Reforming 7mm brass to 257 Wby - PART II

Bigbubba

Bigbubba

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Ok so i have read the other posts on this topic after searching this thread.

Today i tried to resize some 7mm brass. Some of it is once fired 7mm, some is 7mm reformed to 257 and I dont think was fired but might have been and some was actual 257 wby brass once fired.

Grabbed 1 of each, se the dies in the press, lubed each one. Pulled the handle.
They all went through fine. :D

Tried to chamber the empty brass. The 257 will the other 2 wont.:(
Turned the die down a bit more, resized them again. Same deal - the 7mm will not chamber - to be precise - I cannot get the bolt to close all the way - maybe 75% of the way but not 100% closed.:confused:

What should I do now? Set the die down a bit more?
I think it is binding on the shoulder of the case.

So those of you who have done this please advise
 
You may need to set that die down a bit more yet. It sounds as if the refomed case is still a bit long for your chamber, so you need to adjust the die to move the shoulder back a few thousandths more. You may feel a distinct "over center" when you operate the press without a case in the shellholder. Regards, Eagleye.
 
7mm Mag to 257 wby
For sure the OAL is not too long - it is short for sure

I thought I had the cam going over center but maybe not - will try turning to die in a bit more - thanks eagleeye
 
Bigbubba; There is a small possibility that you have a minimum spec chamber, and a die that is just a tad long [inside dimension] In that case, you may have to take .005" off the top of your shellholder, or off the bottom of the sizing die to get enough sizing for that 7mm brass to chamber. [FWIW, it is best to dress off the shellholder] I had a 22-250 that was like that, so made the custom shellholder and marked it so I could identify it for future use. Regards, Eagleye.
 
If it's an RCBS die you're using to go from 7mm rem mag to 257wby you'll have to bottom the shell holder HARD against the bottom of the sizer die...I had to when I did that too. The shoulder sits "goofy" if you don't. After one firing the nice double radius will form and THEN you can back that sizer die out a turn again if you wish. Buying a neck sizer only die would be a better idea...in my opinion.
 
It sounds like the 7 brass was fired in a different RM rifle and had not been reformed to 257 W before firing? If so check the brass dimension carefully below the spot where your sizing die actually has any effect ie: just in front of the belt. The rifle the brass was fired in may have had slightly larger chamber dimension at that spot. Do you have the same problem if you absolutely know the barss has not been previously fired?
 
7mm Rem mag to 257 WBY mag


I had this exact problem before. I ended up taking quite abit (3/16") off of the bottem of an old die, so i could bump the sholder to where i wanted. Then used a new die to resize after that. The cases are already too short, But I trimed them to uniform the lenght.

I tried just sizing with a FL die but couldn't quite close the bolt.
 
First off, find out if the cases are being stopped by the shoulder or body of the case. If its the body, then cutting the die is going to push back the shoulder too much. You may cure one problem by creating another. Take one of the cases that you can't chamber and mark up the body with a Sharpy or smoke it and try to chamber it in your rifle. If the rub marks are on the body, then the problem is the rifle that produced the oversized donor cases.
When I first tried to neck down 7 mm to .257 I used some mystery cases that I had laying around, since I'm cheap, they were already there, and I didn't want to buy a bag to find out if it was going to work. They were tight above the belt so I took the expander rod out of a .300 Win Mag small base die and ran them through to fix that up.

I'd be willing to bet that brand new 7 Rem mag cases will neck down and chamber with no problems.
 
7 RM to 257 Wea

Dogleg said:
First off, find out if the cases are being stopped by the shoulder or body of the case. If its the body, then cutting the die is going to push back the shoulder too much. You may cure one problem by creating another. Take one of the cases that you can't chamber and mark up the body with a Sharpy or smoke it and try to chamber it in your rifle. If the rub marks are on the body, then the problem is the rifle that produced the oversized donor cases.
When I first tried to neck down 7 mm to .257 I used some mystery cases that I had laying around, since I'm cheap, they were already there, and I didn't want to buy a bag to find out if it was going to work. They were tight above the belt so I took the expander rod out of a .300 Win Mag small base die and ran them through to fix that up.

I'd be willing to bet that brand new 7 Rem mag cases will neck down and chamber with no problems.
Click to expand...



Check this above out as I have the same problem. On mine if you mic the case above the belt it is .509 and the 7mm RM's are .513. Very small difference but the bolt would not close on this 7mm either. I got a couple of 257's from a friend and same thing the bolt would not close. I took some new 7mm RM brass and reformed and no problems it would fit. You probable have a tight chamber like me. RCBS said to send them 5 fired cases from your rifle and the die and they would look at it. Call them and find out.
Best of luck Piping
 
Just curious - what does it say on your sizer die below the knurling? I hope it has "FL" in there somewhere and not "neck"....

I kind of skipped a step I did too - I took out the decapping rod from my RCBS 7mm rem mag die, and ran my Federal once fired brass into it with shell holder (again) bottomed out HARD on the die - and I visually made darn certain the shell holder hit that die. There were a couple that sized damn hard at the base - but they DID size with some 240 pound gorilla persuasion on the end of the handle - I blame me for picking up range brass - but hey - it was all packed neatly in the federal boxes and everything just waiting for me to grab it! Seemed like a high percent of them were shot in some really "generous" chamber - others that FL size die barely touched.... Without the decapping rod installed in the die the neck stays sized down almost tight enough to grip a 6.5mm bullet - makes the drop to 257 cal a bit easier....
 
ok, so - I turned the die down about 1/4 turn.
Ran them back through - bolt closes "easy" about 3/4 of the way and then with "minimal" force (but some force) closes completely....vs with the 257 wby case the bolt practically drops closed.

So I could load these up and shoot them ....so my question is after firing them will they be easier to chamber next time?
or the same?

Thanks guys for the help. Still have not got any new 7mm to try
 
My resized 7mm cases are often a little harder to chamber on the first time into the chamber. I found if I ran my fingers down the case, there was the smallest of a bulge just below the shoulder from the brass being forced around the corner into the round shoulder from the angled 7mm shoulder. After beng fired once and subjected to the enormous chamber pressures they find their own uniform dispensation of material you could say and that bulge is gone along with the tight chambering. You will want to watch that you don't have thick necks, this could cause tight chambering too, but it is a different feel when you chamber them. THe bolt stops or encounters resistance about 3/8" of an inch from where it should go down and is a like that right until the lugs are ready to drop into thier raceway or locks.
I have a barrel with a tight neck that if you haven't turned the necks, that bolt won't go any further forward than the point where the case neck touches the neck portion of the chamber, about 3/8" of an inch from where the bolt should drop

JT.
 
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