Neck tension

[VinceMule]

are you saying each piece of brass was fired 300 times?

yes
6 XC
40.5 (3050 fps)41.5g of H4350(3150 fps), Rem 7 1/2
Berger 105-108, Hornady 105 A max
Reamer and brass match with .002 clearance on the web on new brass, which is considered a Match chamber, and I use Whidden bushing full length sizer, FL sizing on every firing.
.147 freebore chamber, .275 Neck dia
.400 long neck to use on the Palma formed brass, which dropped pressure, my best guess
8T X caliber barrel, 31" finished length
.2370 bore dia, ifrom breach to muzzle
RAS Tuner/Brake
This is without a doubt the very best shooting barrel I have ever owned, and I have had several dozen 6 and 22 ppc's of which none had a Tuner/brake
I had .007 leade growth in 900 rounds
Throat dia grew .0002 in 900 rounds, both of which I attribute to the long neck.

 

[Phil Rizzo]

Must be a Creedmoor…..

 

[BrentM]

For fun and since I had never done it before....... took my neck turning mandrel (.264) and tested 2 bushing sized cases. Sized one with .286 bushing and another with a .291. Running the mandrel through each and measuring the OD..... both are .292.

 

[SSG Graybush]

Tubb as you know has a HUGE neck on his 6 XC design, so you size it down with a .005 bushing and there is spring back.

I made 6 XC cases from Lapua 308 Palma cases. On one barrel, I have 30 cases formed, and I have over 300 firings on those 30 cases using H4350 with 105-108g bullets. 31" barrel is producing 3150 fps shooting very tiny bug holes with the RAS tuner/Brake. I do anneal and full length size every firing with a Whidden bushing FL sizing die.

I believe he designed it with no neck turning in mind, but my Peterson brass OD is 5 thou larger fired then sized. It's a bit much. But it shoots consistent holes at 100. Criterion may have took a bit to much metal. I shoot a 112 gr Barnes MB, cci 400, 39.6 grs of H4350, at 2917 fps, ES of 12, moa is ~ .25. I use a Redding comp seater die with a vld seater stem, but I have to seat long, sort by CBTO, and press by lots to the desired CBTO. The MB's will give a varying CBTO if I don't, and it affects accuracy, slightly. I could only get 112 gr MB's at the time of build, so I figured them out and stayed due to their .612 g1 bc.
It's like Barnes uses 6 machines to press these bullets, and each has a slightly different ogive where my die makes contact. But they shoot.

 

[Taylorbok]

I believe he designed it with no neck turning in mind, but my Peterson brass OD is 5 thou larger fired then sized. It's a bit much. But it shoots consistent holes at 100.

Cortina advocates .005" neck clearance.
I have some chambers with .005" and some that are like .001" and in general the ones with less clearance seem to shoot better. That is just my very limited experience

 

[BrentM]

Cortina advocates .005" neck clearance.
I have some chambers with .005" and some that are like .001" and in general the ones with less clearance seem to shoot better. That is just my very limited experience

.001? Yikes. I would flinch every time I pulled the bang switch

 

[xsn10s]

.001? Yikes. I would flinch every time I pulled the bang switch

 

[swampbug]

Cortina advocates .005" neck clearance.
I have some chambers with .005" and some that are like .001" and in general the ones with less clearance seem to shoot better. That is just my very limited experience

.0005 per side. Don't want to be laying next to you.

 

[Taylorbok]

.001? Yikes. I would flinch every time I pulled the bang switch

.0005 per side. Don't want to be laying next to you.

Meh never caused an issue in the 2 chambers that were like that. One was a 300 RUM the other a 22 Creed. I actually saw an interview with Cortina and a BR shooter (can't remember who) He intentional set up his chambers that way. Mine was not intentional, just a reamer the smith had but both seemed to shoot any load well, I've actually been considering the next reamer I order to do it intentionally.

EDIT: The BR Shooter is Bruce Teel

 

[BrentM]

Yeah I can see a comp rifle but a hunting rifle….. yikes. Moisture, debris, boogers, wife's hair…..

 

[VinceMule]

I do not believe that there is a way to know which bushing will work the best without trying various sizes. I reload at the rifle range, and I have seen various sizes work better/worse per caliber. I suspect that powder burn rate, and primer choice has a impact. One thing for darn sure, as you give the bullet more grip, the pressures go up(.002-.005 bushings or mandrels), and it is trial and error to find what groups the best.

Work hardened brass leads to helter skelter results, no matter the methodology used in sizing. A guy that is annealing with just a candle is way ahead of a guy that does not anneal at all.

During reloading, pay close attention to how the bullet seat,. When you chamber a round in the rifle, also pay attention on how uniform the bolt is closing from round to round.

 

[wasskeet]

Dasher here with no-turn neck. It is running about .007" clearance with Peterson brass. Seems to do very well, but I expect I won't get away without annealing after a few firings.

 

[MagnumManiac]

Interesting, my own reamers have .003" neck clearance, BUT, I turn my necks to have .004"-.005" max.
My custom 25-06 match reamer has .006" neck clearance and I find it a PITA to keep brass consistent… I have to use thicker necked brass mostly, Norma is thinnner, so it gets used in my Kimber, which has .004" clearance with factory match chamber.

Cheers.

 

[PatriotHenry]

.0005 per side. Don't want to be laying next to you.

I believe that is total, not per side. So 2.5?