A recent trade for a VSSF in 220 Swift has led me on a quest to get to 5,000fps. There are several cartridges capable of doing this and the Swift is one of them.

First, of course, one needs a light bullet weight. Very light. My choice was for the 35gr Berger. My opinion and forty years of working with the Swift leds me to Winchester brass. Stuffing said brass with H335 got me close to goal at 4,792 fps, however, some pressure signs were becoming apparent. VV offers some powders that may help me cross the 5M boundary safely and I await a shipment of 2lbs that should arrive tomorrow.

Accuracy was surprisingly good considering the bullet's rotational spin, with 5 shot groups running .685 MOA. I'm surprised the bullets didn't disintegrate on their way to the target.

To the question of "why?" there is no answer and none needed. But, should I try to justify my labors it would be to test the theory of hydrastatic shock as we near coyote hunting time.

In the interim I take some glee when a few gather at the bench to look at those chronograph numbers.

more to follow, if the goal is met

Handloader,

Now thats a speed record. Almost a mile in a second! Get it to 5,280fps and you will have a round going a mile a second! You can forget measuring the speed in feet per second at that point.

Keep us updated

Dimitri

In my .22-250 when I get up around 4800fps my bullets disintegrate from barrel friction and they never reach the target... o.O


-DallanC

I can't even imagine that sort of speed out of a bullet. But then again, I suppose it is attainable. Just a thought, but, what would a load like this be doing to the throat....mucho erosion methinks.

Maybe a solid copper bullet is the way to go, although pressure could be a problem using them.

I'm not an engineer, but I would imagine that anyone with a lathe and the knowledge to do very close tolerance work could produce a bullet of the appropriate size and weight to overcome the problems of pressure and disintergration on route to the target.

A light bullet travelling at that speed would be devastating on a yote....or any varmint for that matter. I have this mental picture of a PD taking a chest shot.....instant RED MIST !


Cheers, Vince

Vince,

I'm told Remington Accelorators in 30-06 did that on small game, and they were only going at 4080fps at muzzle.

Dimitri

I am thinking that a max'd out load in my 22-250 AI using a molyed 33 gr. Speer TNT bullet might get me close if the bullet would hang in there. Curious if you can get there..........let us know.

Vince wrote:

I can't even imagine that sort of speed out of a bullet. But then again, I suppose it is attainable. Just a thought, but, what would a load like this be doing to the throat....mucho erosion methinks.

I am pretty sure the M1A Abrams Tank shoots its shells at over 6,000fps


-DallanC

Found this at Reloaders Nest


Load 1200 in caliber .22-250 Ackley Improved

LoadID 1200
Bullet Berger MEF
BulletWeight 35 grs
Powder Vihtavuori N135
PowderWeight 46 grs
Primer
Brass Make Remington
Barrel Length (inches)
C.O.L (inches)
Velocity 5130 fps
Group 0.929 (inches by 3 shot at 100 yds)
Submitted Date 3/18/2002 1:25:00 PM
Submitted By
Gun Info
Comment

Energy 2041 ft-lbs
TKO 5.69
OGW 248 lbs

www.reloadersnest.com/...oadID=1147

DallanC wrote:

Vince wrote: I can't even imagine that sort of speed out of a bullet. But then again, I suppose it is attainable. Just a thought, but, what would a load like this be doing to the throat....mucho erosion methinks. I am pretty sure the M1A Abrams Tank shoots its shells at over 6,000fps -DallanC

That is awesome, especially for such a large heavy round.

Found this info:

M1A ABRAMS TANK

5500fps, and from a projectile you measure in POUNDS..not grains. Devastating to say the least.

Cheers, Vince

Scary tanks.

0.6 gallons a mile. or 300 Gallons in 8 hours. Not that feul friendly though.

I wonder if a really light sabot'ed shell (kinda like the Tank shells or the Remington Accelerator shells) would increase the speed by allowing you to use a really small bullet ??

Dimitri

Dimitri wrote:

Scary tanks. 0.6 gallons a mile. or 300 Gallons in 8 hours. Not that feul friendly though. I wonder if a really light sabot'ed shell (kinda like the Tank shells or the Remington Accelerator shells) would increase the speed by allowing you to use a really small bullet ?? Dimitri

I don't think that an accelerator would make any difference to the bullet disintergrating. If it was going to break up then it would. Now, I suppose a solid copper bullet in an accelerator...interesting thought. Speed for the sake of speed.

Cheers, Vince

Vince,

The sabot would be simply pressed copper and that will engage the rifling not the bullet itself so I think it might hold up better.

Dimitri

Bullet disintegration in flight is a product of rotational speed. The Swift, for example, has a 1 in 12 twist; at 5,000 fps, it would have a rotational speed of 300,000 rpm. 4,000 fps = 240,000 rpm, 3,000 fps = 180,000 rpm, etc. While velocity slows from the moment the bullet exits the muzzle, rotational speed remains fairly constant and degrades little.

The rotating speed of the bullet to achieve stability varies and (help from ballisticians appreciated here) probably relates to velocity factored by mass (?). Relative to 22 caliber bullets, 150,000 rpm seems to be the minimum optimum rpm. Speer advises that some of their 224 varmint bullets shouldn't exceed 3,400 fps. OTOH a Barnes TSX in 45gr couldn't possibly disintegrate.

Now, if Barnes offered a TSX 30gr in 224, 5,000 fps and beyond would be relatively easy out of the Swift or 22-250 AI. mc223 cites reloadersnest.com and the amazing speed achieved by the 22.250AI using VV powder. VV seems to have the ability to take velocity to higher levels within safe pressure constraints. In my case, I am using new brass for each new level of velocity and monitoring case head expansion very carefully.

Next session is Friday, 7am, testing H335 and the 35gr Berger.

report to follow

Dimitri wrote:

Scary tanks. 0.6 gallons a mile. or 300 Gallons in 8 hours. Not that feul friendly though. I wonder if a really light sabot'ed shell (kinda like the Tank shells or the Remington Accelerator shells) would increase the speed by allowing you to use a really small bullet ?? Dimitri

I'll bet after the tank runs out of ammo, it's gas mileage gets better

Handloader, in your quest for 5000 fps, I'd be interested in knowing the shooting details, i.e. are you allowing the barrel to cool between shots, barrel prep., how often do you clean the barrel, etc.

Other threads have addressed such issues, but, I'd like to know more about your shooting considerations as opposed to bullet type, powder, primer, and brass used.
Keep it coming...

[quote="Handloader"]Bullet disintegration in flight is a product of rotational speed. The Swift, for example, has a 1 in 12 twist; at 5,000 fps, it would have a rotational speed of 300,000 rpm. 4,000 fps = 240,000 rpm, 3,000 fps = 180,000 rpm, etc. While velocity slows from the moment the bullet exits the muzzle, rotational speed remains fairly constant and degrades little.

I just would like to add another way to think about rotation. At 100yds from a 1 in 12 twist velocity is not a factor. The bullet rotates on its axis 300 times. It would not matter if the Bullet velocity was a million Fps. The barrel sets the rotation. Rpm is for car engines and Dremel tools.
Bullets disassemble due to centrifugal force across the center axis usually due to poor balance and stress from the initial contact with the rifling and the resultant thinning of the jacket material.