220 Russian fire formed to 6mm ARC

[CZ527 Guy]

Sorry getting a bit impatient waiting on a barrel for  the CZ 527 bolt action. Like doing this kind of thing converting 220 Russian by fire forming to 6mm arc. Primary question I am looking at is what to plan for when fire forming. Does the case over all length OAL become somewhat shorter when blowing out & establishing the new shoulder?

 IF so how much change in the OAL shall I plan for when fireforming? May see the new barrel in the coming 5 weeks though I am prepared for more like 9 weeks.

If a Savage bolt action was available I think I may pick one up just for fire forming & who knows I may even like it.

[mkihne]

Sorry getting a bit impatient waiting on a barrel for  the CZ 527 bolt action. Like doing this kind of thing converting 220 Russian by fire forming to 6mm arc. Primary question I am looking at is what to plan for when fire forming. Does the case over all length OAL become somewhat shorter when blowing out & establishing the new shoulder?

 IF so how much change in the OAL shall I plan for when fireforming? May see the new barrel in the coming 5 weeks though I am prepared for more like 9 weeks.

If a Savage bolt action was available I think I may pick one up just for fire forming & who knows I may even like it.

You could expand to 6mm and use a longer bullet to provide a jam. This should fireform nicely(I have formed 6ppc this way.) You could create a false shoulder by first sizing to 6.5,maybe in stages, then size to 6mm until you get a slight “crush” fit for the case. A false shoulder can also be formed by neck turning but only useful if chamber neck is smaller than SAMMI.

[CZ527 Guy]

Fireformed 220 russian to 6mm ARC brass today with two different approaches with a savage Axis rifle that showed up at my FFL this early afternoon.

Initial aproach was loading fairly inexpensive HBN coated pulled 100 gr bullets that the tip was looking really inconsistent or poor. These bullets were jamed into the lands. Brass shrank roughly .012" on the OAL.
To my surprise the pulled bullets shot fairy well considering the appearance of the tip & pull marks. Shot under 3moa at 100 yards with a moderate charge of Ramshot TAC ignited with a CCI 450. Cases. These bullets were sorted as the worst condition of the 500 ish bullets that were purchased.

Second aproash amounted to leaving the neck & OAL alone charging again with a moderate charge of Ramshot tac. Seating a bulk 55 gr 224 cal bullet & firing away. Not sure what I think about sending a 22 cal bullet rattling down a 6mm bore! These rounds actually headspace with the case mouth.

As may be expected the accuracy with the 224 cal bullets was dismal.

[StoneHendge]

I would be real careful with the latter method. It's been years since I first fireformed 6x45 from 223, but there is (at a minimum) vigorous debate over the what happens when a .224 bullet is sent down a .243 barrel. Effects on barrel aside, I wonder if there is enough pressure to fully expand the case against your chamber walls.

* The only difference between .223 and 6x45 is the width of the case mouth.

[Lemonaid]

Check out the new JRB 220 Russian to 6PPC video, there is some good info to be gained there.
https://www.youtube.com/watch?v=WiBJndtzT00

[CZ527 Guy]

Watching this video now, & I have been watch & reading a lot on this operation for years now. My favored barrel is expected to be the Pacnor that Ill be seeing in less than a month, Hopefully! Darn - nearly 2 hr video.

So this Savage barrel has been my dedicated fire forming barrel. Checked my group size on the first fire-forming option w the ugly point pulled 6mm bullets. Accuracy actually came in at less than 2 MOA with an 8 shot group @ 100 yards.

I was very pleased with the quality of the end product with both processes. Luckly neck turning will not be nessisary for our 6mm Arc application.

Neighbors may not like if I was fire-forming out the loading room window., even with no projectile.