case displacement and overpressure

[five.five-six]

I am loading up some mixed .223/5.56 brass 26 grains of varget with a 55 grain projectile.




I measured my tightest chambered gun @ 2.259 OL for this bullet to touch the lands and am building these at 2.249 to give me 10/1000 jump

this load fulls most cases just about to the bottom of the neck, however several have ended up compressed loads, almost to the top of the case, all of the cases that did this are head-stamped C J 93 (could be C L 93)

I picked those out and set them aside, should I be concerned about overpressure with them?

[five.five-six]

[22popnsplat]

If you are going through the trouble to get the bullets .010 off the lands , I usually find the best accuracy around .030 off the lands . You should be sorting cases by headstamp at least , or as many do take those sorted by headstamp and sort by weight also. Also as a general rule you need to reduce loads for military brass as it is thicker and has less internal capacity witch increases pressure .

[five.five-six]

this brass is pretty much mixed, I did sort out 150 cases marked LC 96, and picked out 50 that were within 1 grain of each other in weight, those are getting SMC 69 grain projectiles

the stuff I am working on now is just plinking ammo, for the mini14 and 14" M4


for my match stuff, you are saying go with .030 jump?

thanks

[five.five-six]

the other thing is that I can't always read the date... sure my eyes aren't what they used to be, but even with magnification, many of the stamps aren't deep enough to be legible or have been marred

[22popnsplat]

This subject takes up a couple of chapters in a good reloading manual but my basic method for good ammo is to sort brass by headstamp and then by weight after its been processed or just buy some good brass (I use lapua when I can) . I will sometimes sort bullets by weight also but if you find a bullet that benifits from weight sorting its not a match bullet. I will then pick a powder trying to use what I have around and start low and work up, Rarely do I find a load at the top end of the data to be the most accurate. I will usually start with the bullet .010 off the lands and find the most accurate powder charge and then start backing the bullet off the lands in .010 increments until I find the best seating depth. I have a few guns were you cant get anywere near the the lands and have found that often the most accurate is to seat the bullet to the base of the neck .
hope this helps a little