Archive for January, 2021

Loading the Berger 115 gr. FB HP

Tuesday, January 12th, 2021

I confess that when I began my journey with the .300 Blackout a few months ago I held a very narrow view of the cartridge.  Like many on the outside, I considered it to be a very effective short-range military/tactical/self-defense round.  One most prized for its heavy-bullet-at-subsonic-speed proficiency. 

The whisper in its predecessor’s name gave a clue.

Now, having spent at least a little time on the inside, I see a much different world.  The “little round that could” is actually quite astonishing in what it can do.  Or, let me turn that around… when I survey the landscape of things I might ever want a centerfire rifle to do, there’s not much I wouldn’t put on the back of the .300 AAC Blackout and not feel entirely confident about.

Among other things, my explorations of the Barnes 110 and 120 gr. TAC-TX bullets, some of which I’ve posted here, gave tantalizing hints at the accuracy potential buried deep in the round’s DNA.  That led me to wondering what an actual target bullet might do (albeit, from a hunting rifle platform, not a true target gun).

The Berger 115 gr. Flat Base Target bullets showed up a couple days ago.  Yes, it’s a hollow point design… but that’s for weight distribution along the projectile’s length, not for expansion in tissue.  If you’re going to shoot animals with it, shoot ‘em in the eye.

I have load manuals, from different sources, going back decades.  But never having shot a Berger bullet before, I don’t have a Berger manual.  Probably wouldn’t make any difference, anyway, as I don’t believe they have any .300 Blackout data in their manual.  And there’s none online at their website.

So I dropped a little note to Berger, telling them I had some ideas, but that I had their bullets on the way and would be happy to entertain any data they might have available.  A nice gentleman got back to me and said he’d pass along my request to their load development team, but that it would probably be two to four weeks before I heard anything.  My guess is they’ll confirm “sorry, ain’t got any.”

No worries.  The two Barnes bullets with which I’ve been playing are all-copper designs, a pretty big caveat.  But they bracket the Berger, weight-wise.  And the Sierra 125 gr. MatchKing is close by, as well.

Running some models in Quickload, and having already calibrated that software to the present lot of powder I’m using, I determine to go pretty quickly to the edge, rather than the more measured, slow walk that we usually employ.

The Berger is a short, little pill.  And the .300 Blackout has an abbreviated case neck.  So seating depth becomes the first question, one upon which everything else hinges.

Measuring five samples of the 115 gr. bullet, I find they’re reasonably close to the nominal length of 0.940” that Berger specs.  The longest sample is 0.944”… and that’s what I plug into Quickload.  (Quickload’s database is correct with respect to the Berger, but it is frequently wrong regarding bullet length.   And because bullet length directly affects seating depth, and because that affects pressure, it’s critical to get it right).

Dispensing successive powder charges of 20.0, 21.0, and 22.0 grains of W296 into a fired case, then dropping a Berger into the neck until it rests on that powder, I measure the prospective overall cartridge lengths.  What I’m assessing is how much of the bullet’s shank – the actual bearing surface – is held under neck tension, at 100% load density.

21.0 grains of W296 comes in at a 2.099” OAL – call it 2.1.  Quickload tells me the pressure with that load and that COAL would be just over 53,000 psi.  Pretty close to SAAMI max.  And looking at it, I decide I don’t want any less than that being held within the case neck.  So 2.100” becomes the farthest-out COAL I’ll go.  And, having said that, I wouldn’t mind having more of the bullet in the case neck.

Berger may not have any load data.  But Nosler does.  Nosler’s 110 gr. Varmageddon is a conventional flat-base, lead-core design, like the Berger.  Nosler shows a COAL for their bullet of 2.025.”  I don’t have a sample of the Nosler on hand to measure, but the Quickload database shows the Varmageddon at 0.920… 0.020 shorter than the Berger.  The Berger would run much higher pressures at a 2.025 COAL, versus my tentative 2.100, of course.  But maybe split the difference?  Add the 0.020 extra length of the Berger to Nosler’s seating depth / COAL and use 2.045” as my COAL?

Modeling that (2.045 COAL) in Quickload shows 20.0/W296 at just over 100% load density, with pressure 500 psi over SAAMI maximum.  Okay, so this is very nearly as far as I want to go.

I’ll stop here and observe that the reason I have honed in on load density is because more often than not that’s where we’re going to find best results.  Sure, we’ve all experienced the surprise of a nice load appearing on the lower part of our start-low-and-work-up-slowly ladder (which usually equate to lower charge densities).  And we’ve seen examples where a rifle demands max or higher-than-max pressures before it will perform (which usually equate to compressed charge densities).  But a good general rule of thumb, for most rifles, is that their sweet spot is most likely to be found somewhere not too far from that 100% load density threshold. 

That said, there’s no free lunch.  Seating your bullet deeper so as to maintain a high charge weight density means retreating from the lands in your bore.  The exact opposite of what you usually want to do.

All of which is to say… it’s complicated.  Some parts of this fascinating endeavor are a zero-sum game.  You optimize one aspect, at the cost of another.

The one thing that is not unclear with this little project of mine is that caution is needed.  Nosler shows 19.5/W296 as their maximum load.  And I’ll be driving a slightly heavier bullet, at charge weights a fair bit beyond what the Nosler ballisticians ran their’s.

The real question is… how comfortable am I with Quickload’s modelling?  For sure, this is the kind of load development I never would have done before the advent of that software and an accurate chronograph with which to validate it.

To “stack the tolerances” in my favor just a bit, I do two things.  I change my case capacity spec from 25.1 gr (the most recent sampling of Norma brass I’ve done) to a slightly more conservative 24.8 gr.  That means Quickload will show pressure, earlier.   And I add just a smidge more case capacity by extending my COAL to 2.050.

Satisfied with the models I show with those changes, I load fifteen rounds, three rounds each, in 0.2 gr increments, from 19.4 to 20.2 grains of W296.  Quickload predictions are:

  • 19.4 = 51,300 psi / 2334 fps @ 98.5% load density
  • 19.6 = 53,091 psi / 2358 fps @ 99.6% load density
  • 19.8 = 54,951 psi / 2382 fps @ 100.6% load density
  • 20.0 = 56,884 psi / 2406 fps @ 101.6% load density
  • 20.2 = 58,892 psi / 2430 fps @ 102.6% load density

And so off to the races…

  • Berger 115 gr. Flat Base Target bullet (SKU #30421)
  • Norma Brass (previously-fired once)
  • Federal Small Rifle primer
  • Winchester 296
  • Ruger American Ranch rifle (16” barrel).
  • 50 Yards
  • LabRadar Chronograph

Actual, versus predicted:

One more reminder, especially when playing with max and over-max loads… we tend to look at actual results such as I’ve posted above and see them as precise.  They’re not.  They’re averages.  There will be excursions both higher and lower.

No, I would not recommend this approach to handloading.  But, yes, I did some fool things as a kid.  And I’m apparently still doing them.

I do very much like this bullet and am looking forward to working more with it.