Do I have a bad die?

Rumrunner

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So I have been sizing and depriming for my 7mm weatherby mag, 338 win mag and 416 rem mag. This is my first foray into rifle reloading.
Press is a rock chucker supreme.
416 dies are Lee
338 and 7mm are RCBS
I first started with the 7mm and it was very difficult to size. Down and up was very difficult. After about 25 cases the depriming pin broke and the rod was bent. Ordered a new one.
Sized the 416 without any issues. Very smooth.
Received the new decapping rod this week and decided to have another go.
Resized some more 416. No problem.
Resized the 338 and no issues.
I measured the pin depth and locked down everything.
When I started the 7mm it was difficult again. I stopped and reset/remeasured everything. Broke another pin and bent the rod. I’m at a loss now. I set up the 7mm the same as the 338 and there were no issues with the 338.
I checked the inside do the 7mm die and no obstruction. The air gap was not clogged. I then measured the resized brass and all were good. Then I measured the brass I had not resized/deprimed to see how far out it was and how much work the die was doing. All of the brass I measured was very close to spec and really didn’t need sizing. Like 2-3 thousands at the shoulder. The base, belt and neck were 1-2 thousands to spec.
I’m at a loss? I have been asking some friends with years of experience reloading and they are puzzled also.
The only thing I can figure is the sizing die is out, although it is new. I did check and it is engraved 7mm weatherby magnum.
Anyone have any thoughts?
 
Been reloading for 25 years and that does seem odd.

I would send the 7mm sizing die back to RCBS and have them inspect it and install the new rod.

While RCBS does make quality dies, there can always be an issue and maybe something slipped pass their quality control.
 
I hate to ask stupid questions, but just to make sure it's not something simple.....are you ensuring the cases are lubed both outside and the neck prior to sizing?

EDIT: Tex beat me to it by a moment.
 
Are you sure that the die is 7mm Weatherby Mag and not a 7mm Rem Mag? It should say on the die.

Other than that lubercation is the key, I like Hornady Hot Shot spray lube.

Other than that contact RCBS they are a great company and will help you out.
 
I used the same lube on the same pad for the 416 and 338 without issues.
Yes it is engraved 7mm weatherby magnum.
 
For kicks and giggles, you may want to try and clean out the die with brake cleaner. Spray a bunch of that up into the die and give it another go. Also retry with already sized brass. Once resized, the brass should go up and down again quite easily. If it doesn't, something is definitely off.
 
As an experiment to isolate issues, try sizing a piece of brass with the decapping assembly completely removed.

If that feels ok, next reinstall the decapping assembly, but leave it a bit loose so it free floats i.e. do not screw it down tight. The goal is to let self center.
 
I’ll try the brake cleaner tomorrow. I did run an already sized brass and it was still difficult.
I’ll remove the decapping assembly and try that.
I really appreciate the suggestions and help to narrow down the issue.
 
About the only way to bend the decapping rod is to have it adjusted down too far so the expander button was hitting the bottom of the cartridge.
 
I thought about that. Pin length below the die should be .400 +/- .025. I set it to .390. Used the step on the back of the micrometer. Double checked units and zero. I don't know the nominal pin length. Perhaps the pin was too short?
I will look at the expander ball and into some of the cases to see if there are any signs of abrasion.
 

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