WalkaHeap1989 I'm have difficulty finding your photos. Actually finding the private messaging area. Could you please just send them directly to my email.  histcollector@gmail thank you gary Bettcher. 

Proper alignment is relative here, but a level or magnetic angle finder across the flat behind the rear sight ears and on the flat part of the gas cylinder with the front sight removed will get you there.    A cheap digital angle gauge will do the trick too.   I've got a buddy that uses a pair of rods that are 18-24" or so that go through the hole in the rear sight ears and another smaller diameter rod that goes through the hole in the front sight and you just eyeball things into alignment.    Unlike many other USGI rifles of the era, there are no alignment marks to line up.    

Well you're best bet for the collar disks are a reproduction set:   https://www.ebay.com/itm/284659807434    

Mr. Bushido,   Would there be any other names or phrases on there that would correlate to Mr. Tojo that the Sea Bees wouldn’t know about to authenticate it as original??

I vote for the Cessna T-37.  Maybe not loud in decibels but it had a distinctive high pitched screaming whine even at taxi power. 

Ordnance.com has more info and pictures and even a video.   https://ordnance.com/120mm-m358e1-armor-piercing-projectile.html

Thanks for the feedback everyone! I can't seem to shake why the paint would be underneath the powder charge residue on the inside of the grenade, but I'll look into stripping a small section and seeing if any of the original paint survived beneath it

This site has cases and projectiles…..   https://ordnance.com/explosive-ordnance-deactivated-inert-or-empty/american-artillery-ammunition/army-air-force-artillery-ammunition/4-7-inch-120mm-ammunition/120mm-m58-t123-tank-gun-ammunition-used-in-the-m103-heavy-tank-120x660mm-r-and-120x833-r.html   They are selling the cases for $1500 and AP projectiles for $750. 

I was station on the old pro in 1980 our captain was Michael C Colley was a trip to watch them load ICBM's on the Boomers was on it in Guam and Diego Garcia

So, there are two types of brass casings. One is for the AA gun, the other for the tank gun. The AA gun casing very rare, the tank gun more common but difficult to find. The AA projectile a Holy Grail, the Tank AT projectiles still can be found.    I have both the blue ( TP-T) and black ( AP-T) projectiles. I made an “ adapter” from wood to enable the projectile to sit on the brass casings ( even tho they were seperate loaded) for display purposes.