Cracked sizing die why ?

[fiftybmg]

I don't believe a brass case can crack a sizing die, no matter how out of spec the case. If the base is stretched out, the worst that can happen is the case getting jammed in the die if it's not lubed properly.

The metal the die is made from is very hard, and maybe brittle.

The only way it might crack is if it falls a distance to a very hard surface, or is hit with a hammer. There is not enough force using a hand on the press handle to cause the ram to impact the die hard enough to crack it.

How many stuck cases have you removed from the die, and did you use a hammer ?

 

[KMG]

Never had any stuck cases, less than 100 sizing, & never dropped or hit the die with anything. It was brand new. Seems to be more of a die/ case hardening, issue than a brass issue.

 

[Kmccord]

Apply RCBS Lube -2 , using a pad. Lube inside of necks.

There have been many post online when spray lube has been the problem. Lube must fully dry before sizing.

But cracking 3 FL dies very strange. I would guess the web is expanding from high pressure? Reduce the powder charge after buying new brass. Do not use brass fired in the first rifle.

When FL sizing , at the top of the stroke, make sure the shell holder and FL die are in contact. Use a flash light if needed.

If the shell holder is in full contact every time and rounds will not chamber, then remove a few thousands from the shell holder. Do not use this shell holder for any other cartridges.

The 300 wsm has a working pressure of 65,000 PSI. Very close to when brass will no longer spring back after firing. The web area may never spring back above this pressure.

Are the primer pockets tight in the used brass. If pockets become loose within 5 firing, pressure is to high.

Be careful on sanding the shell holder, I had the same problem with a custom 28 Nosler, tight tolerance I have the Redding FL die and I shaved a few thousand off the shell holder. What that created was a thinner lip and if not lubed correctly, you will need a stuck case remover, I had a one of mine that busted the lip on the shell holder and a stuck case in the die. What I did was remove a few thousand off the die. Something else I have done is just bump the shoulder back .002 instead of a full length sizing, that may help in preventing the die to crack.

 

[LoneTraveler]

Sounds to me like the die makers have got a "Heat" of bad steel that will not harden and temper proper are causing the problem.
Or they all have gotten their Heat Treating/Quinching process out of specs.
If brass forming would crack a proper made die, There would not be wildcat cartridges we love so much.

 

[BountyHunter]

Been there, done that... I felt like I was splitting wood with my first 7rum... I went through three fl dies before I finally sold the rifle. Remington cut the chamber too fat and the web was expanding enough to act as a wedge and drive the bottom of the reloading die open, causing a split...
It's your chamber, not your die... Set it back and re-chamber, re-barrel, or sell the rifle...

google JL Precision, Jim Carstenson. He can take a redding body die, 10 pieces of brass fired 3x and custom hone that die and convert it to FL sizer with bushings. Last one he did for me was $80 and 3 weeks.

 

[MNbogboy]

If brass in the case head below where the web starts has stretched from overpressure or an oversized chamber you cannot size it back by normal squeezing it in a die. As others said it will "stick". However, as Trickymissfit said the larger case in a 7/8-14 threaded die is near "border line" for strength when normal force is applied.
Being these magnum sized cases have split for several people who answered this post and have had similar case/chamber size problems it probably is not the die or die material. Probably only took one "hard" push to crack the die and maybe not noticed right away because the stress from the oversized brass was "relieved" by the cracked die.
The belt less mags run at normally high comparative pressure. Exceeding these pressure limits is risky. Oversize case head measurements are a clear indication of overpressure (or bad chamber) or both.
A custom die like BountyHunter mentioned could be a remedy for the bad chamber. But there is no remedy for making overpressure loads that swell case heads.

 

[ehryk]

I had a 300 WSM and cracked a Redding body die. The press I use is a Forster co-ax press and by design has no support for the die beyond the collar. I think in a conventional press, this may not have been an issue. I haven't had the problem with the rest of the calibers I shoot.

 

[Lefty7mmstw]

I don't believe a brass case can crack a sizing die, no matter how out of spec the case. If the base is stretched out, the worst that can happen is the case getting jammed in the die if it's not lubed properly.

The metal the die is made from is very hard, and maybe brittle.

The only way it might crack is if it falls a distance to a very hard surface, or is hit with a hammer. There is not enough force using a hand on the press handle to cause the ram to impact the die hard enough to crack it.

How many stuck cases have you removed from the die, and did you use a hammer ?

With me it wasn't bad steel, as I used both redding and rcbs dies... it was fat brass. With a 7rum you have a lot of solid brass in the web and 65Kpsi will push it wide and wedge crack your die if your chamber is too fat at the base of the case. Three different broken dies do not lie... No stuck cases either, so don't hang it on beat up dies... The wsm the op is talking about is a similar situation. The rum and wsm dies really ought to be threaded for a 50 bmg press or something as the steel thickness really isn't that great at the base of the case on a normal die thread.

 

[kiwikid]

Is there enough thread protruding out the bottom of the press to screw on another die collar to give the base of the die more strength?

 

[Lefty7mmstw]

Is there enough thread protruding out the bottom of the press to screw on another die collar to give the base of the die more strength?

nope

 

[fiftybmg]

Case diagram for 300 WSM says it's 0.555" at it's widest.

.338 Lapua is .587, and uses a standard die body.

Are there also problems with the .338 Lapua sizing dies ?

 

[Lefty7mmstw]

Case diagram for 300 WSM says it's 0.555" at it's widest.

.338 Lapua is .587, and uses a standard die body.

Are there also problems with the .338 Lapua sizing dies ?

probably, but you don't really see the lapua in cheaper rifles that are prone to crappy build practices either...

 

[MNbogboy]

probably, but you don't really see the lapua in cheaper rifles that are prone to crappy build practices either...

Good point, chambers to print, actions & barrels that "contain" the pressure not subject to excessive chamber expansion.
Also probably not "stretched" (pun) to their limits by the shooter/reloader because there is plenty of oomph there in the first place.

 

[bigedp51]

I buy bulk once fired Lake City 7.62 brass and some of it was fired in machine guns. And when sizing these cases some times I had both hands on the press handle. Meaning this was the most force required to size these cases in over 47 years of reloading. And my point being I did not crack my .308 Win die.

You do not state how much force was required to size your .300 WSM cases, but I will guess you were not hanging on the press handle with both hands.

My guess is the dies need to be a larger diameter and thicker to keep from cracking.

There were two tricks to sizing 7.62 machine gun fired brass.
1. Use a .45 ACP carbide die to size the 7.62 case first then size the case again with a standard .308 die.
2. Use a 30-06 sizing die first then size the case again with a standard .308 die.
3. And do not even think of using a small base die to size the cases with first.

I state the above because you may need to have a custom honed die with a larger inside diameter made for the first sizing. And then possibly use a standard die for the second sizing.