Thanks everyone, in the middle of house painting hence the late reply (trust me I'd prefer to be at the range!). Now to answer some of the comments before the next coat. The rifle is 6 years old and has less than 500 rounds through it. I mainly hunt pigs, goats, foxes, roos (tagged of course) and long range bunnies but do very little range shooting. The type of projectiles I've tried so far with mixed results - Speer 55gn HPBT - Nosler 55gn ballistic tip - Hornady 55 & 60gn VMAX - Sierra 55gn SP, 60gn HP. Factory loads tested - Winchester 55gn SP (absolutely useless) - Sako 50&55gn gamehead (sprayed every where). Outback Ammo 69gn Matchking. The Outback Ammo has been the most successful for accuracy but at $35 a box from local store can be very expensive plus no good for hunting.
I thought the accuracy might have been me so got a friend to test it with same results. I did have success with Nolser ballistic tip 55gn using 24.5gn 2206h with .5moa at 100m but at 200m started to spray out to 4" random groups.
Wm.Traynor: magazine can only take rounds no more than 57.8. The scope is a Leupold VX1 and I've checked mounts seating etc. The property owner on my last shoot suggested trying another scope as he had issues with the Leupold. I'm going to put my old Tasco on and test that.
bladeracer: "Have you tried the 69-77gn bullets?" No, with these projectiles are they seated the same lenght as a 55gn projectile, this is were I'm getting confused about the overall case length for the larger projectiles, plus not sure if they fit in my magazines.
BRNO_Bigot: "If NONE of them give you any joy, maybe having the rifle looked at by a decent gunsmith will help - bedding, scope mounts, crown etc, etc ..." Problem in Canberra is finding a decent gunsmith, last one I went to ruined my previous .223.
Rikta: "My go to load was 69gr Noslers over 23.2gr of BM2 for consistent .5 Moa groups with some around .3 Moa for 5 shots. Do you seat these the same as a 55gn pill, what is the overall case lenght?
Thanks again all, I really appreciate the advice. Now back to the bloody painting!