For many years the Japanese military rifles were looked down upon because of their rough appearance and their less than butter smooth operation. But in recent decades they have been given more credit for what they are; brilliantly designed and well built weapons which were far ahead of their time in many areas.
The Japanese were the first to realize the advantages of a chrome lined bore in tropical environments; it doesn't rust. It is also rather impervious to corrosive ammo. The entire bolt and firing mechanism consists of only six parts; bolt body, extractor, extractor collar, firing pin, firing pin spring and safety knob. The two piece stock is ugly, but it saves wood. The bolt cover did a good job keeping dirt out of the receiver and a smart soldier knew that pinching it slightly eliminated the rattling sounds it made.
The bad ones are easy to spot. The upper tang at the rear of the receiver will be intregal WITH the receiver. The receiver itself will have almost no machining marks because it is a cast piece. The bore will not be chrome lined and the rear sight, if there is one, will usually be a simple apature tack welded to the barrel. The safety knob will probably be smooth, without the knurling present on a production piece.
Which brings us around to ammo. 7.7 Japanese ammo is the easiest thing in the world to make. Run 30-06 cases into a 7.7 full length die and trim the neck. Use 303 British loading data. There were rumors, spread years ago, that the 7.7 Japanese round is larger than the 30-06 at the base, and that it was dangerous to make ammo from 06 brass. Not true! Go look it up in Cartridges of the world. They are within a couple of thousands of each other, with the 7.7 actually being the smaller of the two.
I have found that my 7.7s are pretty much equal to any Mauser or Springfield I have fired. I get two inch groups with all of them on a good day
Enjoy that Arisaka!