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Sabot Rounds

65K views 60 replies 14 participants last post by  Fixitguy 
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#1 ·
What are the advantages of sabot rounds? I have seen the plastic leftovers on the range and I know sabot rounds are a popular ammo type for destroying tanks, but what are the advantages of a sabot bullet?
 
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#28 ·
Nekekami,

Projectile diameter is 4.81mm? That would put it roughly at about .18 caliber, if I'm not mistaken. Are these bullets custom casted for the Swede sniper teams, or is this a caliber size in Europe that just hasn't made it to the US? I have never heard of a bullet this size. Is it available as a chambering in European sporting rifles, not as a sabot round but as a factory-loaded .18 caliber bullet? Although it does sound roughly like whats in our .17 remington centerfire rifles, although an admittedly unpopular and slightly obscure caliber in its own right.
 
#31 ·
Jake:

The current projectiles are currently casted in Sweden, but the original projectiles, in the Winchester SLAP, are casted in the US.

They are specially made for use in sabots, and I wouldn't want to try and make a conventional round out of it. It's a tungsten penetrator, pure and simple... Except for the lack of fins, it's a scaled down version of the tungsten penetrators that tanks use in their anti-tank ammo.
 
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#33 ·
Oh, I didn't think that the actual sabot would be used as a sporting caliber, just wondered if the bore diameter was. But I had forgotten that it was the same diameter as the projectile in the Win SLAP.

And thanks all for the pronunciation! :)
 
#35 ·
Mel:

Uhm, wouldn't it be the other way around, really? The lighter the bullet is, the faster the rate of twist must be? I mean, looking at 5.56x45 and its 1 in 7 to 1 in 9 twist, compared to 7.62x51 and its 1 in 10 to 1 in 12, and so on.

And, as I mentioned, our current round is somewhat more accurate than the SLAP round, because it uses a heavier projectile than the original SLAP. Higher weight for its diameter makes it less susceptible to wind, doesn't lose velocity as quickly. But you won't get the same muzzle velocity as with the lighter projectile. A trade-off that might be worth considering.
 
#36 ·
Well, actually, the required rate of twist is caliber and weight dependent. You must compare bullet weights in the same caliber. The reason most all the new crop of .223 rifles are at LEAST 1:9 is because the bullet weights have gone up. For the same given caliber, the required rate of twist to stablize a bullet must increase as the weight of the projectile goes up. There is actually a formula out there that computes this for you. I believe the length of the bullet comes into play also. I know to stablize the 69gr .224 bullet, you need at least 1:9 twist, if you go to 75+ you need 1:8, etc. Just like .308, 175 is very marginal for 1:12 twist barrels, 1:11 is ideal, 1:10 gets you to the 180's +.

MEL
 
#38 ·
Well, since the sabot seperates from the bullet once it leaves the barrel, it does not have an impact on the stabilization of the bullet. In order for the bullet to become stable it needs to achieve a certain RPM, now, I am NOT certain if the extra velocity of the bullet (if its up around 4000fps) would effect the required rate of twist, everything I've read seems to indicate that it doesn't. BUT, I need to fully state that I am NO expert in this. I just know what is required normally to stabilize a bullet, and the ROT of a .308 rifle probably will not be enough for the heavier .224 bullets. Of course, the ROT for what you are shooting is completely different, as that bullet must be EXTREMELY long. 95gr in about a .18 cal. YIKES! I'd really like to know the BC of that projectile.... and how I can get some :)

MEL
 
#39 ·
Mel:

It's not very long. It's just quite heavy. Tungsten-Carbide of that grade usually is. As for the BC, it's roughly 0.52.

But, for internal ballistics, you _have_ to include the sabot in the calculations. The rate of twist is lower, but you have a higher velocity that reduces the flight time and gives you a flatter trajectory.
 
#40 ·
.52 !!! :shock:

Holy freak. Thats awesome. Guess I need to invest in some tungsten.

Yes, less time of flight is great, but if the bullet is not stabilized (not enough rpm) it will lose accuracy, and in a bad case, even tumble (as is evenent with trying to shoot new NATO 5.56 (SS109?) in old M16A1's with 1:12 twist). I've literally have seen perfect SIDE profile holes of bullet passing through a target TUMBLING. This was from old M16A1's. Thats not good for accuracy!! This is purely external ballistics.... is it spinning fast enough when in flight.

Anyway, I wont know until I test them.... I do appreciate your info

MEL
 
#41 ·
Mel:

Tungsten isn't that hard to get hold of... The problem is managing to make something useful out of it. It's hard, it's very heat resistant, and it can be quite brittle too at times. Still feeling up to the task? :wink:

About the BC, something's still making me suspicious about it, but I've put it through 5 different BC calculators, I've done the calc manually, and I've had colleagues checking it out, and they are giving me matching data.
 
#44 ·
Mel:

I'll put together a table for you when I'm done with my school project(which had a serious setback due to a HD crash.... The necessary files were all in a backup, but the system etc needed reinstalling).

If nothing else, I'll go out and shoot a couple of series so I get data for the same weather conditions, and thus a better pool of data.
 
#49 ·
Well Im going to the range tommorow to try some sabot rounds for my 300 Win Mag. I'm trying out 4 different loads to see if i can get some accuracy out of them. With all loads im using 55gr hornady v-max bullets. The first is 60gr of IMR 3031, Second is 64gr of IMR 3031, Thirdly im trying 66 grains of hodgon Varget, and Finally im trying 70.5 grains of hodgon Varget.

Assuming I make it to the range tommorow i will report back to you all and let you know how the accuracy is on these, and if i get decent accuracy I will borrow a friends chrony to check the velocity. Hopefully now i will be able to shoot some yotes with my 300 (which is all i really want to do).
 
#51 ·
Well the tests got pushed back, hopefully i will be able to test these on friday afternoon if not I will get out Sunday for sure.

*edit* it should also be noted that i am seating the sabot/bullet to the same depth as a fatory 300 load (3.330 if i remember right), eabco lists there length at 3.00 i am going to try them at the normal lenth to have them closer to the lands, I will also fire 3 rounds, then clean with a bore snake and Break Free powder blast so i can hopefully get a true accuracy report. I will also compare it to Factory Federal loaded 180 gr Nosler Solid base, and my own hand loads with 165gr hornady btsp, and 200 Gr sierra Game Kings (both of which i am using RL-22).
 
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