Resizing

[fguffey]

Do some/all of your rifles show quite a bit of difference?

I have at least 25 8mm57 Mauser barrels, out of the 25 18 of them will have .110" case head protrusion. I purchased 4 Mausers that were advertised as suspect, I removed all of the barrels and then selected one 30 Cal wildcat barrel and one bolt to test fire all 4 receivers. There was not .001" difference in the length of the chamber when testing all 4 receivers. Again, I used one bolt for all 4 test.

A reloader can off set the length of the chamber with the length of the case from the shoulder to the case head. I have always thought there was a problem with cases available from manufacturers, they do not sell cases to reloaders that know what they are doing. If they sold cases to knowledgeable reloaders the cases they sold would not chamber.

F. Guffey

[J-cat]

Re OP’s question:

Only the finest rifles are machined correctly and have bolt faces square to the bore centerline. Your typical RemmySavageWin has bolt face runout which causes the case head to conform under pressure out of square to the bore center. You take that case and put it on a level surface and it will tilt to one side. When you neck size only you retain that mechanical aberration. This in turn will make the bolt harder to close with each reload cycle, ultimately leading to bolt lug and/or recess damage.

FL sizing with .002” clearance makes the bolt happy and does not shorten case life.

[fguffey]

Only the finest rifles are machined correctly and have bolt faces square to the bore centerline.

Long before the Internet a shooter/reloader/writer for gun magazines published his results, again, he purchased 500 cases from one manufacturer and sorted, fired and sorted again etc. etc. and then he starter over with what most would call culls. He found if he indexed the cases that did not standup straight accuracy improved.

F. Guffey

[LynnJr]

Guffster
If the cases won't stand up straight how did he get them in the chamber?

[J-cat]

Bolt action rifles have a lot of camming force that enables successful chambering of crap ammo.

[russ69]

I reserve neck sizing for benchrest cartridges only. Only used when I'm going to use a couple of wind flags.

[bazineta]

One advantage of neck-only sizing is that you're quite obviously not moving things more than you'd prefer, because you're not moving them at all. However, I prefer to FL size, but in a controlled manner, using a gage (Redding Instant Indicator in my case) to ensure that the case isn't being over-sized.

I think that having something like that to validate the amount of sizing is key, as the threads on standard dies are very coarse, especially when dealing in thousandths. When I've installed sizing dies per the manufacturer's instructions, most often it results in an over-sized case.

[fguffey]

I reserve neck sizing for benchrest cartridges only. Only used when I'm going to use a couple of wind flags.

Reloading forums are overloaded with replies like: "Mature reloaders do like bench resters as in bench resters have been full length sizing their cases for 2 decades" and then there is that other quote "the case can fit the chamber like rat scat in a fiddle case". And I am going to assume the pendulum has changed directions and headed in the other direction.

F. Guffey

[smoothy8500]

Only used when I'm going to use a couple of wind flags.

So, you ignore the flags in XTC?

[tonyjr]

I only do neck sizing .
When checking OAL , I seldom come across a long one .
Here it is over an hour to 100 yard range . 1/2 [ depending
on traffic ] to 50 yard or indoor range .
I found no difference between FL and neck sizing , but only
did sighting in when I was hunting . 20 reloads w / F L and
20 with neck sizing , group sizing was close enough to blame
myself , wind or just position . Off hand standing or kneeling .
Even now , my ladder tests are off hand .

[smoothy8500]

Hmmmm, fascinating...

[tonyjr]

smoothy8500
If I need to shoot something , I won't have time to set up
a bench rest .
Other than when I was hunting , the only time it came in
handy was in 'Nam and once in Mexico . A rabid dog was
coming up street - people yelling and slamming doors -
anyway it took 3 shots , one bounced off head , one in
leg and the last thru chest .
There , if they even think the animal is rabid , they burn
where it lays .

[LynnJr]

Kevin750
When Benchrest shooters full length resized there brass the chamber matches the dies perfectly. You can buy a 5 die set that incrementally runs in 1/2 of a thousandth increments so you end up with a perfect fit.

When your running factory chambers most dies you can buy off of the shelf will oversize the shoulder area of the brass which tends to raise your extreme spreads.

Neck only sized brass doesn't get larger with each firing it looses it's ability to spring Ackley and this causes it to get sticky in the chamber.

[kevins750]

Kevin750
When Benchrest shooters full length resized there brass the chamber matches the dies perfectly. You can buy a 5 die set that incrementally runs in 1/2 of a thousandth increments so you end up with a perfect fit.

When your running factory chambers most dies you can buy off of the shelf will oversize the shoulder area of the brass which tends to raise your extreme spreads.

Neck only sized brass doesn't get larger with each firing it looses it's ability to spring Ackley and this causes it to get sticky in the chamber.

Thanks Lynn, I have been doing a lot of reading about sizing lately,I will probably never compete seriously but fascinated by the different processes.

I have shot good groups both ways and am getting ready to stretch it out hopefully to 1K.

[smoothy8500]

If I need to shoot something , I won't have time to set up
a bench rest .

Just interesting that you do ladder tests offhand. Most everyone else worries about verticle dispersion and it is pretty hard to control any movement offhand...at least my offhand anyways.