Here is my first practice attempt at removing the fence to replicate the XM177. I used a Dremel grinding bit but I put it in my drill press. I moved the lower around by hand which explains the crappy lines and mistake marks. I don't have pictures of the bit I used as I pushed too hard near the end and promptly destroyed the bit. I found the shaft but the rest is somewhere in my garage.



I found the bit finally. It has 15 angled flutes. I didn't destroy it but some off the flutes are broken on the end. Here is a very crappy photo. My camera sucks as this is with macro on.

I have done that on several DPMS lowers , and the method i use is tocarefuly grind off the fence until it is almost flush with receiver -w- a 1"x1/8 thick fiberglass wheel in a dremel flex shaft pencil grinder , , and then do a final "blending" with a 3/4" orbital emery 220 grit sanding disc , and it comes out real well , as you can cut right up to the remaining portion of the fence that the dust cover rests on and not gouge it ---  i can TIG weld aluminum - so this takes the pressuer off me - if i make a mistake !    

could you post this information in this thread please? www.jobrelatedstuff.com/forums/topic.html?b=3&f=118&t=261161

It is a thread asking questions and info about converting A2 lowers to A1 specs.

Done.

i would use an angle grinder with buffing pad and carefully grind away at it. it would end up flatter that way imo

TANGO:  did you grind down the A2 reinforcement  on area where buffer tube screws in ?

I haven't gotten brave enough to tackle the reinforced area yet. I'm still working on the "Primative Pete" method and I need to figure out how I'm going to tackle it with my redneck tool box.

Simple - Toss it into a Monarch CNC machining center and program the machine to remove the fence.  

Seriously, I think the best way with standard home tools is to emphasize hand work as much as possible. Go ahead and use a dremel or whatever to take off 80 to 90% of it, but use caution not to use power tools when you get close.  Switch to files, take off another 10 to 15%.  For that final bit, I'd start with 220 wet/dry paper backed by small files or steel blocks.  A good set of needle files in various shapes will help a lot towards the end of the job.  When you are truly done, a bead or sand blaster will blend the area and prep it for moly or anodize.

The overall idea is to keep the flat surfaces flat, and if you attack it with a handheld dremel or even 220 paper in your fingers, you are probably going to dish and/or gouge areas you don't want to, unless you limit the power tool use to the really tall portions.

You can protect (somewhat) flat areas that you don't want to touch during the power-tool phase with fiberglass tape.  You can see if you miss a bit as the tape scores or gouges.  It does help a bit.  Of course, remove the tape when the time comes to blend.