I have an action block for clamping a standard A3 or A2 into a vise, but it won't fit my DPMS hi-rider upper. Do they even make a block for this upper? How would I tighten the barrel down without it? Just pad it really well and clamp it down? THANKS

I believe the [url=http://www.bushmaster.com/shopping/gunsmith/om-003.asp]Bushmaster Action Block[/url] will work on a high-rise upper.

Great, now what to do with my other block which is basically brand new!)(*&^%$#@

I've seen in the Shotgun News that DPMS has something called The Claw.  It's not on their website but you have to call it in.  It looks like a block which you can mate your upper to their lower to do barrell work.  

What it looks like is a block of plastic that you put in a vise.  It's got the proper pivot pin and take down pin to hold your upper in place for you to do work.  It runs about $40 bucks.

Hope this helps, I might get one too myself.  

Next time you should ask here before you buy.  [:P]

Actually, this is my first Hi-rider upper, I had an A3 I am parting out that it works perfect for. Could always sell the other one, but it cannot hurt to have 2.