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Canuck Bob
05-10-2010, 12:44 PM
I did a search but missed any detailed discussions. I am wondering about the possible problems seating heavy bullets that sit below the case neck of the cartridge. I am specifically asking re: 303 Brit but also as general learning.

What problems with both plain base and gas checked bullets?

Does the lube in the lower grooves get blown out?

jonk
05-10-2010, 06:17 PM
It can. Probably not the biggest issue as the rotational forces sling the lube out in the main. The big thing is the possibility of the gas check being knocked off. When seating below the neck you'll just have to see.

Plain base I see fewer issues with if you use a light load.

Most 303s I've seen though have a fairly generous throat, swallowing even heavy bullets with the base even with or above the neck.

Bass Ackward
05-10-2010, 06:34 PM
It amounts to inconvenience mostly from contaminated powder from exposure to a lube.

The only real danger for cast, regardless of the base configuration, is if you use heavier charges of ultra fast powder and or or softer bullets.

Deep seated in the case amounts to an unsupported base hanging in mid air. The pressure wave will cause the base to deform until it becomes supported by the only material in the proximity which is the brass case. Thus requiring the case to size down the base and let it get out before it acts as an obstruction.

This is referred to as riveting. How would you know if this is happening? You won't until you extract the case and it no longer has a neck. Obviously, the sharper the shoulder, the more prone the .... clog would be.

But it is so infrequent. Sort of like chamber ringing. It does happen, but is it worth losing sleep over when every time you pull the trigger you are igniting a potentially explosive reaction?

The correct answer is your answer.