6mm cartridge?

[huntall]

what is a 6mm competition match cartridge and what cartridge is it wildcatted from?

 

[rijndael]

.243 is the parent case.

It's pushed forward for a 31 degree shoulder.

 

[huntall]

what difference would this be from a 243 AI and what advantages would it have?

 

[rijndael]

The .243AI has a 40 degree shoulder.

 

[Cheechako]

Maybe I'm a little dense, but what the hell cartridge are you guys talking about??? All my flat screen monitor says is 6mm cartridge. I think there is more than one.

Ray

 

[rijndael]

Maybe I'm a little dense, but what the hell cartridge are you guys talking about???

In his first post he asked about
'6mm competition match'

That's called a 6CM.

 

[joesr]

I'm the designer of the 6CM.

It is basically a 243 win case with a 31 degree shoulder. In changing the shoulder length from 20 to 31 degrees I split the difference and added a little to the neck and a little to the body.

What is the advantage over the 243 AI. It depends on what game you are shooting. The reason I kept the 243 Win tapered body was for feeding in rapid fire competition.

This cartridge works exceptionally well for me.

However, if you are shooting slow fire only then you can get better velocity with the 243 AI.

The key is not the cartridge but how you load it. Stay away from faster burning powders, even H4350 is too fast and burns barrels. H1000 is the best powder I've found for the 6cm. Possibly with the 243 AI there is enough room for Retumbo or N170.

Good shooting,

Joe

 

[huntall]

Thanks for the info. I can't hardly believe the wealth of knowledge that the 6mmbr.com forum produces for us green horns. I have shot firearms since I was old enough to pick one up, some 38+ years ago but feel as if I'm still in diapers when I'm on this sight.

 

[Dubya]

I'm the designer of the 6CM.

It is basically a 243 win case with a 31 degree shoulder. In changing the shoulder length from 20 to 31 degrees I split the difference and added a little to the neck and a little to the body.

What is the advantage over the 243 AI. It depends on what game you are shooting. The reason I kept the 243 Win tapered body was for feeding in rapid fire competition.

This cartridge works exceptionally well for me.

However, if you are shooting slow fire only then you can get better velocity with the 243 AI.

The key is not the cartridge but how you load it. Stay away from faster burning powders, even H4350 is too fast and burns barrels. H1000 is the best powder I've found for the 6cm. Possibly with the 243 AI there is enough room for Retumbo or N170.

Good shooting,

Joe

Hey Joe, would you post a print of your 6CM. I know Ackley did a 30 & 40 degree have not heard of a 31 degree .243. Also the Whitley 6SLR is a 30 degree is based on the .243, but not sure on body dimensions.
What brass you using (Lapua-Win or ?)
Thanks.

 

[MOShooter]

The should on the 6CM is blown out to 31. The neck is lengthened on the 6slr to chance the shoulder to 30. It gives the 6CM a little extra case capacity.

 

[johnfred1965]

whitley also advertises a 243 improved 30. Would that be closer to the 6CM than the 6SLR?

ps: I always thought 6CM was Creedmoor, glad to know these are two different rounds

 

[Dgd6mm]

whitley also advertises a 243 improved 30. Would that be closer to the 6CM than the 6SLR?

ps: I always thought 6CM was Creedmoor, glad to know these are two different rounds

Yes Whitley's 30 degree .243 cartridge is closer to Joe's 6mm Competition Match.
If you pm teele1 he may be able to post a reamer print. I have one buried somewhere on my computer and have never posted a picture on here.

 

[Iowa Fox]

anyone have a picture of the CM and SLR case side by side. Who here has experience with both?

 

[MOShooter]

I'll see if I can get one next time I shoot with Ryan. They are pretty close. The 6CM has a couple of grains more capacity.

 

[Dgd6mm]

Water capacity is a more, like 2-2.5 grrains different then the parent case .243. I may be wrong, but my understanding is the SLR I believe is just the opposite from what I've read.

 

[Dgd6mm]

anyone have a picture of the CM and SLR case side by side. Who here has experience with both?

Search on here if you haven't yet. I think there is one or two. Robert Whitley may have posted one after he came out with the SLR, he used to shoot the 6CM.

 

[thekriebles]

anyone have a picture of the CM and SLR case side by side. Who here has experience with both?

 

[MOShooter]

Water capacity is a more, like 2-2.5 grrains different then the parent case .243. I may be wrong, but my understanding is the SLR I believe is just the opposite from what I've read.

The SLR has very little if any less capacity than a 243 win.

 

[Iowa Fox]

Thanks Guys. Pics always help an old man.