what is your outside neck diameter 300 WM

[bob4]

Have decided to buy Forster dies for my 300 WM. Their bushings they send with the bushing bump/neck die kit are [SIZE=-1] .334", .332", .330" diameter. I am consistently measuring .340-.339 on a loaded cartridge with Hornady brass and Bergers 175 VLD in them. Do others get this measurement with a 300 WM? I'm thinking, with my limited knowledge, those bushings are smaller than I'd want and need to order separately. . , .338, .337 .376 ?
[/SIZE]

 

[Jaxdialation]

The Forster bushings ARE too small. You are correct. Don't worry about what measures others get. I suggest you order a .338" which is .001 to .002" smaller than your loaded cartridge measure.

Have decided to buy Forster dies for my 300 WM. Their bushings they send with the bushing bump/neck die kit are [SIZE=-1] .334", .332", .330" diameter. I am consistently measuring .340-.339 on a loaded cartridge with Hornady brass and Bergers 175 VLD in them. Do others get this measurement with a 300 WM? I'm thinking, with my limited knowledge, those bushings are smaller than I'd want and need to order separately. . , .338, .337 .376 ?
[/SIZE]

 

[Broz]

With Redding Comp bushing dies, and a variety of brass, Lapua, RWS, WW, RP, Bertram and some others, loaded rounds are from .333" to .335" My most commonly used bushings are .331" and .332"

Jeff

 

[el matador]

I use Norma brass, .333" bushing and .335" with loaded ammo. I use neck lube when seating and it works great.

Do you have consistent wall thickness around the necks?

 

[bob4]

Thanks all.

Do you have consistent wall thickness around the necks?

I've never checked.
I'll double check those loaded rounds one more time then order -.001 -.002 smaller.

 

[bob4]

Well I hope the only dumb question is the one never asked.
Am I supposed to measure the very top of the neck? That certainly measured different but consistent.

 

[el matador]

I like .002" smaller, for a couple of reasons. The brass is going to spring back a little bit after coming out of the die, so right there you lose .0002-.0005". Then after a few firings your brass will get slightly thinner as the case stretches and gets trimmed. All that can add up and leave you with near zero neck tension if you're using .001" smaller.

I've never tried Hornady brass, but I had some Winchester brass with fairly thick necks one time. After measuring it I noticed up to .002" of variation from the thinnest to the thickest areas. If your brass is that far out it would be best to neck turn everything for a nice concentric, consistent lot of brass that will work great with the bushing dies. If it's concentric already then get the right bushing and go to town.

 

[DocB]

Hey fellas, just tagging in for the education! Thanks, carry on!

DocB

 

[FEENIX]

Hey fellas, just tagging in for the education! Thanks, carry on!

DocB

+1! I always try to make room, it never hurts ... and best of all, it's free!

 

[el matador]

[SIZE=-1]I am consistently measuring .340-.339 on a loaded cartridge[/SIZE]

Depending on your chamber this might not be good. My 300 WMs are measuring .340-.341" on fired brass. SAAMI min chamber dimension is .3407". So if you have a SAAMI min chamber and ammo that's .340" at the neck you've got less than .001" clearance in there. That could create pressure problems. Hopefully you have a piece of fired brass you can measure and hopefully you are a little over SAAMI min. .002 to .005" clearance is ideal. Most factory rifles will be over the SAAMI min by several thousandths and you'll be fine. Higher end or custom guns will often be very close to the minimum chamber dimensions. If your fired cases are less than .342 at the top of the neck I would turn them down for sure.

 

[DocB]

+1! I always try to make room, it never hurts ... and best of all, it's free!

I like free!!

DocB