I'm instructing on (civil registered) CT4's at the moment - if I'm flying a programmed military sortie I can exercise my IRT for all approaches as it's considered a state aircraft.
If I private hire the same aircraft for the weekend, I have to avoid cloud.
Seems kind of stupid really - this would be a fairly clean cut example of identical competencies.
I fly an Australian registered turboprop IFR, but when it was the same aircraft on the American register I couldnt touch it without sitting their exams and converting a license. Sure in terms of skills required, zero difference, it's the same plane, but their rules and regulations are different, and there are a few gotchas going in either direction.
Exactly the same deal for the military guys here in Oz. Absolutely no doubt most of you have the skills to take a CT4 do IRT until the cows come home. But if you want to do the same in a civil regs, without exemptions, then there's an expectation you take the time to learn the civil regs and knock off the exam. Not too long, hard or expensive. It's not as if they're making you do 200hrs of training, should be no reason after knocking off the exam you can't do a quick checkride and get signed off.
The company I work for has seen more than a few ex-military guys break the rules and have to come in for tea and bikkies because they didn't take the time to learn the differences.