Freebore and overpressure

[Seabeeken]

Carbon ring can do it.

^^^^ this

 

[Barrelnut]

Carbon ring can do it.

Not sure how big a problem carbon rings can be with a lot of freebore. I thinking carbon rings are bigger problem when you seat long to the lands of jam them.

 

[Muddyboots]

so do you wanna tell us what happened?

 

[Mikecr]

Yes it does. I have had popped primers and blown out of pockets because I left oil in the chamber.

NOT because of over pressure though, and it also does not cause primers to blow out.

 

[Beluebow]

NOT because of over pressure though, and it also does not cause primers to blow out.

I've seen guys break the bolt handle off trying to beat it open over a little water in the chamber.

 

[Mikecr]

The question in title with this thread is about overpressure.

Yes, a wet lube in the chamber is a bad thing.
It causes cases to slam back against the bolt, and then blow the shoulder forward from there. It flattens primers, and doesn't do the case webbing/head any benefit.

This has ABSOLUTELY NOTHING to do with the load 'pressure', and is not a valid pressure problem.
It didn't happen due to an overpressure condition.

 

[YZ-80]

This was that little excerpt from the old Hornady manual that I was referring to, to the extent it applies.

 

[K.E.C. Darkside]

so do you wanna tell us what happened?

Well everyone has given legit cause and you still haven't replied.
And like myself, we have all experienced what some might think is a embarrassing moment. If you have been Reloading long enough- **** happens.

 

[Muddyboots]

Well everyone has given legit cause and you still haven't replied.
And like myself, we have all experienced what some might think is an embarrassing moment. If you have been Reloading long enough- **** happens.

Yep, be nice to hear what happened cause there can be always something new that can be learning experience for all of us.

 

[assasinator]

freebore IS NOT a catch all to reduce pressures.

type and brand of bullet, bearing length, tightness of bore, etc.

that is the reason for starting loads and approaching max loads cautiously.

its complicated, for example if you have a loose bore, a long freebore, and you add a crimp even to bullets without a cannelure, pressure rise.

amount of bullet in the neck(neck tension).

powder speed for teh bullet weight. i use 3031 for 375 taylor using a 200 and 235 gr bullet. try that with a 250 and it will likely explode.

too complicated for a pat answer.

-bill

ps. i use caliber and a half free bore.

 

[hemiford]

Yep, be nice to hear what happened cause there can be always something new that can be learning experience for all of us.

It occurred to me maybe you're asking me ? If so, I apologize for causing a bit of confusion.
I never had an incident at all, I'm only asking here to learn from the brain trust.
I appreciate everyone's advice and experience.

 

[Quintus]

Mixing headstamps can do it.

 

[243winxb]

When guns kaboom, most times its the wrong powder used or a gross overcharge.

There was a Sako defect/recall years ago, around 2004, where barrels burst. Not common.

asking here to learn

Kaboom Photos

 

[assasinator]

Say you have a chamber with a lot of freebore, something like a Weatherby. Your chambered cartridges are "well short" of touching the lands.
Also let's say you properly trimmed your brass length, and have good neck clearance and known non-excessive neck tension, perhaps no neck crimp either.

What would be possible causes of overpressure / pressure spike at that point ?

A tight bore ?
Wrong (too fast) powder ?
Too little powder fill, or too highly compressed ?
Unclean, oily chamber ?
Cold temp load workup then shot on a hot day ?

What else ?

I'm trying to get a handle on what could cause an accidental and catastrophic pressure spike.

dont forget that a shorter than minimum COAL can cause overpressure also.