Wildcatting

The need for speed is an addictive pursuance that usually results in an insane amount of effort and cash to achieve even the smallest degree of performance advantage. However, there are some times where ballistics can play into your hand and offer an unusual and ‘get out of jail free card’ with regard velocity gain.

Maximum ceiling

Most medium sized projectiles can be pushed to a ceiling velocity by either maximum powder capacity, pressure limits or decreasing the weight of the projectile, or all three. Using a lighter bullet is the easiest way but there comes a point where the diameter of a bullet or calibre restricts the useable bullet weight available.

In .30 cals, the real limit is 90-grains using 30 cal pistol bullets and that is still a short stubby little fellow with a low BC. Lapua used to make 73-grain 30 cal bullets and I have used J4 jacketed customs with 5 ogive form but with a small lead content to fill the lower bullet’s cross section to keep a good shape, yet limit the weight. However, there is another way around the problem and it’s been used for many a year now and owes a lot to artillery and tank gun ammunition shell technology; sabots!

Nice fit

The word sabot is French and literally means shoe! It basically uses a light weight, calibre-diameter casing to hold the smaller and lighter bullet and acts as the donor calibre or diameter bullet. In this way, a synthetic sabot weighing no more than 6-grains can be used and when combined with say a .224”, 40-grain bullet you have for all intense and purposes a 30 cal bullet weighing 46 grains.

You also have the benefit that the actual bullet is streamlined with a good BC, certainly better than a calibre-sized, stumpy and light .30 cal pill. The only limiting factors are safe reloading practice and the correct ‘donor’ bullet achieving a good grip/fit in the sabot; also, providing a proper gas seal (obturation) and cleanly releasing the bullet as it exits the muzzle. Sabots go back a long way in history, but perhaps their most practical use has been on tank guns from WWII onwards. A small and light tungsten penetrator with a pointed alloy nose cap to give a good BC sits in a number of synthetic petals. It’s then launched at well over the standard velocity and imparts a massive amount of kinetic energy on target, to penetrate a tank’s thick armour.

Accelerator

Remington had the idea to produce factory ammunition using sabots in their Accelerator ammunition range. These were available in .30-30, .308 and 30-06 and were an attempt to allow users of rifles in these calibres to also shoot lighter 55-grain 0.224 bullets for varmints. It sort of worked but one of the limiting factors of all sabots is accuracy. You may well achieve higher velocities but accuracy was never any better than the original .30 cal and often worse, which is why eventuality it died a death.

Factory ballistics for the 30-30 was 3400 fps and 1412 ft/lbs energy with a 55-grain bullet. The .308 Win, using the same bullet, was 3700 fps and 1735 ft/lbs, whilst the 30-06 could achieve 4080 fps and 2033 ft/ lbs, wow! In the old days, I use to pull the sabots and re-use them in different 30 cals such as 300 Win Mags and 300 H&H- that was fun! I have tried experimenting with lathe-turned sabots and some using smaller bullets than 0.224 cal too. But the best compromise were the ready-made sabots from E Arthur Brown Company from the USA, once easy to find!

Load up

The Brown sabots are polycarbonate, I have used Teflon, Nylon or Delrin before. The Browns are grey coloured with a 0.308” diameter and 0.537” long, with six (0.224” long) petals that fold back to release the bullet in flight. There is a slight dip to the base to aid in gas sealing and the bullet recess is 0.430” deep, so good for 0.224 bullet weights from 30 grains to 90 grains. Importantly, the sabot only weighs 6-grains, so with a 35-grain, lead-free NTX bullet the all-up projectile weight is of 41-grains, let the fun begin!

You need to use a faster than normal powder to achieve decent velocities in the larger parent bore. NOTE: all sabots were loaded no more than 0.20” seating depth in the parent case due to pressure reasons.

In the field

First up: DO NOT USE A MUZZLE BRAKE OR SOUND MODERATOR, as the sabot starts to open the instant it hits the air at the muzzle and you will come a cropper. I forgot with an aluminium muzzle brake and it cut perfect serrations around the orifice!

There are certain other important points to realise when shooting sabots. In a magazine, recoil can cause the sabot/bullet to jump out, or telescope to a shorter COL, thus increasing pressure. So single load only in my view to be safe!

Primer choice is incredibly important as well because on ignition you are trying to push essentially two projectiles at the same time and they have a differing mass, and so from pure inertia, the heavier bullet wants to get down that bore quicker than the sabot as it also has more momentum. What can happen is that quality primers such as Match or Magnum that burn intensely and for longer, usually, will ‘bump’ the bullet out of the sabot and that’s not good for accuracy.

I use Federal 210 primers, as from experience with my loads they seem to be the most consistent for sabot use and maintain the integrity of this double payload. Next, is that sabot can trash a chronograph in one shot! Most fly up to 20-25 feet, so put a shield over the delicate parts on any chrono.

Friction fit

Finally, differing bullets have differing frictional qualities on their outer surface, due to the jackets used. Gilding metals on non-lead bullets are tough and slippery and so sabots can be loose. Lubalox or Barnes MLC types can be tight, which can be good. Flat-based bullets are defiantly best, as they sit very well in the sabot and allow a good grip. Boat tails have better BCs but can topple or yaw in the sabot on firing and can be pants to be honest.

I have used sabots for crows only and a few rabbits and they have been fun but the non-use of a sound moderator is a bit limiting, as in urban areas, it gets you noticed and in Scotland it scares off wary crows with the report.

I have also tried using the old Sussex Armoury sabot airgun ammunition that uses a .22 cal sabot and 0.1625” bullet for a total weight of 14.4-grains and then load this sabot within a 30 cal sabot! Iffy at best but 5563fps from a 300 RUM- yikes!

Also, with the Browns sabots I used lead air gun pellets, such as the Daystate Predator that is a hollow point lead pellet with a hollow point at a weight of 40-grains designed for FAC air rifles. Paper patching .14 and .20 cal bullets is also possible but that’s all for later!

Conclusions

The reality is that it will not out-shoot a standard .22 centrefire but from a pure point of interest in reloading it is great fun. Also, you will achieve some startling velocities from your deer gun. It really got me thinking and using my friendly lathe operator custom built sabots for .14 cal bullets are now achieving 6000 fps- oh yeah!