AR sight tower question

Flamehead · August 16, 2005, 18:47

I hope it doesn't offend anyone that I ask a question about an AR here. I trust the opinions on the files more than any other site.

I am going to do some work on an old AR upper. The front sight tower is canted to the left. Not severely but it needs to be fixed. It has roll pins securing it.

My problem is that it (sight tower) is obviously much softer metal than the barrel. My plan was just to drift out pins then straighten and redrill. I am afraid my bit will just walk right into the tower rather than cutting the barrel steel. Would I be better off just removing the tower and round filing the grooves for the roll pins? Anybody have experience doing this with an AR. Any input or ideas much appreciated. Thanks.

TheOtherChris · August 16, 2005, 19:14

Quote:

Originally posted by Flamehead
I hope it doesn't offend anyone that I ask a question about an AR here. I trust the opinions on the files more than any other site.

I am going to do some work on an old AR upper. The front sight tower is canted to the left. Not severely but it needs to be fixed. It has roll pins securing it.

My problem is that it (sight tower) is obviously much softer metal than the barrel. My plan was just to drift out pins then straighten and redrill. I am afraid my bit will just walk right into the tower rather than cutting the barrel steel. Would I be better off just removing the tower and round filing the grooves for the roll pins? Anybody have experience doing this with an AR. Any input or ideas much appreciated. Thanks.

If the front sight base is held with roll pins instead of taper pins, it is most likely an AR that was built using a Nesard barrel. If that is the case, the best way to correct that barrel is to remove the barrel from the upper and alter the index pin to realign the whole barrel/sight. File one side and weld the other til it is straight.

If you try to rotate the sight base on the barrel, you could block the gas port (doesn't take much) and have cycling problems. I've seen gunshow builders that used to smack the front base with a big hammer til it was alligned. Not the best answer.

Good luck,

**W.E.G.** · August 16, 2005, 21:07

It would be helpful if we knew WHY the sight tower is canted.

Did the prior owner cant it to get it to line up with a mis-located gas port?

Does the upper CYCLE with the sight tower canted?

If you twist the tower, and block the gas port, you will have a single shot rifle with a straight sight tower.

Some folks install AR sight towers by just using green Loctite to secure the tower. I've seen at least one just held just by Loctite that you could not move by grabbing and twisting - or dropping the rifle on the sight tower. AMHIK

Flamehead · August 17, 2005, 07:30

I don't know why it is canted. Rifle runs like a swiss swatch as is. Old gun but in practically new condition. It is a Nesard barrel. Sendra reciever.

Thanks for the replies. I think the method theotherchris described is what I need to do. I may be better off sending it to a REAL gunsmith as I have no experience at removing an AR barrel. Would this be fairly simple endeavor? Thanks again.

TheOtherChris · August 17, 2005, 10:24

Quote:

Originally posted by Flamehead
I think the method theotherchris described is what I need to do. I may be better off sending it to a REAL gunsmith as I have no experience at removing an AR barrel. Would this be fairly simple endeavor? Thanks again.

Which method? filing and welding the index pin or smacking with a hammer?

You may wish to buy a new barrel and swap it yourself.
If you choose to have a gunsmith align your barrel, you may find that the additional labor will be more than the cost of a new barrel.

A true WECSOGer would do it in the garage.
Removing a barrel is not difficult if you have a barrel wrench and either a receiver or barrel clamp.

Para Driver · August 21, 2005, 22:32

had the same problem on a Colt's barrel... it did not come with any gas port drilled at all.. and the sight was canted left, must have been the special Kalifornia model...

so I had the gunsmith mill a hole where it was supposed to be at TDC, and bought one of the (Yankee Hill) gas blocks that has the two perpendicular screws that make it pinch wherever you set it..

my super neato trick was to lay the flattop receiver and the flat top gas block on top of the kitchen counter which is deemed as 'flat enough' and then torqed it down. still took a couple of clicks to get it centered.

might just try to walk it in next time at the range, should only take 1-2 degrees of twist to get it perfect.. if misalignment causes gas interruption, then I think the proper thing to do is chamfer the gas port on the barrel, just like the crankshaft on a high performance car..

August 16, 2005, 18:47	#1
Flamehead Registered FALaholic #: 14372 Join Date: May 2004 Posts: 458	AR sight tower question I hope it doesn't offend anyone that I ask a question about an AR here. I trust the opinions on the files more than any other site. I am going to do some work on an old AR upper. The front sight tower is canted to the left. Not severely but it needs to be fixed. It has roll pins securing it. My problem is that it (sight tower) is obviously much softer metal than the barrel. My plan was just to drift out pins then straighten and redrill. I am afraid my bit will just walk right into the tower rather than cutting the barrel steel. Would I be better off just removing the tower and round filing the grooves for the roll pins? Anybody have experience doing this with an AR. Any input or ideas much appreciated. Thanks.

August 16, 2005, 21:07	#3
W.E.G. Administrator Silver Contributor FALaholic #: 1211 Join Date: Oct 2000 Location: Virginia Posts: 31,056	It would be helpful if we knew WHY the sight tower is canted. Did the prior owner cant it to get it to line up with a mis-located gas port? Does the upper CYCLE with the sight tower canted? If you twist the tower, and block the gas port, you will have a single shot rifle with a straight sight tower. Some folks install AR sight towers by just using green Loctite to secure the tower. I've seen at least one just held just by Loctite that you could not move by grabbing and twisting - or dropping the rifle on the sight tower. AMHIK __________________ . . . Ask me about the Mason-Dixon FAL Collectors Association.

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August 17, 2005, 07:30	#4
Flamehead Registered FALaholic #: 14372 Join Date: May 2004 Posts: 458	I don't know why it is canted. Rifle runs like a swiss swatch as is. Old gun but in practically new condition. It is a Nesard barrel. Sendra reciever. Thanks for the replies. I think the method theotherchris described is what I need to do. I may be better off sending it to a REAL gunsmith as I have no experience at removing an AR barrel. Would this be fairly simple endeavor? Thanks again.

August 21, 2005, 22:32	#6
Para Driver Registered FALaholic #: 6350 Join Date: May 2002 Location: Texas Posts: 6,297	had the same problem on a Colt's barrel... it did not come with any gas port drilled at all.. and the sight was canted left, must have been the special Kalifornia model... so I had the gunsmith mill a hole where it was supposed to be at TDC, and bought one of the (Yankee Hill) gas blocks that has the two perpendicular screws that make it pinch wherever you set it.. my super neato trick was to lay the flattop receiver and the flat top gas block on top of the kitchen counter which is deemed as 'flat enough' and then torqed it down. still took a couple of clicks to get it centered. might just try to walk it in next time at the range, should only take 1-2 degrees of twist to get it perfect.. if misalignment causes gas interruption, then I think the proper thing to do is chamfer the gas port on the barrel, just like the crankshaft on a high performance car..