Okay.....I learned that the OAL listed in most books is generic and each gun will have it's own. I think most books list a 22-250 max OAL at 2.350 and I was making 4 leaf clovers with my 12BVSS at 100 yrds with a 2.480, not even kissing the lands. Is this the same for the casing (brass) max length??? With actions all being slightly different in lenght, how do you know when you really need to trim your brass and what the new trimmed length should be???

Thanks!

make a chamber cast. that will give you the exact measurements of the chamber for that rifle.
Chambers are genneral to a saami spec. for factory rifles.
Acustom rifle may vary,
the recommended trim length has a lot to do with the saami spec standard.
most cartrage length will have a (for this (+) tolerance and no (-)

quote:

Originally posted by hivelosity:
make a chamber cast.

How do you do that????

The case length and the OAL are two different things. As you know, the OAL is how long the finished cartridge can be, predicated on magazine length or chamber diminions. The case length is based on how long the case may be before the case mouth will impinge into the leade, pinching the mouth of the case into the bullet and creating a pressure situation. There is a certain amount of slop or safety built in and, as posted, only a chamber cast will tell you how much, however, every load book will tell you what the maximum (generic) case length is and what your "trim to" length is. The easy way is not to let your case grow beyond the maximum. When you trim, your cases may be a bit longer or shorter than the "trim to" length without a problem as long as they are shorter than the maximum. What you want is for them all to be uniform for your best accuracy.
The book max for 22-250 is 1.912" and the trim-to-length is 1.902".

So I'm guessing then what is more important is getting the bullet to the proper distance from the lands without touching.....and having the casing as close to the end is not as important??

That does make sense. The bullet doesn't know how far back the neck is and probably doesn't care. Does the casing grow when it's shot or when it's re-sized???

quote:

So I'm guessing then what is more important is getting the bullet to the proper distance from the lands without touching.....and having the casing as close to the end is not as important??

Having it close to the end is not important but having it two long so that it crimps down on the bullet when you close the bolt can cause dangerous pressure spikes. Trim to standard or even a littler shorter and you will be fine.

max length of just the case is 1.912 and trim it to 1.900.
if you start with brand new brass, full lenght size it,shoot it, then use a neck sizer on it and make shure the oal is the same. then just neck size from then on out.
with neck sizing,you wont get as much case stretch and can shoot the cases more times before you have to trim
some reloading manuals will give you oal of loaded ammo and for trimming. the figure i gave youy is out of my accurate reloading manual