Afternoon shooters,
Years ago, I started making 243 brass from 308 brass and did so for quite awhile with no problems.
One time while shooting with a friend, he fired his 243 Ackley improved, and when he opened the bolt a number of pieces dropped on to the blanket.
Things like the extracter of his Sako, a primer and possibly other misc. parts and pieces.
Those many years back, we had no idea what caused the problem and it was not anything which ever happened again.
I still have that case somewhere in my stash, and it shows signs of very high pressures.
Some years later, another friend, also a reloader told me of the possibility of blowing up my 243 because of the 308 to 243 brass forming and then provided me with an artical which documented the demise of a nice pre-64 Winchester 243.
The owner had been, like myself and others, converting 308 cases to 243 Winchester and then using them without any other modifications.
From that time forward, while still forming and firing formed 308/243 cases to this day, I have made it a practice to always outside turn the case necks before that first firing in the 243.
As already stated, this is a situation of things being overly tight and the run away pressure it can cause.
Personaly, I turn the outside of the necks rather then reaming the inside.
I chose this way in the interest of consistancy.
If you ream, the reamer will follow the line of the already established case mouth opening, even if this is not center to the case or chamber.
While outside turning trues up the neck by removing more metal from the thickest portions of the neck, while little if any from the oft times thinner sides.
Anyway, while the 06 to 25 is not as great of a change as the 308 to 243, it seems that neck turning might also be a wise step.
One way or the other, it surely won't hurt.
Keep em coming!
CDOC