I have been loading for a few years (since 1965) and have run into a problem with one rifle.
Since the beginning of this year I have bought three M700 Milspec 5R rifles which have proven to be exceptionally accurate with the loads I have developed for them. I have experimented with seating depth, but then again, must limit myself to ammo that will fit the magazine for hunting.
I have found that the Bergers perform at thier ultimate best in my .300 when loaded out to within .020 of the lands, so that has become my hunting load.
The rifle I am having a problem with, and the problem is getting consistently good groups is an older M700 BDL in .30-06 (standard thin hunting barrel). The rifle will accept ammo with bullets seated farther out than the recommended 3.340 in my manuals. As a matter of fact I had loaded some Nosler 165 gr. Accubonds out to 3.480 and they chamber well and operate thru the mag fine. That is right at .010 off the lands. But---I just can't get the tight groups I am looking for--3/4 MOA or less. It's more like 1 1/2 MOA at 100 yards.
I use primarily two sources Hornady and Lyman loading manuals and both have COL at 3.340. I sat down a while ago and loaded some test rounds using the 165 AccuB at a depth giving a COL of 3.345 and will shoot them Monday to see if there is an improvement in smaller group size.
Now, the rifle does shoot very good groups (1/2 to 3/4 MOA) with the Sierra Matchking 168 gr., (COL 3.340) but that's not a hunting bullet.
It appears that the rifle may like ammo more to standard specs than I have been loading. Do y'all think I may be headed back in the right direction.
For Tango's sake these measurements were not taken with a Lee tool, but with Hornady ss dial calipers.