I have used 3 groove Lilja barrels with great results, they are as accurate a barrel as I have shot in my custom rifles
Only thing I will say is that in some of my 1-8 twist barrels in 22 and 6mm calibers, they seem to tear bullets apart in rounds like the 22-6mm AI or 6mm-284 when using the match type VLD bullets such as the Berger bullets and the A-Max bullets at less them top velocities.
The Sierra Mks handle more speed.
I have talked with many shooters who have fast twist small caliber rifles with big cases that shoot these bullets great at much hogher speeds then the 3 groove will.
The only difference inthese set ups is in teh number of rifling so I assume this effect bullet integrity to some degree.
If your going to built a fast twist, high velocity small bore rifle for use with the VLD bullets, I would go with a 5 groove or 6 groove barrel.
With stouter bullets they perform amazingly well but on the thin jacketed bullets they seem to tear bullets apart faster then a 6 groove.