I tried a few factory examples of 110g-125g supersonic ammo to see if my 16" AR15 really preferred one or more of those specific bullets.  It shot the Hornady Black 110g V-Max with outstanding accuracy.

I noticed this was a common theme for the 110g V-Max for quite a few reloaders, especially with H110 powder, so I rounded up a supply of both.

While loading some up this evening, I saw my Hornady 10th edition shows a COAL of 2.050" for this bullet.  Checking my factory ammo I found a COAL of 2.095".

The factory 110g V-Max has a cannelure while the boxed versions for reloading do not.  Pulling a factory bullet revealed they appear identical in all measured dimensions...the presence of a cannelure seeming to be the only difference.

When I seat my reload at a 2.095" COAL, the Hornady comparator shows an identical measurement at the ogive for both cartridges.

Some internet research indicated some differences of opinion about the proper COAL for this bullet combination but no definitive conclusion.

I'm just curious why Hornady's manual would list one COAL while their own factory ammo with the same bullet is delivered with a different COAL.  Anyone run into this with this particular bullet?

Perhaps minimum OAL to prevent overpressure with a max load?

Yeah, I had considered that, but I notice Hornady made it a point that their data is based on a 16" AR15 platform where, if I understand correctly, it would be less of an issue considering the longer throat that an AR15 300BO usually has over some bolt rifle applications...again...if my assumption is correct.

And I understand that the stated COAL in the manual is the minimum, and it applies to at least 5 different 110g bullets in their listing.  It just seemed like a rather wide variance and maybe one where they would have noted an explanation.

I did some more research this morning, and it seems there's more data recommending a COAL closer to 2.100" than others for the 110g V-Max.

I hadn't paid attention to this before, but I notice that the 300BO doesn't always follow the "general" guideline of at least one bullet diameter for proper case insertion, especially with some of these shorter, lighter bullets.

dryflash, I see your .250" method mentioned frequently, for good reason.  I'm thinking feeding may be the main reason Hornady has this COAL on this particular bullet.

I think I see a dim light bulb getting a little brighter...perhaps...LOL!

Ever since I learned to put the ogive from you, it has always worked.

I know you are using the same bullet as the factory...  are you also using the same brass, powder, charge, and primer?  The factory may have gone a little long to reduce pressure a bit in a near max load...  your (book) load may be lighter...  I could speculate more but you get the idea...