bullet and case neck runout

[Green Lizzard]

with a long bore rider like the 314299 or the lee 200 grain 30 cal do you still think runout is important for best accuracy?

[MtGun44]

IMO, getting the boolit started straight is THE most important thing for accuracy.

A long way of saying "YES". Get the front into the barrel and the rear off to the
side .005 or .008. . . . . . can't do anything good. Of course - I am thinking of
case neck runout, is that what you mean? If the case neck is really true, but the
nose is a bit out, it may be straightened up as it chambers. Try spinning and find
a crooked one and then chamber it and pull it back out and recheck.

I have found that straighter is always more accurate when loading for rifles. Seems
less likely to be crooked in pistols, but Hornady has floating chamber seaters for
both rifles and pistols as std now.

Bill

[cbrick]

Bill is right. Chamber a canted bullet and how it's slammed into the bore is it's new shape and how it's going to exit the bore. It's possible that chambering it might straighten it some but if your looking for accuracy I wouldn't bet the farm on it. Spin your sized brass with a dial indicator, either NK or FL before seating a bullet and see how much run-out it has. Then seat a bullet and spin it again to see what your seater die is doing.

Rick

[Hickok]

Yes, bullet runout affects accuracy. I have tested this myself. Rifle ammo having runout of .005" to .010" is a 2 moa group. Reload same ammo and keep runout to .003" or less and I cut groups in half, usually 1 moa or less. (This was with jacketed bullets)

[44man]

Nine times out of ten the size die is at fault, NOT the seat die. Most size a case neck too much and when the expander is pulled out the shoulder bends. I used to send all my Redding dies back with fired brass to get lapped out for minimum sizing. Now Redding makes collar dies so no expander is needed.
Next is to neck turn just enough to make thickness even all around, once fire formed they will be as straight as you can get. You need to be .002" or less run out for best accuracy. That should be out on the bullet but cast is hard to measure because not many are round so I resort to measure the necks on loaded rounds.
I shoot cast from my Marlin 30-30 and found necks running .020" and more run out, roll a round on the bench and laugh. Rifling will NOT straighten them. I neck turned and fired them, now instead of spraying a target I get down to 1" and less at 100 yards, best group was 3/16". Can't do it all the time, a lever gun is sensitive to hold. Yet the improvement can be seen.
Revolver loading needs a better inline seat die and the Hornady works best. Same thing applies so get them in straight. If you see more base bulge on one side, that round is a stray.
I made my run out tool about 60 years ago for Weatherby brass, worst ever for bending necks. The 30-30 case shown in it has .0005" neck run out. 129688
Seating a cast boolit and rolling it on the bench shows no wobble.

[farmer66]

I am interested in trying to measure runout. I use the RCBS SIL 165 in 30/06 to get 2 inch groups. How is the preferred way to measure runout? Lathe or v-blocks? I can imagine v-blocks located at the base and neck of the brass and measure the bullet runout. Is the suggested value of .003" TIR or offset?

Thanks in advance,

Ken

Edit: I see 44 man posted the same time and answered most of my questions.

[44man]

I am interested in trying to measure runout. I use the RCBS SIL 165 in 30/06 to get 2 inch groups. How is the preferred way to measure runout? Lathe or v-blocks? I can imagine v-blocks located at the base and neck of the brass and measure the bullet runout. Is the suggested value of .003" TIR or offset?

Thanks in advance,

Ken

Edit: I see 44 man posted the same time and answered most of my questions.
Mine has "V" blocks and I need to hold the case tight in them as I turn it. One near the base and one shy of the shoulder. I made it adjustable so any case will fit and the dial indicator is fully adjustable too.

[44man]

You can buy good ones today but back then, they were hard to find and expensive. That hunk of metal let me head shoot a chuck at 550 yards from sitting with my .300 Weatherby. The Mark V with a 26" "B" barrel is a wonder. Why I sold it still eats at me. By bedding and floating I made that rifle shoot every load under 1/2" at 100 all day. I did not measure center to center, I measured from the outside of holes.
You might say BR techniques are a waste with a hunting rifle but it is darn hard to find any rifle that is not improved by the little extra work.
Cast is more important because a boolit does not take kindly to an off center start.
As I have repeated over and over, brass is the enemy.

[Hickok]

This is what I use, and it works well for me. http://www.sinclairintl.com/reloading-equipment/measuring-tools/concentricity-gauges/rcbs-case-master-gauging-tool-prod37690.aspx