Hello. IF the pistol's in excellent condition, $425 is not a bad price for a classic Hi Power. If made in the '70's, the serial number will probably be something like 71C12345 or 74C67890. The first two digits are the year of manufacture with the "C" being for "commercial."
These pistols will have a single-side, small thumb safety, the walnut stocks mentioned previously in the thread, a magazine "safety," and smallish fixed sights with only the rear sight dovetailed into the slide. The front sight will be a semicircle staked to the slide. On the earliest of the '70's pistols, the bushing does not extend outward quite as much as some of the later ones. All of the ones I've seen had spur hammers and if blued, the finish is a bright, polished blue all over; no matte blue.
This generation Hi Power will have the humped feed ramp and will likely be a bit picky as to what JHP rounds it'll feed without work on the ramp. If you intend to shoot ball, there's no problem. Some of the blunter JHP ammo might indeed hang up. If you opt to go with some JHP ammo, I'd try
Federal 115-gr. JHP (9BP) as it's rounded ogive usually feeds pretty well in most guns. It is not of the latest design, but even though standard velocity (usually around 1170 ft/sec in the HP), it seems to work pretty good in tissue, at least in the animals I've shot with it and in the photographs of it I've seen when bullets were pulled out of felons. It normally groups well out the Hi Power. Another standard velocity round I'd look at is Remington's standard velocity 115 or 125-grain JHP. These are not the Golden Saber rounds, just plain jane JHPs...they group out of the Hi Power.
If you do plan to use the gun for defensive purposes and don't want to alter the barrel, you might consider the Corbon 100-gr. "PowRball." This IS a +P round and I would use the heavier springs if shooting much of it a tall, but it is costly so that probably won't be a big issue.
I've found it to be extremely consistent out of the Hi Power w/std. factory bbl. Based on 10-shot averages, I got the following from a Mk III Hi Power:
Average Velocity: 1473 ft/sec
Extreme Spread: 46
Std. Deviation: 17
The round should feed fine in any Hi Power, humped feed ramp or not.
If interested, I've got more on this round at:
http://www.hipowersandhandguns.com/CorbonPowRball.htm
Information on the Federal 115-gr. JHP and the Hi Power is at:
http://www.hipowersandhandguns.com/HiPowerFederal115.htm
If you plan to shoot primarily standard velocity ball, the factory 17-lb recoil spring should be fine, but if you intend to shoot very many (as in several hundred +P or +P+ rounds), I'd suggest using a Wolff conventional 18.5lb recoil spring. Depending upon when your pistol was made, it will have either a 26 or 32-lb recoil spring. I cannot remember when the change was made, but it was in the 1970's. My '70's vintage HPs were made in '71 and '72 and have the lighter mainspring so it was after that. I THINK it was around '75 or '76, but could sure be wrong.
Best and good shooting.
