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Old May 20, 2012, 02:20 AM   #1
Junior Member
Join Date: May 20, 2012
Location: Utah
Posts: 7
Newbie Reloading questions about measurements

Recently took up reloading. Have been reading/studying for hours and have been very meticulous and probably anal. I have so far ran into several unanswered questions.

#1 - Started preparing some 243 Win cases for reloading. Brand new winchester brass, Remington 9 1/2 Large Rifle primers. Couldn't get them seated past flush. Using Redding Big Boss press with primer attachment. Initially thought it was primer seater needed adjusment. Checked and rechecked measurements on seater, all correct. Then I thought maybe I had some bad brass with primer pockets not deep enough. Bought a primer pocket iniformer from Sinclair- primer pockets were all correct. Then started measuring primers and the actual primer thickness was greater than the saami spec standard for large rifle primer pockets. Went back to to supply store and with the reloading expert we started measuring different brand Large Rifle primers and got sugnificant variations from one company to another. All except the Remingtons were less than the primer pocket depth so you could seat them slightly past flush as recommended. Remingtons were actually taller than the primer pockets. The only way to even get them flush was to crush the primer in, which I obviously didn't do.

#2 I purchased a Lee case trimmer for 45 acp and found that the trimmer has an outside diameter that doesn't fit in to all sized cases correctly. Using RCBS Carbide die sizer and various once fired brass the case comes out with max prox diameter of .472, distal case diameter of .4665, and inside diameter of appx .447-.448 (depending on the actual case neck thickness). The Lee sizer I purchased has an outside diameter of .447 which, if the case neck happens to be a bit thick, wont fit into the case which happens about every 2-3 cases. I know most people don't trim 45 acp but as a newbie I'm following the published guidelines closely for now to learn the craft propperly. I've had a similar problem occasionally with the Lee 45 Colt trimmer not fitting into a sized case.

What I can't figure out is why case outer diameters don't match SAAMI specifications. I at first thought it was a defective die or some anti-rust coating I missed in the die that made it size the cases smaller than SAAMI spec. However, when I measured two different factory loads (Speer and Hornady), they both came out at .472 outside diameter the whole length. SAAMI specs show a slight taper from .476 proximal to .473 distal. The SAAMI specs don't match with factory ammo (or visa versa). Are SAAMI specs refering to maximum acceptable diameter or do the factory ammo producers and die makers have their own numbers they go by.

#3 Reloaded some 45 Colt for brother-in-law. He tried them and he had bullets keyholing at 20 yards with 6-8 inch groups. Started checking loads carefully and found that the lead projectiles measured .450 maximum when the box was labeled .452 Colt. Took them back to the store and the guy there opened several boxes of the same brand and they were all the same. I've found some of my lead projectiles for 45 acp and 45-70 are a little over stated diameter but never under, especially .002 under spec. Went to the actual SAAMI website and pulled up the 45 colt specs and, as far as I can tell, their drawing has a mistake on it. They have the bullet diameter listed as ".4560-.0060" while everything I can find says .452 inches. Page 52.

Here is my concluding question. Everyone stresses to check and recheck, measure and remeasure in order to avoid mistakes. How can this be done with such variation in factory equipment and factory specs? Am I missing something? Help please.

Last edited by krackum; May 20, 2012 at 03:09 AM.
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