Lyman .357 Mag Resizer

Uncle Buck · June 9, 2012, 02:58 PM

Guys, I have a very perplexing problem and I can not figure it out.

I have been using a set of Lyman .38/.357 dies for a few years now, being to cheap to invest in a carbide die set. I have never had any problems until yesterday evening.

Most of the brass is fired from either a Ruger Blackhawk or a GP-100, although a few pieces do come from other .357 mags.

My fired brass measures 0.380" around the cylinder. Length is good and does not need to be trimmed.

I am trying to run these through the die to decap and resize them, but am having a heck of a time doing it. After struggling to get them through the die, the resized brass measures 0.373", which is under the book calling for 0.379".

I have checked some other .357 Mag ammo that I loaded using these same dies and the finished cases measure 0.378 ~ 0.379".

I have lubed the brass cases. I have not ever had a problem using these dies before and can not figure out what is going on with them. I have loaded more than 2000 rounds in the past with this set of dies.

I have cleaned the dies also. What in the world is happening here?

Shootest · June 9, 2012, 04:57 PM

Just a thought but is your decaping pin bent?

243winxb · June 9, 2012, 05:56 PM

Spring back after sizing may be different between nickel & brass cases? Brass fired in other firearms at maximum loads would be harder to size? Lube type can make a difference? Minimum body diameter is .373" if you check the SAAMI drawing. .379" - .006" http://www.saami.org/PubResources/CC...7%20Magnum.pdf

moxie · June 9, 2012, 07:17 PM

Your die could need cleaning, causing cases to stick while sizing. Ultimately, spring for a carbide die if you can. They are worth it.

Regarding dimensions. You are giving dimensions for a finished round, but measuring just after sizing. Remember that your second die, the expander, is going to increase the OD of the case a tad. And finally, inserting the bullet in step three can also increase the OD. So don't worry about measurements until you have a finished round.

Uncle Buck · June 9, 2012, 10:00 PM

I tried to run the cases through with no decapping pin to see if it would make a difference. None at all. Usually I can sit in my chair at the bench, pull the handle down and then up and I have a resized, decapped case. This time I have to really get on the handle to push it down and stand up to raise the handle on the press.

Tried both nickle plated and plain brass. Same results.

Although I used both brake cleaner and carb cleaner to try to clean the die, I do notice an awful lot of scoring on the inside of the die. Make the cases I have run through very ugly and scratched looking. Could/should I use a little bit of emery cloth to try and clean it up?

I am using the Hornady One Shot. Same stuff I have used since I started reloading this cartridge.... Brass has never been fired at max loads... Good call on the spring back.

I am stumped and it will be a few days before I get my carbide dies. I am thinking of trying very fine emery cloth, since I am replacing the dies anyway.

Thanks guys.

Note: I put a piece of very fine steel wool on a .40 cal bore bush and ran the thing in my electric drill. Definitely improved the die. I am guessing I did not get the thing clean enough. I put some bore cleaner in it and ran the brush/steel wool at high speed for about a minute.

I ran a few cartridges through two of the .357 Mags and they seem to be fine.

June 9, 2012, 02:58 PM	#1
Uncle Buck Senior Member Join Date: June 21, 2009 Location: West Central Missouri Posts: 2,592	Lyman .357 Mag Resizer Guys, I have a very perplexing problem and I can not figure it out. I have been using a set of Lyman .38/.357 dies for a few years now, being to cheap to invest in a carbide die set. I have never had any problems until yesterday evening. Most of the brass is fired from either a Ruger Blackhawk or a GP-100, although a few pieces do come from other .357 mags. My fired brass measures 0.380" around the cylinder. Length is good and does not need to be trimmed. I am trying to run these through the die to decap and resize them, but am having a heck of a time doing it. After struggling to get them through the die, the resized brass measures 0.373", which is under the book calling for 0.379". I have checked some other .357 Mag ammo that I loaded using these same dies and the finished cases measure 0.378 ~ 0.379". I have lubed the brass cases. I have not ever had a problem using these dies before and can not figure out what is going on with them. I have loaded more than 2000 rounds in the past with this set of dies. I have cleaned the dies also. What in the world is happening here? __________________ Inside Every Bright Idea Is The 50% Probability Of A Disaster Waiting To Happen.

June 9, 2012, 04:57 PM	#2
Shootest Senior Member Join Date: February 9, 2011 Location: Just outside Cleveland, Ohio Posts: 722	Just a thought but is your decaping pin bent? __________________ The private ownership of firearms is an American Heritage. Anyone who disputes that is Anti-American and unpatriotic. NRA Life Member

June 9, 2012, 05:56 PM	#3
243winxb Senior Member Join Date: July 26, 2011 Location: USA Posts: 1,730	357 magnum Spring back after sizing may be different between nickel & brass cases? Brass fired in other firearms at maximum loads would be harder to size? Lube type can make a difference? Minimum body diameter is .373" if you check the SAAMI drawing. .379" - .006" http://www.saami.org/PubResources/CC...7%20Magnum.pdf

June 9, 2012, 07:17 PM	#4
moxie Senior Member Join Date: October 17, 2006 Location: TX Posts: 513	Your die could need cleaning, causing cases to stick while sizing. Ultimately, spring for a carbide die if you can. They are worth it. Regarding dimensions. You are giving dimensions for a finished round, but measuring just after sizing. Remember that your second die, the expander, is going to increase the OD of the case a tad. And finally, inserting the bullet in step three can also increase the OD. So don't worry about measurements until you have a finished round. __________________ If you want to shoot...shoot...don't talk! Tuco USAF Munitions 1969-1992 RVN 1972-1973

June 9, 2012, 10:00 PM	#5
Uncle Buck Senior Member Join Date: June 21, 2009 Location: West Central Missouri Posts: 2,592	I tried to run the cases through with no decapping pin to see if it would make a difference. None at all. Usually I can sit in my chair at the bench, pull the handle down and then up and I have a resized, decapped case. This time I have to really get on the handle to push it down and stand up to raise the handle on the press. Tried both nickle plated and plain brass. Same results. Although I used both brake cleaner and carb cleaner to try to clean the die, I do notice an awful lot of scoring on the inside of the die. Make the cases I have run through very ugly and scratched looking. Could/should I use a little bit of emery cloth to try and clean it up? I am using the Hornady One Shot. Same stuff I have used since I started reloading this cartridge.... Brass has never been fired at max loads... Good call on the spring back. I am stumped and it will be a few days before I get my carbide dies. I am thinking of trying very fine emery cloth, since I am replacing the dies anyway. Thanks guys. Note: I put a piece of very fine steel wool on a .40 cal bore bush and ran the thing in my electric drill. Definitely improved the die. I am guessing I did not get the thing clean enough. I put some bore cleaner in it and ran the brush/steel wool at high speed for about a minute. I ran a few cartridges through two of the .357 Mags and they seem to be fine. __________________ Inside Every Bright Idea Is The 50% Probability Of A Disaster Waiting To Happen. Last edited by Uncle Buck; June 9, 2012 at 10:30 PM.