Forming 6mm XC / 6xc from Winchester 22-250 brass.

[Niles Coyote]

Couple questions for those of you who have formed 6mm XC brass.

When I run the Winchester brass into my redding die I get the mushroom look and the neck appears to remain nearly same length as before the sizing, somewhere around .25" long rather than .3"+...

Are there any tricks you have learned to grow the neck or does it fix its self after firing? My limited experience forming cases has been with Ackley improved cartridges and that experience makes me think the neck will stay the same length and just slowly grow with use/resizing.

Also, do you happen to have a good fire forming load?

And where did you end up with formed brass loads?

I have looked at some other treads and IIRC, it looks like most users are around 37.5-39.5 with formed cases using H4350 and 105-107 weight class bullets.

I have H4895, Varget, H4350 and H4831sc on hand and plan to use 105 class bullets with limited use of some 95 bergers.

I’m considering picking up a varmint bullet for forming so I am not using up precious 105’s.

 

[varmint slayer]

http://www.6mmbr.com/6xcforming.html

 

[HodgdonExtreme]

I bought a used RCBS 308 FLS die for $10 at a LGS, then ground ~.200" off the bottom of it on a bench grinder. Then radiused the opening with a dremel.

If you run the 22-250 brass up into the 308 die before the xc die, it'll lay the outboard edge of the shoulder back, and prevent the mushroom tip effect.

EDIT: just measured, mine are ~.005" longer than "spec" after two firings, and a light trim (Giraud - to get a nice in/out chamfer) prior to first firing and after each firing.

If the chamber was cut for "traditional" xc, the Winnie brass will bulge a little at the .200" line of the case. This is not a problem but doesn't look great. Just be sure you've formed the cases to achieve a slight "crush fit" in the chamber for fireforming.

I was running 105 bergers for FFing. I believe I used 38 or 38.5gr H4350, for ~2930fps from 24" barrel, vs 40gr in FFd brass for 3050fps. Both loads shot great. In fact, I shot several matches while FFing brass.

 

[HodgdonExtreme]

Forming 6XC Cases from 22-250 Brass

That was written by Larry Medler, a friend and fellow member of my gun club.

 

[missed]

I use the Larry Medler method myself and use a Lee 308 die that I have shortened to bump them. I use Lapua brass and it works awesome. I have ff during matches also with no loss of accuracy. My ff recipe is about 100fps slower is the only difference.

Sent from my XT1080 using Tapatalk

 

[Temp9]

So all you guys using the non-mushroom method, what length are your cases after the first fireforming and sizing?

 

[Niles Coyote]

Thanks for the info guys! It's good to hear accuracy is good during forming, I won’t bother getting any lighter bullets then. I'll give the method linked above a try and [MENTION=67941]Temp9[/MENTION] I will let you know the result if no one else comes along in a week or two.

 

[HodgdonExtreme]

So all you guys using the non-mushroom method, what length are your cases after the first fireforming and sizing?

EDIT: I found 4pcs of brass ready for FFing. These measure between 1.995 and 2.000".

I usually trim via Giraud, but don't have a shell holder for 22-250, so I manually debured the virgin brass and die-formed it. Afterwards, I use a 6xc/6SLR shell holder to trim/debur the cases after each firing.

After 2 firings (FFing once and then a full power load), with a minimum trimming/dusting with a Giraud after each firing, my Winchester measures ~1.992", or ~.005" over spec. I never did measure what that chamber would accommodate.

Bottom line: There is no need to worry about case length from using 22-250 brass.

 

[HodgdonExtreme]

Please re-review my postings, I've edited them after doing some measuring @ the bench.

 

[Temp9]

EDIT: I found 4pcs of brass ready for FFing. These measure between 1.995 and 2.000".

I usually trim via Giraud, but don't have a shell holder for 22-250, so I manually debured the virgin brass and die-formed it. Afterwards, I use a 6xc/6SLR shell holder to trim/debur the cases after each firing.

After 2 firings (FFing once and then a full power load), with a minimum trimming/dusting with a Giraud after each firing, my Winchester measures ~1.992", or ~.005" over spec. I never did measure what that chamber would accommodate.

Bottom line: There is no need to worry about case length from using 22-250 brass.

HE,

Thanks for the info. Is that case overall length? I generally trim my Norma 6XC brass to 1.910", and the Berger manual suggests trimming to 1.8994". 1.992" is quite a bit longer than spec.

By the way, forming with the "mushroom" method gives me cases approximately 1.882" after two firings. Quite a bit shorter than I want, which is why I was curious about the other method.

 

[HodgdonExtreme]

HE,

Thanks for the info. Is that case overall length? I generally trim my Norma 6XC brass to 1.910", and the Berger manual suggests trimming to 1.8994". 1.992" is quite a bit longer than spec.

By the way, forming with the "mushroom" method gives me cases approximately 1.882" after two firings. Quite a bit shorter than I want, which is why I was curious about the other method.

Dammit!

Subtract .100" from all my measurements... misread my caliper. They're all 1.89xx, not 1.99xx.

 

[Temp9]

Dammit!

Subtract .100" from all my measurements... misread my caliper. They're all 1.89xx, not 1.99xx.

Haha, that makes more sense now. Thanks for the clarification.

 

[cjgemm]

Straight from the man...

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