257 Weatherby case sizing

[Lenny Foffa]

I had a small problem with two cases, in 270 Weather Mag. That case has the same dimensions a the 257 Weather Mag. After 4 reloading's, two of the 30 cases, would not allow the bolt to close when reloaded. I adjusted the sizer die by screwing it down into the press, several times, before those two rounds would chamber. I have left the die at that level since. All my empty cases will chamber easily and allow the bolt to close. I am using the Hornady head space tool Size E for shoulder bump, but it seems very inconsistent. I need help using the tool . Right now I'm just letting the rifle tell me the cases are sized correctly and will allow easy chambering and easy bolt closing. This may mean I am sizing the cases more than is actually needed???

 

[Philward]

I'm going to use the D size one to measure. I was having kind of the same issue, pies calling over pretty good and still didn't bump shoulder back. I put a 2.5thousandths feeler gauge under the case and it sized down to 2.1165 from 2.118. Those measurements were when using the C size 375 comparator. D is a 400 . But even with the shoulder bumped back the cases still were too tight closing the bolt.

 

[Lenny Foffa]

Phil, this was a mystery to me. Why two cases out of a box of 30 cases, matched by weight cases, that were loaded 4 or maybe 5 times, and fired in only my rifle. ?? I must be doing something wrong!!

 

[Window]

I had a small problem with two cases, in 270 Weather Mag. That case has the same dimensions a the 257 Weather Mag. After 4 reloading's, two of the 30 cases, would not allow the bolt to close when reloaded. I adjusted the sizer die by screwing it down into the press, several times, before those two rounds would chamber. I have left the die at that level since. All my empty cases will chamber easily and allow the bolt to close. I am using the Hornady head space tool Size E for shoulder bump, but it seems very inconsistent. I need help using the tool . Right now I'm just letting the rifle tell me the cases are sized correctly and will allow easy chambering and easy bolt closing. This may mean I am sizing the cases more than is actually needed???

I would say yes. If you bump the shoulder.002 and it won't chamber, the small area in front of the belt is the cause and the Larry Willis collet die will solve that. You can crank your sizing die way down to get it to chamber but you'll be bumping your shoulder back way too far and will risk case head separation. I've never had a case head separation but I've had a few over the years that wouldn't chamber because of what your mentioning and I just set those aside and move on. I load for a ton of Weatherby's and some chambers cause this more than others because on chamber dimensions. So to answer your question, bump the shoulders .002-.003 at most and if you have an excessive number of brass that won't chamber, purchase a Larry Willis collet die and solve the problem. The consistency and your group size will that you and your brass should last for many loads.

 

[Philward]

After firing some recent test loads using once fired cases that I just prepped at beginning of this thread, I checked the headspace measurement of the fired ones using the Hornady D comparator and they were 2.1055-2.106". The other cases that I had sized at same time as the ones I checked just now were 2.107". The loaded rounds were snug but not real tight to close the bolt. When sizing them before, the press was camming over with lots of tension. So today I measured the cases, fired ones and ready to load ones and after seeing the discrepancy started measuring shell holders, I have a #4 and #43 only difference was 0.0015 difference in height of the top flange, where it would rest on top of RAM on bottom and top surface where it would touch the die. I already tried a 0.0025" feeler gauge under the case when sizing and it showed some improvement but not enough. So I made a 0.005" shim from brass stock I have and sized one of the fired cases. After about 3 adjustments of the die I achieved a shoulder bump to 2.103. Tried case in rifle and bolt closed easily, no drag or resistance. It seems I may have a short chamber or the die is a little long. Press is still camming over but not real tight or hard. So I guess I'll be sizing with a 0.005" shim from here forward. And just fyi new cases are 2.0955" using the D comparator from Hornady.

 

[KNOTFERSAIL]

After firing some recent test loads using once fired cases that I just prepped at beginning of this thread, I checked the headspace measurement of the fired ones using the Hornady D comparator and they were 2.1055-2.106". The other cases that I had sized at same time as the ones I checked just now were 2.107". The loaded rounds were snug but not real tight to close the bolt. When sizing them before, the press was camming over with lots of tension. So today I measured the cases, fired ones and ready to load ones and after seeing the discrepancy started measuring shell holders, I have a #4 and #43 only difference was 0.0015 difference in height of the top flange, where it would rest on top of RAM on bottom and top surface where it would touch the die. I already tried a 0.0025" feeler gauge under the case when sizing and it showed some improvement but not enough. So I made a 0.005" shim from brass stock I have and sized one of the fired cases. After about 3 adjustments of the die I achieved a shoulder bump to 2.103. Tried case in rifle and bolt closed easily, no drag or resistance. It seems I may have a short chamber or the die is a little long. Press is still camming over but not real tight or hard. So I guess I'll be sizing with a 0.005" shim from here forward. And just fyi new cases are 2.0955" using the D comparator from Hornady.

What I have done that works like a champ is take 600 grit sand paper and a couple drops of water (wet sand) and run the shell holder back & forth and in no time you can you can peel .001 or more if needed off the depth of the shell holder.it's also easier on your press cause you don't have to cam over as hard but you get the case in the die for the proper sizing and shoulder bump.
Hopefully you follow me

 

[Philward]

What I have done that works like a champ is take 600 grit sand paper and a couple drops of water (wet sand) and run the shell holder back & forth and in no time you can you can peel .001 or more if needed off the depth of the shell holder.it's also easier on your press cause you don't have to cam over as hard but you get the case in the die for the proper sizing and shoulder bump.
Hopefully you follow me

I follow. I think the die is the real problem but I have no way to take 5thou off the die squarely and don't want to modify the #4 since I also reload for 7rm. The 43 shellholder was for 300wsm I had previously. I guess taking 5 thou off that one and use for sizing 257 would work ok just need to sand off evenly.

 

[KNOTFERSAIL]

I follow. I think the die is the real problem but I have no way to take 5thou off the die squarely and don't want to modify the #4 since I also reload for 7rm. The 43 shellholder was for 300wsm I had previously. I guess taking 5 thou off that one and use for sizing 257 would work ok just need to sand off evenly.

Light even stokes and it will come out nice and even.I did my shell holder for my 257 and marked it so it's dedicated for that brass.
If I remember factory RCBS shell holder depth is .125 and took mine to .119 …..I think

 

[19 Badger]

Just to be sure, are you measuring the fired cases with the primer removed or still in the case?

 

[Philward]

Just to be sure, are you measuring the fired cases with the primer removed or still in the case?

Primer removed. I have a decapping die for that. 125 is correct