Chambering a blank?

[WestKentucky]

I have looked online and can’t find the answer to this… what is the difference between chambering a barrel and “chambering” a full length sizing reloading die?

I know that the die needs to be ever so slightly tighter than the barrel chamber because A. Brass springs back a bit coming out of a loading die B. Ammo has to be small so that it feeds rather than presses into place, and C. Brass springs back minimally after firing which allows it to eject out of the chamber, so it has to be smaller to ever spring back instead of get stuck.

If a person were to cut a rifle chamber, then take the reamer down a couple thousandths in diameter then chamber a hard steel die blank would that work for sizing?

I’m just trying to wrap my brain around the mechanical and machine tool differences in the two very similar but also very different cuts. For simplicity let’s say it’s a steel die not a carbide ringed pistol die.

 

[WestKentucky]

Maybe it makes more sense to say it this way… you chamber the chamber to chamber spec, and you cut the die to a smaller dimension to make the ammo match the dimensions you are wanting to achieve. Clearly the reamers are similar but reloading die reamer is slightly smaller. In this random SAAMI print I took straight from the saami website, it looks like ammo dim is 10 thousandths under chamber dimension, and since ammo is springy maybe a reloading die be ever so slightly smaller than that even…maybe .012 smaller or so.

 

[NMexJim]

Full length dies are built to return brass to SAAMI spec which will allow the reloaded cartridge to fit, in theory, all firearms in that caliber. I’m sure there have been exceptions, but generally a reload using these dies should fit all firearms in that caliber.

There are small base dies that take the bass a bit smaller than SAAMI for use in some semi-auto rifles.These ensure feeding under rapid fire conditions. The early Browning BAR sporting rifles sometimes needed small base resizing.

And then there are custom dies which are usually built to a fired case from a specific rifle. This gives the customer a custom fit for that particular rifle.

It’s all about finished cartridge size.

 

[243winxb]

If a person were to cut a rifle chamber, then take the reamer down a couple thousandths in diameter then chamber a hard steel die blank would that work for sizing?

Roughing Reamers are said to be smaller then Finish Reamers. So.......Maybe?

 

[Kp321]

Pretty much any other 30 cal, just don't push them to fast. What other 30cals do you have

Roughing Reamers are said to be smaller then Finish Reamers. So.......Maybe?