Help with COAL and head space

[RBDMTJager]

I have all of Hornadys LnL inserts for measuring COAL but none for 450BM or a loaded cartridge with a bullet of .452" diameter. I checked Hornady's website and they didn't list a insert for .452", but did list one for .458" which I have. Does the .458" insert work with a .452" bullet as I suspect or not?

So my question is without a correct for caliber insert how does one measure COAL of the 450 Bushmaster? and if Hornady doesn't make one who does?

[s4s4u]

So my question is without a correct for caliber insert how does one measure COAL of the 45o Bushmaster?

I use a dial caliper.

[RBDMTJager]

So my question is without a correct for caliber insert how does one measure COAL of the 45o Bushmaster?

I use a dial caliper.

No offence but that will not give an consistently accurate OAL of a loaded cartridge from loaded cartridge to loaded cartridge as you are measuring from the tip of the bullet to the base of the casing as the length of a bullet from its base to its tip can and does vary significantly, this is why it is recommended you always measure loaded COAL from the base of the shell to the ogive of the bullet after it has been seated to determine you loaded cartridges OAL as the measurement from bullet base to ogive of any bullet is a much more consistently accurate length bullet to bullet VS bullet base to tip.

I did some more searching at Hornady's WS and the literature I found indicates their .458" COAL insert works for bullet diameters from .451-.458" so Ill be OK measuring COAL for my 450 BM reloads.

This is my first straight walled case I am reloading for and first rifle cartridge larger than .358" I have ever reloaded for.

[Hoot]

I have to wade in on this one. While I am in agreement with RBDMTJager on the technical merits of using an ogive comparator for measuring COAL in the 10 or so bottleneck calibers that I reload for, in the case of the 450b, practice can diverge from theory (see sig). Over the past 12 years, I've loaded just about every conceivable brand and model of bullet for the 450b, over (2k reloads and counting) many of which were Factory Seconds and Blems and I have yet to encounter a single bullet where the ballistic tip or spire point was so different from the rest of the ones in the box that it would have put the loaded round in jeopardy of running into the lands before the bolt was in battery or that the bullet's base to tip OAL was so long that in seating it to a given cartridge OAL ran the danger of seating the bullet so far into the case that is threatened to cause excessive pressure.

In fact, the only bullet that ever raised an eyebrow was the Hornady 300gr XTP Mag and that was because it kissed my rifle's lands at 2.22 COL due to it being a hollow point. Having an AR based 450b, I loaded many but not all bullets to a COL of 2.26, especially the heavier ones due to their length. A few shorter bullets did require a COL of as low as 2.05 in order to get a minimum shank seating depth of 1/2 caliber or to have the taper crimp drive down into a cannelure. If like me, you have a set of Hornady bullet ogive comparator inserts, by all means use them but I don't know if there is one in the set for the .452 bullet. It is a good practice to buy the Hornady Case Length Gauge and a Case Gauge case for each caliber you reload for to measure each of your rifle's distance to lands for the bullets you intend to load for it. That's how I discovered the issue with the Hornady 300gr XTP Mag. I keep a spiral bound logbook for every caliber that reload for and on the last page, I keep a record of the DTL for the various bullets that I use in that caliber/rifle.

Hoot

[s4s4u]

So my question is without a correct for caliber insert how does one measure COAL of the 45o Bushmaster?

I use a dial caliper.

No offence but that will not give an consistently accurate OAL of a loaded cartridge from loaded cartridge to loaded cartridge as you are measuring from the tip of the bullet to the base of the casing as the length of a bullet from its base to its tip can and does vary significantly, this is why it is recommended you always measure loaded COAL from the base of the shell to the ogive of the bullet after it has been seated to determine you loaded cartridges OAL as the measurement from bullet base to ogive of any bullet is a much more consistently accurate length bullet to bullet VS bullet base to tip.

I did some more searching at Hornady's WS and the literature I found indicates their .458" COAL insert works for bullet diameters from .451-.458" so Ill be OK measuring COAL for my 450 BM reloads.

This is my first straight walled case I am reloading for and first rifle cartridge larger than .358" I have ever reloaded for.

It really isn't that big of a deal. I have loaded over a dozen different chamberings and have always used a dial caliper.