I was reading about an action pillar that was used on the older BRNO rifles. It
seems the pillar also fits "modern" 452s. It fits the 452s that use a center action screw between the mag well and the sear. I has a notch ground in one end to clear the sear, and goes thru the stock to create a "post the action sits on and is solid between the trigger guard and the action. It is available from Denny, AKA brnoman, on rimfire central. I don't have his email anymore as my computer crashed and wiped out my contacts!
LOL! anyway the bottom line is I have the special mounted in a varmint stock and I shoot at targets that are 7/8ths of an inch around and at 50 yards if I'm 3/8ths off, I
wasn't doing my part! It has made the rifle that much more consistent!