300 vs 338 Win cases

[Hegland]

Just out of curiosity does anybody know how Winchester arrived at different case dimensions for the 338/264 magnums than the 300, instead of simply necking the 300 up and down?

I’ve never loaded these but I was always sort of smitten with the long body of the 300 and thrilled by the punch. However, the slighter taper, longer neck and shorter case length of the 338 I find intriguing.

Thanks for your thoughts and insight.

 

[Antelope_Sniper]

The .338 Win Mag was introduced in 1959, While the 300 Win Mag didn't come out until 1963. Back in 1959 I'm not sure how many long actions were actually being maufactured, and the .338 fits in a standard length action.

 

[GRT338]

I don't remember how long ago I got this info,but got it from a Federal Rep that called on our Gun Depart. when I worked. We got into the discussion of the higher pressures of the 300 Win M, and the brass that they (Federal ) were mfg. at that time. So I don't know if this statement still holds true or not, but here goes. I took the 300 Win Mag Federal brass and necked it up to 338 Win mag, pulled the decapping rod from the 338 Full length die and made 338 cases from the 300 Fed. Brass. It had a longer neck of course, so I trimmed it to 338 specs., re-installed the expander ball and full length sized the cases again. I found out I could shoot higher loads of IMR4350 behind the 225 and 250 Partitions through my 338 Win Mag without excessive indicated pressures. I could chronograph the 225's @3000fps, and the 250's @2860fps. Still have the same cases and have reloaded them 5or6 loadings now some 20+years later. Federal rep said the case for the 300 Win Mag was made thicker in the web/belt area because of the higher pressures of the 300 Win Mag. For my 338 Federal 300 cases are the only brass I use in my 338.. All FYI about the different brass. Best of luck and shoot straight. GRT338

 

[JungleJim]

Both the 300 Win Mag and the 338 Win mag were designed to fit in Winchester's standard length 30-06 action. All three 30-06, 300 WM and 338 WM have a SAAMI maximum COL length of 3.34.

The reason the 300 Winchester Mag ended up with a longer case body (powder column) is simple, take a look at a 300 Weatherby.

The 300 Weatherby was commercialized in 1948 had some very good velocity numbers in a .308 bullet but was more or less for the well to do at the time. Because it required a more expensive to produce at the time, extra long H&H length action.

Winchester simply wanted to bring out a .308 bullet round with good velocity that could come close to a 300 WBY Mag velocity wise and still fit into their own standard length 30-06 action so that the average Joe could afford one (buy one). It was really good marketing on Winchester part IMHO.

 

[JungleJim]

GRT338 The SAAMI maximum average pressure specification for the 300 Winchester Mag and 338 Winchester are the same.

300 Winchester Mag is 54,000 CUP or 64,000 PSI crusher/Piezo.
338 Winchester Mag is 54,000 CUP or 64,000 PSI crusher/Piezo.