Walkalong said:
918v said:
I think the crowd is still confused. There is the bulge and there is normal case expansion. The bulge is dangerous. Normal case expansion is not. The bulge can be removed, but the case is unsafe.
Worth saying again. Any .40 case my normal sizer cannot size gets recycled. I feel like if it has bulged bad enough a normal sizer cannot size it properly, it has been over stressed and needs to be trashed. (Recycled)
+1. Normally, case expands out to the chamber dimensions but when chamber/mouth are generous and/or less supported, case wall/base expansion can occur beyond what resizing dies can resize the brass.
Below are comparison pictures of 40S&W Gen3 Glock and Lone Wolf barrels. As you can see, Glock chamber mouth is generous around the case base but the Lone Wolf chamber fully supports around the case base. If hot loads are fired in barrels with generous chamber/mouth, case base expansion can occur that may not be resized by typical resizing dies and will require the use of push-through resizing by Lee FCD or Redding G-Rx dies. IMO, FCD/G-Rx dies should be used only once on overly expanded/bulged cases and recommend that subsequent powder/charge loads should be used that won't bulge the cases so they can be resized with regular resizing dies. However, some resizing dies (like Dillon) have larger radiused die opening and have more difficulty resizing all the way down the "Glocked" cases and will require the use of dies like FCD/G-Rx.
Coldfinger said:
How can I easily identify the bulged cases? Obviously if you see a bulge its got a bulge but one could be very slight and difficult to see with the naked eye. Is a bulge you can't see with the naked eye even a bulge to worry about?
As 918v posted, there's a difference between normal case expansion and bulged cases that begin to resemble "guppy" bellied cases. Below are examples of what I consider overly expanded or bulged cases that can be difficult to see -
http://www.thehighroad.org/showthread.php?t=589292
You can see the case expansion/bulge more clearly in this picture
Some of these bulged cases did not come from Glock chambers. These are definitely non-Glock primer marks as Glock primer indents have distinct rectangle impression from the breach walls.
Coldfinger said:
Is the case still "safe" after removing the bulge?
That depends on the amount of case expansion (thinning of case wall) and how many times the case has been reloaded/resized (work hardened). Keep in mind that when a case wall/base overly expands/stretches, there is THINNING of case wall/base that CANNOT be made thicker again even by push-through resizing with FCD/G-Rx dies. If the case has been reloaded several times, now you need to factor in work hardening of the brass in addition to thinner brass. If the case continues to be bulged/resized with hot loads, thinner case wall/base and work hardening will contribute to case wall failure/rupture. Often posters of KaBoom will state that mid-range or below max loads caused the KaBoom - Perhaps the particular case that caused the KaBoom had case walls thinned and weakened from repeated reloadings/resizings. With mixed range brass with unknown reload history we may never know.
If you pick up mixed range brass, you have no idea how many times the case has been reloaded, whether the case was overly expanded/bulged and fixed, whether the case walls have thinned, etc. For this reason, I do not use near max/max charge loads with unknown mixed range brass. YMMV
Should I just throw the bulged cases in the recycle bucket?
I use mixed range brass and the test I use with cases that look like the pictures above is after my first resizing attempt won't fully resize the case, I will rotate the case 90 degrees and attempt to resize again. If the case won't resize fully on the second attempt and freely drop into the tight chambered Lone Wolf barrels, I will deem the case too far expanded/stretched/thinned and toss the case in the recycle bin.
One of the cases in the picture above resized with regular Lee carbide resizing die on the first attempt.