300 win mag

[ntrngr]

When i fall, i fall hard. A year ago i had no 300 wm, now i have 3. In every bottle necked rifle cartridge i have ever loaded, you either have to FL the casings or only neck size but keep the casings sorted for each rifle.

The 300 win mag seems to defy this. The fired casing from each rifle will chamber properly in the other two. Am I crazy? ...or just lucky. Someone give me a clue. My current theory is that the guns are so close dimensionally and since the 300wm headspaces on the band an not the shoulder, different guns are less relevant.

Opinions, please.

 

[patience0830]

When i fall, i fall hard. A year ago i had no 300 wm, now i have 3. In every bottle necked rifle cartridge i have ever loaded, you either have to FL the casings or only neck size but keep the casings sorted for each rifle.

The 300 win mag seems to defy this. The fired casing from each rifle will chamber properly in the other two. Am I crazy? ...or just lucky. Someone give me a clue. My current theory is that the guns are so close dimensionally and since the 300wm headspaces on the band an not the shoulder, different guns are less relevant.

Opinions, please.

Sounds like chambers are almost alike and the headspacing on the belt has a lot to do with it.

 

[drm-hp]

Ignore the belt!
Treat it like any other bottle neck cartridge and the brass will last alot longer. Check the dimensions for each rifle as you would normally, and act accordingly. In an off the shelf rifle the belt dimensions are almost universally cut deep to being obscenely deep.

 

[billybob44]

HA.HA..I'm just getting into .300 Win. Mag. loading myself..
Keep up the information..Bill.

 

[ntrngr]

More data. Just like ever other loading book, it appears that the pressure on the "never exceed" charge is nothing but pure BS. I know pressure when I see it and the never exceed charge doesn't show excessive pressure. In fact, its nearly 5% below anywhere near the REAL never exceed charge. I suppose these never exceed charges are for people that don't know how to run a micrometer and a magnifying glass. Jeez... On my own again.

Currently loading 73gr of 4831 behind a 180gr soft point.

I bought a couple hundred 130gr Speer soft points. I'll be loading them next. Target date: Thanksgiving.

I love 4831. I hope the case will hold enough to give me good pressure with the 130 grainers.

 

[ntrngr]

I started at 77gr. Primer flat but not formed to the outside of the primer pocket, no cratering. Pressure guess: 45,000. 78gr, closer forming to the outside of the primer pocket and a partial start of cratering. Very close to 50,000. It varies with primers, of course, but these are Winchesters, so the cup is about average. I've got 79gr and 80gr ready to go but I don't shoot after 9pm. Neighbors are 1400ft away and, well, they think I'm making bombs back here the way it echos down the hollers. When I get done with the series, I'll show pictures. I'll mic them all to see if we're growing, but, with a banded case, I'm doubting we're getting any of that at these pressures.

 

[natdscott]

Dunno, but when you rebarrel, have them set it up so it headspaces off the shoulder, not the belt.

 

[ntrngr]

I ended up at 81gr of 4831 using the 130gr bullets. I had a distinct crater ring. No need to push it. I stopped there and loaded 40 of them.

 

[ntrngr]

I had a bunch of IMR4320. Two full pounds. One was still the original factory seal. The other had been opened but had a sealing metal lid screw on cap.

I calculated the starting charge at 60gr behind the 130gr bullet. This was a bit difficult because the powder in my Lee loading manual that were faster and slower were ball powders. They are much denser.

I stepped up 2gr at a time and ended up at 74gr before I got the pressure signals what I was near the top. Understand that it is cool, so, on a hot day in Indiana the 74gr charge will be plenty.

 

[ntrngr]

HA.HA..I'm just getting into .300 Win. Mag. loading myself..
Keep up the information..Bill.

All I can say is its *BIG*! I think 30-06 is probably the biggest cartridge I've loaded, ever. Not done any magnums. These things feel huge! But, all is working well.

 

[Gufnstuf]

Nosler had an article stating that the .300 win mag does not headspace off of the belt. It is just a remnant of the parent cartridge.

Sent from my iPhone using Tapatalk

 

[billybob44]

All I can say is its *BIG*! I think 30-06 is probably the biggest cartridge I've loaded, ever. Not done any magnums. These things feel huge! But, all is working well.

Same here for me, other than if you figure in the 45-70Govt.
I also did some "Cut Down the Brass" loads for that back in the day of making some Short Brass Deer loads.

Keep your load info coming..How about some 168Gr. and 180Gr. loads??..Bill.

 

[DadSmith]

Another nice thing about 300 WM is you can load it at 308 Winchester velocity if you want a lighter load.
When I say that I'm taking about what would be considered maximum for a 308-win with powders like Varget.

I had a Savage 110 Tactical years ago.
It like 220gr Winchester Silver Tips.
It shot sub MOA out to 300yds.
It just loved that ammunition.