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

[Ol` Joe]

Mag brass with a belt doesn`t headspace of the shoulder and should not move any farther into the chamber no matter how the cases shoulder and chambers shoulder relate. If the case shoulder is too far forward the case won`t fully chamber, if it is back away from the chambers front the belt will prevent the case from going farther in.
I suspect some other factor is in play here.

[Jack]

Rapier, is 78 grains of RL-22 a compressed load with your brass and bullet? What I'm thinking is, if the load is compressed, there is pressure from the powder trying to move the bullet forward a bit- and, you only have half the neck sized to hold the bullet against that pressure- not a great deal of grip on the bullet.

[Rapier]

Jack,
It is not a compressed charge and the OAL, as measured with a caliper, was exactly the same measurment as the dummy case. The powder charge goes just below the bottom of the neck. The bullet base is within the neck. All this was already taken into consideration prior to writing the post.

If the headspace in this case had actually started on the belt and stayed on the belt, the bullet in the fire formed and neck sized case would not have contacted the lands, because the belt did not move. Plus, a belt to base measurment does not shrink, it grows, which would not extend the bullet in the OAL series of measurments when the OAL remains the same, the bullet ojive would be moved back as the base to headspace meaurment extends. The base to headspace measurment had to shrink to allow the bullet to go forward. After 50 years reloading, decades of building custom rifles and having owned several hundred belted case guns, I am more than framiliar with how they are "supposed" to headspace.

The only part of the case that could move and cause the bullet to go forward, after neck sizing, was the shoulder. What I conclude occoured is that the previously fired case, in another chamber, did not actually resize with just the die use, to properly fit my gun's chamber and that the resized case was just barely over length at the shoulder and had a crush fit. When it was fired in my chamber it actually shortened due to rebound and then allowed the case to properly headspace in my chamber, which then created a situation where the reload's OAL (which was exactly the same as prior to firing) now had a chamber fit that allowed the bullet to go forward just enough to contact the lands.

I solved the problem by resetting the OAL after fireforming, please read the post. This was not written to get advice, it was written to give you guys a heads up when you start a reloading process based on a once fired case from another gun. Fireformed in your rifle, the case might just change the way the case fits within your chamber in such a manner that the reloaded round could become unsafe, very rare, but I now think possible.

The post boils down to this: Simply check the finished product in your chamber before you shoot the reload after you fireform it. Easy fix, just check it.

I have never, to my knowledge, seen this happen before and believe the occurance to be worth a mention and a caution, once I discovered it to have happened. You have been advised and warned so do as you wish.
Ed