Full length sizing.

[jss227]

I just neck size for my bolt guns. Each gun is marked with a small painted square on the receiver, and the ammo for each gun has the same color painted on the case, and the boolit powder coated to match. It makes life easier when the boys and I shoot multiple guns of the same caliber.
Anyway, why full length size for a semi auto if the brass is going to be shot in the same gun? The chamber doesn't change.

[Winger Ed.]

The chamber doesn't change, but the brass does.
It expands on firing, and then contracts--- just a little.

Sometimes the brass gets 'sticky' and doesn't want to chamber up or extract during the semi-auto's cycling process.
With a bolt gun, when that happens, you have the ability to use a little more force/leverage to open/close the action if needed.

[Tatume]

Neck sized cases can be stubborn in my across the course match rifle, especially in rapid fire. My cases get full-length sized in an RCBS X-die. With the X-die there is no reason to neck size only.

[Winger Ed.]

^^^^ this^^^^



This subject has come up from time to time over the years on most shooting forums.
In all threads on the subject, the folks that shoot for cash & prizes, all say they full length size.

[BK7saum]

You will need to full length resize eventually, more often as the pressures increase max for the caliber. I want everything to be consistent. Resizing and bumping the shoulder 0.001-0.002" each time is consistent. Neck sizing twice and FL sizing the third time is not consistent.

[Recycled bullet]

I like to partial full length size.

[jss227]

Thanks for the info.

[Larry Gibson]

Keeping the fired cases germane to the rifle they were fired in, I seldom FL size with the majority of my cast bullet loads. This is because the pressures of most cast bullet rifle loads are low enough there is really little expansion of the case.

[jss227]

Thank you, Larry.

[popper]

FL size to insure chambering.

[Baltimoreed]

Been reloading lead boolits in my krags and 03s and only neck size my brass. But my krags are weird enough that the brass has to be full length sized to work in any of the 3 but the 03s are fine with neck sized brass. I segregate the neck sized 30-40 for each rifle, trying not to overwork my 30-40 brass.

[M-Tecs]

I gave up neck sizing only about 40 years ago. I do size for specific shoulders bump amounts. I am a big fan for the RCBS Precision case mics or the Hornady case comparators.

[GONRA]

jss227 GONRA sez - ALWAYS FULL Length Resize for Semi Autos! !!
(Avoid Slamfires! !!)

[popper]

Gonra is very correct! A 308w going off in the house is very noisy and breaks stuff.

[jss227]

jss227 GONRA sez - ALWAYS FULL Length Resize for Semi Autos! !!
(Avoid Slamfires! !!)

But slamfires can be fun

[Winger Ed.]

But slamfires can be fun

True. However-
Most are better to read about than to have happen to ourselves.

[Larry Gibson]

Most "slam fires" occur with factory or full length sized cartridges. The root cause is a poor trigger job or worn/broken parts, mostly the poor trigger job as in adjusted/honed to too light or not enough sear engagement. In semi-autos the jarring of the action closing causes the hammer to "bounce" off the sear actually firing the gun. It can easily happen with bolt actions also by "slamming" or closing the bolt fast. In full auto's it can cause what's called a "runaway gun". Other than that of the unintentional discharge(s) there's no real danger of damage to the gun.

Now an OBD, "out of battery discharge", is another story.

[fixit]

I agree with the partial full length.... just a little resize of the body, and you get a neck size in the bargain! If they get too snug, I'll go and bump the shoulder, but otherwise, it's good.

[BK7saum]

I agree with the partial full length.... just a little resize of the body, and you get a neck size in the bargain! If they get too snug, I'll go and bump the shoulder, but otherwise, it's good.

I have had issues with partial resizing. When partial sizing of the body occurs, brass has to go somewhere. Where does it go? It increases the base to shoulder dimension. The brass being squeezed pushes the shoulder forward. In my experience, partial resizing causes more problems than it solves. It is either neck size or full length resize. I prefer to full length resize for consistency when shooting high pressure loads.

Low pressure cast loads can go several/many reloads without full length resizing. One other factor to consider is shoulder setback. Shoulder setback of low pressure loads may mitigate the shoulder movement with partial resizing. I have had shoulder setback severe enough to cause failure to fire from headspace issues.

Full length resizing of brass in bolt-action rifles has worked flawlessly for me. I set up dies and verify shoulder bump to 0.001-0.002". Brass lasts many reloads in even my high pressure magnums.

[popper]

IIRC the russians put a spring on the FP to prevent AK 'full auto'.