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Wildcatting:Sub-Sonic Mania!

I tested the Schultz and Larsen Legacy in 300 AAC Blackout and was really impressed at not only the build quality of the rifle but the calibre’s unique performance. It’s not for everyone, it’s one of those cartridges that has to be used to be appreciated and wisely too. Many say what’s the point, but don’t knock it until you’ve tried it! The Blackout, as with the 300 Whisper, which it emulates, has a dual purpose. That of super and sub-sonic velocity, which is interesting to some but not to others.

What can you do?

The Blackout is not legal for large deer in England and Wales but is OK for Muntjac and CWD and in sub-sonic only for vermin. Though in super-sonic is target capable. For me its sub-sonic abilities for silence and accuracy for long range plinking, yes plinking, is so much fun. It really tests your abilities to judge range, read the wind and keep that barrel clean for optimum performance. Due to the slow, heavy nature of the sub-sonic projectiles, you really have to have a good back drop, especially when shooting steels. We set out targets at unknown distances out to 500 yards and then have a competition to hit or ring the steel with 15 shots, no sighters! It’s expensive plinking, not due to the powder charge but those heavy .30” bullets are pricey!

Case in hand

Firstly, the super-sonic velocities are certainly better with 1 in 10” twist rifling for optimum velocity with medium pressure. Trouble is, it’s not enough for 200-grain+ plus bullets needed for sub-sonic use! So a 1 in 7 to 7.5” rate is favourite! If you use the 110 grain V-MAX supersonic loads in the fast twist barrel you will notice that the primers are flattened, meaning high pressure that can lead to primer pocket expansion.

The other thing is that with a super-sonic load, a longer barrel helps increase velocity but the converse is true with subs, you want it short to avoid too much velocity and especially fouling; more later. The Blackout is small, being based on the .221 Fireball cartridge and simply necked up to .308”, which leaves a small, 23° shoulder to headspace off. That’s an issue for reloading to get it right. The case is 1.400” long with a trim length of 1.390”. Head size is typical .222/.223 at 0.378”.

To die for

Case capacity is 24.95-grains of water and dependent on bullet seating depth, this decreases to 20 grains or less. However, as with many subs, the throats are long in the chamber to accommodate the bigger bullets up to 240-grains. It’s designed to use fast burning powder, to peak pressure quickly, which is ideal in a short barrel but I tried a variety to ascertain the limits. Loading subs has a lot to do with neck tension and seating depth, to get best results but the key is consistency, as they are merciless if you get it wrong!

I had three good makes of die to choose from; Lee, Hornady and Lyman. The Lee Pacesetters from Hannam’s are an excellent choice, giving good prices and build quality. You get good instructions with all you need to reload, including a powder scoop, shell holder (very handy). The set consists of three dies - seating, full-length re-sizing and crimp if you desire. Lyman offers a seater and full-length re-sizer. The Hornady custom grade are again full-length re-sizer and seater, with spare seater stem and primer de-capper. They use a fast zip spindle system and supported bullet seater casing.

Load up

For data, I used the Hornady book 9th edition, as well as the Vithavouri reloading manual and of course the Quickload and QuickTarget ballistics program. For subs, you are looking for a total powder burn within the 17” barrel, which is no problem in the Legacy. However, other Blackout rifles go for shorter tubes, so experiment.

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You can use powders such as IMR 4198, H4198, IMR 4227, H110, Lil`gun, Vit N110 or Vit N120, as well as Trail Boss or Tinstar. Some of these proved too slow, with only the lowest or minimum charge achieving a sub-sonic velocity. You can sub-sonic any of the bullets from 110 to 240-grains with careful reloading but the top choice are the heavyweights for best retained down-range ballistics!


From long years of sub-sonic use, I know fouling is a problem and so heavy Lapua 200-grain B416 bullets, with the twin driving bands for sealing, maintains velocity and reduces copper fouling significantly. Even with the other standard bearing surfaces of the conventional types, the Legacy seemed not to foul as much as similar barrels shooting subsonic .30 cal projectiles. I used the superb new Lapua 300 Blackout cases from Hannams and Federal, small rifle Match primers. Sabots are always interesting, although my stock of these mini synthetic ‘shoes’ is dwindling. They enable a smaller .22 cal bullet to be fired in a .30” bore, but you can’t use a moderator as the sabot might get caught up inside!

Jones, 90-grain custom bullets are flat based and sit well in the sabot at a total of 96-grains. Best load here was the 9-grains of Vit N110 for 1057 fps/238 ft/lbs energy with 1” groups. Trailboss was a bit inconsistent in this load. A fun sabot load was the 50-grain V-MAX bullet and 9-grains of Vit N120 for 1083 fps/146 ft/lbs but inconsistent results.


My favourite light bullet sub-sonic load has to be the Hornady 90-grainXTP, as it expands easily. Best was 5.5-grains of Trialboss and 1077 fps/232 ft/lbs and great accuracy of 0.75” at 100 yards. The 110 and 125-grainers were fine but as with the 90s, you had to use a small amount of powder to achieve sub-sonic velocities and any slight variation in load, neck tension or seating depth and the ballistics varied, so I would skip these and the 150-grainers and go to the best heavy bullets.

I tried various 208, 210, 215 and 240-grain bullets, see the table! But by far the best is the Lapua B416 Sub-sonic bullet, due to its weight and design that reduces friction. In the Legacy, the best load was the 9.5-grains of Vit N110 with a COL of 2.14” for 1037 fps/478 ft/lbs and unbelievably consistent 0.35-0.45” 3-shot groups at 100 yards!

Head for the hills

Now with a superb load, I headed for the hills and fitted the equally superb Recknagel 70 MOA mounting system to the Legacy, to maximise sighting in at 500 yards. I sighted in at 100 yards, drops were -34.2 inches @ 200, -107.8” @ 300 yards, -223.8” @ 400 and a whopping -386.8” @ 500 yards. Yet it still has 937 fps @ 200 and an impressive 833 fps @ 500 yards, that’s the beauty of slow bullets below the supersonic threshold, as they lose velocity/energy slowly.

The wind deflection calculated at 10 mph from 3 o’clock is interesting, also with only 2” @ at 200 and 24” at 500 yds, hardly anything! The Recknagel mount, with its 10 MOA stepped adjustments makes short work of sight correction and returns to zero exactly: it’s an amazing scope mount for switching between super and subsonic loads.


Hannam’s Reloading 01977 681639 - Vihtavuori, Lee, Lapua
Norman Clark 01788 579651 - reloading dies, supplies, bullets
Alan Rhone 01978 660001 - Schultz and Larsen, Recknagel
Edgar Brothers 01625 613177 - dies, bullets and powder n JMS Arms 07771 962121, Quickload and Quick Target www.quickload.co.uk

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