Anyone own a 7mm 300 Win Mag?

[Broz]

Nate, I am in the final stages of my reamer design. I was wondering how much additional room you left for case growth as far as neck length? I am thinking of .030 ~ .050" and let the cases grow some of that extra compressed brass from necking down. My thoughts are this could reduce some of the donut from forming ?

What you say ?

Thanks

Jeff

 

[Kiwi Nate]

Hi Broz, yes, definitely.

Here are some specs:
Parent .300 Win mag design
Max case length 2.620"


7mm Practical
Max case length 2.657"

So I am .037 longer in the neck than the .300 (its actually a nice round figure in metric!)

Be sure to clean the chamber properly when cases are short to avoid carbon caking. This can happen with any over trimmed brass, culling loads are a classic example. If the chamber gets caked, the neck is unable to expand properly and pressures go up, resulting in fliers. Also happens with under powered loads that don't obturate properly. Rem .260 and 7mm08 factory ammo (pre-2001) is a classic example of underloaded ammo that caused carbon caking. A lot of guys sold off their rifles without ever having known that this was a cause of fliers. Easy to test, just pop a bullet in a once fired case, make sure it passes in and out of the case neck easily, you know, usual stuff.

 

[Broz]

Got it! Thanks man!

The new Hart blank was shipped today. Better get the reamer ordered.

Jeff gun)---------------------------------------------------------------------------------------------

 

[Nieko]

Broz and Nate,
I am waiting for my reamer for my 7-300 win, having it set up to shoot 180VLD's, I went with a 26 inch #3 Broughton, so hopefully we can see the rusults soon.

 

[Kiwi Nate]

Cool, its a great cartridge for sure. Will be interesting to see all of the results. We have had another three on the go here in NZ.

 

[Broz]

Broz and Nate,
I am waiting for my reamer for my 7-300 win, having it set up to shoot 180VLD's, I went with a 26 inch #3 Broughton, so hopefully we can see the rusults soon.

Great! In theory the Broughton should be faster than the 6 land Hart I used before but the last Hart was a 28 1/2 ". So please post your results. I am a huge Broughton fan and used one on my 300 win. But the last 7mm-300 I had was so darm accurate I had to try to reproduce it again.

Jeff

 

[zuba]

Broz, what kind of barrel life did you get from your old barrel? And what bullet and velocity were you getting? I've got a 30" 8.5 twist brux sitting around...

 

[Broz]

Broz, what kind of barrel life did you get from your old barrel? And what bullet and velocity were you getting? I've got a 30" 8.5 twist brux sitting around...

It has 700 plus and still driving tacks. We have not changed the seating depth either so I feel the throat is holding well.

We have seen 3200 but the program drops match well using 3175 for a MV with 180 Bergers and a G1 BC of .659.


Ordered the reamer this am.

Nate, did you usually use a no turn .316 neck? I ordered this reamer with .3155" neck.

Jeff

 

[tresmon]

I chambered mine today!

28" Mike Rock SS barrel.

7mm-300WM .313" tight neck throated for 189grn Cauterucio VLd's.

I'll get the scope on it monday and start breaking in the barrel...

 

[JARHEAD1371]

Don't forget the pics!!!

I chambered mine today!

28" Mike Rock SS barrel.

7mm-300WM .313" tight neck throated for 189grn Cauterucio VLd's.

I'll get the scope on it monday and start breaking in the barrel...

 

[Weaselthis]

We'll be looking for the pix & load data & Pix & goofy looking grins & pix......LOL
Congrats, TresMon!

I chambered mine today!

28" Mike Rock SS barrel.

7mm-300WM .313" tight neck throated for 189grn Cauterucio VLd's.

I'll get the scope on it monday and start breaking in the barrel...

 

[tresmon]

I'll say it before anybody else can chime in. Velocity is far SECONDARY to accuracy.

But just for fun:

I was creating my own reloading data for the custom cartridge because none exists.
That load was 79 grains of retumbo behind a 180 SMK.

7mm, 180 grain match king
7-mm-300WM ("7mm Win Mag")
30" Rock 8.9 twist
Savage 110

 

[JARHEAD1371]

I'll say it before anybody else can chime in. Velocity is far SECONDARY to accuracy.

But just for fun:

I was creating my own reloading data for the custom cartridge because none exists.
That load was 79 grains of retumbo behind a 180 SMK.

7mm, 180 grain match king
7-mm-300WM ("7mm Win Mag")
30" Rock 8.9 twist
Savage 110

How about the pics of the rifle and groups?

 

[SidTheKidd]

How about the pics of the rifle and groups?

Ill second that! Post um up!