284 Winchester Brass/Blue Followers Trade

[paulmark3010]

I have been wanting to experiment with 284 Winchester brass but I can't justify buying any. I have two brand new Fulton Armory followers that I am willing to trade for 50 284 brass. Once fired would be great, new would be ok too. I want to cut/trim it myself, so only unaltered brass please. Paul

[Hoot]

When you get your brass Paul, start the out at 1.705 trim length. The chamber will tolerate it and they won't be so darned short after firing them the first time.

Hoot

[paulmark3010]

Thanks!

[Al in Mi]

I may have some in my stash, but will be Saturday before I get back to look.

[paulmark3010]

When you get your brass Paul, start the out at 1.705 trim length. The chamber will tolerate it and they won't be so darned short after firing them the first time.

Hoot

I got the brass on the way. It is once fired 284 Winchester. Why does this brass get shorter after the first firing?

[pitted bore]

I got the brass on the way. It is once fired 284 Winchester. Why does this brass get shorter after the first firing?

paulmark3010-

Here's an attempt to answer your question, based on what I've observed and read. I may have some facts messed up, in which case the real gurus on the forum will be along and straighten out both of us.

It's not unusual for many cartridges in many chamberings to get a bit shorter with the first firing. The brass expands to fit the chamber, and the spring-back is almost never complete, so the case ends up being larger in diameter than when it started. The brass for the expansion has to come from somewhere, and it often comes from the front of the case. The result is to make the case shorter. This is especially true with straight-sided cases like the 450B.

The shortening effect may not be as noticeable with bottleneck cases, because the neck will adhere to to the chamber neck walls under high pressure, so the brass for expansion may come from the case body, usually just in front of the thick base. With the neck anchored, pressure can move the rest of the case back and outward, so the case stretches like taffy. With straight cases, there is less grabbing of the chamber wall at the neck, so the case doesn't get similarly stretched.

Hornady & TL/C designed the 450B case with a relatively constant neck wall thickness for about the first half inch back of the mouth, before the case walls begin to taper to a thicker base. This thinner neck can sometimes adhere to the chamber wall, especially with pressures above SAAMI standard, so the case can stretch lengthwise like a bottleneck case. I've found this in some of my trials with my bolt guns, especially after the first firing.

With cases formed from 284 brass, the internal "neck" does not exist and the 284 case becomes thicker continuously from the case mouth on back (unless some reaming alters the case internally). Because of this, there is likely to be no mechanism for the case readily to stretch lengthwise when fired, and brass movement toward the chamber walls will result in the case getting shorter.

OK, people, where did I go wrong or get totally befuddled?

(Hoot, I'll get to your brass measurements Real Soon Now. It's only been about seven months.)

--Bob