For you bench rest guys, quit reading now, you already know this.

Was shooting some old .270 handloads at the range the other day. Shooting Nosler 130 ballistic tips on top of IMR 4350. One five shot group had two flyers.

In the past three years of so I have really started to up my game and got into measuring everything. Recently acquired an RCBS concentricity measuring tool to add to the collection of "stuff"

Pulled the two cases that gave me the flyers and measured them up when I got home. Found the case necks had a .0035 variation while the other cases were within .0015.

Ran the cases on the neck reamer, got them to within .001, reloaded and repeated the firing. No flyers.

lessons learned:

1. Original loads were built years ago when I would load to manual specs without measuring cases or seating depth off the lands.
2. Case neck concentricity does matter
3. As you grow, up your loading game for precision. Control the variables you can (case length, necks, charge weight) within reason. You bench rest guys are still light years ahead of me.
4. Never quit learning

We all hate "Flyers"......... !!

Thank you for the information.

* What distance were you shooting, elpac3?
* What size groups were you attempting to achieve?
* How far from the other shots were the "flyers"?

I ask because back in 1979/80, I loaded some .223 Remington rounds into range pick-up brass that had not been processed, measured, trimmed, or chamfered; primed with a mix of CCI regular, magnum or bench rest primers (whatever was available) and loaded with volumetrically dispensed powder that was only checked to ensure it was not overweight.

My process, procedures and technique have since much improved.

But the funny thing is that at the 100 yard distance I normally shoot, the 1979/80 rounds are no less accurate than rounds I loaded in 2016 where many more variables are controlled for.

At long distance, the effect of every variable on repeatability is magnified and like elpac3 says, variations in the ten-thousandth of an inch can be significant.

Shooting at 100 yards, in prep for some 400 yard shooting. Want to get the group to 1/2 minute - which I have with the ballistic tips, proper seating depth and accurate powder charge. The flyers were 2.75 inches out, with the remaining 3 shots about .75"

"Ran the cases on the neck reamer, got them to within .001, reloaded and repeated the firing. No flyers."

Generally, most bench rest shooters prefer to turn the outside diameter of case necks rather than reaming the inside, as it provides greater neck wall thickness uniformity. Also simple to do. I have one of my Forster case trimmers set up to do only that, but as I don't shoot bench rest any more, I seldom use it now. I also have a tubing wall thickness micrometer I made up myself. I don't remember the last time I used it.

I was a cci man years ago, had pretty good groups in my rifles.
Then one day tried a 180 and 200gr BT in my 1903 custom 30-06
with Winchester primers with the IMR 4350 powder loads.
All groups went to under an inch at 100 yards for the old rifle
and 3 @ .21 at 2660fps was good enough for my hunting load.

You can never tell what you will do or try and be amazed at the outcome.
Tight groups.

You are absolutely correct - my bad. I am using the RCBS neck turn tool, not reamer, taking material off the outside of the neck. I have also found using the Lee collet die provides very uniform necks as the neck is compressed down on a mandrel rather than expanding the inside of the neck with a ball being pulled through it.