300win mag 215 berger help

[bowkill02]

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

 

[brentc]

First thing I'd say, maybe I missed it, but before you give up on a proven combo, do a seating depth test. I have my best luck between .040" and .060" off the lands by my measurement with Berger hybrids. Your velocity swings are most likely due to the light conditions with your chrono. 2850-2900 fps is right where it needs to be. Some guys are pushing up past 2900 with 26" barrels, but that is the exception rather than the rule with heavy bullets in a WM.

 

[barefooter56]

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

Please contact us at [email protected] or call us at 714-441-7202 . The BERGER BULLET techs are on the phone from 8am to 4:30pm EASTERN time MON thru FRI . Calling may be better because issues like this in most cases are better discussed over the phone and not by email.

 

[bowkill02]

First thing I'd say, maybe I missed it, but before you give up on a proven combo, do a seating depth test. I have my best luck between .040" and .060" off the lands by my measurement with Berger hybrids. Your velocity swings are most likely due to the light conditions with your chrono. 2850-2900 fps is right where it needs to be. Some guys are pushing up past 2900 with 26" barrels, but that is the exception rather than the rule with heavy bullets in a WM.

thanks for the reply. I have tested seating depth out to 40thou but not beyond. are light conditions as critical with the magnetospeed??

 

[barefooter56]

thanks for the reply. I have tested seating depth out to 40thou but not beyond. are light conditions as critical with the magnetospeed??

The Magneto Speed works off the magnetic impulse of the bullet going over the sensor. Light conditions have no bearing on the velocity readings at all.

 

[bowkill02]

ok then if light is not playing a factor why such a swing in velocity, day to day? I must be missing something and its probly right under my nose
thanks for all the suggestions

 

[barefooter56]

ok then if light is not playing a factor why such a swing in velocity, day to day? I must be missing something and its probly right under my nose
thanks for all the suggestions

Are you starting your testing with a cold/clean barrel?

 

[bowkill02]

Are you starting your testing with a cold/clean barrel?

Cold, Yes. Clean, NO. I have exactly 42 rounds down the tube since last cleaning. I spoke with the smith that put the rifle together and he advised me not to clean so frequently. upuntil 42 rounds ago I was douching the tube after every range session, I was advised to let the barrel reach a copper/fouling equilibrium and it was suggested the rifle may shoot better with a fouled barrel

 

[barefooter56]

Cold, Yes. Clean, NO. I have exactly 42 rounds down the tube since last cleaning. I spoke with the smith that put the rifle together and he advised me not to clean so frequently. upuntil 42 rounds ago I was douching the tube after every range session, I was advised to let the barrel reach a copper/fouling equilibrium and it was suggested the rifle may shoot better with a fouled barrel

Even a cold /fouled barrel MAY need a few rounds down it before you start your testing. Personally I do not let the barrel get to "stone cold" between shots. I usually do all my test group one right after another , (BUT I do not chamber the round until my sights are back on the target between shots). Then let the rifle get to where I can touch the barrel and not burn my fingers before shooting the next test group. I usually use 3 shot groups for testing until I get to the chronograph stage after my load is worked up. Then I will go with 10 shot group to get a more accurate SD (standard deviation) number. How did your second test group "open up" ? Horizontal, vertical, angular?

 

[bowkill02]

the second group sighted high and to the right, which seems to be what I am running into each time. I just loaded up 5 @ 75.5gr and 5 @75.0gr and was thinking about headed out to see if my groups from this morning were a result of fatigue. im just satisfied with 3-5" groups at 300 yrds. also I think im going to leave to magneto speed off for this one and see if that maybe is affecting my harmonics. inconsistent readings from all my load testing is almost leading me to believe maybe the chrono aint to accurate. Good or bad when I get home tonight ill give her a good cleaning and touch base with you on my findings.
I just wasn't expecting to run into so much grief tryin to find a load that would produce moa or better considering all the quality components im working with. thank you and ill keep you updated.

 

[drbill]

The last load development on a 215 berger 300 win mag rem 700 was 74.5 h1000 0.010 off lands. 2891 fps. I use labradar on 400 yd ladder testing for general speeds. Finish load development. Then use magnetospeed last to finalize speed alone.

 

[bigngreen]

Take the mag speed of the barrel, they are awesome to get a velocity when you need it but right now you don't.

 

[brentc]

thanks for the reply. I have tested seating depth out to 40thou but not beyond. are light conditions as critical with the magnetospeed??

No. The light conditions are not critical with the Magnetospeed. For some reason I had an image of you shooting across a Prochrono or something of the sort.

Bigngreen is correct. The magnetospeed is great for obtaining a velocity once the load is developed, but for precision shooting or zeroing, take the Magnetospeed off because it will cause fliers and POI shift.

 

[bowkill02]

ok, well i'm back from the range. and you guys are correct about the magneto, it does in fact change point of impact. I set back up at 300 yards with a 5 shot group of 75/75.5gr h-1000. the mirage was kinda bad but I did manage a 3.65" group with the 75.5gr load. the first 3 shots were under 2.75" and the las 2 dropped low opening up the group, coulda been the mirage. the 75.0gr load grouped a touch over 4". I think I would be satisfied with consistent .75moa group but I would still like to see better. any advise for tightening that up?
I'll load a few more and see how they do at 500yrd in a few days and keep my progress posted
thanks all for you imput