"I'll never admit we are carrying enough ammo on our tanks; Load some more!....."(quote of Sgt.Bob Hurley, 'Hawk Hill', 11mar69, 1/1st Cav, Viet nam)....
A notorious 8mm mil/surp was out there was FN 1950s made, with double 'A' on the head stamp. It has a reputation of delayed firing, and not firing at all, 3-5 rounds every 15.(hvy rd,197gr)
Turkish 8mm, everyone is familiar with, is pretty much sure fire, but brings other problems too. Cracked brass at the mouth of the case, over-charged powder, are the most common with the war year dated, but gets better late 40's and very earluy 50's....
Acouple years ago, a group of old guys here at KCR, experimented with the Turkish ammo, by disassembling the rounds, weighing charges and using a chronograph to measure muzzle velocities. They found 40 grs would put the 154-157 grain bullet at nearly 2800 fps, which was fast enough...They found so many cases over-charged, some with up to 52 grains which put this light-weight bullet at 32-3300 fps; Far too powerful, with wild recoil.......Therefore, some of us, will pull the bullets, dump the powder, and re-measure to 40grs, and re-seat the rounds....I have used belts this way in my semi-mg-34, and it runs smoothly, and reliably.
Egyptian 8mm was all around in the 80's and you still may find guys with it. It is loaded powerfully, for the Hackim semi-8mm, and is fine in 98ks. I have never tried any in the 34s, or disected the rds. Has a squiggle letter with a 'Y,9r' on the headstamp.(hvy rd,197gr)
Around mid-80's, there was the Chinese 8mm round our in mass. a light rd, 154 gr, with good brass. The 1953 date on the head stamp, one adds 12 years to, for the new chinese calendar since 1912(Boxer rebellion), has also a diamond in a circle on the head-stamp. I have some of this, and it runs well/smoothly thru 34 sa and 34 fa. Hard to find now.
All know the Yugo, 197gr ammo that usually comes in 900rd case, is good 98k ammo, but i never had any luck with it in my sa 34. I never went into exploration as to why though....You might have better results than I.
Other than the Romainian we have mentioned, there may be some East german 8mm in steel case out there in someones possession , that functioed well in the sa-34, and of course the 98k.
Long gone 8mm surplus ammo is ,British WWII 8mm they made for their machine guns for the bows of their tanks, called the Bessa(I think) mg. The prominant mark on the head-stamp was a 'K-II" for the Koenig ammo factory, with the date. Canada made the ammo too, but with a boxer primer, and headstamp that had '7.92mm with two digits for the year. Good in the 98k, but I shot thru thousands of rds before the sa 34 came out. .......
Gone from the market too is Italian made 8mm for that Besa mg the Brits bought from Italy between the wars. For a while in the 80's, a lot of this Italian 8mm was spotting rounds, and would explode upon impact on a hard object. (like the much sought after B-Patrone of german WWII fame! Amazing!...I shot thru them with 98ks way before the sa-34 was around. (nuts!)
In the mid-90's pre-WWII Polish 8mm hit the market, hvy-197gr rounds, and this stuff was very reliable. a 'PK' and 'DZ' marking on headstamp with the year. Guys may still have this round in quantity too. Don't know how it would perform in the 34 though, it did well in the 98k, also scoped 98k, as my shooting exploits were noted in the book 'German 7.92mmMilitary ammo' by Kent. (good bed-time reading, put you right to sleepy-bye!)
Can't forget the Portugese made, hvy 197gr, in beautiful brass case, 1970's&80's dates, everyone wants. I have a few thousand rds, but have not yet tried it in the 34s....He may have that stuff. It has been high priced in recent years, and was getting hard to find, before this new ammo drout began in 2007.........
.....of course, you may really luck out, and find the surplus he has for sale is german WWII !!!....I need not tell you what to do then!