the small bolt stem is about .344"
a large stem is about .429"
all 5.45 x 39 guns / AK 74 use small stemm bolts an have a .395 face
all large stem 7.62x39 /ak 47 have a .440 aprox bolt face.
223 bolts can be in either small or large stem an be spring loaded or not .
bulgy 223 large stem spring loaded . Rmy 223 small stem not spring loaded .
it don't matter if the trunion is 22 or 23 mm the bolt an correct csarrier will work with it .
you need to choose a bolt by th e round yur wishing to build , a 9mm, 7,62x25 will use a ak 74/ 5.45 x39 bolt an carrier trunion.
in todays world a trunion is getting over a $100 an a bolt an carrier is another $150.
If EOD sells there blow back bolt carrier set ups still it might be worth just getting one of those . a blow back does not needa regular trunion with lugs. for $120 a trunion is now selling of rIt would be worth buying a block of stell in 1/14" an drilling a barrel bore in it an makint it from scratch if you have nay skills.
If prices keep going the way they are id thnk a a plow back ak kit from scratch would be very doable to sell.
if our doing a gas gun in a rifle calibure you need a bolt for that calibure . a 5.45 bilt can be made to work on a 223 case its a little big but they work.