I'm working up a load using 162gr bullets, starline brass, CCI BR primers and AA 4064 in my 7mm-08 with a 22", 1:9.5 twist barrel.
The gun itself has proven to be able to shoot the 120gr ballistic tip bullets consistently at or under .75" but I personally want a heavier bullet for my style of hunting. It doesn't like any loading that I've tried in the 140gr range and haven't been able to get ahold of anything in the 150gr range.
Ok so now here's my issues. Using 3 shot groups I've been able to isolate an apparent accuracy node between 38.5gr and 39.5gr based on group location (POI). I then picked a middle charge weight of 39gr and started adjusting seating depth. I was already as close as I want to be to the lands with a .010" jump so I started working back with 3 shot groups. .025 seemed to do ok but .020" and .030" strung vertical with about 1.5-2" groups. .070"-.085 jump all had the same POI with just a shade over 1" of vertical stringing. Once again pick the middle of this node at .080" jump and carefully load 20 rounds.
Now at the range I intend to run 4, 5 shot groups to verify this load before loading a few hundred. What I found is usually 3 shots would land right around .5"-.6" and 2 of them would string vertical some as much as 2" always high and it isn't consistent, as in it isn't the 1st 3 are good then the last 2 are flyers so not caused by a hot barrel. I know this would usually indicate velocity changes but this isn't reflected through my chrono. I'm getting 2647fps average, 11fps SD and 18fps ES over the 20 shots.
This is the same method I've used for years to get good quality loads with multiple component combinations for every rifle I have. For whatever reason this is different. At this point I'm personally thinking it has something to do with the added recoil on the plastic stock but I'm not sure. It's just a factory savage 110 that I've relieved some of the stock from to prevent barrel contact.
The gun itself has proven to be able to shoot the 120gr ballistic tip bullets consistently at or under .75" but I personally want a heavier bullet for my style of hunting. It doesn't like any loading that I've tried in the 140gr range and haven't been able to get ahold of anything in the 150gr range.
Ok so now here's my issues. Using 3 shot groups I've been able to isolate an apparent accuracy node between 38.5gr and 39.5gr based on group location (POI). I then picked a middle charge weight of 39gr and started adjusting seating depth. I was already as close as I want to be to the lands with a .010" jump so I started working back with 3 shot groups. .025 seemed to do ok but .020" and .030" strung vertical with about 1.5-2" groups. .070"-.085 jump all had the same POI with just a shade over 1" of vertical stringing. Once again pick the middle of this node at .080" jump and carefully load 20 rounds.
Now at the range I intend to run 4, 5 shot groups to verify this load before loading a few hundred. What I found is usually 3 shots would land right around .5"-.6" and 2 of them would string vertical some as much as 2" always high and it isn't consistent, as in it isn't the 1st 3 are good then the last 2 are flyers so not caused by a hot barrel. I know this would usually indicate velocity changes but this isn't reflected through my chrono. I'm getting 2647fps average, 11fps SD and 18fps ES over the 20 shots.
This is the same method I've used for years to get good quality loads with multiple component combinations for every rifle I have. For whatever reason this is different. At this point I'm personally thinking it has something to do with the added recoil on the plastic stock but I'm not sure. It's just a factory savage 110 that I've relieved some of the stock from to prevent barrel contact.
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