Odd question. Mak 90 is a version of the AK-47 rifle. 7.62 is the caliber of the round fired by the rifle (actually 7.62 x 39 mm). I suppose you could calculate the energy of the fired round in KSI (1000 psi).
100-400 USD
100-400 or so
300-600 USD
Check the auction sites. You give no description. Broad range 100-400.
400 USD or so
300 m or so
100-400 USD
100-400
1 in 9.45
300-800
300-800
Realistically, 400 and 200 respectively. In the current market add a couple of hundred on to the MAK and maybe 150 on the SKS