Armory Sponsor
Posted: 8/24/2008 3:58:23 PM EDT
|
I polished and sorted my 223 brass, and then measured it with my calipers. Basically waht I did was set the calipers to the book (Hornaday & Lyman) dimension of 1.760 and locked the calipers at that size. I then passed all the brass through the calipers. if it passed through the gap (therefore being </= 1.760) I categorized it as good to go and if it didn't then it went in the no-go pile. Obviously the no-go pile will need trimming to get it back down to or under 1.760, BUT is my go pile good to go for progressive reloading? Logic (at least in my head, FWIW) states that once it goes through the sizing die it will get smaller, not larger so cases that are </= 1.760 will remain in spec. This is LC and IMG brass if that matters. |
|
Measure your brass for OALafter resizing. Sizing will grow the brass as it is being returned to a smaller size. My method, tumble clean, inspect brass lube and size tumble lube off, check every case with a case gage clean primer pocket/flashole remove crimp if needed measure for OAL, trim if needed case prep complete, 550 time. |
forgive the ignorance, but how does resizing INCREASE OAL if it is shrinking the brass back DOWN to size? is it squeezing the extra back out the neck? |
|
Your brass expands every shot. Hence it expands a little bit and the overall dimensions of the case get a little larger and the overall thickness of the case gets a little thinner. When you resize it pushes the brass through a die but your case thickness stays about the same. You are pushing the neck of the brass back and squeezing the body of the brass in during a full length resize. The expanded brass needs to go somewhere and it will go through the mouth. Therefore after sizing you need to check your OAL. If you are neck sizing only you are less likely to see as much expansion of the brass and your brass will last longer since you are not squeezing it as much every resizing. It is generally not recommended to neck size for a semi auto. You can find people arguing both sides. But it is good practice to check your brass after every sizing even if you neck size. The RCBS X-Die is another subject for you to look into. |
Where can the brass go during sizing? The thickness doesn't increase (during normal resizing operations, not so for making wildcats), the brass has to flow lengthwise, and mostly it flows from the shoulder into the neck. Always size, then trim. Or check the length to find out whether you want to trim. If you choose to crimp the bullets, then every case needs to be trimmed to identical lengths in order to achieve a uniform crimp on every cartridge. |
Armory Sponsor