Hey guys. I've been reloading for a few years but never gone as far as mic'ing necks and turning. I'm going to start for a 7wsm that I'm having built. For now though, I know how schitty Win brass is and I'm now checking necks for my 308. I have a tube mic and was just wondering what would be considered the line in which you pitch the brass? I've checked several case necks on this Win brass in 4 quadrants and som run from .012-.0129. Just under a thou difference in thickness all the way around. I have a mitutoyo mic with the vernier scale so I was wondering, do you guys read all the way to .0001? Point being, without turning, what is acceptable thickness variance all the way around
Neck wall tolorences? When to scrap brass
- Thread starter Dshooter
- Start date
That's not to terrible for in neck turned brass. I've shot federal brass from my 223 and its more like 2thou varience. With a neck turner you could clean it up to 12 thou or so. It really helps consistency when using a redding bushing die
idahoorion
Silver $$ Contributor
Guys, I think he is talking about neck thickness variation, .001 per seems pretty good for factory brass. in using a neck sorting tool on Win brass my early findings are about 2/3 of the brass falls with in .001 to .0015 and that lapua is closer to .001 for all brass.
Since the op is using a mic he is likely much more accurate than my Sinclair gauge so how much is too much.
Idahoorion
Since the op is using a mic he is likely much more accurate than my Sinclair gauge so how much is too much.
Idahoorion
Keith Glasscock
Gold $$ Contributor
That is pretty good brass. My 6br Lapua isn't much better before turning.
Hey thanks guys. Like I said I'm new to the 'neck' business. I was surprised then if being within .001 is good; all except 1 piece that I measured tonight was actually within .0009. I sure hope they don't make us a mic that reads to .00001. I'm going to be screwed with this OCD. Ha. I read this forum too much. I don't shoot benchrest or f-class but now I find myself weighing cases, bullets, and not to mention all on my FX120i which reads to .02 gr. Man I'm in waaaay to deep. Thanks for the help though guys. Much appreciated
http://www.6mmbr.com/casenecktools.html is hard to find, but helpful. Regards JCS
My feeling is that if you are going through the trouble of reading a vernier .0001 mic at quadrants, you might as well go through the trouble of neck turning.
The trouble with using a 1/10's mic is finding a neck turner that leaves a finish worth measuring to that scale. I have the K&M neck turner, it is a wonderful little tool. It is very easy to set up depth of cut, and it keeps it's adjustment once set up. Setting the shoulder stop is a pita, and the finish while nice, is not worth measuring with a 1/10's mic both because the cutter profile is not ideal, and you are guiding the case by hand. The K&M website claims you have to use a properly sized expander, and that their expander is perfectly matched to the neck turner anvil. I use their expander, and it is not perfectly matched, in fact it fits my Forster neck lathe better. With two hands on the drill, and the cutter clamped to the bench, a pretty nice finish can be achieved, but it will never be consistent because the pilot is not a perfect fit, you can't keep the case perfectly in alignment, and the shell holder will occasionally come loose which can score a case neck.
My ancient Forster neck lathe leaves a much nicer finish, but it is a pita to set up the depth, and it can get knocked out of position. But it holds the case in perfect alignment, and because the cutter has a better profile (it just uses the tip if a set screw machined round and flat), the finish is much better and fits the fillet at the neck when turning off a donut better, even though it is crank driven rather than power driven.
The 21st Century set up looks better, but it is pricey. I'm going to make a holder set up for the K&M parts and that should do the trick.
If you are thinking of neck turning, I would get something cheaper than the K&M or go the distance with something that is really BR quality. The K&M is really nice, but is too expensive for what it does.
You can eyeball quarter 1/10th's easily on any mic/indicator, and this is perfectly adequate for your usage. I don't see any sense in using a 1/10's mic if your not shooting competition. a .001's indicator is easier, faster, cheaper, less delicate. BTW, that vernier mic is the thing to use, I always laugh when people say "never use a dial caliper, use a mic!" then pick up a mic with a digital scale.
The thing to remember is that any neck turner will give you better cases than factory, and any case turner will give you consistent tension. The quality of the finish has an effect on the release similar to how the quality of the barrel crown has an effect on bullet exit.
The trouble with using a 1/10's mic is finding a neck turner that leaves a finish worth measuring to that scale. I have the K&M neck turner, it is a wonderful little tool. It is very easy to set up depth of cut, and it keeps it's adjustment once set up. Setting the shoulder stop is a pita, and the finish while nice, is not worth measuring with a 1/10's mic both because the cutter profile is not ideal, and you are guiding the case by hand. The K&M website claims you have to use a properly sized expander, and that their expander is perfectly matched to the neck turner anvil. I use their expander, and it is not perfectly matched, in fact it fits my Forster neck lathe better. With two hands on the drill, and the cutter clamped to the bench, a pretty nice finish can be achieved, but it will never be consistent because the pilot is not a perfect fit, you can't keep the case perfectly in alignment, and the shell holder will occasionally come loose which can score a case neck.
My ancient Forster neck lathe leaves a much nicer finish, but it is a pita to set up the depth, and it can get knocked out of position. But it holds the case in perfect alignment, and because the cutter has a better profile (it just uses the tip if a set screw machined round and flat), the finish is much better and fits the fillet at the neck when turning off a donut better, even though it is crank driven rather than power driven.
The 21st Century set up looks better, but it is pricey. I'm going to make a holder set up for the K&M parts and that should do the trick.
If you are thinking of neck turning, I would get something cheaper than the K&M or go the distance with something that is really BR quality. The K&M is really nice, but is too expensive for what it does.
You can eyeball quarter 1/10th's easily on any mic/indicator, and this is perfectly adequate for your usage. I don't see any sense in using a 1/10's mic if your not shooting competition. a .001's indicator is easier, faster, cheaper, less delicate. BTW, that vernier mic is the thing to use, I always laugh when people say "never use a dial caliper, use a mic!" then pick up a mic with a digital scale.
The thing to remember is that any neck turner will give you better cases than factory, and any case turner will give you consistent tension. The quality of the finish has an effect on the release similar to how the quality of the barrel crown has an effect on bullet exit.
Just remember it is not just the neck that is inconsistent but the whole case. This can create all sorts of other problems. I use the NECO gage to check cases used in precision firearms/shooting. Try Googling "Banana cases" if you would like more info. 
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