ive got a large amount of 6mm casses.i want to turn into .257 rob.after opening mouth to .25 cal. do i need to fireform ?and , what is a good way to fireform? i made some out of 30-06 cases, not good.. ran through 7mm trim, then .257 trim ,then reamed .257... thanks to all...
Don't have time to look in detail but the shoulder angle is different. Issue will be shoulder contact to the chamber. I believe the 257 has less shoulder angle than the 6mm. Your die might clean it up. Did you run the brass into a roberts die?
As usual just my $.02 Paul K
Posts: 12881 | Location: Mexico, MO | Registered: 02 April 2001
Don't quote me but I have found that about 7-10 G. of 700 X will be more than adequate to fire form a case.I do this with wildcats but then again I use cream of wheat as well.If you don't savvy what I just said,go back to reloading 101.
Posts: 4483 | Location: Austin,Texas | Registered: 08 April 2006
I fireform with bulk bullets and fast powders. I've never been able to get on the cream of wheat wagon.
I have not done the conversion you are trying but I would take brass fired in your gun and measure headspace then start long and work your way back to it with your new brass so that you have a snug fit. Fireforming might not be necessary as a final step but I would just for my peace of mind.
Bengal, I second what Norman Conquest said. I charged cases with 10 grains of AA #5 (one grain slower than Unique, so Unique would work...), filled the case with corn meal or Cream of Wheat to the bottom of the neck, and plugged the mouth of the case with Kleenex.
Now: this was turning '06 cases into 7.65 Mauser cases. I would suggest you start low and work up until you get the proper shoulder angle, just like you would if using projectiles.
Posts: 4748 | Location: TX | Registered: 01 April 2005
You guys know that you can't fireform unless the case is held back against the bolt face; the difference is six degrees of shoulder angle. When you expand your necks, see if the case is a snug fit in the chamber, meaning a little pressure on closing the bolt. If it is, just load and shoot normally. If it isn't, you can expand the necks more to get more shoulder contact, or easier, seat some bullets touching the rifling with minimum loads and shoot them. But you can' t just fire form cases unless the are a tight fit first. And if they are a tight fit, you don't need to fire form; the first firing will do that for you.
Posts: 17661 | Location: USA | Registered: 02 August 2009
You guys know that you can't fireform unless the case is held back against the bolt face; the difference is six degrees of shoulder angle. When you expand your necks, see if the case is a snug fit in the chamber, meaning a little pressure on closing the bolt. If it is, just load and shoot normally. If it isn't, you can expand the necks more to get more shoulder contact, or easier, seat some bullets touching the rifling with minimum loads and shoot them. But you can' t just fire form cases unless the are a tight fit first. And if they are a tight fit, you don't need to fire form; the first firing will do that for you.
As close as those cases are as long as you have something to headspace against just load and shoot them. No need for a seperate fireforming.
As usual just my $.02 Paul K
Posts: 12881 | Location: Mexico, MO | Registered: 02 April 2001
That is exactly what I was trying to say only you are more concise than me! I tend to use 10 words when one might work. Of course, Confucius said that one picture is worth a thousand words but I am too lazy to take a picture.
Posts: 17661 | Location: USA | Registered: 02 August 2009
I have limited experience in fireformimg as I only have one wildcat cartridge but I've found the only way to get nice sharp edges on cases is to fire them with a bullet loaded. They don't have to be high power loads but there needs to be more pressure than cream of wheat or other filler.
As dpcd mentions, size them down enough so they chamber and then use something cheap or cast your own and load them up.
for every hour in front of the computer you should have 3 hours outside
Posts: 7794 | Location: Between 2 rivers, Middle USA | Registered: 19 August 2000
Originally posted by dpcd: You guys know that you can't fireform unless the case is held back against the bolt face; the difference is six degrees of shoulder angle. When you expand your necks, see if the case is a snug fit in the chamber, meaning a little pressure on closing the bolt. If it is, just load and shoot normally. If it isn't, you can expand the necks more to get more shoulder contact, or easier, seat some bullets touching the rifling with minimum loads and shoot them. But you can' t just fire form cases unless the are a tight fit first. And if they are a tight fit, you don't need to fire form; the first firing will do that for you.
On the nose roger
Old age is a high price to pay for maturity!!! Some never pay and some pay and never reap the reward. Wisdom comes with age! Sometimes age comes alone..
Posts: 10226 | Location: Temple City CA | Registered: 29 April 2003
Originally posted by Mark: I have limited experience in fireformimg as I only have one wildcat cartridge but I've found the only way to get nice sharp edges on cases is to fire them with a bullet loaded. They don't have to be high power loads but there needs to be more pressure than cream of wheat or other filler.
As dpcd mentions, size them down enough so they chamber and then use something cheap or cast your own and load them up.
Mark,
I don't know if you know this or not but you can blow the forward portion of the case down the bore with incorrect uses of a filler and wrong powder charges. What I'm saying is you can certainly get pressure!
As others have said fireforming without a bullet will not normally give you a sharp shoulder. But first real loading takes care of that.
As to the 6mm to 257. Quick drawing says running through your 257 die will probably not cut it. The read line is the 257 black is the 6mm Black line from the red is simply the 6mm new neck.
I'd run the brass over a 277 expander then into the 257 left long enough to give a crush fit in the 257 chamber. Or jam the bullet into the lands. Simply running the brass in the die will not give you anything for headspace for a COW either. Unless your 6mm brass is LONG and your 257 chambered to the short side.
As usual just my $.02 Paul K
Posts: 12881 | Location: Mexico, MO | Registered: 02 April 2001
If you have a more tapered or smaller sizing die you may be able to squeeze the shoulder a little and cause the shoulder to bulge forward enough to chamber shoulder. This is a phenomenon that many reloaders run into when trying to partial full length resize or use a FL die to neck size.
The fired case is like an inflated balloon and tries to squeeze forward when compressed on the sides.
Posts: 13978 | Location: http://www.tarawaontheweb.org/tarawa2.jpg | Registered: 03 December 2008
As close as those cases are as long as you have something to headspace against just load and shoot them. No need for a seperate fireforming.
roger
