According to Wm. C. Davis, Jr. in "Some Simplified Interior Ballistics for Handloaders"

Case capacities in grains of water are as follows.

.22-250 45grs
.22 Swift 48grs
.243 Winchester 54grs
.257 Roberts 55grs
.25-06 Remington 66grs

My questions and observations are as follows:

The 223 WSSM (with its� supposed super efficient design) is not advertised as being faster than the .220 swift which holds only 48grs of water. The last article I read (I believe by Craig Boddington) placed the velocity some ware between the 22-250 and the .220 Swift.

However, the 243 WSSM is using the exact same case and is billed as being the equal or even slightly faster than the .243 Winchester which holds 54grs of water.

Now Winchester is releasing the 25 WSSM and is billing it as being the equal of the 25-06 Remington which holds 66grs of water! (Again using the same case)

Am I missing something here ? !!

Observation #1:
.220 Swift can have good barrel life as long as you don�t try to get maximum velocity out of it. However, many people feel the .220 Swift is about the upper limit on .224 caliber.

This is evidenced by the relative unpopularity of larger .224 cal. Wildcats such as the 22-243. (Cheeta, Clark, etc) Also, many of the .224 wildcats that are built on larger cases are not intended to shoot light weight bullets (like those offered for the 223 WSSM). Instead they are designed to shoot 70-90 gr bullets.

So is the 223 WSSM case way over bore for the .224 dia ?

If not, then how is it big enough to keep up with the 243 and 25-06 ?

When was the last time someone said a 22-243 or 22-06 had good barrel life ?

Why doesn�t the 223 WSSM produce more velocity than the .220 Swift ?

How does a case that is suppose to duplicate the 243 Winchester also have the capacity to duplicate the 25-06 ?


(Re-printed from "small calibers" due to higher traffic on this forum)

J.W. How can the 220 Swift hold less water than the 243Win., since it's basically a necked down 257Roberts, or 6mmRem. albiet .028" shorter, surely the 6mmRem and Roberts can hold more water than the 243Win. which is .160" shorter than the 220Swift, something sure is fuzzy. Jay



PS. I got 54grs. with the 6mmRem. filled to half way up the neck.

IIRC the base of the case of the 220 Swift is ~.440" and the 243 is .470".

I have 22-250 and .223Rem rifles.
I don't use the 22-250 becuase it is too overbore, just makes noise, gets hot, and burns up the barrel.
The added range can't be more than 50 yards, and I don't need it that bad.

Jay, the basis for the 220 Swift is the 6mm Lee Navy. It is a semi-rimmed case.

As far as the velocities: I get more than Swift velocities with my WSSM and heavy bullets.

I suspect, strongly, that Winchester is keeping pressure down on the lighter bullet to prevent the chambering from getting a "barrel burner" reputation. JMO, Dutch.

This is real simple. Manufacturers provide optimistic data for the new and better gee-wiz and more conservative numbers for the �old and obsolete�. As a student of history, the difference between the 7mm Rem Mag data when it was introduced and when the 7mm STW was introduced is amazing. Now look at the difference between the 7mm STW, then and now, with the intro of the 7mm RUM.

Some call it marketing. You don�t want to know what I call it�

The 22, 243, and 25 WSSM have brought nothing new to the table, IMHO.

I just saw the case capacity listed for the WSSM on another thread at 54-55 grs.

I predict some burned out throats in .223 in short order if people reload to the 62,000 psi max.

I also see some reloaders quickly disenchanted when they realize they can get the same velocity when they load .243 Winchester to the same pressure as the WSSM.

Finally, I see reloaders greatly annoyed when they realize their 25 WSSM won't duplicate the 25-06. Instead they have a stubby 25 Souper !

The spin doctors strike again !

Politics and Marketing seem to be the only two occupations where the more you can lie the more money you can make.

More like a +P 25 Souper. That does allow the 25 WSSM to essentially match factory 25-06 velocities. If you are going to load your 25-06 to high pressures or use a long barrel and slow powders, then a hand loaded 25-06 will pull ahead again, at least in terms of velocity.