I have 100 rds. of starline brass for the Socom.  I have had trouble with bullet seating.  The dies are CH4D.  An empty sized case will go all the way into the die to the crimper.  When I attempt to seat a bullet the case will only go a 1/8" or so and get very tight.  Last night I finally got one to seat all the way to the crimp grove and to my amazement the bullet and case neck stayed in the die when I extracted the case.  It took considerable force both ways.  I have tried the Barnes 350 gr X SP, Speer 350 gr. FN, and Sierra 300 gr FN.  The Barnes is the one that ripped the caseneck off.

The average case mouth thickness on my starline brass is .0014.  This is new unfired brass.  Can someone with new starline brass take a few measurements and let me know?  I think the brass is too thick?  

Thanks

John

It sounds to me like your seat die is out way out of adjustment and you have the seat die turned in too far and are making contact with the crimp shoulder before you should.  Take your seat die and remove the seating stem.
Put a case into the shell holder and run it all the way up WITHOUT the die in the press.
With the case all the way up, screw down the seat die WITHOUT a seating stem until you feel the crimp shoulder contact the case mouth.
Back off the seat die one full to two full turns and lock the die in place.
Now, put in the seating stem in and adjust until the bullet is at the proper depth.  Do not worry about if the bullet is at the crimp groove or not.  Just get it to the correct 2.250 OAL.
Now, seat your bullets to this depth but DO NOT CRIMP.
If you want a slight amount of crimp you need Lee's factory Crimp die if your bullet is not at the crimp groove. The Lee die will crimp even without the bullet's crimp groove lined up with the mouth.
If using the CH-4D die, seat all your bullets first.
Then remove the seating stem or back it way off.
Unlock the die and adjust the die down until the crimp shoulder just bumps the case mouth.  If the crimp groove is not lined up with the case mouth, you want to turn down the die about 1/8 turn, no more, just enough to remove the bell you put on the case mouth but not enough to crimp.  I have found that the .458 SOCOM does not tend to cause bullet set back or extraction under recoil so a crimp is not really needed.

Lube Lube Lube.  What kind of lube are you using.  I use the CH4D dies and it does take a bit of force to get the bullet to seat but I lube up the case and the bullet.  Even creates a ring of brass shave around the top rim of the case on new brass its so tight.

Good point.  Get rid of any type of spray lube and stick with either the roll on RCBS lube or better yet, use this lube and kiss all your sizing problems good-by once and for all.  This is the best sizing die made bar none.

Quoted: Good point.  Get rid of any type of spray lube and stick with either the roll on RCBS lube or better yet, use this lube and kiss all your sizing problems good-by once and for all.  This is the best sizing die made bar none.

I use the RCBS lube and its pretty good.  Still need to go with a bit of elbow grease on the 458 but it works.

Big-Bore

I had adjusted the die as you described with an empty case.  Once I started seating the bullet the case would only go about 1/8" into the neck portion of the die.  I experimented and sanded the neck of a case down to .0010 and problem solved.  I think I will use your suggestion and seat the bullets first and not worry about crimping.  I'm not going to sand the rest.

IceHandluke

I took your advice and now use imperial sizing die wax.



Thanks for the answers.

John

The actual problem is due to the fact that CH4D made the dies off Marty's early print that had the neck too tight.  In order to get the dies to work, will will have to seat the bullet before the case neck actually enters the neck portion of the die.  Back the die way off and turn the seating stem way down.

If it makes you feel anybetter my new starline brass has .014" neck wall thickness as well.  

Have never had the problem but do not crimp the SOCOM in the CH4D's.  Get the lee dies if you want the factory crimp.  BTW Lee will make you a crimp die (only the crimp die) for around $15.  You need to send them a case trimmed to length.

As Tony suggests don't run the seating die down.  

Fine, it's .014"   Bman2219 did you get your bullets seated?

Yes,  I backed the die out as suggested.