6.5CM Brass to 6CM

[weisenbu]

This may be a dumb question, but I’m going to ask anyways…

I have a bunch of never fired 6.5 CM Lapua brass. I also have a Hornady 6.5 CM match grade full length bushing die with a .291” bushing for my old 6.5CM rifle. Since I no longer own a 6.5CM rifle but do own a 6CM rifle, could I simply buy a smaller bushing (e.g. .269”) and insert it into my 6.5CM die to resize my Lapua brass to be used in my 6CM?

Would it be smarter to also buy an intermediate bushing (e.g. .280”) and resize the neck in 2 steps?

 

[Nine Banger]

I resized 100 Hornady 6.5cm brass to 6cm over the last 2 nights.

I spray the body of the cases with one shot and then dip the necks in graphite and size them in one pass with "regular" dies, then trim and tumble.

I do the same thing with 22 creedmoor.

I don't use bushing dies but I imagine whatever is the equivalent bushings size will take you straight there in one pass.

 

[Mtnmilsurp]

I resized some Peterson 6.5 CM to 6 CM in a full length sizing die and it worked fine.

 

[khuber84]

I believe lapua 6cm has slightly thicker necks than their 65cm. The 65cm neck once sized down will gain a lil thickness, so I think they'll land pretty close.

Using a bushing die, will leave a lil bit of the neck unsized, it's not a big deal as it'll form out upon firing. However it MAY cause interference on the first firing via HEADSPACE, maybe not as well depending on how much bump your using.

I use 271 bushings with my 6cm lapua brass, gives me 0025-003 neck tension. Making a pass from 65 to 6mm with a 271 bushing will likely size it a fair bit under the 271 diameter due to the big step. Either use a slightly larger bushing for correct sized neck, a mandrel to bring them back to desired diameter, or use the expander ball. I personally don't use the expander ball on any my bushing die, I just use the appropriate bushing for my desired sized neck, which is generally 002-003 under a loaded case neck diameter.

 

[TaperPin]

A 6.5 haas about 8% more brass in the neck than a 6mm so when sized down would be about 8% thicker, or .001”ish thicker, so not much. Should neck down easily in one step.

 

[khuber84]

But lapua 65cm VS 6cm is 7% thiner in neck wall thickness, so it's gonna be lost in the noise. Stuff is likely all formed from same cups, hench why the smaller neck has more thickness.

 

[weisenbu]

Has anyone tried converting 6.5CM brass to 6CM brass utilizing a FL 6.5CM bushing die with a 6CM sized neck bushing?

 

[khuber84]

Has anyone tried converting 6.5CM brass to 6CM brass utilizing a FL 6.5CM bushing die with a 6CM sized neck bushing?

I've converted a ton to 25cm, with 282 bushing, using a 272 or so to make 6mm would not be much different. Just make sure you run a 6mm expander, or 241 mandrel through necks after.

 

[weisenbu]

Awesome, thank you!

How do I know what size bushing and mandrel to get? The case necks are .014” thick. I was thinking .243” + .014” + .014” - .002” neck tension, which would be a .269” bushing. I’ve never used a mandrel, so not sure how that factors into the equation or changes things. I also don’t fully understand spring back either.

 

[khuber84]

Awesome, thank you!

How do I know what size bushing and mandrel to get? The case necks are .014” thick. I was thinking .243” + .014” + .014” - .002” neck tension, which would be a .269” bushing. I’ve never used a mandrel, so not sure how that factors into the equation or changes things. I also don’t fully understand spring back either.

Your going to gain near 001 neck thickness necking down. You'll land around 272-273 loaded diameter.
I run a 271 TiN which is a lil smaller than standard steel 271. That gives me 002-0025 nk tension without an expander.

I'd get 270 and 271 bushings, and a 241 or 2415 mandrel. Bushings will typically size a lil under their stated size a touch. They definitely will go under making a jump from 65 to 6mm in one pass. I definitely prefer a carbide mandrel, but the 21st century non carbide mandrel are good too.

My preference is to use a bushing that gives me the desired sized neck diameter in one operation. I don't use a mandrel unless my bushing selection is sizing more than needed. Some guys prefer to oversize the neck with a smaller bushing and add in a mandrel step to bring it back up to desired diameter.

 

[weisenbu]

That is awesome info - thank you for taking the time to write that up!

 

[TradLife406]

I converted my creed to 22. Stepped it down to .270 which is my 6 um bushing.
Then down to .250.