270 WSM 165gr VLD load help

[270 Sender0]

Any of the cut rifle barrel manufactures should be able to cut what ever twist you want. At one time Mcgowen offered a buttoned rifle barrel in 1-9 but I haven't seen it as an option for a year or so.

The 1-10 at my elevation (5612, 40*) with the 165 Matrix has a Miller stability factor of 1.49 and in a 1-9 twist a factor of 1.84 and the 1-8 a 2.33.

The numbers you use for stability factor, 1-10 twist at 1.49, is the lower number better or the 1-8 twist at 2.33?

 

[bigngreen]

The 1-10 is on the edge of the slow end which seems to have some good points but I would be happier with a 1-9. According to what I'm getting, I'm barely stable but at 1-8 just into over stable range, what it totally means I'm still learning!

 

[AlexF]

The 1-10 is on the edge of the slow end which seems to have some good points but I would be happier with a 1-9. According to what I'm getting, I'm barely stable but at 1-8 just into over stable range, what it totally means I'm still learning!

Marshal Ambrose from Matrix Ballistics replied that 1-9 twist is the recommended twist for 165gr and 175gr 0.277 Hunting VLDs. The 165gr will stabilize in 1-10 twist under most conditions (sea level and temp over 40F) but the 175 will not.

Alex

 

[pitbull320]

well the good news is that the matrix bullets are shooting and as of the other day I can say that they work on game also I used a 175 out of my wife's Aps 270wsm on a big black bear at 862yrds and he folded right up unfortunately did not recover the bullet but there was a golf ball size exit so that tells me that they hold up on game

 

[elkaholic]

Sounds to me like they work......Rich

 

[bigngreen]

well the good news is that the matrix bullets are shooting and as of the other day I can say that they work on game also I used a 175 out of my wife's Aps 270wsm on a big black bear at 862yrds and he folded right up unfortunately did not recover the bullet but there was a golf ball size exit so that tells me that they hold up on game

Excellent!!!

 

[AlexF]

well the good news is that the matrix bullets are shooting and as of the other day I can say that they work on game also I used a 175 out of my wife's Aps 270wsm on a big black bear at 862yrds and he folded right up unfortunately did not recover the bullet but there was a golf ball size exit so that tells me that they hold up on game

Congradulations for you long range black bear!
What was the twist of the rifle used and what load did you use?

Alex

 

[pitbull320]

it is a 28" lilja 1-10 65gr of retumbo fed 210 at 2981 with an es of 12 I'm very happy with the results of the matrix bullets and yes I did say a 1-10 and the 165 and 175 shoot 3/4moa groups at 1000yrds I also shoot the 169.5 wildcats and they shoot just a little better

 

[bigngreen]

What BC's have you been using with the Matrix bullets, I've used .650 with the 165's and it seems close but haven't gotten them nailed down yet.

 

[AlexF]

What BC's have you been using with the Matrix bullets, I've used .650 with the 165's and it seems close but haven't gotten them nailed down yet.

You should use the bullet SD and look at a similar bullet which would be an hypotical 7mm 175 VLD or Matrix's 7mm 190gr VLD.

1. Looking at Berger 7mm (0.277") target bullets: 168 VLD is .316 G7 and 180 VLD is .337 G7 so the 0.277" 165 VLD can be estimated at .326 G7 (or .636 G1).
2. Another way to get an estimation is to use the same form factor as Matrix's 7mm 190 VLD (0.978) and divide the bullet SD (.307) by this number G7 BC = .307 / 0.978 = 0.313 G7 (or .613 G1).

I'm Canadian so for me Matrix has to be as good as Berger, therefore 165gr VLD BC is .326 G7 (or .636 G1)

One important note, VLD as G7 shaped bullets while standard spitzer are G1 or G8 shaped bullets. You'll get much better calculations if you use G7 bullet model and G7 coefficient to calculate external ballistics.

In any case, run out and get a copy of Brian Litz's (Berger Bullet's ballistician "Applied Ballistics for Long Range Shooting 2n Edition"

Alex

 

[270 Sender0]

it is a 28" lilja 1-10 65gr of retumbo fed 210 at 2981 with an es of 12 I'm very happy with the results of the matrix bullets and yes I did say a 1-10 and the 165 and 175 shoot 3/4moa groups at 1000yrds I also shoot the 169.5 wildcats and they shoot just a little better

What is your whole set up? I have a Rem. Sendero action with a 26" Douglas barrel 1-10 in 270 win. I'm hoping that I might get close to what your getting at 1k yards.... do you have a link for the 169.5 wildcats? I've been using 140 Accubonds and they have worked well.

 

[pitbull320]

bigngreen on the 175 I have been using .700 and my drops have been right on out to 1200yrds I haven't had a chance to do much with the 165 but it looks like at 3030fps they will be about .660 but I have only shot the 165 to 1k a few times but hoping now that my bear is out of the way I can do some more test

 

[pitbull320]

270 sendero it is a win m70 short action with a #4 28" lilja barrel with a pk brake and the full Kirby touch to it.The stock is a thumb hole laminate pillar bedded and that's about it other than it's a shooter just like all my APS rifles

 

[bigngreen]

bigngreen on the 175 I have been using .700 and my drops have been right on out to 1200yrds I haven't had a chance to do much with the 165 but it looks like at 3030fps they will be about .660 but I have only shot the 165 to 1k a few times but hoping now that my bear is out of the way I can do some more test

That's about what I was thinking, I've shot the 165's out to 1435 yrds and I was minute of rock with .650. When my barrel gets back I'll have to drag out my large wood frame and cardboard to get it any closer.