Interesting case failure

Snow Dog

Snow Dog

CGN Regular
Rating - 100%
69   0   0
Location
Somewhere around Toronto
A few days ago I went to the range and did some shooting with another club member. Towards the end of the session I brought out my S&W M57 in .41 Magnum and let him fire off a few rounds of factory ammo. After he finished firing and kicked out the empty brass we found one that was split in half with the other half still in one of the chambers. I fished out the other half and took a close look at both pieces. It appears to me that the brass had some sort of defect - perhaps a burr from the forming machinery at the factory had scored the inside of the case? Anyone ever see something like this from factory ammo? I've taken a close look at the revolver in question and there are no indications of any problem with the cylinder. I think it is just one of those rare defects that get by the factory quality controls. Your thoughts?

M1.jpg

M2.jpg
 
I'm always paranoid about the cases, usually winchester, that have the crimping in the middle of the case. I can just picture that happening. Was that a winchester case? Does anyone know why the cases have that line in the middle???
 
What you have in some of the heavier loads is a canelure applied to the case to prevent the bullets from backing into the case when under recoil.
If the canelure is applied too heavy (deep) then the results ,as you have seen, is case seperation.... Common on softer brass (ie; Remington)
John
 
Your case failed due to overload in the longitudinal direction, with visible necking and formation of shear lips on all fracture surfaces. At least, that is what it looks like from the somewhat blurry pictures.

What makes you think there was a defect? I can think of a couple reasons why there wouldn't be one:
- I don't see one
- cartridge cases are deep drawn, which orients all defects longitudinally. This was a circumferential failure.


This guy had similar problems, only a few months ago. Pity he took the images down.
http://www.canadiangunnutz.com/forum/showthread.php?t=289952&highlight=separation
 
Hey BR - yes, the pics are a bit blurry, I can't shoot a camera worth a s**t! ;)
Here's a couple more pics to show the area of failure in relation to a loaded round - you can see that the failure happened almost at the halfway point in the cartridge. I've seen cases crack around the mouth or case head seperation but not right in the middle - and in a revolver the extraction, of course, comes well after firing so I doubt that contributed to it. Do you think an overcharge would cause this? It just seems strange for a case to fail in that area. I'm wondering if I should fire off the remaining ammo or send it back to Remington to look at.

M3.jpg


M4.jpg
 
Don't mean to sound rude - but to do anything with regards to investigation we need to know a few more facts.

- Date Purchased / Lot Number
- Storage conditions before firing
- Ambient Range Conditions when discharged
- Bullet weight and advertised style
- Dimensions of un-fired rounds ( case head - mid - before crimp - at crimp)
- Dimensions of fired cases (case head - mid - before crimp and where crimp was)
- Brass Hardness - Lee used to make an in-expensive device that determined this really easily
- Primer used, looks the same - is the same - might be different from other fired cases?
- Firing Conditions... anything at all noticeable?.... louder report - less recoil - more recoil, not just for the the round fired but for the ones before and after....
- Was the shot more or less accurate than normal... ie. hot or light load?
- Was the load the same load as all others.... i've seen hunting rounds put into match ammo boxes cause some one had a bad day at the factory and dropped a case before tape/glue


Definitely contact the factory and work with them to determine the problem.... dont' be adversarial and don't worry about the money spent on the box of ammo. If you help them figure out an "oops" they will be more than happy to compensate you.

Also - as hard as it seems - have you actually checked the size of all the chambers in your revolver... if one is slightly large... it's fine - but with one of the cartridges slightly over... you get the idea. Tolerance stacking = that one in a million chance of winning the anti-lottery.

I hope you do follow the path to discovering things - but don't get surprised when the techs start broadsiding you with questions.... especially when they might seem odd.

o/ many happy shooting sessions to you and yours!!!


ps- getting the brass examined is good too - just get it back after, the factory will need to see it. No destructive testing, formative testing should be fine (hardness tests).
 
Last edited:
In my opinion, remington brass blows. I've had 3 case failures in my M1 carbine reloads. 2 of which got stuck in the chamber. All 3 were remington brass.
 
Snow Dog, I got exactly the same type of failure in some new-bought .357Mag Winchester cases that I loaded myself. When I mentioned the problem in the Reloading forum, some suggested it was a chamber-spec issue, but I don't believe that to be the case as I've shot many rounds through that gun and only ever encoutered the problem with that specific lot of brass.

It's really up to you to fire'em or not, but I found there were no risks associated with that type of mid-case rupture. Like you, I only noticed upon extraction that the case had ruptured.
 
You must log in or register to reply here.
Back
Top Bottom