Hey, guys. I know this must have been covered before, but I'm getting ready to twist my Imbel kit together on an older, Coonan receiver (I've checked for defects pointed out by Gunplumber and it seems GTG) and I want to purchase headspace gauges. In my limited experience, only a no go and/or field gauge is really needed. Would you guys say this is correct? I want the weapon to safely feed both 7.62x51 and .308, so am wondering which spec to use, and whether the Clymer or Forster gauges would be better for the FAL. (I know there are a plethora of gauges out there, some specifically for the M240B or M14) Any help would be much appreciated. The only other thing I need are a few 922R parts and an FAL barrel vice. (I've considered making my own out of hardwood, or having a friend cast it from bronze and cut it in half.)
I'm really looking forward to getting this thing up and running. I'll be shooting mostly milsurp 7.62x51 and cheap bulk ammo through it, so ammo recommendations (or ammo to stay away from) would also be appreciated. It will be a scoped, 21" fixed stock. (poor man's DMR.) Thanks! - Morg

I use a go and a no-go, both Clymer IIRC.

^This

SAAMI .308 Winchester
GO: 1.630 in.
NO-GO: 1.634 in.
FIELD: 1.638 in.

FN FAL
GO: 1.6325 in. (FN & Brit/commonwealth. Canadian is 1.6315 in.)
NO-GO: 1.638 in.
FIELD: 1.640 in.

7.62 NATO (M14 US MILSPEC)
GO: 1.6355 in.
NO-GO: 1.638 in.
FIELD: 1.6445 in.

FWIW, both Jerry Kuhnhausen and Clint McKee recommend a 1.631-1.632 headspace for rifles that will be using both .308 and 7.62 NATO. The stated rationale is that almost all 7.62 NATO manufacturers (especially U.S. makers) hold their ammunition to minimum dimensions.
The general FALFiles recommendation seems to be to headspace to the above FAL specs (not surprising), which means your .308 Win "no-go" becomes your "go", and the .308 Win "field" becomes the "no-go". This is based on most of these rifles being used with 7.62 NATO milsurp ammo; while U.S. makers hold tight dimensions, not all foreign makers do.
For a FAL shooting mostly milsurp and bulk .308, the FAL specs are a good choice, IMO.

As to brand of gauge, either Clymer or Forster will work. I use Clymer. You will want a set of pin gauges, too.

This too. Also if you can find it, read Gun Plumbers rundown of head spacing. It will clarify things for you greatly.

Yep!

And if using a newer DSA receiver, get them down to 0.250" or so!