The effects of the transition from super to sub sonic on the 22lr

[renaissanceman]

Please do not take this as a personal attack.

When I see this or read of “banging steel at 400 yards” it’s utterly meaningless to anyone with a technical mind.

I understand the ease and recreation of shooting metal targets. Yet technically it is of no value. Conveys zero useful data. We have no idea if you shot 500 shots to get those hits or 50 shots.

When you are “banging steel” are you shooting a 3” round or a trash dumpster. Car door?

If you want to provide useful information put up a paper target large enough to catch every shot.

Take your highly technical mind back to post #3 and have another go at the reading! This image was directed at the discussion of stability post transition from supersonic to subsonic (directly in reference to someone asking for impacts at 300-400yds). You'll see the nice round splatters on the steel. This was only to show stability at extreme range. It was very windy and the range is in a canyon, so yeah, many of the rounds were landing off the steel somewhere to the left or right, but they were all stable. A few hit the dirt below and ricocheted into the steel (the two less than round spaltters)

It conveys one extremely useful and simple piece of data -- HV ammo is still flying true at 400 yards.

 

[RTH1800]

Take your highly technical mind back to post #3 and have another go at the reading! This image was directed at the discussion of stability post transition from supersonic to subsonic (directly in reference to someone asking for impacts at 300-400yds). You'll see the nice round splatters on the steel. This was only to show stability at extreme range. It was very windy and the range is in a canyon, so yeah, many of the rounds were landing off the steel somewhere to the left or right, but they were all stable. A few hit the dirt below and ricocheted into the steel (the two less than round spaltters)

It conveys one extremely useful and simple piece of data -- HV ammo is still flying true at 400 yards.

But everyone who has shot an .22 RF already knew that.

 

[renaissanceman]

But everyone who has shot an .22 RF already knew that.

Everyone except the person asking perhaps? How many people have personally shot at 400 yards to observe bullets flying without tumbling? Most people who have shot 22lr have not even seen photos of 400 yard shots, I'd wager. Either way, there was a direct question that was asked and answered.

No need to get crazy and say it conveys nothing or is utterly useless which is obviously false. Those with technical minds like yourself should appreciate a very direct and simple answer with one very clear piece of information.

 

[obx22]

Everyone except the person asking perhaps? How many people have personally shot at 400 yards to observe bullets flying without tumbling? Most people who have shot 22lr have not even seen photos of 400 yard shots, I'd wager. Either way, there was a direct question that was asked and answered.

No need to get crazy and say it conveys nothing or is utterly useless which is obviously false. Those with technical minds like yourself should appreciate a very direct and simple answer with one very clear piece of information.

I have shot steel at 400 (on a regular basis) but not with ammo that breaks the sound barrier. The target velocity stuff is surprisingly tight and bullet splashes and recovered slugs are circles.

On the OP’s question/point, I watched a video of fellas firing .22LR at 1000 yds on steel, on a frozen lake. They were able to recover rounds with off center damaged noses. This made me think: if the target were tilted to be perpendicular to the approaching slug, instead of perpendicular to the shooter, wouldn’t all stabile slugs strike nose on? Even with 16 twist, I’m thinking there is a lot less “tumbling” than has been implied over the years.

 

[Milo 2.5]

I have shot steel at 400 (on a regular basis) but not with ammo that breaks the sound barrier. The target velocity stuff is surprisingly tight and bullet splashes and recovered slugs are circles.

On the OP’s question/point, I watched a video of fellas firing .22LR at 1000 yds on steel, on a frozen lake. They were able to recover rounds with off center damaged noses. This made me think: if the target were tilted to be perpendicular to the approaching slug, instead of perpendicular to the shooter, wouldn’t all stabile slugs strike nose on? Even with 16 twist, I’m thinking there is a lot less “tumbling” than has been implied over the years.

I shoot at extended distances quite a bit myself and after someone pointed out keyholing bullets may be bullet deformation, I tend to agree with you. I tend not to look for fired slugs and just notice the flat slugs under the targets.

But I have shot enough at 500 and beyond to notice lags in flight times in certain winds w/o wild misses, and no way to actually measure it.
Shooting a 13tw and ammo that is supersonic, over 1120fps it is rare I see it much now. I can have someone shoot my 16tw beside and me the faster tw is far more predictable.

 

[bulletbluesky]

I have shot steel at 400 (on a regular basis) but not with ammo that breaks the sound barrier. The target velocity stuff is surprisingly tight and bullet splashes and recovered slugs are circles.

On the OP’s question/point, I watched a video of fellas firing .22LR at 1000 yds on steel, on a frozen lake. They were able to recover rounds with off center damaged noses. This made me think: if the target were tilted to be perpendicular to the approaching slug, instead of perpendicular to the shooter, wouldn’t all stabile slugs strike nose on? Even with 16 twist, I’m thinking there is a lot less “tumbling” than has been implied over the years.

At such distances standard velocity 22 rimfire hits the ground level target at steep angles for sure. The bullets are statically stable for sure but the question of dynamical stability is still open?

 

[hpt396]

Amateur here, so don't flame me, this is just theory of mine.

Regarding twist, a sub will have less rpm than a super when it leaves the barrel, so it should remain stable longer. Granted, I have no idea at what rpm either is leaving the barrel, at what rpm it will destabilize, or at what rpm destabilization begins for a given bullet.

Regarding the trans zone of Mach 0.8-1.2, I would think we would want the bullet as close to the target as possible before entering this zone to minimize the effect it would have on accuracy.

Advantage supers in both my theories. So it doesn't make sense to me why the match-grade ammo makers don't make any really good 1200-1400 ft/sec stuff.

Yes, no, maybe?

 

[jgraves]

Assuming 1080fps and 1:16” twist, the bullet is spinning at 48,600rpm at the muzzle.

A good test of supersonic vs subsonic accuracy potential might be to shoot both at distances before and after the transition, and look at relative precision. Ideally you would capture velocity at both muzzle and target to look at drag variations as a function of mv as well.

CCI SV vs Minimag solids immediately come to mind as a good pairing for this test as the dominant difference between them should be velocity and they’re both popular ammo. Possibly Eley Contact and Force as well (same 42gr projectile at different speeds?).

Thoughts?

 

[justin amateur]

I have.

Transition effects cause less than 2 degrees of yaw with a 40 grain 22lr.
On a 0.47 inch long bullet, that's about 0.008 inches of wobble.
Not enough to affect the trajectory, when compared to
the yaw caused by out of balance / factory damaged bullets.

In order to produce a useful comparison,
we will need cartridges made to the same high standard of quality.
When you do find cartridges of similar quality, standard velocity
and high velocity, results on paper are similar.

JG, I tried the 42 grain Eley products at 200 yards.
Contact and Force produced matching 50 shot groups.
If the transition was going to have a measurable effect on results,
200 yards gave it plenty of flight time to amplify the spread.
It didn't.