If you're only shooting ammo in the same gun that it was originally fired in then neck sizing should do it assuming we're talking about a bolt action. Most semi-autos need full-length resizing.

Full length size, or some variation like 0.002" shoulder bump.

I know there is some amount of debate but I really can't see the point of neck sizing only. The arguments for it are usually flawed to me. There is a pro shooter named Eric Cortina and him hating on neck sizing is very gun-nerd funny to me. even has a shirt about neck sizing.

I full length size...... at shooting competitions I have yet to find a person that neck sizes only. Now there are some people that size the body then neck size but that is ultimately FL sizing in my mind- just in separate steps.
I have multiple guns in the same caliber and I don't want to have to assign brass to particular guns which is another reason for FL.

Neck sizing only begets trouble chambering and/or trouble extracting.

.002" shoulder bump yeilds excellent ammo that is also reliable to chamber and extract.

Maybe some people need to see for themselves someone else stomp on a bolt handle with their foot to extract a neck sized brass that has just been fired again.

A lot of people should watch that video and see how world record holders size.

Years ago, when My 220 still had its first barrel, I used a FL die to Partial Resize, which is similar to neck sizing. I’d set the die to size about 2/3 of the case neck. Being a tapered case, sizing in this way did not touch the case shoulders, but would resize near the case head. Nosler reloading manuals back then described the technique, but they left that info out of the newer Nosler reloading books. I made some very accurate ammo with that technique. Over time and repeated firing, the brass would eventually need the case shoulders bumped back a bit.

That Partial Resizing is worth a try if you want to neck size without a neck sizing die. It’s just a version of a FL sizing with the shoulder bump, but without actually bumping the shoulder. I only used that approach with tapered cases like the 220. If you try it with a straighter walled case, like a 22-250 AI for instance, I think the die will touch the outside edge of the case shoulders and move them forward and maybe cause chambering issues. You might could adjust, or lessen the amount of the neck being resized in order to avoid touching the shoulders, but that would depend on the case in question and the degree of taper.

I FL resize nowadays, with a small shoulder bump, but I think I got slightly better accuracy with the 220 with Partial Resizing. Hard to be positive of that though, now that I’m on barrel 2.

If you have a little spare time to try it out, and a tapered wall cartridge case, try it out. Don’t ask how much taper is required because I don’t know.

FL size with a slight shoulder bump, or a full FL size. I will never neck only size again.

Only use for a neck sizer I have it to fix dinged case necks on new brass. Can certainly do it with a FL die as well.

I bump around .03, partially due to the difficulty of actually measuring in the .001s. My Mitutoyos are only rated to accuracy +- .001", and my own user error.

For some reason I can't attach the video and still make it work?

For some reason I can't attach the video and still make it work?

Some videos on youtube have a setting that you cannot imbed the video in a website

the benchrest guys neck size, then FL after few firings

you just have to be mindful of changes and stick the
case in the body die once in a while

When i was just getting into reloading I used a neck sizing die for my 300 wby because I was trying to make my brass last as long as possible. I have a few runs of brass laying around with 10+ firings on them (all norma brass) never been annealed, full length sized every 3-4th firing and neck sized in between. Never had an issue of any kind with it. Ive never attempted it with anything else and probably wont again.

On my bolt guns the majority of them use a belted case and I've never had the problem that you're describing. If I was shooting a .30-06, 270, or 308 would I be more apt to run into the issue you're describing?

While we know the belted magnums headspace off the belt. The shoulders still flow forward. My 7 Rem Mag, and a 7 Rem Mag I loaded for 4 weeks ago, ironically flow the same amount. Virgin, SAAMI brass to fired, the shoulder moved forward .013" in one firing. My thinking is, yes the non-belted cartridges are more likely to wedge in the chamber, but it can still happen to the belted cases. .002" shoulder bump on everything I own, including the 7 Rem Mag. They all shoot great, and give no trouble going in or coming back out of the chamber.

There's no good reason IMO to bump shoulders back after every firing, and to be specific I'm talking about brass fired from a designated rifle only, fire-formed so to speak. Neck sizing for a hunter will result in ammo that is likely more accurate than the shooter is capable of anyway, and what a PRS shooter, competition shooter does, etc is of no importance to me. Only when brass gets stubborn and hard to chamber will I bump shoulders back with a body die, not a full length sizing die. I've been doing it this way for years and my runout numbers are miniscule, especially after annealing brass after every 2 firings. I like the brass to fit like a glove in the chamber with minimal stretch. Fire formed brass accomplishes this.

We are only talking .002 of bump, It will still fit like a glove and be more likely to not stick a case in bad conditions. I wouldn't neck size on a hunting gun, too dusty and dirty to take a chance for me.

I tried neck sizing and lost a lot of consistency on my loads. Went back to FL sizing (.002-.003 shoulder bump) and groups shrunk down again

I use to be a big fan of the Lee collet die and I still like it for ease of use, no lube required, but I don't use them anymore. Now I use a FL die, turning the die down in the press using very small adjustments to just bump the case until the resistance when closing the bolt on a sized case is the same as closing on an empty chamber. You can definitely feel when you've got it right especially if you remove the ejector.

This guy is as good as it gets at what he does and he bumps his shoulders.

Good video as a reply.

Neck sizing can introduce problems. Problems chambering, and/or problems extracting.
Shoulder bumping will not allow those problems to happen. And the ammo shoots just as tight as neck sized ammo.

Yea I started out neck sizing and never liked the way the bolt shut. I learn a lot from everyone here and other sites. I appreciate all the info I collect from all you guys. I bump my shoulders 2-3 thousandths and load some pretty solid ammo doing it