My brother bought a 1943 .30 carbine from an auction and we know nothing of its history (round count, safety, etc).  We're going to start off with giving it a good cleaning & disassembly.  I've built, therefore headspaced, a few rifles so I was going to get the go, no-go, and field gauges and check the headspacing.  Probably also get a muzzle wear gauge since they are cheap.  I also have a borescope so will check out the bore.  Assuming all that checks out, I will be reloading for it since the rounds are pretty expensive.  I have a few 30 carbine empties so I was going to load up a few light rounds using the 125gr (30-30 bullets) bullets that I have and Trail Boss powder (70% fill).  Then if everything seems ok buy all the brass/bullets after that.  Are there any other tests/things I should consider doing before firing?

+new springs

Replace the springs.

I had much better luck with fifteen round mags.  I have purchased bullets from Everglades ammunition who have free shipping.   I’ve used their plated and jacketed round nose bullets.   I’d buy at least 500 bullets and you shouldn’t have trouble finding brass.


https://www.evergladesammo.com/bullets/rifle-bullets.html?caliber=55


Everglades 30 carbine brass is out of stock but Starline website has brass in stock.   I’d buy 500, shooting 30 carbines is like eating chips.


https://www.starlinebrass.com/30-carbine

Also, go online and find the tutorial on where to grease the moving parts for best performance. Use any high grade gun grease and you will be fine. Some folks even use regular synthetic red grease with no issues. Check the barrel for excessive fouling and if so clean with any good fouling remover. Follow the other advice above and you should be good to go.

Highly unlikely it won’t properly headspace. I have never bothered checking headspace on surplus guns, never had an issue in decades.

Bore scope is a waste of time - it either shoots acceptably or it doesn’t. I have had lots of rough bore surplus guns that shot fine. I have also seen some guns that looked goood in the bore that didn’t.

Strip clean properly lube, a replacement recoil spring isn’t a bad idea. Then take it out and shoot.

Reloading is helpful considering the cost of this round, I always used 2400 powder and a 110 FMJ with good results

I've owned well over a dozen USGI M1 Carbines, never checked the headspace, never will. Just shoot it and enjoy it.

Change recoil spring, load magazine, pull trigger 15 times.

As someone who works on guns professionally, I’m going to give you some advice:

Don’t borescope it unless you actually have a problem. It’ll just ruin your day and drive you crazy.

Shoot it and see what it does. Keep in mind, these are not MOA rifles.

Checking headspace is not a bad idea. Since you already have the gauges, no big deal. Just make sure you clean the bolt fact and chamber really well before hand-and make sure you know wether or not you need to disassemble the bolt with your gauges. Some do, some don’t-especially in military calibers.

Hope it checks out well for you.  When you are ready to reload, there are threads in the reload section here.  I worked up one for 115gr cast bullets with H-110.  Great for plinking at low cost per round and excellent expansion for defense or small game.

I sent an absolute wreck of a M1C to Orion7 for the Sergeant package.  $190, but they inspected everything and replaced all the springs and rebuilt the bolt.  Came back running like a champ.

Wolff sells a complete spring service pack with every spring for the M1 Carbine. It's pretty inexpensive.  It was the first thing I did when I got my mine from the CMP back in '07. It's been 100% ever since.

https://www.gunsprings.com/M1+CARBINE/US+M1+CARBINE+/cID2/mID98/dID163#533

Korean 15rd mags are GTG. Just as good as any new condition USGI mags. I also have a few Korean 30rd mags and they work fine too.

Check for safety first.
1. Make sure it isn't reweld, they were cut through rear sight dovetail.
2. Check for bulged / ringed bbl.
3. Check recvr ring for crack usually left side at woodline.
4. Check for broke bolt damage to recvr. Will bulg out recvr at left lug or break / chip lug. Left bolt lug should touch.

If all above is good replace recoil spring and blast away.