Have recently been gifted 500 Hornady HAP 125 gr and 500 Montana Gold 130 gr fmj bullets.
Hornadys are .356 dia. and MGs are .3565 dia. measured with a micrometer.
I know most jacketed 9mm bullets measure .355 to .3555 diameter.
Would these bullets be safe to use in my 9mm pistols?

Are you sure they are not plated bullets instead of FMJ, I've noticed some plated are a little larger due to the plating.. Either way I think you will be fine...But don't load plated using jacketed recipes..

60

The Montana Gold are listed as 9mm/Super and I think are more for .38 Super ammo thus a little larger diameter.

The HAP is offered in both .355 and .356 diameter.

Both are jacket, not plated.

A .38 Super cartridge calls for a .356 bullet.

I personally would not shoot them in a 9mm, which as you mentioned, typically calls for a .355 jacketed bullet.

I’ll shoot a .356 lead or plated like Berrys Bullets, but they are softer than FMJ.

115 HAP are 0.355
125 HAP are 0.356

Shoot away! Not going make a bit of difference.
Guess what a Wilson Combat benchmark load for a 9MM I saw once was...wait for it...
Power Pistol with 125gr HAP!

Thanks for some insight. I do have a 38 Super Les Baer I can use them in, this many bullets would keep me shooting along time.
Slugged my CZ75 and the groove diameter is .356 so I could also use them in it.
Going to slug a couple of other of my 9's to see how much difference there is between manufacturers.

One of the monthly gun mags just had a big article on 9mm actual diameter and it doesn't seem to matter that much.