Project Appleseed

I have about 2000 rounds of brass mostly greek ,brass tumbler an rcbs fl die set primer pocket swaging tool  calipers primeing tool
I am going to keep it simple and just reload to m-2 ball spec's .
Do I need a case gauge?
Must be more carfull then when reloading for bolt gun
messure case's before reloading and messure after reloading

What all am I missing

Thank you in advance

Wade

Get the case guage. You need it to make sure the shoulder of the brass is where its supposed to be after you resize it.

Wade and all-
     Many recommend you use military-style primers, their cups are a little harder than the more common type.  'Scuse my ignorance, I don't know their numbers.  But in any case be extra-careful to avoid any "high" primers, as they will occasionally cause a slam-fire.  Very bad news.  The harder primers are an extra layer of safety against that happening.
     Use a relatively fast powder, like one of the 4895's or Varget, not a relatively slow one like the 4350's or 4831's.  Some loading manuals, like Hornady that I know of, list loads for gas-operated semi-autos separately.  There's a reason for that.  And reloading is for people who believe in manuals.       
     And also be aware that like-numbered powders, like H-4895 and IMR4895, are usually pretty similar but not exactly the same.  Either is good, but make sure the load you get out of a manual specifies the powder you have.  .30-'06 loads with slower powders work fine in bolt guns, but the slower powders have too much pressure remaining behind them when the bullet passes the gas port, and can damage your Garand.   

Be sure to trim your resized casings to something less than max length.  Use your caliper and see if any cases exceed the max casing length.
Max casing length for 30-06 is 2.494 inch, so trim length is 2.484 inch, 0.010 inch less than max.
Lee has the cheapest trim setup, but it's not adjustable and trims to way under the max length. 
RCBS, Hornady trimmers are more adjustable, but more expensive also. 
And you'll need a chamfering tool after case trimming to dress the case mouth.

 Instead of a case gauge,get a Precision Mic from RCBS. Measure several fired rds. from YOUR RIFLE and get an average.
Resize your cases a couple of thousands under the average and your brass will last much longer.

Wade,
Consider useing a primer pocket uniformer. It makes sure your primer pockets are square bottemed and deep enough to hold the whole primer.
Each time you fire a round 50,000 lbs  is squishing your brass any way it can, stretching and thickening the case neck, and some brass moves around the primer pocket.
                                    Clodhopper

If you want to use milspec primers I believe that Graf and Son's has the CCI #34 (I think this is the correct application, I don't have the box right in front of me) in stock.  I got a deal on a case (5000 cnt) for around $75 if I remember correctly.  That was a special one time only offer made in early 2007.  Also, I believe that clodhopper is correct in using a primer pocket uniformer, however none of the greek 30.06 that I have purchased had crimped primer pockets so I did not have to use a crimp remover.

CCI #34 or Win WLR primers will work. When yo useat them, make sure NONE stick up. Remove the crimped primer pockets, if crimped.

Case gauge is optional, but trim a little shorter than the spec (a couple thousandths works, more doesn't hurt). I recommend Full Length sizing for an auto loader, period.

Since you're using M2 bullets, seat to the cannelure, and lightly crimp.

Check the first few rounds to make sure they chamber OK, then recheck periodically after. Every couple hundred between checks is OK.

Stick to powders in the 4895 range.

For mass production of ammo for a Garand or other autoloader, I second (or third, whatever) the case gauge. I just drop every resized piece of brass for 5.56 that I load in there and it tells me if any have excessive, or not enough, headspace. I found a bad batch of LC 95 brass that way. Even with the same die settings as other LC brass I was using, it still had several thou too little headspace. I think maybe it was annealed too much (not by me) at one point and had gotten soft. Whatever the reason, in the scrap bucket it went. I've also found a few pieces here and there of random headstamps that have too much headspace, even with the same dies settings. Also in the scrap pile. I figure it's cheap insurance for 50k PSI next to my face. I full-length resize also. Yep, it kills the brass sooner, but for an autoloader, it's pretty much mandatory for reliable functioning. For just plinking ammo, I might try the RCBS mic die to make the brass last longer, but if it has to feed right every time, I'd full-length size. YMMV. Get a primer pocket cleaner of some sort also. I like the RCBS brush better than the Lee tool personally, but the primer pocket uniformer is also a good idea. I'm finishing a batch of CCI400 primers before I switch over to the CCI41s, and I make darn sure that the primers are flush or lower before they're considered ready to load.