DubbleTrubble wrote:Thanks Hoot.
To make sure I am clear, you don't think there is a "magic" case length dimension as long as it's at or below 1.70?
While I have you then, what other things can I do in the reloading process to minimize feeding and extraction issues? I know that my rifle and it's chamber dimensions will always be a contributing factor.
To be honest, I can count the number of new or 1-fired cases that I've gotten over the years, that were 1.70 or longer, on one hand and have most of my fingers left over. These were from back when the only non-custom platform available was an
AR. So, I'm hesitant to predict what the current crop of cases will wind up being. Semi-auto rifles have looser chambers to guarantee successful cycling. The looser the chamber, the more the shrinkage after firing. If I bought a bag/box of new 450b brass and it had even one case longer than the SAAMI maximum length, I would return the entire bag/box for another one. No telling what other issues might be lurking in them. When fired brass arrives in excess of 1.70, you have to ask yourself, "Where did the extra length come from?" The answer is, "From thinning the walls somewhere down their length!" Thin walls are a harbinger of failure to come. It also means someone shot those cases in a rifle that had its headspace incorrectly set. If the rifle you are using has its headspace correctly set, it will not allow the bolt to close on stretched cases. As much as it represents an imposition for you, you should take the cases longer than 1.70 and see it your rifle will chamber them. If it does, you should have your headspace checked. Assuming it does not, if the number of them isn't too great, I would just toss them. If the majority of them are too long, you should return them to whoever you got them from, along with a warning that their headspace is set to an unsafe specification. This is worth repeating:
That extra brass came from somewhere!" The rules are different for the more mainstream bottleneck calibers. I have a 300 Win Mag that grows its cases a thousandth or two every time I reload them. Being bottleneck cases, which headspace off of the shoulder, the growth is from the shoulder area getting squeezed as the pressure rises during ignition, before the case locks against the chamber wall. That makes the necks elongate. Par for the course but I never reload my 300 Win Mag cases more than 3 or 4 times. I'm just not that hard up for brass and the primer pockets start to get loose around that time anyway, I'm not a worry wart by any stretch of the imagination but when giving advice to someone else, I always err on the side of caution.
Other than that, any advice I would give you is already contained in any reloading manual worth the paper it was printed on. While there is always a case to be made for too little information, rarely is too much information a problem and there is plenty of reading material available on the topic of enhancing your case life. While SAAMI or CIP are fairly tight in their definitions of what represents the correct chamber dimension that allows the head of the case to contact the bolt face, my experience has been that the extractors will reliably pick up the extraction groove of cases that have shrunk far greater than the headspace tolerance. In the case of the 450b, a lot more tolerant.
Hoot