6mm cal help

[Kentuckywindage]

I shoot a 6 creedmoor for coyotes and my buddy uses a 243. I believe the 243 case capacity is actually higher than the creed, so why are his “max” loads in load books using less powder with less velocity.

Also, would a custom chambered 243 with proper freebore actually be able to “step on the gas” more so than the 6 creed? I understand the creed has a higher SAAMI pressure, but wouldn’t an action and quality brass for the 243 handle the same pressures equally?

Thanks!

 

[Bill Norris]

I shoot a 6 creedmoor for coyotes and my buddy uses a 243. I believe the 243 case capacity is actually higher than the creed, so why are his “max” loads in load books using less powder with less velocity.

Also, would a custom chambered 243 with proper freebore actually be able to “step on the gas” more so than the 6 creed? I understand the creed has a higher SAAMI pressure, but wouldn’t an action and quality brass for the 243 handle the same pressures equally?

Thanks!

Just my .02 cents but maybe not worth it. But, anything the 6mm CM can do, the 243 can do it better if the correct barrel twist is used. The 243AI can do even better than the .243.

 

[LHSmith]

Probably because the .243 introduced in 1955 has been chambered in pump, lever, and semi-auto actions which are less forgiving to load pressures.

 

[Bill K]

It is mainly in the faster twist of the Creedmoor and bullet weight.
If you put the same twist in a 243 W and use simular weights they shoot side by side practically.

 

[wyshadow]

I just misread your post

 

[Capt. Oblivious]

What powder and what bullets?

 

[WyleWD]

It is mainly in the faster twist of the Creedmoor and bullet weight.
If you put the same twist in a 243 W and use simular weights they shoot side by side practically.

+1^^^^
Agree! WD

 

[wilbur300wsm]

I know guys that shoot the 243 with heavies. 103-110’s. These are 7.5-8 twist barrels. My best advice is doing a ladder test for velocity and pressure to see what the combo likes. Many times it’s more than a “book” suggest. BE SMART, USE CAUTION AND WORK UP SLOW!!!! But the 243 is an amazing cartridge. It’s just not the latest new kid on the block. My 2cents

 

[wilbur300wsm]

Here’s something some guys may be interested in. I just finished a project. I’m a fan of the 243wssm case. I ordered a reamer and had whidden make the dies. It’s a 243wssm blown forward about.080” and a 35* shoulder. Necks are turned down too .015” wall. An 8tw Krieger at 28”, I slowed the Berger 105vldh down to 3,370 fps. N540 at 41.5 gr. I saw 45.5 gr push them 3,580 but started getting slight ejector marks on the brass. Found a lower node at the mid 3,300 and went with that to save on brass wear.

If anyone would like anymore info about this, I’d be glad to share about the build