Yesterday evening I was loading up a box of .423 caliber A-Square Mono-Solids in 404 Jeffery for use on an upcoming buffalo hunt in Africa. These were not practice loads, but are the "real deal", ment to draw blood (if you knew the ordeal I have to go through to produce 100-percent reliable ammo for this rifle, you would have greater appreciation for this task).

I was seating bullets on top of 78 grains of Re. 15 in my Rockchucker press. I got down to the last four or five, put one in the shell holder, placed a bullet at the case mouth, started running it up in the press and released the bullet from my fingers.......where it promply fell without resistance into the case!

"Hmmmmm," I thought to myself. "I must have forgotten to to size that case. I've never done that before, but what the hey -- there's a first time for everything."

So I took another charged case, put it in the press, set the bullet on the case mouth -- and again it fell into the case without resistance! Now I'm really upset with myself for forgetting to size, not one, but two cases. Then a saner explanation came to mind; what if A-square put a wrong caliber bullet in with rest of the batch?

I immediately put the offending bullet in the palm of my hand, took another one out of the box, and compared them side-by-side. At first glance, they looked the same, however, with a harder look, the offending bullet appeared ever-so-slightly longer. Looking only at the bases, it appeared that the offender was maybe a little narrower, but it was very, very hard to tell.

Only when I broke out the dial caliper did the truth become known -- the offending bullet was a .416 (as I, of course, already suspected).

I was immediatly struck by how dangerous this could be had the bullets been reversed and a .423 caliber bullet gotten mixed in the .416s. What if you were using "soft" brass that stretched to accomodate the bigger bullet. What if said bigger bullet was chambered in a rifle with a "loose" chamber that allowed it to enter. With the mono solids, the results would be bad, to say the least.

Before anyone accuses me of mixing up the bullets myself, it should be said that I don't own a .416 anything and have never bought a .416 bullet. It was a in a new box of A-Squares I opened last night.

The only other similar experience I have ever had was once I bought a bag of bulk .300 Winchester Magnum brass and one of the cases was 7mm Rem. Mag, but was head-stamped .300 Winnie. I found it out when I tried to size the case and the expander ball wouldn't enter. Again, the calipers told the tale (along with a 7-mag that it chambered in perfectly).

Anyone had similar experiences?

Had you not caught it, and fired that ammo at the range to check zero, you would have been scratching your head trying to figure out what went south since the last time you shot your rifle.

George

GA, this happened w/ a box of Hawk 350gr I bought for my .404. About half were .416 & I found out the same way you did. They replaced them of course, just a freak thing.
I have found the Barnes 400gr solid amazingly accurate in my .404. I have several sub 1"/100yd groups taped to my reloading wall-of-fame. My load is 83gr IMR4831 or 84gr RL19 for right @ 2200fps.