300/221 Case Gage

[Mark IV]

Does anyone know where I could pick up a 300/221 case gage? I would like to start forming some brass and do not have a rifle yet to try them out on. Thanks for the help.

[Hoser]

A gunsmith with a 300/221 reamer can make you one. Its best if the reamer that did your chamber is used to make the gauge. I have one for my AR in 223 Ackley.

[Fastshooter03]

Do you mean a drop in guage or something to use with your calipers?
I use the Stoney Point/now Hornady measuring equipment that goes on your calipers for measuring headspace and base to bullet ogive on my other calibers but I don't think I had one that would work(headspace) with the 30-221. It is the only way to really know what's going on with your rifle and dies.
I took my reamer and made my own a few weeks ago the night before deer hunting since we were having trouble extracting live and fired rounds. It turns out some of my ammo was way long on the headspace and some was where they were supposed to be.
THe piece I made was basically a stainless tube with the through hole just over the loaded round's neck diameter and long enough a loaded round won't stick out. I ran the reamer in about half way(could've gone a little further for better support) so basically you drop a fired case into it then measure the distance with a calipers from the tip of the tool to the bottom of the case sticking out and that's what your chamber size is(for that particular rifle/pistol). When you size brass use the tool to set your die so the headspace is a few (.001-.003") shorter than the fired case. You're basically comparing the fired case's headspace to what your sizing your new brass to.

Nick

[MadDog]

I got a 300 Whisper case gauge from SSK Industries. It may not be to the exact same dimensions as your 300/221. It was reasonably priced if I remember correctly.

Joe

[Mark IV]

Thanks guys, yes, I am just wanting a drop in gage. I was really wanting to start forming some brass before my barrel got here so I could be ready to roll. I think I may talk to the guy who is going to make my barrel and see if he will make a gage while he is at it.

Thanks again.

[320pf]

Mark IV,

I suggest that you just wait until your barrel arrives. With the 300-221 Fireball, when you form your brass you can set the shoulder exactly to match your chamber so the headspace is perfect. If you want to get a jump on making brass, I would just trim it to length (~1.400) and not form the shoulder. It you look just like a rimless 357 mag cartridge.

(See my post here: http://www.quarterbore.net/forums/showthread.php?t=1763)

Once your barrel arrives and you mount it in the receiver, you can then start forming the shoulder. Mount the resizing die in your press. With the ram all the way up screw in the resizing die until it just touches the shell holder and then back it out about 0.02" to 0.03". Now make a singe piece of brass and try it in your rifle by putting it in the chamber and gently closing the bolt. It should not fit because the shoulder is too far forward. Do not force it or else the case will get stuck in the chamber and you will have to use a rod to get it out. Now screw down the resizing die a bit and try it again until the bolt just closes with a slight effort. You can check this by coloring the shoulder with a sharpie pen... You should see a ring on the shoulder where is contacts the shoulder of the chamber.

Now you are really close but slightly too long. If you are using a bolt rifle you can run with the shoulder about 0.002" to 0.005" long. When you close the bolt the cartridge will be press into the shoulder of the chamber and will be tightly supported. This should give you very good accuracy because the each cartridge is "fit" to the rifle chamber for the best consistency. If you are shooting a semi-auto you do not want a really tight fitting headspace because it can have an adverse effect on the cycling of the action.

Hope this helps and good luck

320pf