Cartridge accuracy converted to rimless

[LHH]

Some rounds are inherently accurate like the 6mm in rifle and 32 S&W long/38 special in pistols.
A 30 caliber case has the same basic case width, .336 vs .337 as the 32 S&W long.
A 30 caliber case(1.29) cut down to 32 S&W long (.92) would have almost identical case volume, dimensions, etc..
On paper, almost exact match except for rimmed vs rimless.
My hesitation, 30 calibers are not known for accuracy.
Would in the inherent accuracy of a 32 S&W long transfer to the new round if case dimensions are kept the same and the only difference is rimmed vs rimless? No neck issues as both are straight walled.

 

[ebb]

Are you talking about cutting down a 308win or 30-06 sprg case to the same length as a 32 long case?

 

[joshb]

.????

 

[Tommie]

Are you talking about cutting down a 308win or 30-06 sprg case to the same length as a 32 long case?

I believe the man intends to use the 30 Carbine case.

 

[LHH]

Yes, 30 carbine case, not 308.
The question is if you duplicate case volume, size, length and everything except rimmed vs rimless will the end result be the same?

 

[dellet]

In theory yes, but head spacing off the rim is arguably more repeatable than headspacing off the neck.

Comparing accuracy of 32 federal magnum to 30 carbine would be closer.

For what it’s worth cast 32 pistol bullets sized to 309 and loaded in 300 Blackout subsonic can be very accurate out to 100 yards +. But you have the bottle neck.

 

[bsekf]

Some of the break open single shot guys (Encore) think rimmed cases are more accurate. The extractor doesn't touch a rimmed case but with a rimless case the extractor has to have spring pressure on the case to hold it in the extractor grove.

Are you thinking something similar?

 

[Twicepop]

I think the round you have in mind already exists, kinda/sorta. The .30 Pedersen or the .32 French Long. It was developed for the Pedersen device for modified Springfield '03 rifles. It was adopted by the French government back in the late 20s or early 30s as their military pistol round. It's in between the .32 ACP and the .30 Carbine in length, and I think Starline makes brass for it (32 French Long).

 

[LHH]

Thanks for the replys.
My question is more toward the inherent accuracy of certain case dimensions. For example, a rimmed 222 exists as does a rimless. I wonder if case dimensions are the same and the only difference is rimmed vs rimless does it make a difference?

 

[Kurz]

.222 Remington



.222 Rimmed

 

[Dusty Stevens]

Isnt a 307win a rimmed 308win?

 

[357Mag]

LHH -

Howdy !

Don’t sell .308” calibre cartridges short, when it comes to accuracy.
There are no doubt some .30 BR benchrest shooters than can tell you how stupid accurate that cartridge can be.

For some years, the Sierra loading manual’s comments on the .30-06 cartridge included mention that it had been used to win 1,000yd @ Wimbledon.

And.... how many Police and MIL agencies have depended on surgically accurate .308 sniper and counter-sniper weapons .

In recent years, accuracy & performance capabilities of the .300Win Mag @ ELR have come to the fore’.

Just sayin....


With regards,
357Mag

 

[dellet]

Isnt a 307win a rimmed 308win?

Yes, along with the 222 Magnum rimmed and many others like most of the Mauser cartridges.

Many of the popular American rimless cartridges have rimmed versions in Europe. Especially if it was ever a military cartridge, as they are banned in some countries from being citizen owned.

A 444 Marlin is also a good parent case along with the 357 maximum.

 

[Zero333]

7.63 Mannlicher sounds close to what you're describing. The biggest difference is the 7.63 Mannlicher case is 0.828" long.

Click on image to enlarge a little...

 

[std7mag]

I propose a test!

Take 10 people.
Give them 10 cartridges.
Have them throw them to see which one is "inherently more accurate".


There is no such thing.

If you want to experiment and create a wildcat, then do it!
I'm all for it!

 

[LHH]

Thanks.
A related question: Assume you increase or decrease an accurate round like 6BR.
Say everything is 50% smaller, 150% bigger or whatever, but an identical scale model does it maintain all of the good qualities of the original round?

 

[Homerange]

Thanks.
A related question: Assume you increase or decrease an accurate round like 6BR.
Say everything is 50% smaller, 150% bigger or whatever, but an identical scale model does it maintain all of the good qualities of the original round?

Sorta.
Take 308 vs 223 for example, both are similarly proportioned WRT bore and case capacity and both have sweet spots of precision with powders with a certain burn rate yet this is not a road you venture down without a lot of effort and $ to spare.
History has similar examples and some good study is in Cartridges of the World where often there is mention of which a certain cartridge has evolved from.