23 March 2004, 21:19
ClarkRe: Runnout on your varmint rounds...how much?
Quote:
Clark,
THe amount of runnout in ammunition effects much more then just bullets pointing straight down the bore.
You say that anything over .004" RO will be straightened by the chamber. I do not believe this to be true, in fact I have seen bullet run outs continue to degrade accuracy up to and over .015".
Also, a canted bullet will induce uneven stress in the bolt with in a factory rifle with bolt lugs that rarely bare evenly will enlarge groups dramatically.
Also, say you chamber a round with 0.005" run out and even if you chamber that round and the chamber corrects it to 0.004" run out, on one round the bullet nose will be pointed down from that .004" RO while the next one may be pointing to the left the next to the right and so on and so on. This difference in how the bullet engages the rifling will cause groups to grow as well.
I believe run out numbers are huge factors in accuracy, just as much in factory rifles as custom rigs.
Good Shooting!!!
50
If there is one thing I have noticed about posts about concentricity, is that not all observations are consistant.
And yet with one rifle and one concentricity gage, there is usually consistancey. There must be some important varibles out of control, like throat to bullet fit and over all length.
Notice that I was just quoting a source.
I don't know what to believe.
In preparation for groundhog season, I have been sorting my .22-250 and 7mm remington rounds by runout and have found that it signifigantly has increased my consistency. I have been sorting them into 3 different lots. .001 runout for things past 300yds , .002 runout for things from about 150-300yds , and anything more than .002 runout for things out to 150yds. I'm loading my rounds in Redding Competition dies and have found them to be very very accurate dies. i would say that 75% of the time, the runout on the bullet is .001 or less. They do not vary much at all. I'm meauring them on a Sinclair runout gauge. So, how much runout is too much? When I sight in, i use the most accurate rounds possible. Thanks guys,
Ruck