I've tried to remove the index pin on a Bushmaster bbl using a pair of vicegrips but the pin is fairly soft and deforms to the point where I cannot get a good grip with the vicegrips. I guess I could drill it out and try an 'easy out' but I'm a little hesitant to do that. Do any of you guys have a good technique?

Why are you trying to remove it?  There are only a very few reasons to remove it, and scrapping a barrel is one of them?  They are generally press fit in and hard to remove.

Just wondering why you are removing it.

Look above - we hit submit at the exact same time with the exact same thought.

Mongo, how did we post at the exact same second?

We nearly did it again.

This is like the Twighlight Zone.

Quoted: This is like the Twighlight Zone.

[Twilight Zone Music]do-do  do-do...........................

Whoa!

Dudes.

Wow.....seven replies in less than 12 hours. Thanks.

When I fit the barrel to my upper, it was canted slightly to the left. Enough so that it took about 20 clicks of windage adjustment to establish a 'zero'. I guess I'm being a little 'anal' because the position of the rear sight just didn't look right. The rifle shot great...I was just bugged by that little imperfection.

So, I emailed the good folks at Bushmaster with the following....."should I remove some material from the slot in the upper receiver or file the index pin?" Their answer was to file about .015" from the side of the pin and that should return the rear sight to approximately centered. They also said I could remove the pin with a vicegrip or drill it out and they'd send me another one. OR I could return the barrel to them and they'd do it for me!

The shoulder on the barrel extension makes it almost impossible to file on the index pin and my attempts to remove it resulted in a smashed pin.  I smashed it almost .015" on both sides and it still fit in the upper receiver OK so when I checked the alignment, everything was fine. Now the rear sight is centered and the rifle shoots like a champ. Love those ARs!

I'm doing another build but I think perhaps filing the receiver might be the best (easiest) way.

Whaddya think?

Quoted: I'm doing another build but I think perhaps filing the receiver might be the best (easiest) way. Whaddya think?

Is your next build going to be on the same receiver, or are you starting from scratch? If it will be a totally new build, chances are that you won't encounter this problem again, as it isn't too common. If you are using the same receiver with a different barrel, you'll probably still be okay, as I feel that the problem was probably in the barrel, not the upper receiver.

There's also the possibility that the front sight base was canted, not the barrel itself.

This is a new build with an Ameetec upper and Bushy superlight barrel. Yeah, I thought about the sight base being canted but also thought it was easier to correct the problem at the receiver end. To check the sight alignment, I used a piece of paper  with a vertical line drawn and taped to the wall. I rested the barrel on the the front sling swivel and rear takedown pin boss on the upper receiver - not exactly machine shop accuracy so front sight cant may have been the problem all along. Bushmaster explained that there can be small dimension variations from maker to maker and that may have accounted for the problem.