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Forum Index > Precision long range hunting and shooting > 300 win mag load development - Part 2

300 win mag load development - Part 2

15 Nov 2016
@ 12:50 am (GMT)

Mike Kush

I've finished the preliminary load testing for my rifle (half grain increments)

Remington Sendero - 300 win mag
Bullet - Hornady 208grain Amax
Brass - Winchester
Primer - Federal215 (Large magnum)
Powder - Hodgdon H1000


Session 1
Group 1 - 2 foulers

Gr (cc) V1 V2 V3 Group MOA
72 5.13 2624 2594 2
72.5 5.17 2565 2546 3
73 5.20 2639 2638 4 *
73.5 5.24 2638 2642 2647 5 *.9moa
74 5.28 2649 2686 2670 6
74.5 5.31 2682 2656 2674 7
75 5.35 2669 2669 2597 8




Session 2
Group 1 - 2 foulers
Gr (cc) V1 V2 V3 Group MOA
75.5 5.38 2856 2874 2840 2
76 5.42 2907 2886 2884 3 **.6moa
76.5 5.45 2957 2914 2918 4 *
77 5.49 2933 2952 2953 5




I starred the groups from each session I though were most promising areas based on Velocity and Grouping (gave vertical distance more importance).

What recommendations would you have to start next step?
.1 grains from 76gr?

Appreciate the help.

Replies

1
15 Nov 2016
@ 12:51 am (GMT)

Mike Kush

Re: 300 win mag load development - Part 2
Sorry, the spacing I set up for the data did not stay after posted, so it's crowded
15 Nov 2016
@ 01:54 am (GMT)

Paul Leverman

Re: 300 win mag load development - Part 2
There are a lot of people here who know way more than I do, so if their opinions differ, listen to them first.

My thought would be to stick with group 2-3, and see if you can figure out how to lower your ES. I am new to this, so not sure if this will change the group size or not. Do you crimp your bullets? That is supposed to even out your ES somewhat.

Whatever you do, change one thing at a time. See if it works. If not, go back to initial and change something else. If you change all sorts of things, you will never know what changed what.
15 Nov 2016
@ 02:15 am (GMT)

mark whiteley

Re: 300 win mag load development - Part 2
Hi Mike,
you have to love the 300wm,
increments of .1gr are to small for the 300wm,
I would maybe look further into your 2/3 group and try a seating depth trial I'm sorry but there isn't enough info for me to say more,
cheers mark
15 Nov 2016
@ 03:14 am (GMT)

Martin Taylor

Re: 300 win mag load development - Part 2
I'd be looking around/between 3 & 4 (76-76.5) with .2-.3 grain increments. Shot 1 in group 4 is a pulled trigger, blowing that group out.

As Mark said .1 generally won't change much in a big case. Keep the chamber nice and cool to keep consistency in and between your sets.

One tip l will offer, don't land your groups on the aim point. Land them 2-3 inches high so it leaves you to concentrate on the shoot not the developing group.
15 Nov 2016
@ 08:39 pm (GMT)

Ben Law

Re: 300 win mag load development - Part 2
Hey mike, be good to run your loads over a concentricity gauge if u havent already, could be chasing your tail a bit if there out, if theyre all good then you can concentrate on further development and technique.
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