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Posted: 11/22/2007 8:33:12 AM EDT
| I just picked up an old A1 upper assembly. I want to pull the handguards to replace them. My question is what direction should the muzzle be when driving the pins out? Im pretty sure the muzzle should be toward the right. Thank you for any help. |
What exactly are you wanting to replace them with? But to answer your question, they should be taper pins, which are typically driven left to right. So with the FSB upright, the muzzle would be on the left. You should be able to notice one side slightly smaller than the other. |
I'd guess you're replacing the caps too, like from round to triangular...  Which I just did, with an arbor press...upper/barrel/FSB on its side, pushing the pins out with the ejection port door *down*...  I used a hammer and punch once...my thumb still won't straighten out right... 
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If you are replacing a set of triangular handguards with another set of triangular handguards, there is no reason to remove the FSB. You pull the slip ring back to remove the handguards. If you are replacing triangular handguards with round handguards, you can even get the GI round handguards that will work with the triangular endcap. If you have a carbine with triangular handguards, and they were cut a little long to keep them from moving too much, you would have to remove the FSB. But if this is a rifle with triangular handguards, then why are you removing the FSB? Charles Tatum Alamo Professional Arms |
No. You do not have to remove the FSB to remove the gas tube or the barrel nut. Just drive out the tiny 1/16" roll pin that secures the tube to the FSB and slide the tube rearward until it clears the FSB. Now work the tube forward around the FSB until its clear of the barrel nut. |
I usually gently grab it with a pair of pliers or and pull. Once I've squeezed the gas tube flat, I cut it in half with a pair of snips, then use visegrips to pull it out. Then, I go to Midway and buy another one for $12.29... |
Sarcasm noted. The last one that was stuck, I inserted a 1/8" drill (shank first) into the gas tube (FSB removed from barrel), clamped drill + tube in a vise, and pulled/twisted/WD-40'd it...until it twisted into a knot...then I also bought a new gas tube...  I no longer try to remove old gas tubes...just FSB's... 
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Vise grips work as well. Clamp them to the tube close the FSB. Then use a hammer and tap on the grips. I've yet to see the need to remove a FSB to get a gas tube out. I guess I'm lucky. By the way, Way to go Razorbacks!!!!! |
+1 Even heavily carboned up tubes will come out if you 1)drip some penetrating oil in there and let it sit overnight, and 2) clamp a set of vise grips an inch or two down the tube and rap the pliers w/a hammer.
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They make a tool for that. www.bushmaster.com/catalog_parts_gunsmithing_p2.asp#MBC01 |
here's a better one...and you don't have to wait for the tube to seal... 
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My take on the vise/visegrips is this: Even with a drill bit inserted in the tube (to prevent crushing), the tube still gets damaged. Sometimes elongated, sometimes twisted, and can even break off at the weakest point - which is inside the FSB (where the gas port hole is). Prolonged shooting, even with good cleaning, results in a buildup of carbon deposits inside the FSB, between the gas tube/FSB/barrel. This is a good thing, as it seals the gas path off and prevents gas bleeding off to atmosphere instead of being directed back to the bolt carrier where it's needed. The carbon deposits are what make the gas tube stick inside the FSB. Soaking in oil doesn't have much effect. My best results have been to leave it alone and take the [stronger] FSB off instead. No problems with bent tubes hitting the carrier key; no elongated gas tube; no having to drill out a broken tube. If your gas tube slides right out, then more power to you. I'd buy that rifle from you in a minute. It's guaranteed to be low mileage. (I went through boot camp with a guy named Sherman Smoot. I thought it was funny to see it after all these years. He was an 0300, BTW). 
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