Sabot ?

[ken snyder]

Is anyone playing around with sabot bullets. The only ones I ever played with were the Accelerators, and they left a little to be desired. I think but don't know for sure that the accuracy problem was and is not having the correct rifleing twist rate for the bullet. seriously thinking of .458 barrels with .338 bullets.

 

[edge]

IMO, you have several problems effecting accuracy.

1) bullet to sabot runout;

2) sabot to bore runout;

3) bullet sabot consistent separation.

I think that if you can solve this and can find a sabot friendly load that achieving sub MOA is very doable.

I have a smokeless muzzleloader and shoot a variety of bullets but mistakenly went with a 14 twist .458 barrel and that hampers my bullet selection.

edge.

 

[rscott5028]

They seem to work well as a band-aid in certain applications such as overcoming deficiencies of muzzleloaders and allowing one to shoot a much smaller/lighter bullet in a hunting rifle.

But in practice, I doubt it buys you anything for LRH.

Without some kind of R&D breakthrough, I would expect you to lose long range accuracy and consistency compared to a properly engineered 338 rifle.

I've actually never seen the 30 cal/22 call sabots come close to the accuracy of a well-built 222, 223, 22-250. But, my experience is somewhat limitted.

Nonetheless, it's a great concept and I'd be curious to know if anybody's pursuing it.

-- richard

 

[ken snyder]

There are many as mentioned above problems with Sabot bullets. I do not have a good opinion of the ones I have shot. Looking at it as a play around project it has some interesting possibilities. ( safety noted ) Without the introduction of some sort of smart powder we have already taken velocities to their max. A way simplified formula for velocity is pressure, time and surface area. Pressure is at an end, time decreases with velocity, and we end up with surface area ( diameter for weight ) as the current last place to go for higher velocity. I know the military uses them in very accurate Kinetic loads ( the science television channel). At the very least its an interesting topic if no one is currently playing with them.

 

[edge]

I would have to agree.

You do need to shoot the weight of the sabot which will add about 30 - 35 grains to your 338 bullet.
When I shot the 250 grain 338 Accubond the total weight was 285 grains.

If you get it to shoot, you may be able to get velocity at a lower pressure since the bore is so large.

edge.

 

[rscott5028]

[...]When I shot the 250 grain 338 Accubond the total weight was 285 grains.[...]

So, you tried this in a high power application? Or, muzzle loader???

 

[edge]

So, you tried this in a high power application? Or, muzzle loader???

High Power yes, but it is a muzzleloader and not a cartridge rifle
250 grain Accubond at 3,000 fps.

I have shot a break open 45-70 cartridge with a pre rifled sabot but at lower velocity and only in the 1 moa range. I had to load it by feel, partially load it and rotate the cartridge until the rifling caught, then the cartridge was fully inserted.

edge.

 

[rscott5028]

High Power yes, but it is a muzzleloader and not a cartridge rifle
250 grain Accubond at 3,000 fps.

I have shot a break open 45-70 cartridge with a pre rifled sabot but at lower velocity and only in the 1 moa range. I had to load it by feel, partially load it and rotate the cartridge until the rifling caught, then the cartridge was fully inserted.

edge.

That's a serious muzzle loader.

 

[ken snyder]

Sounds like the 250gr. Accubond Sabot was a very succesful experiment. It may not have yielded the desired results, but it did yield results. (( What type of material is being used to make the shoes. )) I wonder how short the barrel could be cut down and still make representation of the origional 3000 fps velocity. Because I'm more interested in a short barrel (legal) for a few reasons. # 1 the obvious benefits of short barrel stiffness and the decreased time for me to wiggle. I'm not sure but as far as velocity goes ( first stop on the road ) a full pressure load with smaller charge weight and faster burning powders should bring velocities up without haveing the need of a large volume of expanding gases needed to keep it going through a long tube, and once the bullet hits a particular velocity, there simply is not enough time left to significantly increase bullet velocity. From a short barrel it could end up a win win situation. If the mechanics of good velocity can affordably be achieved, then the costs of shoe development would be a fun hobby and who knows!

 

[edge]

Here is cutaway view of an Accubond ML sabot:

Most of my sabots for the ML are PVC type II which is corrosive due to small amounts of chlorine gas given off when fired! The bore needs to be cleaned and oiled after every shooting session as a result which is a pain....but these have been the most accurate for me.

If I were molding sabots then some sort of Nylon or PET or some combination would most likely be my choice. Since I machine each sabot individually, sawcut the petals, and debur by hand I need a very different set of specs for my sabot material.

You need a material that is strong enough to not blow a hole in the sabot, a material that is rigid enough to keep the bullet centered in the bore, and will separate cleanly from the bullet in a nearly identical manner every time.
There are two main types of sabots, one type stays intact like most soft ML sabots and open like a flower. The other type like mine and those used by the depleted uranium anti tank shells separate into pieces are made from very rigid material and these pieces carry a lot of energy.
The base of my sabot often travels a hundred yards and has about 400 ft/lbs of energy at the muzzle so you need to watch out for bystanders and ricochets!

edge.

 

[rscott5028]

Is the millitary doing this with the 50 BMG?
i.e. depleted uranium and sabots for superior penetration

If the millitary hasn't found it useful in a shoulder fired rifle with their R&D budget, then it's likely got more than a few problems.

Also, I wonder if a progressive twist barrel would help get your velocity up without premature shredding of the sabot?

...the idea being to shoot extremely high BC bullets at high velocity/rpm

How would that affect the yaw?

Would you be better off to just shoot a well designed 338 cal rifle?

-- richard

 

[edge]

The 20mm Phalanx does/ used to shoot a spin stabilized sabot round MK 149 AP
I don't know the accuracy of that round.

In ML season I am limited to a 44 caliber bore so a straight 338 is not an option.
I would say that 99% of folks would Probably be better served with a standard long range rifle.

Now since it is easier to get high velocity with a larger bore without exceptionally high pressures and since plastic is pretty easy on barrels and "whatever else" there may be an advantage if the sabot were designed properly.

edge.

Is the millitary doing this with the 50 BMG?
i.e. depleted uranium and sabots for superior penetration

If the millitary hasn't found it useful in a shoulder fired rifle with their R&D budget, then it's likely got more than a few problems.

Also, I wonder if a progressive twist barrel would help get your velocity up without premature shredding of the sabot?

...the idea being to shoot extremely high BC bullets at high velocity/rpm

How would that affect the yaw?

Would you be better off to just shoot a well designed 338 cal rifle?

-- richard

 

[ken snyder]

IT is always better to get a standard everything available cartridge. I've been building my own wildcats for years and whenever I've come up with something new a basically no difference cartridge shows up in a reloading manual with all of its ducks in a row. There are no new cartridges just new names with a convenience factor. All of the African volume brass has been folded, spindled and mutilated to the nth degree. I realize that we are at a dead end without a new powder catagory. Please don't take me wrong when I say Ive been there and did that. I like many have a spirit that always requires something new even if its old to someone else. Sabot has my interest.

 

[Jinx-)]

3000 fps that's some serious stuff , I like 250 gr TC shock-waves they group like 0.6" - 0.8" @ 100 when I use 777, its about 1700 - 1800 fps, I also tried APP, but groups were allover.