As bore increases the bullet weights increase and need greater powder capacity for their inertia, though the greater bore also provides greater efficiency. Length of case is not included in this poll.

Here is a multi-question poll to see where trends are for casehead and body size at at various bore sizes.

Question:
What is the optimum casehead/body for 24-28 calibre?

Choices:
less than .460"
.473" (like 270, 7-08, 30-06)
.532/.511" (like belted magnums)
.532" (beltless magnum casehead)
.535/.550" (rebated fat magnum)
.590" (Rigby beltless magnum)
.603/.586" (belted "Rigby"/Weatherby)
.640" (Gibbs)

Question:
What is the optimum casehead/body for 30 calibre?

Choices:
less than .460"
.473" (like 270, 7-08, 30-06)
.532/.511" (like belted magnums)
.532" (beltless magnum casehead)
.535/.550" (rebated fat magnum)
.590" (Rigby beltless magnum)
.603/.586" (belted "Rigby"/Weatherby)
.640" (Gibbs)

Question:
What is the optimum casehead/body for 31-39 calibre?

Choices:
less than .460"
.473" (like 270, 7-08, 30-06)
.532/.511": (like belted magnums)
.532" (beltless magnum casehead)
.535/.550" (rebated fat magnum)
.590" (Rigby beltless magnum)
.603/.586" (belted "Rigby"/Weatherby)
.640" (Gibbs"

Question:
What is the optimum casehead/body for a 40-50 calibre?

Choices:
less than .460"
.473" (like 270, 7-08, 30-06)
.532/.511" (like belted magnums)
.532" (beltless magnum casehead)
.535/.550" (rebated fat magnum)
.590" (Rigby beltless magnum)
.603/.586" (belted "Rigby"/Weatherby)
.640" (Gibbs)

Question:
What is the optimum casehead/body for a 50 calibre over?

Choices:
less than .460"
.473" (like 270, 7-08, 30-06)
.532/.511" (like belted magnums)
.532" (beltless magnum casehead)
.535/.550" (rebated fat magnum)
.590" (Rigby beltless magnum)
.603/.586" (belted "Rigby"/Weatherby)
.640" (Gibbs)

 

While pondering the 'fat short mag' thread a natural observation or question arises. What
are the optimum casehead diameters for various calibre?

As diameter increases, the area increases by a square. Projectile weights increase by a square as well, if kept to the same length, and increase by more than a square if trying to maintain increased proportional length. The natural conclusion is that increased bore sizes would benefit from increased casehead diameter.

It would be interesting to see where various people draw the lines.

The problem with the poll is that it only reflects an opinion on one area of the cartridge while ignoring the case length. LOL... Move into case length and you open another can of worms...

quote:

Originally posted by capoward:
The problem with the poll is that it only reflects an opinion on one area of the cartridge while ignoring the case length. LOL... Move into case length and you open another can of worms...

Agreed.

But adding length would have tripled the questionaire just giving 'short', 'medium', and 'long' options of each casehead.

Another item left out was a .473" casehead with a .50" body (.284 Winchester rebated). However, down at the 24 and 25 calibre level the standard .473" seems to provide plenty of space already.

Anyway, I'm leaning to the .532" beltless as optimal for 30-39 calibre. It's remarkable that it has taken so long for a case to be available (375 Ruger), and then the relatively slow uptake on what would seem to be a natural design.

you left out the rebated case of the 284 winchester.

All the rimmed rounds were just ignored.

I couldn't finish my vote selection because the Jeffery case head dia was left out of the options. It is not a rebated fat magnum.

quote:

Originally posted by B von Gruff:
I couldn't finish my vote selection because the Jeffery case head dia was left out of the options. It is not a rebated fat magnum.

you're right, it's sort of a rebated fat Rigby, and the original had fat primer pockets, too.
If you think that it is the best 24-28 or 30 calibre then you might choose either Rigby or Gibbs as the closest, and still communicate the basic idea.

quote:

Originally posted by 416Tanzan:

quote:

Originally posted by B von Gruff:
I couldn't finish my vote selection because the Jeffery case head dia was left out of the options. It is not a rebated fat magnum.

you're right, it's sort of a rebated fat Rigby, and the original had fat primer pockets, too.
If you think that it is the best 24-28 or 30 calibre then you might choose either Rigby or Gibbs as the closest, and still communicate the basic idea.

Well if that is the case then the poll is worthless if close enough is close enough. I didn't say it was for the 24-28 or the 30 cal options either.

I think the 404 head size

quote:

Originally posted by 416Tanzan:

quote:

Originally posted by B von Gruff:
I couldn't finish my vote selection because the Jeffery case head dia was left out of the options. It is not a rebated fat magnum.

you're right, it's sort of a rebated fat Rigby, and the original had fat primer pockets, too.
If you think that it is the best 24-28 or 30 calibre then you might choose either Rigby or Gibbs as the closest, and still communicate the basic idea.

Not really - 404 Jeffery specs are .543/.545", it's an animal unto itself.

NOt only was the 404 Jeffrey an animal unto itself, so was the 500 Jeffrey.

However, in principle,
the 404 Jeffrey was the inspiration of the fat standard rebated magnum (that is, over .532+" [e.g. .550"] body with something close to .532 casehead),
and the 500 Jeffrey was like a fat rebated Rigby (over .590+" body [e.g. .620"] and something close or just under the Rigby casehead).

Also, in voting so far (18), it is somewhat surprising yet very understandable that the beltless magnum (aka 375 ruger basic, .532") is making such a good showing on the 30-39 calibre range when considering how few commercial cartridges use such a design. Truly a natural cartridge design that was overlooked in the general scheme of cartridge development.

i pretty much stuck with the standard size [having the x57 case in mind the whole time up through 358]
untill the bullet diameter got into the 40-50 cal area.
it really makes much more sense to have a slightly rebated rim when you get into the bigger diameters just for the bolt face, however a really rebated rim compared to the case diameter does not make sense to me.
and having a somewhat tapered case or bottlenecked,or sloped
does even over having a straight walled case.
so the rim must follow along with case diameter.

Rebated rims make sense in only two scenarios - 1st, PF actions and 2nd, when the rim diameter exceeds .585" and the bolt diameter is .700" (or should I say .695" actual). Otherwise rim and case body should be the same size.

For an update after about a month, 24 votes,
it looks like the .532" beltless is the 'sleeper' case for calibres over 30 and shy of 50.

One might expect more factory rifles than just the 375 and 416 Ruger to use such a standard length case.

Personally, even if repetitious, I think that a 338 Ruger (built on the 375 Ruger case),
would be about optimum in terms of balance for that calibre and equal the 340Weatherby ballistically. It edges out the 338WinMag, great that it is, sort of like the 30-06 outperforms the 308 when push comes to shove.

Nice to design a poll which gives you the results you wanted up front......



.

quote:

Originally posted by TX Nimrod:
Nice to design a poll which gives you the results you wanted up front......



.

Actually, I'm a little surprised at the results. I was expecting more of a showing of the 'fat magnums' in the 31-39 range and I was not expecting a strong showing of the 'beltless magnum' in the 40-49 range.