Vertical stringer

[wallypedal]

I think I've read nearly everything in every forum discussing vertical stringing with Encores. I've got one barrel, a 7mm-08, that's got it bad.  It seems that for some this has been a somewhat common problem I have so far:

• pillar bedded one of the old Rynite forearms (not Prohunter). Got the screw holes too close maybe to the screw diameter. Opened them up some
• checked barrel to frame gap and adjusted case sizing to .001 to .002"
• trimmed all cases to minimum trim-to length
• have a properly fit hinge pin (barrel and frame)
• locking bolts are good fit in lug, stronger spring, good engagement with frame
• using durasight heavy alloy base and rings w/3-9x40 Leupold. Have not tried conversion to six screws or filler under the sight base front overhang - this may be the next experiment
• am getting what I think is excessive case stretch when firing, but have not found a good definition of an acceptable range. The loads according to the chronograph are at what most people achieve. Maybe it's a slow barrel and the loads too hot....
• have checked the PH buttstock for tightness, it is loctited down and doesn't look to be a problem. Other barrels shoot OK.
• the crown is fine, the throat is centered

Any suggestions?   One thing I keep wondering about is the advisability of having two screws holding the forend on. It seems like this introduces the possibility of variable stresses, especially as the barrel warms up. Also some stress potential if the forearm screw holes are not perfectly aligned with the threaded holes in the barrel.
Interested in any constructive suggestions or experiences..
Wallypedal
 

[wallypedal]

I went back to the range today after making some of the changes mentioned.

• all 2x fired brass, trimmed and carefully sized, checked for chamber protrusion
• cleaned both forearm screw holes in the barrel, and made sure the screws were not bottoming out
• opened up the screw holes in the forearm pillars, they were snug
• measured each cartridge for chamber protrusion before and after firing
• BACKED OFF two full grains from the load I was using, 49.0 gr. H414, 120 Nosler BT, CCI 250 primers, 2.775 COL. Loaded up 47.0, 47.5, and 48.0 instead.
• Everything grouped better, no fliers.  47.5 gr. was noticeably the best for 5 shots with lots of time between. Less than MOA for sure at 2985 fps. average.
• Significant to me was that protrusion after the shot was had grown about .004", max .005" with all loads. It was twice that or more with 49.0 grs. A certain amount is expected.

I know all the admonitions and wisdom from books and forums, but discovered it's still easy to deceive one's self. I think we all want both speed and accuracy, but there is a little voice that tells us we should be able to get to everyone else's max. And if that max velocity is around 3000 fps, we want that magic number too. I didn't think I was seeing "pressure signs" so I went for a load that consistently went 3000 or more. I had gone up to the point of diminishing returns and excess pressure for my rifle without realizing it. The 5 rounds at 48.0 averaged 3K anyway! One more grain wasn't giving me anything but trouble. I do believe the other changes I made contributed as well, but I'm really pleased with the 1.5 gr. less powder load. Need more groups to absolutely verify, but it went so well I'm pretty sure I'm on the right track!

[samh]

I have a 26 inch heavy 25/06 barrel on my Prohunter. The first centerfire barrel I've used on it. I also have a 25/06 Tikka T-3, that I've had for several years. I handload and the Tikka loves hot loads, right up to the edge of max is where it shoots best. When I started shooting the Prohunter I used a few of my Tikka loads, as I already had a bunch loaded up, 117 Ballistic tips with a max load of IMR 4350. The T/C would shoot the first one out of a cold barrel way high, then shoot a 3 shot group that was great right on POA as long as the barrel was warm. Not very good for a hunting rifle. I was needing some new brass anyway, so I picked up a couple of boxes of Hornaday 117 gr., SST, factory loads and the Prohunter loved'em. Shot several 3/4 inch, 3 shot groups at 100 yds with all going into the same place, hot or cold barrel. Just got done with the first week of modern gun deer season here and I got an 8 point the first morning at 100 yds and a 7 point at 250 yds the same afternoon with the Prohunter and the SST bullets. 
My guess is the break open action of an Encore just won't handle the pressure, that a locking action like a bolt action can, without flexing or giving in some way that effects accuracy.