30-378 WBY

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Orcon

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I've a question about a cartridge I do not reload for nor ever intend to, but my friend does and I'm worried that he may unintentionally murder himself. The nominal web dimension is .582" but what is the standard amount of diameter growth at the pressure ring just above the belt on a case like this?
 
Bart B. Would be someone to ask this question as he probably has experience in that area ...

But with over pressure loads ... the brass will expand until confined by the chamber wall OR until the yield strength of the brass is met ...
 
Thanks Jim.

He's starting to get stuck cases in as few as 2-3 firings and has to knock 'em out with a cleaning rod. I asked him to make some measurements on all of his brass and it seems like his dies are sizing properly for sufficient chamber clearance. So I asked him to mic for case swell just ahead of the bolt, new brass measured 0.581" his once fired brass 0.585" and the sticky/stuck cases at 0.587"-0.589". This is a problem, no?
 
Sticky cases after a few firings are a good sign of too much pressure.

More common with neck only sized cases that are on the soft side; even with normal safe loads.

A way out of square bolt face also compounds the problem because the first time the case is fired, its head takes the angle of the bolt face. It's not squared up when resized. When it's neck or partial neck sized, reloaded then chambered 180 degrees out from when new, the bolt binds. Firing that round tends to stick up the bolt again.

I'd need some detailed dimensions on the cases to do any further reasoning as to why they stick. Case headspace, from new to first firing and after each sizing would be the best place to start.

Also, set the cases on a flat surface on a table set into the corner of a small square. Then spin them about their head axis. If the case mouth center spins around in a circle, the case head's out of square.
 
It sounds like he has to back off some in his loads. Do you have any knowledge of his load? Powder bullet etc.

While browsing through a LGS I came upon a box of Weatherby brand 30-378 ammo - $175 Ouch!
 
I'm not discounting the possibility of an out of square bolt-face. He had the receiver and bolt trued when the 'smith installed the barrel, I'll tell him to check.

I'm assuming pressure because the barrel was chambered without the generous free-bore that Weatherby cartridges were designed with. He wanted to seat VLDs to mag length and be able to get near the lands, though I don't think he fully appreciates the relationship between jump and pressure.
 
Well, adding all those things up equals higher pressure numbers.

Did the 'smith caution him about that?
 
I would assume the 'smith did, but even if he didn't I've told him no less that a dozen times about reducing charge weights with short jump loads. Seems to think that losing 100fps is an absolute deal-breaker. Moving a 212gr bullet at over 3000fps is nothing to sneeze at in my opinion.


It sounds like he has to back off some in his loads. Do you have any knowledge of his load? Powder bullet etc.

While browsing through a LGS I came upon a box of Weatherby brand 30-378 ammo - $175 Ouch!

Can't speak for the COAL or distance to the rifling but this is his load:
99.5 gr H1000
212 ELD-X
WBY brass
Fed 215
Hornady's 10th Edition lists a max of 100.7gr

At nearly $4 per case, reloading isn't exactly cheap the way he's burning up brass.
 
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