Concentricity Tools

[Tozguy]

a lot of things can happen to the brass. Dents, deformations, and various twists. Sometimes these warps are not plainly visible to the naked eye.

Even new brass is not perfect. I have found some new Lapua 6BR brass that has the odd defect that makes it unusable for top accuracy (folds and creases only visible from the inside with a borescope).

It your rounds are curved like a banana that gauge would pick it up. It will show if the cartridge is off-axis along its length.

If it was an occasional round that showed run out then I would suspect a defective case. Is it not preferable to have run out and concentricity checks on the brass earlier in the process of reloading?

Getting back to the original question, calling the tool a concentricity tester is possibly not an accurate term but it sounds good.

 

[lordbeezer]

Yes on early testing of brass. “Match” brass is weighed and put into groups. Necks checked. Primer pockets uniformed. All standard stuff. Then set aside for certain gun. Time consuming but fun in the end. Sorry for rattling on.

 

[Tozguy]

Definitely a labour of love, love to make good ammo and love to discuss it with other reloaders.
So rattle on my lord I'm enjoying it!

 

[pontiac428]

@lordbeezer, since you have experience with measuring cartridge runout, can you share any insights about what you've learned by doing it?

My highpower match rifle is a 6BR that shoots 1/4 MOA off bags. I don't think that any more accuracy will help me win matches, because my hold and wind reading aren't even close to 1/4 minute. My F/TR shoots 1/2 minute on a factory Rem barrel. At 600 yds, I still can't blame the rifle. I use Forster and Redding dies, non-bushing/no-turn clearances. I turn and ream my necks on the 5th reload. That's the background on why I never bought into runout. I'm not entirely sure on how to control it, or if it's worth it.

 

[lordbeezer]

I was mentored years ago by guys that shot 100yd bench rest. Why start with bullet left ,right ,up, down in bore and depend on rifling of barrel to steer bullet to straight in milliseconds. Start as straight as you can make it. Few thousands out would take them from first place to way back of pack. Isn’t turning and reaming necks helping a bullet start straight? I try to have every round the exact same. Do I? No but trying builds confidence that each bullet will go in same hole(doesn’t always work) ..can’t say yes straight round does better but can’t hurt. Rattling on again.

 

[pontiac428]

Okay, so you use the gauge to find the high spot, mark it with a sharpie, and then find its ideal clocking on the range and index the rounds to that spot from then on? Makes sense that the bench rest guys need every hair's width worth of competitive edge. Being a sling shooter, it also makes sense why I haven't tried much to chase the marginal gains beyond basic load development. So long as my vertical stringing on the long range is under a minute I can work on other things like marksmanship to improve my score. Even though it looks fun to make, I don't think I should... Maybe after I retire.

 

[middle.road]

@lordbeezer, since you have experience with measuring cartridge runout, can you share any insights about what you've learned by doing it?

My highpower match rifle is a 6BR that shoots 1/4 MOA off bags. I don't think that any more accuracy will help me win matches, because my hold and wind reading aren't even close to 1/4 minute. My F/TR shoots 1/2 minute on a factory Rem barrel. At 600 yds, I still can't blame the rifle. I use Forster and Redding dies, non-bushing/no-turn clearances. I turn and ream my necks on the 5th reload. That's the background on why I never bought into runout. I'm not entirely sure on how to control it, or if it's worth it.

I do believe that I was lost in the woods by the end of the second sentence.
Though I did kind of understand "...turn and ream necks."

 

[lordbeezer]

no. All match brass weighed then placed in 50 round ammo boxes according to weight by two grain variances. After loading do same with runout. More than 2(or 3) thousands get put into my ar10 or fal boxes. I’m gonna try some with more runout to see the difference if any. Hopefully this is not tooo far off track of original post. Reloading can be quick .size prime.powder. Seat bullet. Done. Or it can be as detailed as you see fit.

 

[silverhawk]

no. All match brass weighed then placed in 50 round ammo boxes according to weight by two grain variances. After loading do same with runout. More than 2(or 3) thousands get put into my ar10 or fal boxes. I’m gonna try some with more runout to see the difference if any. Hopefully this is not tooo far off track of original post. Reloading can be quick .size prime.powder. Seat bullet. Done. Or it can be as detailed as you see fit.

With your concentricity tester, do you grab measurements from two points on the bullet, or just one?

joe

 

[lordbeezer]

Sometimes I do. If ok just in front of brass I will. If runout ok just behind point of bullet I won’t.earlier in processing brass I check neck runout. If it passes muster i continue with process. I have I think every brand of match brass for 308. My most consistent brass I make from LC 54 30-06 brass. Weight. Runout. Neck. Doesn’t make much sense but it is what it is. I really don’t mean to rattle on. Don’t ask me about my 30 half pint I made up to have a 30 cal ar15 round. (Before the 300 series rounds)