I'm going to CMPicon to buy a couple of Garands this week and a half dozen cans of ammo. Don't have any experience with Garands, but want to get a couple while I still can. Make good safe-mates for my STG. I want good shooters that will hold their value, maybe something I can add value to via re-parking, etc.

I know they have different grades and the Service Grade at $595 is probably as high as I am thinking about going for each, unless there is a good reason.

At present, there are no SGs at the stores; they have been held bak to fill orders. They have Field Grades out. With careful scrutiny, you can still get a good rifle.
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The Special Grade at $995 is new wood and barrel, but I don't know how good the barrel is or who made it. Is it worth a $400 premium?

The CMP barrels have a very good-excellent reputation. Since you are getting essentially a new rifle, it is a great value. They have little collector’s value but make great shooters since they are carefully assembled & fitted.

Get all 10 cans of ammo - it's an annual allotment & they may run out by year's end. The Greek ammo is a good value you can't match. An'd, you save shipping (but pay sales tax).
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Other questions:

Most seem to be Springfield Armory receivers. Any reason to pick another manufacturer? Not really, unless you just want a Winchester or HRA, etc.
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Any problems to watch out for with mix and match parts? Not really. They were designed to be interchangeable. One with all matching parts would be of interest to a collector and make little difference to a shooter.
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I understand that they will check T.E. and M.E. for you. What else besides a sound stock and decent metal can I check for. I don't think they allow test firing...

In the Garandicon, bore condition is key to how well the rifle will shoot, closely followed by stock fit. The muzzle gauge is used to check how much wear has occurred to the lands in the bore. The gauge reads between 0 and 8, 0 corresponds to .300" (perfect) to .308" (worn slap out) Many new barrels will read between 1 & 2; a 0 is somewhat rare; some will go as high as 3.5; depends on when & who made it. Inspect the muzzle as well as gauging it. The crown should be free of nicks, burrs or any other defect. Muzzle condition is more important than throat condition so pay more attention to it. The throat erosion (TE) is also measured between 0-8 and the closer to 0 the happier you will be. Inspect the bore (bring a bore light & magnifying glass for close inspection of all parts) to make sure there is no rust or pits, etc. Once you find a rifle with a good bore, take it to the counter & ask the armorer to inspect it for you;they are very helpful. These are the things that must be good:
1. Stock fit. Unlatch the trigger guard & with the metal seated in the stock, grab the rear sight & try to move the metal fore & aft in the stock. There should be no movement; if there is, the action will shift in the stock every shot & accuracy will suffer.
2. Headspace. It was supposed to be checked during inspection prior to being sent out for sale but double check; on rare occasion, a rifle with improper headspace sneaks through.
3. The op rod. Closely look (magnifying glass) at the tip. It should be round with a nice sharp edge. (I bought a Garand once where the op rod must have been dropped on a concrete floor as one side was flat which does not happen from any kind of shooting or normal wear; they swapped out that op rod as it was not serviceable). Also look at the tab; the hooks & the bolt locking lug recess. All these areas should be free from any burrs or excess wear. The armorer will do this for you.
4. The gas cylinder. Ask the armorer to gauge this for you. They have a special gauge for this which they do not lend out!
5. The trigger housing assembly. The lugs on the trigger guard should be round or nearly so; when worn, they develop a flat where they latch into the receiver. The trigger guard should latch with some effort.
6. Inspect all the metal for rust, pitting, damage, etc.
7. Inspect the stock, inside & out for cracks, splits, missing chips, etc. Garand stocks typically crack at the clip latch area. The USGI fix was to repair the stock with brass pins which is OK if done well.

After that, its all appearance & what's pleasing to the eye! Your rifle will need some cleaning & the stock some TLC. Many people like boiled linseed oilicon for the stock but I prefer Tung oil (Formby's) It dries much faster, goes on easier & has the same look after a few coats.

If you know for sure you are going to buy a Garand, right now, before you go, find the Orion 7 website ([Orion 7 Enterprises Inc. ]Orion 7 Enterprises Inc.) & order a new op rod spring & clip latch spring. Change springs before you shoot the rifle. When you get the rifle home, take the old springs out & throw them away. Even if you get a rifle that was never issued, the springs are 50 years old. The op rod spring is the only thing that prevents the bolt from hitting the heel of the receiver; a weak or worn op rod spring allows the bolt to hit so hard that it can crack the heel & destroy the receiver. The Army replaced op rod springs every 5000 rounds when the rifle was in service; match shooters replace them every year. The Orion 7 op rod springs are the best made & cheap, about $10. Don't scrimp here; some springs cost a couple dollars less but are not as good. Some sellers offer surplus GI springs for $5 but they have the same problem - they're 50 years old. The clip latch spring also often fails & causes premature clip ejection. It's cheap too, perhaps $2.

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Does anyone know if they have any .308 Garands (that's a long shot, I know, but caliber sprawl... the Navy had .308 Garands) Very unlikely!

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Make sure your paper work is all in order before you leave home! Double check everything & make sure you meet each requirment. I wathced one fellow arrive with out 1 bit of documentation & he could not buy a thing!