DIE #4 450 BUSH USE

[snyder1941]

NEWBI HERE JUST TRYING TO CLLECT MY THOUGHTS FOR RELOADING . IT SEEMS TO ME THAT THE USE OF DIE #4 IS CRITICAL FROM A SAFETY
POINT OF VIEW . TO CHECK FOR PROPER NECK SIZE DO YOU USE A CASE WITHOUT BULLET INSERTED AND THEN MEASURE MOUTH . HOPE MY QUESTION
MAKES SENCE .

[Hoot]

Be careful to specify which manufacturer's part designation you are referring to. Different manufacturer's shell holders have different number designators.

Any .4728 rimmed / .4091 extraction grooved (AKA .308) shell holder will work. Hornady manufactures the brass below tolerance by a significant amount. Unlike the .284 Winchester brass you can buy, which is almost exactly those dimensions, Hornady 450b brass comes in at .465-.467 rim / .399-.401 groove. I assume this is to ensure functionality in a dirty AR action.

Case neck size will have the largest impact once it is loaded. The main concern is not having it so small that it fails to catch the lip where the chamber ends. That having been said, I would go as far as say that most if not all 450b brass reloads do not reach that lip because the cases grow shorter as you shoot and reload them. They are in all likelihood headspaced by being retained up against the bolt face by the extractor since I've yet to have a case, either new or old actually actually touch the lip when retained in the bolt. Still, we maintain spec by making sure the mouth is not too narrow.

I adjust my taper crimp die to yield .476 case mouths. It is a compromise to yield good neck tension and not be too narrow so as to pose a safety issue.

Hoot

[pitted bore]

snyder1941-
I assume by "Die #4" you are writing about the fourth die in the Hornady die set -- the taper crimp die.

It may or may not be true that "the use of die #4 is critical from a safety point of view" as you state. One critical point of safety is that the reloaded round conform to dimensional specifications. If the mouth of the case has been belled or flared with the expander die, then the taper crimp die is needed to remove the bell or flare. Otherwise there could be problems with feeding or seating of the cartridge properly in the chamber, which might contribute to an unsafe condition.

When reloading, if seating the bullet results in a bullet held firmly in the case and in a case mouth with no flare that measures about 0.476" OD as Hoot indicates, then there may be no need to use the taper crimp die.

The other safety issue concerning the taper crimp die #4 might involve insuring the bullet is held firmly in the case. If the bullet is too loose, there might be some problems with incomplete powder ignition or hangfires, which can be dangerous. If the bullet is loose after being seated, then a crimp of some sort is needed.

Checking for "proper neck size" is not really a problem with the Hornady die set in my experience. After resizing, check to make sure the bullet can be seated without crumpling the case. Measurement is usually not necessary at this stage. If the neck is too small, then use the expander die to bell the mouth the minimum needed to permit seating the bullet. Use of the taper crimp die is needed to remove the bell from the mouth. It's at this point in the process that the OD of the mouth is measured, as Hoot points out.

If this isn't clear, please ask again. As Wildcatter points out, safety in reloading is the paramount concern.
--Bob

[Hoot]

Boy, I'm batting a thousand lately with Emily Latella syndrome (old SNL). Just finished a thread on the correct 6.5 Grendel shell holders for press and priming and still had that on my mind. Bob to the rescue again. Going forward, "I'll be silent and thought a fool, instead of opening my mouth and removing all doubt."

Hoot