Partial Sizing of Bottle-Neck Cases?

[dovehunter]

I am gearing up to start reloading for my new .223. Up to this point I have always fully full-length resized all my bottle-neck cases but thought I may try something different with the .223. I have frequently read over the years that it is a good idea to adjust your full-length resizing die not to bottom out against the shell holder for reloads that will always be used in the same gun. I have also read somewhere that a good rule of thumb for doing this was to place a matchbook cover between the bottom of the resizing die and shell holder when adjusting the die. Is partial sizing (and also the matchbook cover bit) a sound practice or just a lot of bull?


Now don't start talking neck-sizing dies here as I intentionally did not get them on the off chance that I (or maybe my son for whom I reload) would get another rifle in the same caliber.

[Adam Helmer]

dovehunter,

I partial resize all my bottleneck cases even for the three Match M14s I have loaded for. Rather than use a matchbook, I suggest you use the Individual rifle to "tell" you when you have sized the case enough. I relaod for specific arms and have the rifle at the bench when I reload for it. I back off the resizing die a half turn, run a lubed case into the die and then try it in the rifle. If NO GO, I turn the sizing die down a bit and try that case again. Once I get a slight crunch fit, I lock the die and record the setting for future reference. I put a reloading data sheet in the box of reloads indicating the specific rifle the loads are for. Backing off the sizing die to size to the case shoulder is critical in my 7mm RM. Failure to do so gives case seperations quickly.

Recently a guy came by with his .300 Weatherby dies and components to load for his Remington 700 rifle. I asked him where the rifle was and he said at home. I told him he had to go get the rifle so we could load for it. He went and got his rifle and then we reloaded.

Adam

[Ol` Joe]

You`re best to do a minimal resizing like Adam recommended. The 223 and other straight(er) walled cases like the 308 based brass tend to size some in the body area when partial sizing and this moves the shoulder foreward some. Brass with a taper such as the 30-06 work better IMO...........

[Adam Helmer]

Ol' Joe,

Thanks for the concurrance. I size for specific rifles by having them at the bench to "Tell" me when the case is sized just enough.

The instructions with most reloading dies instruct to set the resizer die down to the shell holder and then move the lever and give it a quarter turn more. NO, No, No: that is far too much and with the .303 British and the 7mm RM will give case separations on the next one or two firings! Each gun is an individual and requires individual sizing.

One more thing: Be sure to put a dated loading slip in each box of reloads with all the loading data for future reference. Be sure to state if it is the 1st, 2nd or 3rd loading and date of last case trimming.

Adam

[Catfish]

I have had trouble in some rifles when partialy sizeing the necks, but in over 90% of them it seem to work. As far as haveing any advantages I have seen none in accuracy, but with some custom rifles that had over sized chambers it would help with the cases splitting just over the web if you could get them to chamber. The only way to know if you`ll like it is to try it.

[Ridge Runner]

yep I always punch a size bigger expander ball through the first case and use it to set the FL sizer to partial FL resize to min. headspace. I very seldom ever have to trim and get excellant case life unless its one of my LR rigs that I run pretty hard.
RR

[Rocky Raab]

Partial sizing works, but as some of the guys above have said, you MUST at least touch the shoulder. If you stop before you size all of the neck and also bump the shoulder, you leave a bit of space between the die and the shoulder. Then, because you are squeezing all the OTHER brass of that case, the brass expands into the only place left - and that causes the shoulder to move forward. You may well end up with a lot of loaded ammo that won't chamber. Don't ask how I know that, OK?

To set up, adjust the die full down against the shellholder, and then back it off a full turn. Size a case. It probably won't chamber. Screw the die down a tiny bit at a time, trying each case in the rifle until the slight amount of resistance you feel when closing the bolt just disappears. (Use a fresh case each time or the gun test won't work.) Then come down a final very small amount (perhaps 1/16th turn of the die) and lock it. Resize and test all the brass again; the bolt should close with only a whisper of "feel." Test again after firing and sizing those cases. If the "feel" is the same after the firing/sizing, the die is set.

[PJgunner]

This is how I set up my sizing die for bottleneck cartridges.

1. Take a once fired factory round and blacken the neck and shoulders with a Magic Marker or Sharpee pen. Some people like to smoke the neck and shoulder, but I find the Magic Marker/Sharpee pen a bit better.

2. Carefully lubricate the case.

3. Loosen the lock ring on the sizing die and back off about two turns from when the die is set to touch the shell holder.

4. Size the case. Note where the marks are on the case and turn the die down about a half a turn and size again. Turn down some more, and resize again. What you are looking for is the marks on the blackening just touching the shoulder.

5. Clean the lube from the case and try it in the rifle. It may chamber just a bit on the snug side. If so, turn the die down ever so slightly, lube and size again. Wipe off the lube and try in the rifle. If it slides in as easily as a factory round, you should be good to go. If not, usually one more very slight adjustment should fix the problem.

6. Tighten the locking ring for the die and you're done. You have just set your sizing die up for a custom fit to your specific rifle, rather than a generic one size fits all guns.

Paul B.