fire forming help

[harleybug]

I got my new barrel mounted and its throated for 180 bergers. I have a few boxes of winchester ammo. Can i shoot them through my gun with regular hunting bullets for the forming. Then do i just use a neck sizing die. Also for i have brass that was fired through my old chamber, can i reload them half way to save powder for the fire forming.

 

[Lefty7mmstw]

What caliber??
You are being rather general.
We can't give you thumbs up or down unless we know what you are trying to do.

In any case, a 1/2 charge is usually not a good idea and may lead to a squib load... Usually a mild load for fireforming but it depends on what you are forming from and into.

 

[g0rd0]

my general rule (and I know that this will come under fire), if is using factory ammo shoot it and it will fire form to your chamber. If you have neck sized reloads for a different barrel disassemble, FL size and load to your manuals start load

 

[257ackleyhunter]

theres a few ways you can fireform...the way i do it if i reload unfired brass is ill do a light load to the bullet weight your using the seat the bullets into the lands so its almost difficult to close the chamber this will put the bullet hard into the lands so when you fire the case will form well to your chamber. but if your using factory loads it should be ok...best way to do it is fire one round and inspect the case

 

[SidecarFlip]

All the above or.... Fireform a couple cases and have a reputable die maker custom machine a bushing die to your case dimensions. Then you can FL the cases to the chamber dimensions. Thats what I do for extreme accuracy and consistency.

Every die maker offers custom machined dies. I prefer Whidden but RCBS does them too.

Expect a month or more lead time.

 

[harleybug]

I didnt think caliber made a diference for fireforming. But its for a 7mm rem mag. Also i thought it was better to just neck size ur formed loads because wouldnt a fl die resize to sammi specs.

 

[SidecarFlip]

I didnt think caliber made a diference for fireforming. But its for a 7mm rem mag. Also i thought it was better to just neck size ur formed loads because wouldnt a fl die resize to sammi specs.

For sure. Custom dies are made to your fireformed brass and are uniquely made for that case.

I don't own one NS die.

 

[SidecarFlip]

For sure. Custom dies are made to your fireformed brass and are uniquely made for that case.

I don't own one NS die.

I probably need to be more specific. Standard off the store shelf dies will form to SAMMI spec (or close)

Custome dies form to the case you supply to the die manker. Custom dies are all bushing dies (far as I know).