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Posted: 7/10/2003 7:17:06 PM EDT
Got tired of messing with a finicky FAL (junk from CDNN)and bought a nice pre-ban, heavy-
barrel AR. Its a DPMS and the groups are absolutely on top of one another, it's about 98% clean, and the function is flawless. Of course there will always be an issue with a used rifle, and this one seems to have the front sight assembly canted 1/16th to 1/8th of an inch to the left. With the rear sight adjusted all the way to the left, I'm still shooting about 6 inches right. How can I adjust the front sight assembly? The front sight pin is absolutely straight and the assembly is pinned on. I guess I can put a red-dot on it and have a fabulous keeper, but I like to shoot with iron sights. . .something primal about it. Can the barrel be rotated slightly? Can the barrel extension be rotated (how)? can the pins be removed (how). I field stripped this thing in the Air Force and qualified on it several times. . .but I don't have any in-depth knowledge. Hope you can help cause GAWD I love this rifle!
Dave
Link Posted: 7/10/2003 7:19:51 PM EDT
I don't know how it is done but I think the barrel can be re-indexed to line up the sights. You could always send it back to the manufacturer............ I'm sure you'll get some good answers to your question. Welcome to arfcom! [wave]
Link Posted: 7/10/2003 7:40:21 PM EDT
[Last Edit: 7/10/2003 7:43:25 PM EDT by markmcjunkins]
A couple of methods are often recommended here. One way is to give it a good smack with a leather hammer. Trying to figure out which way to adjust it to. Another is to pull the barrel nut off and shim the barrel index pin. Another member here had the same thing not long ago. Maybe he'll help. I tried a search for it but nothing came up. Keep reading the old posts, it's in there somewhere. Found one. [url] http://www.ar15.com/forums/topic.html?b=3&f=66&t=164662[/url]
Link Posted: 7/10/2003 9:00:30 PM EDT
My rule of thumb for being able to move the front sight (rotating the barrel in the upper) is that the rear sight must be able to be adjusted to zero out the rifle (with room left between the rear sight and sight housing side wall). Since you rifle/rear sight has run out of room to zero, it's time to pull the barrel and check it out. By trying to just rotate the barrel so the front sight is in the correct position, you stand a chance of rotating the feed lips and bolt entry channel (lugs) out of position for clean engagement. Where you want to start, once you have the stripped barrel in hand, is to make sure that the barrel extension pin is on the same index line as the front sight tower, and the pin is not bent. If there on the same plain and the pin is not bent, then using a receiver block to hold the receiver in the vise, pick a point at least 25' way to look down the barrel bore, then the sights (a bore laser keeps you from having to look down the barrel). Once you have the center rear sight/front sight tower seeing the same point as the bore, you can shim the extension pin in the receiver to keep the barrel from rotating during tighten, or just tighten up the barrel is the pin is tight in the receiver socket slot. Then once you have the rifle back together, use a leather mallet to slip/rotate the barrel in the receiver to fine-tune the front sight so it and the bullet point of impact are seeing/reaching the same point.**** NOTE: WE DO NOT USE THE MALLET TO DRIFT/ROTATE THE FRONT SIGHT ON THE FRONT OF THE BARREL, JUST TO SLIP THE BARREL/EXTENSION IN THE RECEIVER. What I have not covered was if the barrel extension pin and front sight are not on the same plain. Depending on the amount of index the two are off, will determine the way to correct the misalignment. Bottom line is that you will need to pull the barrel and check the extension pin and sight tower indexing out. If you lack the tools, post in the hometown forum to see if anyone around you have the tools, and can give you hand pulling apart the upper. *** Each type of ammo/manufacture will shoot to a different point down range. Before you begin to fine to a rifle for a dead center rear sight, make sure that the ammo being used for final tuning is the same that you will be using for a while. If you game plan is to use different types, then fine tune the front sight so that for the majority of types of ammo, you only need to adjust the rear sight a few clicks off center (left or right).
Link Posted: 7/10/2003 9:02:13 PM EDT
Just to add, I know FAL's also. So if you have the FAL still, post the problem that you are having and I will help you out on that rifle too.
Link Posted: 7/12/2003 7:08:22 PM EDT
Thank you for the info. Re-indexing is a little beyond my expertise. But, I have an aquaintance who has the necessary armoror's kit and knowledge. . .just happens to be out of the country for a few months. I thought the fix might be something easy I could do. As to the FAL, it is sold. I'd put the orriginal grips back on a nice scope receiver cover, and scope. It was fairly accurate, but would only accept one particular mag (it was a metric and I'd tried several) and the safety was filed down to rotate past the catch point. I was keeping TAPCO in business buying parts. Too much hassle. Thanks again for all your help! Dave
Link Posted: 7/19/2003 4:10:49 AM EDT
Here is another thread on the same topic. The 2 trains of thought ("whack it" or "pull barrel & adjust") are going on here as well. Take your pick [:\] [url]http://www.ar15.com/forums/topic.html?b=3&f=4&t=165221[/url]
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