OAL deviation

codenamepaul

What would you consider the max OAL deviation to be? This is pistol and rifle. I find I am pretty picky about .001-.002" or am I being way too picky. It takes pretty constant adjustment to stay in there.

Tailgunner1954

When bullets are made, they do a good job of controling the OGIVE contact point to base dimention, but they let the distance to the tip run wild. If you measure your bullets from the base to (for 30cal) to the .290 diameter you will find they are quite consistant (+/- .001), even though the base to tip dimention can vary by +/- .010 or more. Most rifle dies use a ogive contact ring when seating, again letting the OAL run wild.
Distance from the ogive to the lands is what you want to have be consistant for rifle, the only thing to be concerened with on the OAL is weather of not they'll function through the magazine.
In handgun (pistol or revolver) the seating plugs are more of a nose contact type, and a flat seater plug will keep your OAL more consistant (but than the distance to the lands will vari). Handguns are not quite as "precise" as rifles, when it comes to their intended usage.

codenamepaul

So-that said-how do I adjust the OAL to optimize this. If I can't get a consistant OAL, how can I ensure the distance to the lands stays consistant?

Tailgunner1954

That's where tools like the stoney point thingy come into play. The tool has a hole in it that sets aganst a point on the ogive and you than measure the base of your cartridge to the top of the tool, effectivly ignoring the OAL (as long as it's short enough to operate through your mag). You can make your own tool BTW, all you need is a hole that's slightly (.020-.030) smaller than your bullets diameter
OR you can simply set your die to produce ammo that AVERAGES your desired OAL and (as they say in new yawk) fa-get-about-it.

Are you making ammo for serious BR usage, or for hunting / casual target usage? For the first, I'd worry about keeping the distance to the lands as consistant as possible, for the 2nd, I wouldn't sweat it at all. IE: I don't worry about it in my hunting rifle, on average, I'm getting 1/2 MOA groups with it (it's a Mauser, but it ain't a stock Mauser [:D])

codenamepaul

It's all plinking/target stuff I reload right now. Just happened to wonder if I was being a bit *. It's not a huge deal making the adjustments to keep it in the 1 or 2 thousandths range for OAL. I check every 5 rounds or so and may need a tweak every 20 or 30. Doesn't seem from the answers I'm getting to be a bad way to go about things and just keep doing what I'm doing.

JustC

Ditto,..a comparator is the right way to measure ogive to land distance. Hollow points can be uniformed VIA a meplat trimmer.

HandgunHTR52

paul - Once the die is set for a given bullet you shouln't have to change it. As Tailgunner stated rifle dies use an ogive contact ring to seat the bullet. As long as that doesn't move (i.e. you aren't adjusting the dies) then every round you load will have the same leade. By constantly adjusting your dies based on OAL your rounds are actually less consistant than you think they are as it is the ogive of the bullet, not the nose, that first contacts the rifling in the barrel.
If you intend to remain * about it, get a Hornady (formerly Stoney Point) Bullet Comparator and one of there OAL tools that require the modified cases. That way you can accurately determine the OAL of the round with the bullet touching the lands and then adjust from there.