Check Your OAL After Fire Forming

[Rapier]

I had an occurrence on Saturday that was a first in 50 years of reloading. After fire forming my 300 Win Mag brass and reloading it, I decided after I got a strange feeling, to go back and check the loaded round in the rifle’s chamber. The extracted bullet had land marks all the way around. It did not have land marks when I sat up the dummy round before fire forming the brass!

This is the trail of events: A friend gave me 40 rounds of once fired Remington factory 300 Win Mag brass in the original 20 round factory boxes. I then polished the brass, full length resized it, prepped it fully and then I set up a dummy using 168 Hornady HPBT Match bullet without powder or primer. The process was my old stand by, using black magic marker and 1/8 turn on the seater plug until the land marks disappeared. Then the actual loaded rounds were put together using 78gr of R-22 with CCI 250 primers using the previously locked down seating die. One of the problems with the black magic marker process is that you do not actually know exactly how close you are to the lands, but I prefer the method over the use of my other equipment for setting up the OAL and I keep going back to the old magic marker method.

This load shoots well, at .60 inches, is 2grs below maximum of 80gr for this rifle, and of course the brass was well formed after firing.

The brass was then neck sized to 50% of the neck length and reloaded with 78gr of R-22 and the 168gr Hornady using the die that was locked in place and produced the same OAL as the dummy.

The only thing I can figure that must have occurred is that the bullets were setting very close to the lands and that somehow the shoulder of the fired case ended up shorter by a hair than the original full length sized cases, after they were fire formed. So when the fired case was inserted and the bolt turned, the ejector of the Remington drove the bullet into the lands. This is the only explanation I could come up with.

So I moved the OAL from 3.505 to 3.495 and reset my dummy to match. Had I not checked the rounds, I checked two at random with the same result, I would never have suspected nor would I have known the bullets were jammed into the lands. A situation I do not like, especially with a belted magnum.

The moral to this story is check your reloaded ammo after fire forming to make sure the OAL you started with is still safe.
Ed