Accuracy question, undersized bore rider

Both of my nose sizing dies were made by Buckshot over on the cast bullet board.

The first is a reloading press mounted die where the bullet are pushed in nose first and then tapped out with a rod. By setting the heights of the die at the top of the ram stroke, you can control how far down the nose you want to size.

I used this die in sizing the top two bands of 311467 to ride the lands. This has worked very well for me.

The second die works in a Lyman or RCBS machine and looks just like any lube sizer die except it has no holes for the lube. The bullet is pushed in nose first and ejected with the tool upstroke. This die contains shallow body size cylindrical portion to keep the bullet aligned. I had this cut .311. So, bullets need to be sized .310 or .311 before having the nose sized.

A few years ago, I tested two 311291 molds of varous vintages. One threw bullets .311 X .302 and the other dropped it's bullets .315 X .304. I sized the larger bullets .311 X .302 and shot the two bullets on the same day to see how much damage nose and body sizing did to the bullets. I did size the bodies in a nose first push through sizing arrangement.

I used a very accurate Browning Traditional Hunter SS rifle in 30-30. I fired 4 ten shot groups with each bullet. This came to a total of 80 rounds fired. I would have to look up the powder charge, but it was in the area of 14/2400.

I took the targets back home and measured the size of the 8 groups. I found the sized bullets fired groups a hair smaller (average) than the unsized bullets. The difference was very small and could have been made by a couple of rounds a fraction of an inch out of the group by the shooter (me).

Again, I would have to look it up but both bullets gave about 1.75 MOA (100 yards) average of the 4 targets.

I suppose if one were shooting an unlimited class bench rest rifle, the difference between sized and unsized bullets would have been greater. But that day in my sporter, sizing didn't matter.

This took place in 2006 or 2007 and I have ceased to worry about the effect of bullet sizing since that time. I think how you size is more important that how much you size. Of course having a bullet throw a bullet the exact size you want is the best of all world. However, I am plenty happy with a larger bullets I can size the nose and body the way I want them. I have never tried bumping up bullets, so maybe that works as well, I don't know.