Full Length or Neck Only; What's Best Resizing for Accuracy?

[tim_w]

Im a little slow, so what are you advocating?

Its ok after this thread I'm not even sure what I mean anymore.

Seriously what I am advocating for LR hunting is sizing a case only the absolute minimum needed to reliabily chamber and extract from your chamber in the conditions you hunt in. For most that means a chamber die setup that gives you not more than 0.002 body clearance and 0.001 in headspace. Why? Even if we assume a case could have 0.010 case body clearance and shoot the same tiny groups? Case life. Min clearance also does not hurt accuracy I'm fairly sure no one is arguing that point I hope.

Sorry if how I stated things made it confusing.

A large part of this thread seems to be going in circles IMO.

IMO fl sizing done correctly allows for looser tolerances between things (chamber runout square bolt face, case runout etc) being deadnuts perfect with only the smallest degree in accuracy/consistency possible loss which I can only see coming up in BR comps. Most people on here are not concerned with 0.100 moa 5 shot variances. But it does seem the majority want to use the highest accuracy node possible without case pressure signs abd getting the most reloads from their cases. IMO best way to do that is hold sizing sized clearance as close to chamber as allows reliable in the field chambering.

 

[Buck Buster]

40 or more full length sizings of 308 and 30-06 cases using maximum loads is common if done right.

 

[Buck Buster]

40 or more full length sizings of 308 and 30-06 cases using maximum loads is common if done right.

I have some military brass 30-06 cases that probably were loaded 80 or more times, we have had then since back in the 50's ! Some have been tossed but some have been around a long time !

 

[J E Custom]

But wouldn't it work just the same if you were to do it after firing then after turning necks everything would realign on the next firing? The reason I am asking is I'm considering starting to turn necks. Want to be sure if I do that I don't have to start with new brass.

I turn all of the necks on my cases, some are new and others are once fired. I have some friends that don't re load
and they save me their brass because it goes with my reamers and chambers. when It is fired without first turning,
It will take two firings before it is perfectly concentric inside the neck and on the OD of the case.

If I turn the case when new, it only takes one firing to do the same, and I can start load development sooner and work the brass less.

So the answer is yes you can turn after the first firing, but it saves the case from being reformed by the chamber because once it has been fired with the neck thickness difference, it will adhere/form to the chamber and move the neck bore off center by the amount of the difference, and then have to move it again.

It is just the best way I have found to true my cases If I can do it on the first firing.

Jerry

 

[Tikkamike]

I turn all of the necks on my cases, some are new and others are once fired. I have some friends that don't re load
and they save me their brass because it goes with my reamers and chambers. when It is fired without first turning,
It will take two firings before it is perfectly concentric inside the neck and on the OD of the case.

If I turn the case when new, it only takes one firing to do the same, and I can start load development sooner and work the brass less.

So the answer is yes you can turn after the first firing, but it saves the case from being reformed by the chamber because once it has been fired with the neck thickness difference, it will adhere/form to the chamber and move the neck bore off center by the amount of the difference, and then have to move it again.

It is just the best way I have found to true my cases If I can do it on the first firing.

Jerry

Thank you sir. I'm going to send you a PM I have more questions if you don't mind

 

[Bart B]

For what it's worth, back in the day of belted magnums winning matches and setting records, new cases or double sized fired cases I mentioned were most accurate. Military teams often used new cases taking home a lot of the awards and setting records giving their once fired cases to civilians.

 

[Bart B]

In the late 90s and 2000s that was the practice after they moved in 1990. They had a lot of problems with ogive variance when we really started measuring them in late 90s. As I said, I found a variance of.018 and sent a box or two back to prove it. I retoured Sedalia plant 2-3 years ago and Rich made a point showing the new process, one machine and one operator and the positive effects it was showing. Every machine had a slightly different set of dies just due to wear etc.

Every tour I've had at both of Sierra's plants showed each bullet making machine's set of dies had it's own lot number that stayed with those bullets through testing, cleaning, inspection and packaging. If a die needed adjusted or replaced, or a new lot of jacket metal or lead cores, a new lot number was assigned to subsequent bullets. I doubt they ever had more than one machine (set of dies) making a given bullet at the same time.

Only rejects sold as seconds in the plant's store sometimes had mixed production lots.

 

[Bart B]

Sierra had different machines/dies and different operators all running down the line into one box. they had as much as .018 variance in one 100 rd box. I sent several back to sierra techs. Rich M. was a 1k shooter and Sierra tech and was key in getting the one operator/machine into one lot.

Rich Maholz was one of their customer support services telephone operators, never worked in production nor in their test range and played no part in bullet quality areas.

A slight die position adjustment or polishing a scratch in a die would microscopically change subsequent bullets but accuracy still met specs. Sierra did this in their California plant and no other mass produced match bullets were as accurate

Mid Tompkins is the one who convinced Bob Hayden (a top man at Sierra but stubborn at times) to assign a new lot number to a given machines bullets if any change was made. Mid also provided other quality improvement suggestions to their bullet making.

 

[IHFarmer07]

 

[338 dude]

Does one method end up with bullets better centered in the bore when fired? If so, why?

Neck sized would have to do what you were saying simply because it is a closer fit to your actual chamber full sizing gives you more slack and therefore would allow the bullet to slightly be more off-center Simply put although people do both and opinions do very

 

[antelopedundee]

nm

 

[Bart B]

Neck sized would have to do what you were saying simply because it is a closer fit to your actual chamber full sizing gives you more slack and therefore would allow the bullet to slightly be more off-center Simply put although people do both and opinions do very

Where's the rimless bottleneck case shoulder and body in the chamber when the round fires for both resizing methods?

 

[338 dude]

Where's the rimless bottleneck case shoulder and body in the chamber when the round fires for both resizing methods?

I am a neck Sizer and that should enlighten you as to my opinion

 

[RD57]

I've done both, I do both ... I let my rifles determine what technique to use (not the internet). Having a great day shooting is what it's all about! Good thing the government isn't trying to tell us how to reload (yet)! LOL