Would it be ok to fire the 570grains Barnes X bullets in my 500A2?

(Bullets are .509", perhaps in order to reduce pressure?
Could one expect satisfactory precision whith this round?)

It will work perfectly. It is quite normal that bullets (especially monolitics) are a litle bit undersized. Gerard Schultz from GS Custom told me that the monoliticbullets will expand a little because of the pressure. I orderes bullets for my 577 (.585" bore) and they measured .582".. I was worried aboyt this and contacted Gerard. He told me that a 15 mm coppercylinger will expand 5-7 microns all depending on the pressure beeing in the range 40-60000 psi

yep... perfect

jeffe

I have also used them in my A2 and they work just fine.