I originally started all of this with a factory gun; only having mounted optics. After shooting the Powershok with not-so-great results (but still fortunately harvesting an elk), I reached out to Grayboe and ordered an adjustable Terrain stock for it. I did drop it straight in and didn't do any bedding, per Grayboe's recommendations. I did a simple "dollar bill" test, running it up under the barrel up to the action with zero interference issues. Torqued to spec using my Wheeler torque driver. Same results on paper without improvement. I haven't made my way into investigating the chamber yet, as I'm personally not fit with the right tools (or knowledge) of how to properly inspect the throat.
After ditching the Federal ammo, I started load development with the Hornady GMX using RL-17 and H4350. Ran velocities between 2,600-2,800 fps looking for nodes and found nothing acceptable. That's when I finally ditched the GMX and have since moved on to the Barnes TTSX. While not hopeful, this will be the final straw of development before contacting Bergara, or just seeking out a re-barrel. Unless of course anyone can point me in a direction to self-rectify the issue that I haven't already investigated.
I hope to not offend by a thread hijacking.
Ok at the risk of being dragged out and hung. I'll place some facts in this post. I have 5 custom hunting rifles, a new AR15 in 6MM ARC, a 450 Marlin bolt gun built by Mike Burris on a Mauser action with a shilen air guage barrel, a Howa 1500 in 223 with some tweaking, a 6MM Remington on a 700 action, (I can't remember the smyth) and a 358 Norma Magnum completely built on a Remington 03 action by Harry McGowan.
The 6MM Remington, the 358 Norma Magnum and the 450 all have pressure points on the barrels.
The 450 is a dangerous game rifle but at 50 yards with 500 grain bulletts at 2,000 FPS prints pretty much 1 ragged hole until I'm no longer able to hold it.
The 358 and 6MM Remington run around 1 1/16" at 300 yards with top pressure loads. A 250 grain Hornady at 3,200 FPS and a 75 grain VMAX at 3,900 FPS respectively.
All the other custom rifles have floated barrels.
I was recently working on 2 rifles in 30-06 and 1 in 6.5x55. They were shooting all over the place, 4" at 100 yards, damn near off the paper at 300 yards.
The one 06 is a Remington Pattern 17 over 100 years old, the stock was binding, I fixed that with a bit of improvement.
The other 06 is a 43 Smith Carona 03A3, again some stock binding, I fixed that with some improvement.
The 1944 6.5x55 had a synthetic stock that was a bad fit and of course the stepped barrel. I touched up the stock with a little improvement.
Now I write something then run, hide, duck and cover.
I applied a pressure point to the end of each rifles forearm. Now all 3 rifles shoot 3 1/2" at 300 yards and sometimes a bit better with fairly stiff loads.