Forming cases

[pavementends]

Starting a bolt gun build.  I have 200 new norma 22PPC cases. Can I use them to make 6mmARC brass?  No one seems to shoot or need 22 PPC any more.

[Lemonaid]

It should be possible but is it worth the trouble and expense? Using factory brass costs a lot less and avoids many headaches. (converting the brass, fire forming).
Try it on one or two cases and report back, it may work out great!

[CZ527 Guy]

How about would 220 Russian work well or OK to form 6mm ARC? looking to clarify the preferred most straight forward option.

The ppc necks are mighty thin already , are they not?

[StoneHendge]

I don't see why not. I converted 400 pieces of Norma .223 brass* to 6x45 a few years ago and half are up to 4x (the rest 3x). It's performance is the stuff of legends in a few prairie dog towns in SE Colorado. Haven't had a single issue with the necks. Neck thickness went from 0.0145" to 0.0140" on average. Chances are you'll end up with better brass than anything you'll ever find with a Hornady headstamp.

* Brass was from the old Norma TAC .223 - before they had Lake City start making their volume .223 with LC brass with a Norma headstamp. 

** I never find fireforming wasteful since virgin brass should always be fireformed anyways. I use it to practice things I might not otherwise, such as offhand, compromised positions and weak side (my local PRS match director seems to have a fetish for weak side stages). Even if I miss, I know if I had a good break and follow through.

[CZ527 Guy]

Can anyone here provide the inside diameter of the flash hole on factory 6mm Arc brass? Thank you!

[CZ527 Guy]

Checked Sammi & Not listed on the Samimi cartridge drawing.

https://saami.org/wp-content/uploads/202...-06-18.pdf

[grayfox]

New unfired Hornady 6Arc brass cases.... (not from a factory load, but factory new brass).
0.078", #47 wire gauge drill bit.

[CZ527 Guy]

Checked Sammi & Not listed on the  Samimi cartridge drawing.

https://saami.org/wp-content/uploads/202...-06-18.pdf

 Looks like Ill be looking for a 6 ppc decapping pin part #'s for my dies Hornady & Redding.  Thank you!

[CZ527 Guy]

Should anyone visiting this thread go down this 220 russian path as well, I verified W Hornady the Hornady PN for the PPC / 220 Russian decapping pin. 396618 .055 OD for the .060 flash hole.

[CZ527 Guy]

Additional information on 220 russian neck diameter for what it is worth. Prior to fire forming the neck diameter with a seated bullet is ranging from .274 to .275. looks like neck turning to uniform neck wall thickness & provide clearance will be advisable.

[41bear]

I've got 100 Lapua 762x39 cases, bought a few years ago, that I'm thinking about converting to 6MM ARC. Just fire form them to 65 Grendel and run thru the ARC die. It's a process but with ammo being HIGH anything that gets me closer to shooting my new build is worth the effort.

[StoneHendge]

I've got 100 Lapua 762x39 cases, bought a few years ago, that I'm thinking about converting to 6MM ARC. Just fire form them to 65 Grendel and run thru the ARC die. It's a process but with ammo being HIGH anything that gets me closer to shooting my new build is worth the effort.

Just run them strait down to 6 ARC. I have a bunch of Starline x39 cases that have 7-8 firings in them that I took down to 243 LBC (ie, 6 Grendel). You'll probably put more stress on the body / shoulder junction and neck if you fire and then bump / neck down again. Cracks forming in the former were the main reason why I've tossed the ones I've tossed, followed by a couple of necks splitting while seating.

[pavementends]

I have not had any luck reforming 7.62x39 cases,  all I have tried have been once fired (probably AK) and running them through a 6.5 Grendel die and then a 6mm ARC die they wind up with a "belt" neat the base of the case and will not chamber.  Reforming once fired 6.5 Grendel brass works well with no such issues. Recommendations? 
Than you

[Old Bob]

Additional information on 220 russian neck diameter for what it is worth. Prior to fire forming the neck diameter with a seated bullet is ranging from .274 to .275. looks like neck turning to uniform neck wall thickness & provide clearance will be advisable.

I've also resized 220 Russian brass in my Hornady dies. Prior to that I used a flash-hole uniforming tool while the brass was still 22 caliber. It changed the flash-hole size to .076" which is still a hair smaller than the standard .080/.082 that most small rifle primed brass uses. Anyway, the de-capping pin (.070") in my dies will fit through that hole.

With seated bullets (Nosler 55gr Varmageddon), the necks on my brass are .270/.271". Still plenty of room to fit in a perfect SAAMI ARC chamber. There's a good chance your loaded brass might still chamber but I understand why you would want to neck turn your case necks since the SAAMI spec for the neck in the chamber drawing is .275" +.002". Your margin is kinda thin!

Out of curiosity, I checked all 3 flavors of Hornady 6mm ARC ammo & found the widest neck diameter of all the cartridges I looked at was .2695".

[Old Bob]

I have not had any luck reforming 7.62x39 cases,  all I have tried have been once fired (probably AK) and running them through a 6.5 Grendel die and then a 6mm ARC die they wind up with a "belt" neat the base of the case and will not chamber.  Reforming once fired 6.5 Grendel brass works well with no such issues. Recommendations? 
Than you

That's the problem with trying to use once-fired 7.62x39 brass. You get can that belt near the head & also a "hump" at the shoulder. If the brass you tried to resize were range pick-ups, no telling how large the chamber they came out of was.

I haven't resized any 7.62x39 for 6mm ARC but did resize some for 6.5 Grendel. Here's my experience with that endeavor...

I didn't get the belt with Winchester, PMC or Remington 7.62x39 brass I fired in my SKS. I did get the hump though. Fire-forming will get rid of the hump. However, I did get the belt with Lapua brass. Pre-measuring the brass before sizing I found the Winchester, PMC & Remington brass all had .441" head diameters while the Lapua diameter was .445".

My recommendation... stick with Grendel brass until you can get real 6mm ARC brass.

[CZ527 Guy]

My bad with an inaccurate measurement with the caliper on the neck diameter w a seated bullet. Actual diameter works out to be .2715 & quite uniform when measured with a micrometer. Now feeling good about .0035 clearance.

[41bear]

Thanks to all for the heads up, my brass being new, won't have some of the problems stated for already shot or range brass. Plus the effort for using a couple of these to try and gain some 6MM ARC brass far outweighs the loss of same. I'll report back tomorrow on what takes place.

No need to wait. The main problem with converting 762x39 brass directly to 6MM ARC brass is the sloping shoulder of the 39 brass so that it does not get pushed back to properly allow it to go into battery. So if used it will still need to be a two step process. At this time, with powder and primers being in such short supply I'll just use the 39 brass for my 762x39 AR

[pavementends]

I have not had any luck reforming 7.62x39 cases,  all I have tried have been once fired (probably AK) and running them through a 6.5 Grendel die and then a 6mm ARC die they wind up with a "belt" neat the base of the case and will not chamber.  Reforming once fired 6.5 Grendel brass works well with no such issues. Recommendations? 
Than you

That's the problem with trying to use once-fired 7.62x39 brass. You get can that belt near the head & also a "hump" at the shoulder. If the brass you tried to resize were range pick-ups, no telling how large the chamber they came out of was.

I haven't resized any 7.62x39 for 6mm ARC but did resize some for 6.5 Grendel. Here's my experience with that endeavor...

I didn't get the belt with Winchester, PMC or Remington 7.62x39 brass I fired in my SKS. I did get the hump though. Fire-forming will get rid of the hump. However, I did get the belt with Lapua brass. Pre-measuring the brass before sizing I found the Winchester, PMC & Remington brass all had .441" head diameters while the Lapua diameter was .445".

My recommendation... stick with Grendel brass until you can get real 6mm ARC brass.


Thanks OB,  Looking at years of 30/06 brass wishing for a  shrinking machine!
Pavementends