Some ammo I bought has some small cracks in the neck with some rounds. Are these ok to use? I've noticed with wolf after firing the necks are cracked after firing, but this is brass and its cracked before the round has been fired.

-Foxxz

What ammo?  If they are reloads, I wouldn't shoot them unless their from a reputable source like black hills, ect.  Either way, I would be pissed if I put down good money for substandard ammo.  Take it back and demand a refund.

Anytime you have any crack, anywhere on the brass case, gas, like a cutting torch, is blasting flame through the crack onto your chamber.  This "cuts" the chamber or neck wall....the bigger the crack, the bigger the cut in the steel.  Pretty soon, your brass will not eject, as the brass flows, under pressure, into the cracks and sticks in the chamber.  Soon you are buying a new barrel, or, with a bolt gun, setting the barrel back an inch or so in order to cut a new chamber that is free of cutting marks.

If the brass is cracked before firing, pull it down and discard the cracked brass.  If the brass cracks durning firing, then discontinue firing from that lot.

My experience with brass that cracks under pressure, or is already cracked before firing, is don't shoot it.....it will ruin your chamber.

Rifle and pistol ammo having case neck splits should be culled.  If a significant percentage of a lot has neck splits you may indeed have a bad lot.  There may be other, more serious, problems with the ammo.  Time to pull out the micrometer, maybe break some down and assess ductility.  I have seen some splits caused more by improper seating than by brittleness.  

Having said this, we all understand that CCI manufactures an entire line of ammunition with aluminum cases.  Case neck splits of Blazers are common, if not frequent, depending on dimensions in the chamber neck area.  They still make the stuff.........as in it's not damaging guns.  Repeat, these splits are not torching chambers.  This is because the chamber metal adjacent to the neck split is seeing nothing that the chamber metal just 1mm beyond the end of the case does not also see.  Moreover, if you underload almost any centerfire cartridge you will see blackening on the outside of the case.  This is because gas is getting around the outside due to incomplete obturation.  I cannot tell you how many split cases I have extracted from shotguns, handguns, and rifles.  This is not living dangerously.  Chambers are tough.

Case neck splits can sometimes reflect excessive pressure.  But there are many other far more reliable signs.  

Body splits are more disconcerting in proportion to proximity to the case head.  And defects anywhere near the base/case head are always culled.  This is because leakage/failure in this area can result in diversion of gas into the action with potentially catastrophic effects.

The real problems with neck splits are:  unpredictable bullet tension (thereby creating velocity/pressure variations).  A split case neck will often result in a flier.  Split case necks cannot grip bullets so as to preclude telescoping.  Now, telescoping can indeed dangerously increase pressures in some applications (eg. 9mm).  Telescoping can cause failures to feed, can then result in powder dumping into the mechanism with predictable consequences.  Loaded ammo with neck splits may not chamber for dimensional reasons, causing a failure to feed for this reason.

Sam