Cracked sizing die why ?

Bought a set of Redding FL sizing dies this spring for my 300wsm
about mid june I noticed sizing die was cracked at the bottom about 5/8"
called midwayusa they said return it and sent me another one everything was fine till
I bought a different 300wsm had a Remington 700 XCR and now bought a kimber montana
found out some of my hand loads would not chamber in the kimber tolerances must
tighter in the kimber factory loads fit fine
so started checking and the 2nd redding die is cracked also
got a hold of a set of RCBS dies and all was fine yesterday ran about 30 rounds thru them
just to resize
did 12 more tonight again will not chamber in my rifle just empty cases checked the die and that one is cracked also
what in the heck am I doing wrong ??????
I am using a light coat spray lube
have been reloading for over 40 years and never had this happen and now i have 3 in 3 months

Is your ram coming up hard against your die? If you are compressing your ram too hard against your die, it may be cracking them. I know you have to be careful especially with carbide dies (I know this is not the case with your dies) but too much compression with the ram may be damaging them?? Other than that I do not know.

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...

I guess a way to double check and ensure that's your problem is to measure your brass and see how far out of spec it is....man I hadn't thought of that. That really sucks if that is the problem....Hope you get it figured out!!

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.

Nothing to add, just want to follow the thread.

I am curious as to what press you are using.

FWIW - I have a 223 Remington Kimber 84M (Longmaster Classic). It's chamber is cut to the minimum SAMMI dimensions and it is stated in the manual. I believe they call it a Match Chamber. I cannot use a neck die with this gun, everything I reload has to be run through a FL sizer with the die touching the shell holder and I had to be selective about the shell holder I use to get maximum resizing. It shoots great. I can't imagine breaking a die sizing a piece of brass.

I hope you get it figured out.

I am using a lyman press and yes everything is adjusted right where the shell holder meets the die
I have found that the Remington chamber is over spec size of 0.556
measuring cases that have been shot but not resized measures 0.5575-
0.5595
which is fine if shooting factory loads
makes it a bitch trying to reload
and yes my kimber has a match grade chamber

I have one of the first Kimber Montana in 300 WSM when they hit the market in 04-05. It has a pretty snug chamber too. I have and use both a RCBS Full Length and Neck size die. There don't seem to be much difference in handle pressure used to size the cases between both dies. I use the RCBS clear sticky lube. I FL all my cases just to be sure for hunting. I want no surprises in the field, So I run all my loaded rounds for hunting through the magazine and chamber just to make sure.

The Kimber Montana is my favorite action for a hunting rifle. Stainless Steel Action, Sako adjustable firing pin. Mauser Extractor, Model 70 type Safety. With the bolt in the gun, Put it on the middle safety notch. Remove the bolt from the gun and just jump the poppet dent and remove the firing pin for checking, cleaning and oiling with your hands and back together with hand power.

I have seen some 700 Rem. with very loose chambers. My brother had a 700 ADL that he would pick up cases in the field groundhog hunting and at the range, Every fired case just fell into the chamber and the bolt closed. It shot good when I loaded shells and just neck sized them. When he got his start reloading he bought 243 Win. FL sizing die set. The groups opened up to over 2" at 100 yds. and he traded it off.

Mark the cases and boxes of ammo well if you keep both rifle to save a lot of flustration getting them mixed up. Good Luck and Happy Shooting.

Been loading for 50+ years and have at least 50+ plus sets of dies, mainly rcbs but a few of all the others and never saw or heard of a cracked die...the shell holder be slammed against it must be the cause...

taking a page from the old magazine Precision Shooting, and expanding on it a bit.

Cannot remember who made the comment, but he said we were long over due for a larger die diameter (thread size) as case diameters were expanding greatly. It made sense to me when I read it. Then add in the web thickness from the thread root diameter to the I.D., and your getting fairly thin. Still on paper it looks to be OK, but keep in mind that the die with expand slightly as the case is being resized (maybe .0005"). Take this with a heat treat that kinda exceeds the max by about 20% in depth, and you got a problem. I'd love to have seen a cross section of the die at the crack. Think we'll find the case to be a little too deep, or the die was thru hardened. .025" case is plenty enough. Of course there is the possibility that Redding got a bad lot of steel, or even went with a different alloy number.
gary

hello all,
it happened to me too.
tikka T3 300 WSM varmint SS, Norma brass, RCBS Lube -2, graphite powder inside the neck.
i cracked 3 full dies, 1 redding type S and 2 forster.

I have an e-mail in to RCBS. I use a Lee FTC on the last stage and so far no problems. I have no idea how long the die has been cracked.

The short "fat" wsm chambers reduce chamber thickness and therefore allow more chamber expansion during firing.
Savage use large shank (1.12) on all short magnums allowing for more steel around the case.
I believe the tenon is smaller on the Kimber. Thread fit also comes into play here with looser fit allowing for more chamber expansion.
However, if the cases are expanding because of chamber stretch then it would take a lot of force to resize them and that wasn't mentioned.
My .02,
Randy

From what Forster saw about my spent brass, they are out the saami specs. So the tikka chamber (of course i'm talking about only my rifle) it is too wide.