6 WSSM questions- Neck Diameter

[ab_bentley]

Have a customer that wants a 243 Wssm, no issues with it other than the neck diameter. .304" neck diameter isn't going to cut it. So my next question is, what diameter is the correct one? I'm going to cut it .274" if no one has a better option.

 

[Catfish]

One big problem for him will be getting brass or ammo. I have been looking for brass for the last couple of years and found none, I gave up on the build.

 

[ab_bentley]

One big problem for him will be getting brass or ammo. I have been looking for brass for the last couple of years and found none, I gave up on the build.

So this guy currently has a 223wssm along with a few hundred pieces of brass. I've explained the pitfalls, but here we are.

 

[Phil]

Adam,

Tell him to neck that .223 WSSM brass to .20 and add the Ackley shoulder..........


Phil.

 

[mikecr]

Seat a bullet and measure neck diameter. You've done this before, right?
.274 will not even come close for WSSM brass -unless he turns for this.

 

[Zero333]

One big problem for him will be getting brass or ammo. I have been looking for brass for the last couple of years and found none, I gave up on the build.

Not to get your hopes up, I'm saying it right off the bat... I'm in CANADA.... but...
My local gun shop has a several bags of 243wssm brass... I've seen it there for the last 4 years !!! no one wants to buy it.

Life is not fair.

 

[lbran]

tell him to go with a 6x284, much better option! same velocity.

 

[ab_bentley]

Seat a bullet and measure neck diameter. You've done this before, right?
.274 will not even come close for WSSM brass -unless he turns for this.

Mike, done this song and dance a few hundred times. The main reason I'm asking is the original neck diameter is near .304" for a 6mm. Meaning the the neck walls are .030" or near it, which isn't going to work. One guy i know had one in a full custom and he said to turn the necks, but didn't mention the diameter and I won't talk to him again until next month. So yes, we'll be turning necks, but it's the diameter we need to figure out.

 

[Eddie Harren]

Have a customer that wants a 243 Wssm, no issues with it other than the neck diameter. .304" neck diameter isn't going to cut it. So my next question is, what diameter is the correct one? I'm going to cut it .274" if no one has a better option.

https://en.wikipedia.org/wiki/.243_Winchester_Super_Short_Magnum#Design


This is what is posted on Wiki. Dimensions are listed on the RH border. Looks like .304" is excessive as .291 is listed.

 

['Freak]

http://www.saami.org/pubresources/cc_drawings/Rifle/243%20Winchester%20Super%20Short%20Magnum.pdf

FWIW, SAAMI drawings are saying .287” case neck and .289” tapering to .288” for the chamber neck.

 

[mikecr]

.291 seems right for stock 24cal wssm.
You sized a neck, seated a bullet, and measured neck OD, right? Or, you simply measured the thickness?
.304 is not right. If your batch of brass is actually ~30thou thickness(an anomaly), then it's time to look for another lot of baseline brass.

As far as the diameter you want, pick it.
I'd turn necks to ~13thou thickness for .269 loaded + 2thou total clearance for .271 chamber. That's me.
13thou will provide for reasonable neck tension, and 2thou clearance is more than enough but providing a reasonable tolerance to work with.

 

[lbran]

like Mikecr said! I don't like 6mms necks to be more than 13thousandth thick!

 

[ab_bentley]

.291 seems right for stock 24cal wssm.
You sized a neck, seated a bullet, and measured neck OD, right? Or, you simply measured the thickness?
.304 is not right. If your batch of brass is actually ~30thou thickness(an anomaly), then it's time to look for another lot of baseline brass.

As far as the diameter you want, pick it.
I'd turn necks to ~13thou thickness for .269 loaded + 2thou total clearance for .271 chamber. That's me.
13thou will provide for reasonable neck tension, and 2thou clearance is more than enough but providing a reasonable tolerance to work with.

@Eddie Harren / @mikecr
That measure measurement of .304" came from a mocked up case.

I'm thinking I'm going to go with a .274" chamber diameter. I just wanted to make sure that if I turned that much off the necks their wouldn't be serious repercussions, like separated necks.

Adam

 

[mikecr]

My 26wssm necks are turned to 13thou. No problem at all.
Just keep the neck clearance rational and not excessive.

 

[Eddie Harren]

@Eddie Harren / @mikecr
That measure measurement of .304" came from a mocked up case.

I'm thinking I'm going to go with a .274" chamber diameter. I just wanted to make sure that if I turned that much off the necks their wouldn't be serious repercussions, like separated necks.

Adam

Everyone that I know, who has experimented with the WSSM case, has come to the conclusion that the brass is very inconsistent and of low quality.

 

[ab_bentley]

Everyone that I know, who has experimented with the WSSM case, has come to the conclusion that the brass is very inconsistent and of low quality.

You and I both know this, and I explain it to him, but again here we are.

 

[Eddie Harren]

You and I both know this, and I explain it to him, but again here we are.

I have found, over the years, that some will take advice and some won't!
It always amazes me when a customer orders an ultra-lite hunting rifle and then calls back and asks for tactical bottom metal and an oversize bolt knob.