XBR 8208 and 60 Vmax MAX Charge?

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cgbills

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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. However this was in the 223 Remington section and not the 223 Rem Service rifle section; I do not know if that is part of the reason.

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

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 remington max.
 
Re looked at the manual. 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.
 
Your firearm will tell you what max charge is. We as loaders start low and work up to the max charge if that's what we are looking for. I think I speak for most when I say NEVER start with a published max load. Every firearm is DIFFERENT, even the same makes and models can have different max charges. Be safe and start low and work up. Good luck
 
I didn’t go look at the listed data, but add that I cross reference several sources to get an idea where to start. As posted, with average max charge weights known, start a reasonable level below that.

Even when I have a load I’m ready to stick with, it’s never really a max, for the most part.

Some manuals can be a little weak on charges, that’s why the cross reference. Then we may have slight deviation in exact bullet, COL, and of course individual rifles.

I do see the question though, asking why the max is listed as is, 223 vrs 5.56.
 
Generally LC brass is thicker than commercial brass and your max loads may require slightly less powder. The brass is also a component and if you change brass you need to rework your loads.
 
Part of my question is just my interest in the oddity of the powder charges being being reversed form normal convention. Also part of it is I like to have a more solid max charge threshold to build my ladder test. When I get close to the max charge on the ladder test, I like to have an idea of how close i really am.
 
Yes, and you may meet the conundrum when two different manuals have varying max charges with the exact same bullets & components.

That’s where individual evaluation & testing come into play.
 
CGbills,

I normally load until i see pressure, clearly degrading accuracy and/or velocities that are just flat out too high.

I recommend buying some type of a velocity measurement device, and an RCBS bullet puller.

Load up to 24.5 grains or so your 1st run to the range. If you do not see any marring of the brass, go home and load up into the 25's if you were seeing good accuracy up top.

223 LC NATO brass has a higher capacity than most types of brass. Maybe Winchester brass can carry a tiny bit more powder.

You are looking for an "accuracy window. It should be at least 1/2 grain. Also you should be watching your POI. You should not have any large POI shifts in your window. If you load to 24.5 and are getting the worst groups up top, think on that for a bit.

It takes several work ups to find a good load. Just because that charge weight shot good last week, may not mean it will shoot good this week.

LC NATO brass is tough brass. When you get the 1st signs of pressure, back off that load around 1/2 grain. Even more for a daily shooter.
 
I just tested some 60 grain Sierra TMK's up to 24.5 grains of IMR XBR 8208 using Rem 7.5 primers.

Primers look great, i had some extractor scraping start at 24 grains due it it being a 14.5 inch barrel with a carbine gas system. (5.56 NATO chamber) No ejector marks at all.

It was LC non NATO brass. I was getting 2650fps at 24.5 with deteriorating accuracy.

I am scrapping that project. AR-Comp or H4895 next with different primers. Lots of folks love those Rem 7.5's. I seem to always get erratic velocities with them. Maybe i got a funny batch?

I have had better luck with XBR and Fed AR match primers or CCI #41's.
 
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