Rifle only liking overpressure loads

[627PCFan]

After months of testing (and ongoing threads here) Ive come to the conclusion that my ER Shaw Barrel 6.5x55 on my Savage 110 only shoots sub-moa groups at overpressure loads. Ive tried Sierra's, Bergers and Nosler CC's and 4 different types of powders and am tearing up brass left and right. Aside from tossing the barrel aside is there anything I can do to tune it? Its a full bull barrel but thought about having it turned down to a sporter contour in hopes it changes the harmonics, but Ill loose the heat disappation. Ideas?

 

[Zak Smith]

I would recommend double checking the headspace.

If you want to tune the barrel, try threading the muzzle and using a different muzzle device: brake, or weighted "thread protector."

 

[Float Pilot]

1. Check head-space.
2. How long is your throat?
3. Have you run a lead slug through the bore and miked the results?
4. Is your barrel properly free-floated?
5. How is your action bedded?
6. What brand of brass are you using?
7. How is the muzzle crown?

 

[627PCFan]

1. within spec according to a PTG Gauge(i have it set tight though)
2. Haven t measured the throat but asked ER to set it long so I could use more case capacity.
3. No lead through it. According to lore, that's only effective in muzzle loaders, not new manufactured barrels??????
4. Fully Free floated from the action forward (including the barrel nut)
5. Standard Savage 110 bedding
6. I was Win, now Laupa, same results.
7. How is the muzzle crown? 15 degree, and flawless, no problems there.

 

[Zak Smith]

Can you post a picture of the fired cases?