(Silly question) Would .350 legend with .224 sabot be better than .223 Rem/5.56 Nato?

[MC_MuHyeon]

Title says it all. I know that it's a silly question and that reloading plasitc sabot rounds is expensive (also there is no .357 sabot accepting .224 cal bullets that I know of) but I would like to know how much gain in ballistic performance would be with increased bore diameter with same .224 cal bullets.

Winchester states that .350 legend has more muzzle energy than that of .30-30 win, and .30-30 acclerator throws a 55gr .224 cal bullet at 3600ft/s. So I guess the imaginary .350 legend "accelerator" that I thought up would push the bullet at the speed of more than 3600 ft/s, right?

Also, there has been many statements about sabot rounds (such as .30-06 Remington accelerator) saying that they tend to be less accurate than conventional ones. Is this due to slower twist rate of larger bore barrel? Or is it due to bullet seating inconsistencies?

[TX Nimrod]

There are several reasons for less accuracy with sabots. The one I prefer is that the sabot is not solid like a bullet jacket, the plastic will flex under shock and pressure, this random movement is transferred to the bullet. A bore-sized bullet does not have to deal with this extra interferrence.

[MC_MuHyeon]

Thank you for the reply. Assuming your statement on the reasons why sabot rounds are less accurate is right, would sabots made out of stronger materials (aluminum, liquid crystal polymer) with tight tolerances resolve the issue?

[44 AMP]

Consider this, first, the plastic is fairly soft, and second, you are driving it pretty fast. Along with alignment issues of the subcaliber bullet IN the sabot, you have issues with the plastic gripping the rifling.

With the Remington Accelerator rounds you do get varmint rifle speeds, but you almost never get varmint rifle accuracy. Part of that is, of course you're shooting them out of a deer rifle, and the other part is the performance of the sabot slug itself.

Generally speaking the ones I have seen, shooting Accelerators, if the rifle shoots as well as it does with deer ammo, you're golden. Often, it won't. 06 has the reputation for being the worst, but then you're also cracking 4000fps with plastic...

I've never shot more than a handful of Accelerators, I detest the idea of a plastic coating fouling my barrel.

FWIW, the sabot of the 105mm M60 /M1 tank gun is aluminium. If I recall right, the crews said it was very accurate. The 120mm main gun in use now also has a sabot round, but since the gun is smoothbore, there's no rifling for the sabot to grab.

[mikld]

A few years ago Remington made a cartridge called the "Accelerator". It was available in a few sizes (IIRC; 30-30, 30-06 and a few others). I purchased some of the sabots and loaded up a bunch of 55 gr .224" bullets and tried them in my 30-30 Handi-Rifle. Accuracy was dismal and I tried a couple different powders from very light to near max loads and never got acceptable accuracy (my Handy rifle in 30-30 usually gave my 2"-3" groups at 100, mostly my "marksmanship" and with it's .223 barrel produced 1"- 1 1/2" @ 100)

OOPS! Missed 44 AMP's mention of the Accelerator...

[jmr40]

As others have said, it's been tried before in other cartridges. Accuracy has never been acceptable. Not to say that at some point in time the concept may work. It works with the military and tanks.

[Unclenick]

I expect the military accuracy is, as MC speculated, harder materials, but also being able to afford to have each one precision machined and not just popping them out of a mold. I expect the accuracy problem with sabots is that, like lead, they can swage into the rifling deformed to have the bullet's center of gravity offset thousandth of an inch pretty easily. At lead bullet velocities that may not do a lot, but at varmint rifle velocity is another matter.

Example:

3500 fps from a 10" twist.

The angular velocity is:

2 × pi × 12 × 3500 / 10 = 26,389 radians per second.

Multiply that times 0.001" offset:

26,389 × .00025" = 26.4 inches per second drift off the trajectory path.

If the bullet takes 0.09 seconds to go 100 yards, then:

26.4 × 0.09 = 2.4 inches drift away from the mean POI.

After firing a second shot randomly off by the same thousandth but toward the opposite side of the barrel, you've got a 4.8" 100-yard group.

[T. O'Heir]

"...be better than..." For what?
"...tend to be less accurate..." They were far less accurate than the varmint rifle they were made to replace. The idea behind the Accelerator was to let a guy use his deer rifle for varmints. It was more marketing than anything else.
I've never once seen a varmint that cared what rifle or bullet was used to kill him. Where it's legal, using your deer rifle and load for varmints is great practice for deer season too.
A tank gun with APFSDS(Armour-piercing, fin-stabilized, discarding sabot) ammo is firing a depleted uranium penetrator(used to be tungsten carbide) at a much bigger target than a varmint rifle. The sabot is precisely machined as well.
"...would sabots made out of..." You have the money and technology for that? You start getting into odd ballistics caused by varying bullet weights. Isn't worth the time, money and effort.

[44 AMP]

I think "minute of tank" at a couple miles is roughly comparable to minute of varmint at a couple hundred yards,,,