XBR 8208 and 60 Vmax MAX Charge?

[cgbills]

Ok I have a 20in Ballistic Advantage 223 Wylde barrel I am going to start working up a load for using XBR 8208, 60gr Vmax, Lake City brass and CCI No. 400 primers. I looked in my 9th edition Hornady reloading manual. For 8208 and 60gr Vmax in 5.56 NATO it lists a max charge of 24.4. For 8208 and 60gr Vmax in 223 Rem it lists a max charge of 25.3. This struck me as very odd because it is usually the 5.56 NATO listings that have a higher max charge. The 223 Rem is a COAL of 2.26 and the 5.56 is a COAL of 2.25. Still the 8208 loadings are inverse of all the others. Almost every other powder listed under 223 and 556 show the 556 loadings as having more grains of powder.

In order to help clarify, I consulted the Hodgdon website. They list the max charge for 223 Rem (do not have a 5.56 choice) as 23.6 at a pressure of 51,700psi.

Does anyone have an explanation for this oddity in the Hornady manual? Also which charge weight should I use as my max? I lean more toward using the higher 223 Rem max.

 

[Supersubes]

The manual is a guideline. Data they gathered with their test gun and their components. Work up as you normally would, and look for signs of pressure.

 

[cgbills]

I will, but I do like to have a more consistent threshold of were the max charge is. Call it piece of mind. Also I find it peculiar, and my curiosity has me wondering why.

 

[spife7980]

I bet you dollars to donuts that 23.5-23.8 will be your accuracy node anyways.

If you want to know the max you will need to search it. Brass and chambers are far to variable to have a book anything more than guess where they are hedging their bets.

 

[MarinePMI]

As Spife mentions, the standard 8208 node for .223 and heavies is 23.5'ish grs. There's another in the 24.3gr range as well, if your particular rifle/barrel allows it.

And just to add another point; the Hodgdon load data on line is notoriously conservative (almost to the point of being useless for knowing what the top end of a load is).

 

[RLinNH]

I just shot 100 rounds of 69 gr SMK's yesterday. I started out with a 22.7 gr load for 60 rounds, then 23.5 for the 40 others. My Colt A4 like the 23.5 better. I was using Star Line never fired brass. Also, shooting open sights at 50 yds. Kept it Ol' school yesterday, and it feelt good