In the past, I pulled the bullets from 1960's Czech steel cased, light ball (147 grain) 7.62x54r and reloaded them with 150 grain soft points pulled from Norma 7.65 Argentine ammo.
You'll need to resize your case necks before you seat the new bullets, but if using steel cases it's even more important than brass because there's NO springback to the steel cases. I found that with the whole decapping/expander stem removed, I could run the cases all the way into the resizing die without using any lube or dumping the powder from the cases. I'd then bell the case necks slightly and seat a bullet without ever expanding the neck.
Depending on the source of the surplus ammo you're using, it might be beneficial to to weigh and average your powder charges. After checking the charge weights on a dozen of the S&B Czech loads, I found that they were consistent enough not to worry about it.
The resulting loads were actually more accurate than the factory loaded ball ammo, although OAL was a good bit shorter. I never noted any pressure signs, even though the bullets I loaded were 3 grains heavier than those I'd pulled, they were a good bit shorter (no steel core) and had about the same bearing area.
Although these loads worked well and killed several hogs for me, I gave up using them fairly quickly.
The last thing I wanted to do after killing a few hogs out of a sounder was to worry about cleaning my rifle when I had a bunch of pork to process. It wouldn't be so bad with an M44, but I was shooting a PSL and cleaning it was considerably more complicated and time consuming.
There's no way I would have done that if I'd been able to buy $13.75 a box hunting ammo or inexpensive Privi brass. Unfortunately, at that time all I could get was Norma ammo and cases and it was more than I could afford.
The above information is meant only as a guide, I'm NOT claiming that it was 100% safe or that you'll be able to run your cases into the die without lube or seat bullets without expanding the case necks, but it worked for me.
