neck turning?

[TrxR]

If I was to buy a Mitutoyo Micrometer which size ball would be better the smaller or bigger? They offer a 0.188976" sphere or a 0.141732" sphere

Thanks

 

[Martin52]

I have tested & compared both methods together.
The post, rather than ball, produces bad readings in unturned necks

Do you think the same for turned necks ? I use a 0.0001 dial indicator fixed into a K&M neck turner and with turned cases find I can get consistency in readings.

Martin

 

[CatShooter]

If I was to buy a Mitutoyo Micrometer which size ball would be better the smaller or bigger? They offer a 0.188976" sphere or a 0.141732" sphere

Thanks

They are so close in size that it matters little, but if you have a choice, pick the smaller ball tip.

 

[mikecr]

Do you think the same for turned necks ?

No, it works with turned necks.
Hell a bullet & calipers works by then, your half beyond the need of a ball mic.

What I'm suggesting is that a tubing 'post' anvil doesn't work as well as a ball for unturned case necks. I don't see any issue with use of a dial indicator, if it's a good one. Convert the original tool in question to a 'ball indicator' with the indicator always fixed to the ball location, and providing an adjustable stop for ball/indicator contact and you'd have a funny tool that would work pretty good(maybe).
I'll try it

 

[hoverp]

I havent got the rifle together yet but it will be a 308 with a 30 inch heavy palma barrel for F/TR . I will be using Lapua brass. I will also be using one of PT&G 's reamers. Probably his F/TR reamer for unturned necks . I havent decided totally on whether i will be using 155's or 185's but will have to decide before I order a reamer.

TrxR,a little off topic of turning here but I wanted to relay my reamer experience to you .
I have a similar build on my Palma rifle, 30 inch Kreiger, 1-12 Twist, PTG reamer I specified with Dave Kiff for runnning 185 Bergers, and no turn Lapua neck. .003 on each side for a total of .006 neck clearance.no issues there with my Lapua brass, getting .0025 or less runout worst case.

The freebore needs to be long with the 185's , mine is specified @.110
I run the 185's .040 off the lands now which keeps the Berger 185 out of the neck shoulder junction(and avoids the donut). any more than that and its powder compression with 43.6 grains Varget.

when trying to chamber the 155.5 fullbore bullets up in this same chamber I will be jumping .200 to the lands with the 155.5 seated just above the neck shoulder junction.(like .030 MAX) so a pretty long poke.
( Short bearing surface 155s still need some neck to hold them) you might be able to get away with a little less freebore than I ordered on my reamer, say.090 or so but I wouldnt go any shorter than that if you want to run the 185's. you will need the room to stay ahead of the donut.

I have not shot the 155.5's yet but I can only imagine what the outcome might be with jumping .200 but you never know. it might be fine and that would be great to be able to run both.

Patrick