neck sizing help please

.303

.303

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Hi everyone-

I am just 5 months new to reloading. having no issues whatsoever reloading for my 300 WM.

I also have a 303 British and I was informed that pretty much I need to neck size or else will encounter problems after probably the 2nd-3rd use of the brass.

Can someone dumb down instructions on how to neck size please.

I have RCBS press and dies for the 303.

In theory can I just not find out where the point of Full resize is on my die and back the threads off however much to only neck size?? or am I way off base?

Any help is much appreciated.
 
This is really simple for the 303 Br.

Turn your sizing die out about one full turn from being in contact with the shell holder, and size a case.

Test to see if the case will chamber in the rifle. If it does you're good to go.

If it will not chamber, turn the die in about 1/8 turn, and repeat. Try to chamber again. Do this until the case chambers easily.

Lock the die at that height, prime, charge, seat bullets, and go to the range. :)

Ted
 
If you really want to extend the life of your .303Br brass, then you should fire-form them using a small o-ring against the base. This keeps the base against the bolt head, takes up the slop in headspace, and causes the case to then headspace on the shoulder which increases brass life since you are not constantly stretching the case each time you fire it. Neck size only until you have to bump the shoulder back. You should be able to get 15-20 reloadings this way, unless you are going to full bore loads.
 
Use a marker to scribble lines on the neck and down a little more, and keep adjusting your die until the marker is rubbed off the neck and stays on the shoulder. Takes some experimenting, but you'll get it right after two or three attempts.
 
.303 said:
In theory can I just not find out where the point of Full resize is on my die and back the threads off however much to only neck size?? or am I way off base?
Click to expand...

You have it exactly right, and that may be the very best way. The only slight issue is measuring how much is enough. On one hunting cartridge I do a partial FL sizing, that only sizes 2/3 of the neck. I've gotten away with it for a few loads, and I will continue to do so until the bolt starts to tighten up on closing.

Sooner or later I will likely have to push the shoulder back some. Ideally you only want to move it back 0.001-0.002", and no more. The hard part is measuring it. You have been given some good simple methods of getting close in the other posts. The other way is to buy a gauge. Hornady calls it a headspace gauge (incorrectly in my opinion), but it really measures base to shoulder. That is probably the most accurate way to know how much you are bumping the shoulder back.
 
Ron AKA said:
You have it exactly right, and that may be the very best way. The only slight issue is measuring how much is enough. On one hunting cartridge I do a partial FL sizing, that only sizes 2/3 of the neck. I've gotten away with it for a few loads, and I will continue to do so until the bolt starts to tighten up on closing.

Sooner or later I will likely have to push the shoulder back some. Ideally you only want to move it back 0.001-0.002", and no more. The hard part is measuring it. You have been given some good simple methods of getting close in the other posts. The other way is to buy a gauge. Hornady calls it a headspace gauge (incorrectly in my opinion), but it really measures base to shoulder. That is probably the most accurate way to know how much you are bumping the shoulder back.
Click to expand...

I am trying the partial resizing on my 303. thought i could get 3-4 sizings before i would fl size.
 
Mturn... - You're confusing neck sizing using a neck sizing die, with partial resizing using a FL die. If you are partially resizing, you can do this repeatedly without FL resize. The other potential advantage with the partial resize is the ability to use the same brass with different rifles - just resize to the tightest chamber. If you use a neck sizing die, you will end up having to segregate brass for each rifle.
 
cosmic said:
Mturn... - You're confusing neck sizing using a neck sizing die, with partial resizing using a FL die. If you are partially resizing, you can do this repeatedly without FL resize. The other potential advantage with the partial resize is the ability to use the same brass with different rifles - just resize to the tightest chamber. If you use a neck sizing die, you will end up having to segregate brass for each rifle.
Click to expand...

Yes maybe i am.thanks,Could you explain the differance between Partial and neck.Does shoulder get resized with partial.thanks
 
Mturney said:
Yes maybe i am.thanks,Could you explain the differance between Partial and neck.Does shoulder get resized with partial.thanks
Click to expand...

Not much difference. I do partial neck sizing as well as partial FL sizing. In partial neck sizing you only size the neck down. The shoulder and body remain untouched. In partial FL sizing if you only do part of the neck, then you will not move the shoulder back at all. You may start to slightly reduce the body, but probably not much if at all.

If you go one step further still and bump the shoulder back 0.001" you will size the body, full neck, and obviously bump the shoulder. They still may not fit another gun than the one they were fired in. You normally have to ram the shell holder hard against the die to do a real FL, and even then the sized case may not fit a gun it was not fired in.
 
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