So I guess I need some help. I've been trying to work a load for 215 bergers and thing just aren't going my way. I keep getting sporadic results in velocity and accuracy. Im using win brass fed 215 mag primers, h-1000 and of coarse berger 215's. I have turned all my necks to about 80%, I've payed close attention to all my case prep, and im still stumped.
I've worked from 71.0gr to 77.5gr as that is where I started to show signs of pressure. 75.0 and 75.5gr showed the best results with velocity in the 2850-2880fps range. im using a magnitospeed chrony. I've worked from touching the lands to 40thou off the lands in 10thou increments.
Just yesterday I went to the range with several loads ready to test and I found that 75.5gr produced and sd of 4 and an es of 9 with a group of 2.5" at 200 yards and average vel of 2877. 75.0gr produce an sd/es of 10/20 with a group of 1.5" and average vel of 2853. So I ran home and thought I would load up some more 75.5gr and see if I could repeat the low sd/es. well this morning I returned to the range and thought I would see what my 100/300 yard groups would look like. keep in mind all charges were hand trickled to exact amounts, my velocities this morning jumped to an average of 2897 and my sd/es jumped with it. accuracy was right at 1.5" at 100 but accuracy was all over the paper at 300. my weather conditions were almost identical as yesterday. I have had this problem everytime I I try to reconfirm a load with this rifle/powder/bullet/primer combo. Am I doing something wrong? 20fps seems a lot from day to day.
All components are same lot #. Barrel is a 26" Brux #4 with a 1-10" twist mounted to a trued 700 action sitting in an HS precision bedded stock.
Something I do when testing during the summer months is I keep my loads on ice so the powder doesn't heat up as the sun hits it in hopes of consistent powder temps. I am just not finding consistent accuracy and or spreds. Should I consider trying another powder/bullet combo or could it be something else. All loads have been worked on half grain increments so sould I start splitting the difference in weight which by the way I have never really done.
My scope is a vortex viper in tps rings that are lapped on a tps 20mos rail that is bedded to the action.
if I missed anything let me know and ill provide all info I have in hopes of getting to the bottom of this problem. if anyone has similar experiences or advise i'd love to hear about it, i'm getting ready to pull my hair out
thanks
I'm also using the 215gr Berger Hybrid for F-Class Open.
I find that it likes a bit of jump, say .080" in my particular chamber. In fact, it is pretty stable and unaffected by seating depths ranging from .060"-.100".
The only issue in my rifle is that ES goes up as the bullet gets closer to the rifling, the reason is unknown to me, but this is typical with this barrel. It has 803 rounds down and still produces 3/8MoA.
Have you considered doing a .3gr ladder test?
Find your tightest group, then play with powder charge in .3gr increments for 2 loads above and below this level.
At 300yrds/metres shoot each weight at one aiming point. What you want to see is clusters grouping at the same level, loads outside of this are out of the node.
I then confirm the chosen load @ 600 metres, in my instance only, to be sure that the load is stable.
What this is doing is finding a node that is wide and unaffected by charge variation/seating depth sensitive/barometric conditions.
Your problem may be from a barometric condition rather than a temp condition.
I would also try seating further out than what you have it now.
Let us know how you get on.
Cheers.
