300wsm

[Laurie]

PT&G lists its standard reamer as 0.345-inch neck diameter. That's around 7 thou' overall clearance (0.0035" at any given point on the neck circumference) assuming that Norma WSM brass has 15 thou' thickness neck walls. (I don't actually know what it is, but that is a fairly common thickness on 30 cal cases, but it can vary significantly according to make, Winchester often thinner than others.)

7 thou' is more than most people want to run, and it becomes 8 to 9 if a bit of 'clean-up' neck turning is done. 3 to 4 is what people run with.

So, assuming 15 thou' thick necks, you get 0.308 + 0.015 + 0.015 + 0.003 = 0.341" neck for 'a no-turn brass chamber' and reduce that by 0.001" for a very mild neck 'clean-up', or by 0.002" for a turn down to 0.014" neck walls.

Very heavy neck turns as used in small BR cartridges like the PPCs taking the necks down to 0.0085" and similar aren't used in F-Class with these large cartridges, and a 0.001-0.002" extra overall clearance is the norm compared to short-range BR.

However, the trick is to speak to someone who shoots the beast successfully in competition, or a rifle builder who has built one that works - it's much easier to be told the spec you need rather than trying to reinvent the wheel. For many cartridges, the Accurate Shooter website's cartridge sections and/or 'Guns of the Week' has a great deal of accumulated hard experience on offer with very good advice on this sort of thing from those who've been there and earned the T shirt the hard way. But not for the 300WSM I believe as it really isn't that popular a competition cartridge. Unlike here, the 7WSM isn't that popular in North American F-Class, the 284 / Shehane or Remington SAUM seen as preferable, same 'Down Under'. This may be linked to the much higher summer temperatures seen there causing various problems with the WSMs' charge sizes, barrel heating etc. Certainly, only the GB team used WSMs in the last F Class World Championships in Raton in 2013.

[The Gun Pimp]

Just had another thought.would you have a tight neck on the 300wsm for f class.

No - not needed.

[Berger]

Wow laurie you are a wealth of knowledge.thanks for your in depth reply.atb Berger

[Berger]

Would the 300wsm with 230gr hybrids running flat out out perform a 338 lap mag with say 250gr scenars.this 300wsm seems a bit special with an acquired taste.

[The Gun Pimp]

What's your discipline? What ranges?

[Berger]

What's your discipline? What ranges?

practical rifle.200yds to 1000yds

[The Gun Pimp]

300WSM for Practical rifle? You are joking......?

[Berger]

Shooting is ment to be fun GP.some try to shoot a 223 at 1000yds and some use a 338 lapua magnum or bigger for deer and fox control.both not really suitable for the application but it's what you want and like.variety is the spice of life.have you ever been a hunter GP.just a curiosity question.?

[The Gun Pimp]

No Berger, I've never killed anything for fun. I just spend a lot of time and a bit of money making small holes in paper at extreme ranges - usually with small weird calibres.

[Berger]

Yes I know GP.you are going to have to shoot an extremely small group at 1000yds to get your record back from Mr Lenton.killing things for fun doesn't sound good GP.i tend to say culling.managing or controlling.