22-250 Case Length

olsenjb

I'm just getting into reloading with an RCBS kit my wife gave me for Christmas. I have the Speer reloading manual that came with the kit, and the Loadbooks "One Book/One Caliber" 22-250 booklet. The max case length listed is 1.912". All of my once-fired brass is measuring between 1.915" and 1.920". Is there enough lee-way in the 1.912" number that I will be fine with my brass, or do I need to trim them? Thanks for all of your help, and I'm sure I'll have a ton more questions as I learn and get into it more and more.

drsck

The short answer is "probably," but the correct answer is "no." The case length is important relative to the chamber size of your rifle, but it's even more important in relation to the overall length of the cartridge. If the case length is longer than specified, then you often have to compensate by setting the bullet deeper. With some weapons this may not be an issue, but with others, a cartridge that is just a smidge too long will not feed properly, fit in the magazine, or chamber properly. Another concern that crops up with the bullets are set at different depths in order to standardize cartridge lenght is the crip. With most bullets the diameters vary ever so slightly over the lenght, so that if you set the same bullet at different depths the result is different seals between the case and the bullet which, in turn, changes the pressure in the case as the powder burns. The main issue is consistency. Because one of the reason many people hand load is to increase accuracy, one of the important ingredients in accuracy is consistency. As a result, making sure that the cases are all the same length is one step in the process of trying to assure consistency. Some folks not only trim their cases, but weigh them too, separating the cases into different weight catagories and then making certain that they load and fire all the same weight cases together as a group, once again, in an attempt to insure consistency as a step on the road to accuracy. Hope this has helped a little. Best of luck and good shooting -- Steve

Tailgunner1954

Drsck
HUH? Case length and OAL are compleatly independent of each other.

Olsenjb
The max case length is set to insure that the neck does not contact the front of the chamber cut (if it does, a phenominon known as "pinching" will occure, and you will experance the joy of a blown rifle).
When one case in your batch reaches the "max length" than you should trim the entire batch to the "trim to" length (normaly there is about .010 difference between "trim to" and "max"). Your loading kit came with a "Speer" manual, I suggest that you study the introductory "how to" section again. In the Speer #13 that would be the first 125 pages. Pay attention to the cut away drawings of the seating die (page 79?) and realize that the inside of the chamber has a step in it, just like the crimping shoulder of the seating die, and trimming is your only way to avoid jamming into it. Trim to length for the 22-250 is 1.900 BTW.

mrbruce

Sinclair sells a handy little tool that will tell you exacxtly how long your case need to be without hitting.
Sometimes the book length is not correct for any givin barrel, and they need to be checked out to be sure.
Bullet seating depth and case length have nothing to do with each other.

JustC

I have the sinclair chamber length guages and they do work well. You have to drill out the case-head of a case to be able to insert a rod to smack the guage back out of the case mouth after inserting it in the chamber, but after the initial case drilling is done, they are very accurate and will give you a trim to length for each individual chamber. As long as you are a good .005" or so from the leade, you will be fine. Having the max chamber length helps greatly in deciding when case trimming is necessary.