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Once fired brass from different rifle

I had to buy/use a Larry Willis belted mag body die for the 1x fired norma 7rm brass I bought from gunwerks-- just a regular full length die wouldn't size the case down infront of the belt enough to fit in my gun (x-bolt lr)
My experience with their brass was the same.
 
I've had several people state they've used COW (cream of wheat) to form. Not all do it the same. All install a primer of their choice then either use a small amount of powder followed by a healthy dose of COW and top it off with a cotton ball to keep the COW from falling out or wax. I've never tried any of those methods, but seem to work for them? I'd say undersize it, then fire form it to the chamber and compare dimensions from other cases. I'd also state I'm a novice compared to others on here, but still use what works for me after 39 years.
 
Belted mag, size to fit your rifles chamber on the shoulder, just so the bolt closes with a .003" extra this can be measured. With different case brands mixed lots of Brass from different manufactures have different spring back and neck thicknesses...plus they may be more than once fired. After firing in your chamber one brand of case may require a different bushing to get your desired neck tension when sizing FL or just sizing the necks ... example 308 LC and Lapua brass get the same bushing...winchester case a different bushing...or oversize some and mandrel up. I do hundreds of 350 Rem Mag over the yrs. from 7mm R mag 338 Win mag, 300 win mag and a few old 300H&H to 350 mag...but the long cases especially requires neck turning to the shoulder and boring the case necks in a lathe where it's quick to do.
 
The only time I ever had issues with once-fired brass that was full length resized,was brass that was previously fired in a Ruger 1 7mag,then later fired in a Remington 700 7mag.Had a hard time getting the cases to extract after firing.I think it had to be the area just above the case belt that the die doesn't resize.The cases chambered without any issues but after firing them apparently it expanded back to the memory of the Ruger chamber.
 
I've had several people state they've used COW (cream of wheat) to form. Not all do it the same. All install a primer of their choice then either use a small amount of powder followed by a healthy dose of COW and top it off with a cotton ball to keep the COW from falling out or wax. I've never tried any of those methods, but seem to work for them? I'd say undersize it, then fire form it to the chamber and compare dimensions from other cases. I'd also state I'm a novice compared to others on here, but still use what works for me after 39 years.
On a belted magnum ...One advantage is, IT HEADSPACES OFF THE BELT, ...fire forming it with COW is a waste of time... the belt will hold it in place even if you over size the case it will always fire & blow out the brass to fit the chamber ..but that causes head separation if done over & over a minor complaint about the belt, which won't happen if ya headspace off the shoulder after firing in "your" chamber.
When I changed from hunting with a 7 mag to a 338 mag...i just fired the loaded 7 mag in the 338 mag. Fire forming them perfectly, the 7 mag rds are sideways at 20 yds with low velocity and a nice 338 mag case is ejected. The belt can also be your friend.
 
On a belted magnum ...One advantage is, IT HEADSPACES OFF THE BELT, ...fire forming it with COW is a waste of time... the belt will hold it in place even if you over size the case it will always fire & blow out the brass to fit the chamber ..but that causes head separation if done over & over a minor complaint about the belt, which won't happen if ya headspace off the shoulder after firing in "your" chamber.
When I changed from hunting with a 7 mag to a 338 mag...i just fired the loaded 7 mag in the 338 mag. Fire forming them perfectly, the 7 mag rds are sideways at 20 yds with low velocity and a nice 338 mag case is ejected. The belt can also be your friend.
I have no problems with belts on cases or my pants ;) 🤣🤣! Having only 2 cases that have belts (264 & 300wm) I've never checked the depth (lenier) to see if they were/are the same? The forward end of the belt would be where it's headspaced (makes sense) and the depth is only for safety? I've never checker if the belt on the bolt end even touches it (bolt that is)? Probably not as the base would make contact with the bolt face.
 
I have no problems with belts on cases or my pants ;) 🤣🤣! Having only 2 cases that have belts (264 & 300wm) I've never checked the depth (lenier) to see if they were/are the same? The forward end of the belt would be where it's headspaced (makes sense) and the depth is only for safety? I've never checker if the belt on the bolt end even touches it (bolt that is)? Probably not as the base would make contact with the bolt face.
The go gauge for chambering the belted mag in the .535" heads... is "the same gauge" for all ... 300 Win mag, 338 win mag 7mm rem mag , 350 rem mag, 300 h&h mag, 8mm Rem mag, 264 win mag...etc the same gauge sets all these headspaces the same off the belt, the rest of the cartridge can be much longer, shorter, different bullet diameter. But they are headspaced off the belt with a short stubby go gauge, when you close the bolt on the newly chambered barrel.So the first round fired factory ammo or new brass casings in the belted mag will always be off the front of the belt to bolt face dimension, 264 Win mag, 300 H&H, or 350 Rem mag...the same. One belted mag go gauge sets the headspace, with few exceptions, I believe the 450 Marlin belt is wider to prevent it from chambering into the other belted mags.
 
The go gauge for chambering the belted mag in the .535" heads... is "the same gauge" for all ... 300 Win mag, 338 win mag 7mm rem mag , 350 rem mag, 300 h&h mag, 8mm Rem mag, 264 win mag...etc the same gauge sets all these headspaces the same off the belt, the rest of the cartridge can be much longer, shorter, different bullet diameter. But they are headspaced off the belt with a short stubby go gauge, when you close the bolt on the newly chambered barrel.So the first round fired factory ammo or new brass casings in the belted mag will always be off the front of the belt to bolt face dimension, 264 Win mag, 300 H&H, or 350 Rem mag...the same. One belted mag go gauge sets the headspace, with few exceptions, I believe the 450 Marlin belt is wider to prevent it from chambering into the other belted mags.
A reason I have 1 gauge for both cartridges. Also a reason I don't need a 7-08 g/ng gauge is the 308win works on multiple cartridges
 
A reason I have 1 gauge for both cartridges. Also a reason I don't need a 7-08 g/ng gauge is the 308win works on multiple cartridges
But that's not the point,..a belted Mag headspaces off the belt. But a 308 type cartridge off the shoulder, where it can be sized undersize to where it will not even fire...I've seen it.
A belted magnum on the other hand, will fire no matter how much the shoulder is pushed back...or if you are fire forming an improved version of the belted magnum...no need for false shoulders or jamming a bullet, or cream of wheat...advantage to the belted mag...Hence a the point, "sometimes the belted magnum is your friend." But I've never had a problem with them...and are among my favorite tools.
 
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