.300WM load development

[rjlust]

Hello,
I'm new to reloading. I have a model 70 .300WM
I'm currently developing a load for my rifle with the following components:
WW Brass
215 Fed primer's
175 Berger VLD targets
Vihtavuori N160

I started by doing 3 rounds @ 72gr and worked my way up 3 at a time in increments of .5gr
Seating my bullets 50 thou off the lands
This gives me a COAL of 3.545 so I will have to hand load each round. I'm going for precision so hand loading one at a time does not bother me IF it pays off.

Once I see the groupings created.
I will take the best and work from .4gr on the low side to .4 on the high to fine tune the load.

If anyone with experience reloading knows of a better way, or has developed similar loads, I would really appreciate your input.

Thank you.

 

[Hoag]

Welcome to CGN. I'm not sure if you knew, but there is a whole section that is specifically dedicated to reloading. Perhaps you might have better luck with this if you posted it in the Reloading section of CGN.

 

[rjlust]

I did not realize that. I'm still getting used to the forum.
Thank you for moving the thread.

 

[elkhuntr]

Some good items to consider when reloading your WM
Be sure to not oversize brass. Trial and error to adjust die so that fired brass still has some feel upon closing the bolt. Oversizing brass will make those cases last much shorter than expected (read up on case head separation).
Be sure that the seating process feels smooth. ensure you chamfer the case mouth.
Be sure to measure using a good balance beam or electronic scale. 0.5 grains should be fine with this size of case as +/- 0.5 is only a 1% change in charge. not enough to notice.
Once you have a good node (tight group) then move out to 200m and try +/- 0.3 on either side of the favoured charge.
Play in the lower node. I found this within a grain from book max on several rifles in the WMs I have loaded for. The WM does not like to be lower charged. And you will find one near practical max. This will be enticing but it comes at a cost of increased pressure, potential variability and lower brass life.
50-60 thou is a good starting point, you can fine tune using touch, 10, 30 and 50 later on to see if any improvements can be gained with the best charge.
In that order I would suggest .....oops my Yoda moment....
Elky...

 

[rjlust]

Some good items to consider when reloading your WM
Be sure to not oversize brass. Trial and error to adjust die so that fired brass still has some feel upon closing the bolt. Oversizing brass will make those cases last much shorter than expected (read up on case head separation).

This is something I did not check as the die I have resizes neck and case and punches primer. The info I found on head separation was very informative.
I used my callipers to check the neck and it is 2 thou short of chamber size.

Be sure that the seating process feels smooth. ensure you chamfer the case mouth.
Be sure to measure using a good balance beam or electronic scale. 0.5 grains should be fine with this size of case as +/- 0.5 is only a 1% change in charge. not enough to notice.
Once you have a good node (tight group) then move out to 200m and try +/- 0.3 on either side of the favoured charge.
Play in the lower node. I found this within a grain from book max on several rifles in the WMs I have loaded for. The WM does not like to be lower charged. And you will find one near practical max. This will be enticing but it comes at a cost of increased pressure, potential variability and lower brass life.

This is very good info ty. I did not think I would need to go close to max load for a good node. So my loads only went up to 74.5 and max is 76.8 so I will be loading up another 12 rounds.

50-60 thou is a good starting point, you can fine tune using touch, 10, 30 and 50 later on to see if any improvements can be gained with the best charge.
In that order I would suggest .....oops my Yoda moment....
Elky...

Thank you for the useful info Elky,
RJ