I have an old Bruno in 8 x 57s which I am hoping to convert to a .223. I am having a problem finding a barrel in Zimbabwe. Could anyone recommend a good supplier in the States for a .223 barrel that would fit this caliber. Thank you for your help in advance. Any other advice towards this would be appreciated.

The barrel is easy as all the major barrel makers produce suitable barrels; reshaping the feed rails, magazine box, boltface and extractor will be the challenge, unless of course you're building a single shot, then the boltface/extractor is where the work is. My advice it to start with a different action or select a .22 cartridge that will more easily fit like the .22-250

Right on with that advice.

Toomany Tools, thanks for your advise, will look around for a barrel on the net. The problem in Zimbabwe is ammunition so will talk to my gunsmith and see what he thinks he can do, thanks again.

Toomany Tools has good advice. I would not attempt to convert a large bolt face BRNO to a small one. Too many issues.
I would look at convering the action to a cartridge that has a .473 case head. I think a 22 BR of 6mm BR would be perfect. I have a Mauser 98 action 22BR that is very accurate. It has the right case head diameter. You'd get better ballistics with the 22BR than with a 223.

Edit to add: A 22-250 might be a better choice. I think feeding would be better with the 22-250 than the BR cases. I have a 22-250 on a Mauser 98 action that works perfect.

DMB, thank you for your advise as well, much appreciated.