ding or two on the FSB, but this is nowhere near "destroying" the FSB, you can cover that up so that only you know it is there. I've heard of guys Dremeling off FSB, that makes me shiver when I hear that, especially when you can get $10-20 for a FSB on some of the popular auction sites. A couple of properly place $1 punches and a hammer is all it takes and five minutes of careful work and it's off.

Most times it isn't cost effective, but if you are willing to ship, I'll knock it off for you. My payment would be keeping the FSB.


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[Sheriff Bart] Who is this Mongo, anyway? - [The Waco Kid] Well, Mongo ain't exactly a "who," he's more of a "what."



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Posted :: 4/28/2004 11:01:20 AM
Last Edited :: 4/28/2004 11:02:30 AM by mongo001


garr
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Lay the FSB on a piece of wood (MAke sure the Large side of the pins faces down) , Use an oversized punch (I use 3/8") until the pins break free, Giving it a good wack with a big hammer tends to work for me, If you try to baby it with little taps it will not free up the pins.



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Posted :: 4/28/2004 1:33:04 PM

I'm going through the same thing with a couple of OLY barrels.  The only FSBs I've had to remove so far were on Model 1 kits...and they just use straight, steel pins that come out very easily.  The OLYs have the damn pins that stick out about 1/16" of both sides, and even 3 or 4 whacks with a regular punch has already started to peen the end of the pin.  

I've ordered the taper pin starter punch from Brownells (I did it before I got this barrel, so I didn't even know I'd need it..but for $6, I figured it might come in handy ).  I tried a nail punch (concave end) that I had laying around, but it wasn't big enough.  Wild horses, Anna Kournikova and a pistol to my head couldn't get me near Home Despot or Blows on the weekend, so I'm waiting for the BBT before I go any further with this, although I don't need the FSBs for anything, so I *might* have to pull out Mr. Dremel this afternoon.  Can you say "WECSOG"?

Quoted: I'm going through the same thing with a couple of OLY barrels.  The only FSBs I've had to remove so far were on Model 1 kits...and they just use straight, steel pins that come out very easily.  The OLYs have the damn pins that stick out about 1/16" of both sides, and even 3 or 4 whacks with a regular punch has already started to peen the end of the pin. I've ordered the taper pin starter punch from Brownells (I did it before I got this barrel, so I didn't even know I'd need it..but for $6, I figured it might come in handy ).  I tried a nail punch (concave end) that I had laying around, but it wasn't big enough.  Wild horses, Anna Kournikova and a pistol to my head couldn't get me near Home Despot or Blows on the weekend, so I'm waiting for the BBT before I go any further with this, although I don't need the FSBs for anything, so I *might* have to pull out Mr. Dremel this afternoon.  Can you say "WECSOG"?

Fuck, mushrooming of the pin would be an improvement at this point....at least I'd have some notice  that I was actually having an effect on the pin!  After three hours, and another 12 bucks at Home Depot for a pin set, I've got another three ruined pins, and nothing to show for but the finish worn off the taper pin, and a few marks on the FSB. And it doesn't much help that HD/Lowes are closing and I don't have the right drill bit to drill through these fuckers, I've only got bits either too big or WAY too small.  Which BTW, don't even bother with the despot or blows......it takes general 3-5 hammer strikes for the punches I got there to start deforming.

It's why REAL leery of picking up the  cup tip punches from Brownells.....I've laready dropped about 20 bucks on various punches, I'd hate to spend 14-16 bucks on a single punch for it to get f'd up in 3-5 hits.  I'm frustrated enough that even if I manage to do anything with it I'lll probably never shoot her just cause it'd remind me of this shit.  I wonder if maybe Oly does the same thing as Bushy........IIRC from another thread bushy sets everything up on the barrel, then finishes it, such that the finish pretty much acts like a sealant on everything, including these mutherfucking taper pins......

I build up a stripped 16in barrel with a takeoff  front sight tower from a demilled barrel.  You don't do this to save money, you do it to learn how.  I basically broke half the punches in my cheapy lyman set, and a couple of drill bits.  Did I mention the victor  torch also came into play?  Mine was a worst case scenario, as the fsb was almost rusted onto the barrel, but it did come out-eventually.  I even refinshed it and it works fine, just be aware that the pins may not line up with the slots on the barrel by a little bit and it gets more interesting..........I advise refinish AFTER you install.  In my case I got some experience and a colt 1/7 lightweight barrel back into action, spending money on new stuff doesn't teach you a damn thing.

I removed the pins from a RRA barrel last night.  After the pain in the ass problems I had last time around (with a Bushy barrel), I did things a little different this time.

Bought a 3 lbs hammer for $5.00 at a flea market.  Bought the special punch and some Kroil from Brownells.  Used a solid piece on wood placed on a concreate floor.  After soaking the pins in Kroil for about 20 minutes, two hits with the hammer had both pins loose.  Used a regular punch to remove the rest of the way.  Oh yea, this time I hit the pins HARD.  I mean HARD!

You guys are driving these things towards the ejector side?

And to reply to the alignment question.  Gary at JT Dist. told me that he takes two levels and puts them on the rails and then on the GB/FS.  It must have worked because I didn't do ANY clicks for windage when I sighted in the YHM flip-up FS.

Quoted: You guys are driving these things towards the ejector side? And to reply to the alignment question.  Gary at JT Dist. told me that he takes two levels and puts them on the rails and then on the GB/FS.  It must have worked because I didn't do ANY clicks for windage when I sighted in the YHM flip-up FS.

Levels?  Interesting idea.

All the pins I've ever driven out are hammered from the left side out to the right.

Hard_Case,

Loin_dog, Zbrane and I removed three (3) Bushmaster FSB yesterbay. We used Kroil and the 3mm concave punches from Brownells. I was alot of work but doable. If you don't have Kroil use liquid wrench.

Where in NJ are you? Worst case senerio we can do it at Ft. Dix on 6/5. Shoot me an e-mail or IM and I'll see what I can do to help.

Mike

Quoted: Hard_Case, Loin_dog, Zbrane and I removed three (3) Bushmaster FSB yesterbay. We used Kroil and the 3mm concave punches from Brownells. I was alot of work but doable. If you don't have Kroil use liquid wrench. Where in NJ are you? Worst case senerio we can do it at Ft. Dix on 6/5. Shoot me an e-mail or IM and I'll see what I can do to help. Mike

SEE! It's the thread that wouldn't DIE!!!!

I tell you, somebody really does not like me. Nor does this make me very keen on Bushmaster (yes, I know it's not their fault, and actually a good thing it's this sturdy, but I don't think I'll be looking to them for any AR parts in the future if the concept of 'project AR' is anywhere near the scope of useage)...

Wish I could take you up on that, but I won't be around that weekend. Have to do a lot of ferrying people around to different states....woohoo...

Would you care to enlighten me on the directions for the Kroil/3mm concave punch?  I got my order in from Brownells about 2 hours ago. Used a an dropper to apply the Kroil to both sides of the pin. Slathered it on, probably enough to fill two shot glasses, and let it sit for 15 minutes. Five hammer strikes later and my nice new 11 dollar cocave punch is fucked, or at least it sure as helll ain't concave no more. Pins have not moved so much as a hairs breadth.  I figure I give this thing another hour or so to soak in and try it again. If not I'll just send of my parts and have a new upper built.  With my luck I'd end up drilling right through the barrel....

Hard case,    Listen I know you are upset, you need to just walk away from this for awhile. I know you will not believe me but those pins will come out with any decent punch. How are you supporting the barrel? it sounds like you are redirecting the power from your hammer somewhere else. Be patient with me , this is the one job in the whole world where you need to have a very clear mind when doing it.  The pins need to be knocked out from the non ejecter side, I repeat the pins have to be hit on the non ejecter side in order to come out.

Quoted: Hard case,    Listen I know you are upset, you need to just walk away from this for awhile. I know you will not believe me but those pins will come out with any decent punch. How are you supporting the barrel? it sounds like you are redirecting the power from your hammer somewhere else. Be patient with me , this is the one job in the whole world where you need to have a very clear mind when doing it.  The pins need to be knocked out from the non ejecter side, I repeat the pins have to be hit on the non ejecter side in order to come out.

Frustrated more than upset. And yeah.....I quadruple checked on the direction....I'm driving them from the non-ejector side, so they come out in the direction of the ejector. After about a half hour of whacking I managed to get the rear pin out, at the price of a punch that completely snapped. The front one......another half hour and it might have budged, but the finish on it is so far gone on it and the FSB that I can't even tell what's what anymore. I kinda have to take a break, as my left hand is practically numb (it's the ones holding the punch!

I'm resting everything on a concrete floor. The fsb is resting on a piece of wood, and the upper is in an armorers block.

Quoted: Click on the Armalite link at the top.  Click on catalog (upper left corner of screen).  Click on Tools & Accessories.  About half-way down the page is the Front Sight Alignment Tool.  They really think a lot of it; they want $58 for a rod. When I replaced my front sight base (with an Armalite fixed base FWIW), I already had my Aimpoint dot set on the original front sight post.  So, I aligned the new base so that the new sight post was on the Aimpoint dot.  I figured this would get it close enough.  At the range I only needed to make one click adjustment on the windage.   If you use the Armalite tool, I believe you need to attache the tool to a removable carry handle.  I'm actually thinking of buying one of those because I think I just got real lucky. Hey, if you're handy enough you might be able to make one of those rods.

So how does that Armalite tool work?

My understanding is that the Armalite tool sits in the top part of a carry handle.  So, if you don't have a carry handle, I think you're screwed.

Just installed a PRI clamp on front sight/gas block by doing the following:

Center the rear sight windage mechanically using the index mark.
Remove bolt carrier group.
Place upper on sand bags, and look thru the barrel at a 25 yard target center.
Adjust the front sight until the front post was centered in the rear aperature, while insuring the 25 yard target was still "bore sighted" thru the barrel.
Tighten the front sight clamp screws carefully, then re-verify the bore sight/iron sight agreement.

First live rounds at 25 yards were less than 1/2 inch to the right, about 3 or 4 clicks on the rear fixed things nicely.  Trying to move the front "just a smidgen" to allow the rear sight to remain exactly centered proved frustrating and unproductive...

HTH

Paladin

hard-case...here's what I had to end up doing with my problem Bushy FSB.  The heads of the pins became so mushroomed it was impossible to get them out.  The guy that was doing the work for me took a Dremel and ground the heads down concave into the base just a bit.  Then a couple of hard hits with a hammer and punch knocked 'em right out.

If you are mushrooming the taper pins, use a press instead. Hydraulic or even just a hand press. Sometimes slow, even pressure gets things moving that sharp, quick pressure doesn't.

I had a pistol I was trying to sight in one time. I was using brass punches to drift that darn thing. Even with those the steel started to deform on that dovetail. Finally used a hand press and moved it without further deformation.

Hah!

Finally got the damn second pin out. Drilled into it just a touch, then a few whacks and it popped out nice and easy.. Everything seemed to be going just fine with the install of the flip up front sight....got everything leveled properly,, seemed set and very sturdy. Course, since it's me, and my cosmic luck......the bolt carrier would not go in fully to the upper. Well, after checking the possibilities, and taking everything apart....everything points to my somehow bending the gas tube in just such a way that it will catch pretty hard when it tries to go into the carrier key. Argh......and this sucker looked so nice with the RASII and PRI flip up front sight installled. Well, guess I have to order a new gas tube (or two, just in case!).

Thanks for all the comments, advice, and putting up with my incessant rambling.

BTW - the level thing seems to be a great idea. Picked up two pocket sized levels and rested one right on the folded PRI sight and the other on the rail right in front of the 40L. It definitely showed just how off eyeballing can be!