Problem with sizing/trimming...Advice?
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Hmm... You mention that some of the brass is once fired... Suggest you segregate the new and used brass. Unless the brass is once fired by you, I would be suspicious of the brass. (Aside from a safety issue, mixing brass can compromise accuracy.)
You mention that about a third of the cases display this problem - perhaps it is the used brass. The necks may have lost a bit of ductility through work hardening, and are springing back a bit.
Regarding the mandrel - not sure if you have surmised the dia by measurement or you are reading the notation on the mandrel (308). Anyway, sounds like you are close - resolve the brass issue, and polish the mandrel if needed.
You mention that about a third of the cases display this problem - perhaps it is the used brass. The necks may have lost a bit of ductility through work hardening, and are springing back a bit.
Regarding the mandrel - not sure if you have surmised the dia by measurement or you are reading the notation on the mandrel (308). Anyway, sounds like you are close - resolve the brass issue, and polish the mandrel if needed.
Yep, the mandrel (on the trim bar, not the die) *was* .308. Now after a brief conversation with Mr. sharpening stone and Mr. drill it fits the cases just fine.
And yes, the once-fired was by me, and the new brass (also winchester) didn't fit any better. Now everything is both sizing correctly and trimming just fine.
Thanks for the help all, I think I'm back on the rails now!
And yes, the once-fired was by me, and the new brass (also winchester) didn't fit any better. Now everything is both sizing correctly and trimming just fine.
Thanks for the help all, I think I'm back on the rails now!
Just checked mine. The mandrel is .304. Both a new and a sized case measure .3055.
My .303 and 30/30 mandrels is the same size.
Another caliper measures the mandrel at .302 and the case at .305 to .306
The mandrel fits the cases fine. I would say poor quality control. Run it in a drill with some fine sandpaper. As long as you don't reduce the length it shouldn't affect accuracy.
My .303 and 30/30 mandrels is the same size.
Another caliper measures the mandrel at .302 and the case at .305 to .306
The mandrel fits the cases fine. I would say poor quality control. Run it in a drill with some fine sandpaper. As long as you don't reduce the length it shouldn't affect accuracy.
Slash5: Thanks for the measurements - that's exactly what I did, stuck it in a drill and applied a sharpening stone gently until it read .305. Now it's a slip fit on the sized cases, and of course the length is still the same.
Thanks!
Thanks!
Mystic Precision
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If the brass comes out of the sizing die with a 305 ID, that would make me happy. the 308 trimming mandrel must be smaller then 308 as ALL dies will size this much.
My guess is that you have a 303brit mandrel that got in the wrong pile or an oversized mandrel. A 308Win mandrel must be smaller then 308 so either send back or polish down yourself.
No you are not going nuts... I always trim after sizing.
Jerry
My guess is that you have a 303brit mandrel that got in the wrong pile or an oversized mandrel. A 308Win mandrel must be smaller then 308 so either send back or polish down yourself.
No you are not going nuts... I always trim after sizing.
Jerry
"...some once fired, some new..." Once fired and new cases are different. It's not the best idea to mix 'em. Once fired will likely be a bit longer than new. However, measure 'em and trim 'em all the the same length. 2.005" measured with a vernier or micrometer. In any case, you only need to trim if the cases are longer than the maximum length given in your manual. It is less grief if they're all the same length. Just remember that when you trim you'll also have to chamfer and de-burr the case mouths.
