I think you can make one out of a stripper clip.AK Handguard, Lower Tension Spring *NOS*
AK Handguard, Lower Tension Spring, in *NEW OLD STOCK* condition. Sold Individually.This spring fits in the front of the handguard and applies pressure against the lower handguard retainer plate resulting in a nice tight fit.This will fit most models and calibers of stamped and milled receiver...www.apexgunparts.com
OOS, but now you know what to look for.
Field fix.