OAL AND HEADSPACE -Heartbreak and Headache

[Lilswede1]

To practice loading on my Dillon 550B, I measured several factory loads with different bullets. The shortest was 2.220" -Middle - 2.248 (Black Hills V-Max 50 Gr.) - the longest - 2.252 (Black Hills V-Max 50 Gr. Moly).
The Moly's shoot best in my CZ 527 bolt with the uncoated V-Max a fairly close second.
I want to be reloading with 50 gr. Sierra Blitzking (devastating Prairie Dog round) so logic tells me to load to the best shooting factory round - 2.252 and go from there.
I will be using Acc. 2230 powder which meters through the Dillon excellently
(+\- .01 in 20 throws).
I have ordered both the RCBS Precision Mic and the Hornday OAL gage - they will be here in a week or so and I wil be able to make more accurate measurements with them.
For now, is the above a safe method?

[Loader9]

The max length for a 223 is 2.260 according to Sierra. You are limited by the clip/mag in your gun as to what it will accept and feed reliably. Considering it is a bolt I wouldn't expect feeding issues but ya never know. While I load a ton of AA2230 when I can find it, Benchmark is a little more accurate with the 50 gr bullets. It also goes thru a measure like water. If you are buying in 1 lb quantities, you might give it a try. If you've already bought bulk 2230, it will work. I'm using 25.0 grs under a 50 Blitz and accuracy is well under an inch out of all of my 223's. Benchmark has produced some dandy near one hole groups. If 1/2" groups or so using 2230 is good enough for you, you're ready to go. And once you get all of your equipment and start loading, find the best load that comes out of your gun and start playing with the OAL to dial in accuracy. It will surprise you just how things change when changing OAL by just .005.

[30Cal]

As far as measuring where the lands are, the easiest and most repeatable way is to seat a bullet long in a resized case and stuff it into the chamber with your thumb. If it doesn't fall from the chamber from gravity alone, then it's into the rifling. The precision case mic thingy is neither easy nor repeatable when it comes to measuring OAL.

Seat deeper till it does drop free, then measure that case in your case mic.

[rn22723]

First off I hope that you are not swapping between naked and moly coated bullets. Moly is sort of an all or nothing proposition. Moly is hard to clean totally out of a bbl. Plus you dont want a layering effect of fouling moly over copper over moly etc you get the picture.

Most of the time with factory chambered rifle you will have a hard time seating bullets close to the lands. So, for COAL it is best to respect the reloading manual and the general mag length of 2.26" for the 223. Custom chambered rifles can had set for a specific bullet so that even at mag length the bullet has little jump to the lands.

I would buy a dedicated neck sizer die like from Redding and their carbide expander ball and just neck size your brass for the CZ. Of course after 4-5 firings it will need a pass thru a FL sizer to set the shoulder back.

[Shoney]

Your initial Headline OAL AND HEADSPACE -Heartbreak and Headache you insert Headspace, yet your post does not discuss it further.

OAL and Headspace in bottle neck cartridges have nothing to do with one another.

HEADSPACE (SAAMI)
The distance from the face of the closed breech of a firearm to the surface in the chamber on which the cartridge case seats.

Headspace (Sniper Country)
The distance from the bolt face (when the bolt is closed) to that surface in the cartridge chamber which stops the case’s forward movement. For bottle-necked cases, the measuring point is centered on the shoulder and is known as the datum line. For belted magnum cases, the headspace is measured from the front of the belt to the head of the case. In practical terms, the amount of free movement a cartridge has in a closed chamber. This dimension is critical for the safety of the shooter, as well as the accuracy of the weapon system. Insufficient headspace hinders complete chambering; excessive headspace permits case stretching, separation or rupture, endangering the shooter.

CARTRIDGE CASE LENGTH (SAAMI)
The dimensions from face of the head to the mouth.

LENGTH, OVERALL (SAAMI)
Ammunition: The greatest dimension of a loaded cartridge, i.e., from face of the head to the tip of the bullet for centerfire or rimfire or to the crimp for shotshells or blanks (not to be confused with the uncrimped length in a shotshell.)

Overall Length ( OAL ) (Sniper Country)
The total length of a cartridge, measured from bullet tip to base of case.

In most of todays factory rifles, the magazine length is a great deal shorter than optimum spacing off the lands. An OAL that fits in the magazine can be around 0.250" off of the lands. Consequently, if you load at 0.010 off the lands (and on out to 0.050 or even longer), the cartridge will not fit the magazine, and you have in effect, a single shot rifle that has wonderful headspace (again which is totally unrelated to OAL).