Being an army grunt currently I would suggest either the cold Steel recon one or a zt. I have found the pm2 and military to not be robust enough to handle what we throw at it. Remember we don't always have the right tool on hand some sometimes have to resort to using a pocket knife in rather destructive ways. The more overbuilt the better
My dad made it through all of his time serving during desert storm with a bench made 910 Stryker which is only on eBay now.
I agree 100% with the assessment.Most of the men in my family have served and currently my youngest brother is still in the US Army. During his deployments he usually would take a Kabar and a Swiss Army knife. He'd comment and say that the Swiss Army gets used almost every day and the Kabar stays in its sheath on his war belt almost 99% of the time. Also keep in mind that equipment with soldiers is often lost, stolen, or damaged, which may be a factor on how much you want to spend. Soldiers need knives that are practical, useful, and dependable, not something to collect.
Just some thoughts....
I would stay away from knives with delicate tips like the Spyderco PM2 or Military. These are fine knives and I own and love both but I understand the limitations on the tips. If he isn't really a knife guy he might be harder on the tip than is advisable like prying and what not.
The Recon 1 in the new XHP steel is a good choice. It may not be made in the USA but the steel is.
A benchmade Griptilian should get strong consideration. Nice size. USA made. Strong lock. Excellent one handed operation. Extremely durable. Some don't like the plastic handles.
This is where the H&K comes in. These are made by Benchmade. It is comparable in size to a Grip but has G10 handles with full liners. http://www.bladehq.com/item--HK-AXIS-Knife-Folder-Sand-G-10-3--27093
I almost forgot, the HK Axis is what you.might want, it's beautifully put together, pop the blade out and clean it up and it feels like a different knife, it's got a thick, tough, good looking blade, and the lock is a great combination of strong, simple, easy, and fun to use.
Another good option! They have been re-released with the Axis lock!
A little over budget. You will get more value with the H&K Benchmade.
The original on eBay is about on budget on the other hand. Ive tried a grip with axis and the original Stryker and they both lock up about as solid.