Speed of Izh vs. Steyr

[wasatch]

Lock times and barrel times are two VERY different things. The difference in BARREL times between low velocity and high velocity APs is around 1/100 of a second. How are YOUR reflexes?

The difference in barrel time is likely a good bit less than 1/100 s. Total shot development time (sear release to muzzle exit) of an LG110 HP was measured at 4.8ms. See page 3 of this interesting thread: http://www.airgunforum.co.uk/forums/sho ... rious-PCPs

[Rover]

The way I calculated it was: barrel length 12"; pellet velocities 400fps for puny, 500fps for high. 1/400 sec for puny; 1/500 sec. for high. Difference: 1/100 sec.

I could be wrong.

[Rover]

Lock times and barrel times are two VERY different things. The difference in BARREL times between low velocity and high velocity APs is around 1/100 of a second. How are YOUR reflexes?

True, but you can equally ask, how good is your trigger control? There's a lot that can go on in a hundredth of a second, I can run a revolver double action down to .16. (Not in bullseye, obviously.)

The main difference I saw in going back to the izzy from the Steyr was how much second stage creep increased, plenty of time to screw up.

That works out to about 1/6 second; nowhere near 1/100 and has NOTHING to do with barrel time and even less to do with SSP vs PCP.

[j-team]

Low velocity air pistols are great for strengthening your fundamentals. Elite air pistol shooters are not gods. They also flinch and can benefit from pistols that have faster lock and barrel times.

Have you seen the Scatt traces of the worlds best shooters? Most of them shoot on the way into the ten ring, they don't wait till they are there and then shoot.

[wasatch]

The way I calculated it was: barrel length 12"; pellet velocities 400fps for puny, 500fps for high. 1/400 sec for puny; 1/500 sec. for high. Difference: 1/100 sec.

I could be wrong.

Here's my back of the envelope maths:
1/400 = 0.0025
1/500 = 0.002
Difference = 0.0005 or half a millisecond.
Which is close enough but not totally correct because the pellets are accelerating from zero to muzzle velocity.

So in those measurements of the PCP rifles i'm guessing most of the difference must be in the firing mechanism.

[wasatch]

Low velocity air pistols are great for strengthening your fundamentals. Elite air pistol shooters are not gods. They also flinch and can benefit from pistols that have faster lock and barrel times.

Have you seen the Scatt traces of the worlds best shooters? Most of them shoot on the way into the ten ring, they don't wait till they are there and then shoot.

That is impressive. I've thought about it like learning to hit a fast ball--if i think about it the ump calls a strike. Not that I actually get it very often.

[kevinweiho]

Lock times and barrel times are two VERY different things. The difference in BARREL times between low velocity and high velocity APs is around 1/100 of a second. How are YOUR reflexes?

How considerate of you by asking how my reflexes are. I can tell you they’re pretty damn good. No need for beer.

The differences between barrel and lock times are:

Barrel time: is the time elapsing between a pellet starting to leave its seat exiting the muzzle.
Lock time: is the time elapsing between the trigger release and the release of pressurized gas into the barrel.

According to Cardew from "The Airgun from Trigger to Target", the lock time in SSP's is faster than PCP's.

The way I calculated it was: barrel length 12"; pellet velocities 400fps for puny, 500fps for high. 1/400 sec for puny; 1/500 sec. for high. Difference: 1/100 sec. I could be wrong.

Now you mentioned air pistols that shoot between 400-500 fps. A difference of 100 fps., will give an experienced shooter an advantage over “low velocity” pistols.
No human being on earth can hold an air pistol absolutely still while shooting offhand, even the slightest movement or misalignment can affect the POI.

[kevinweiho]

Low velocity air pistols are great for strengthening your fundamentals. Elite air pistol shooters are not gods. They also flinch and can benefit from pistols that have faster lock and barrel times.

Have you seen the Scatt traces of the worlds best shooters? Most of them shoot on the way into the ten ring, they don't wait till they are there and then shoot.

No, I haven’t seen the Scatt traces, but I do know that the current air pistol world record (594) was shot by Jin Jong-Oh using a Steyr LP10E?. All the shots would be an average of 9.9, a very, very difficult record to break!

Would he have pulled off the world record by using a “low velocity” air pistol? I don’t think so.

[rmca]

(...) the current air pistol world record (594) was shot by Jin Jong-Oh using a Steyr LP10E?

No, it was with a LP10, mechanical trigger (for the dismay of all Morini shooters ;)

[hundert]

and the final's world record of 206 was with the Morini

he set them both in Changwon Korea, a bit unfair that you get to shoot in your range, something the majority of people will never have a chance of doing. Competing on your own range is a big plus, not counting the stress from being in a different time zone and other travel related stress.

I even claim that it's very likely he wouldn't have broken it had they been shooting eslewhere.

The Morini trigger is a dream, no doubt, the best trigger out there

Top shooters can't hold the 10 ring, they hold 75% of the 10 ring, which means 75% of their shots are in the 10, which corresponds to a series of 97-98 on average, which translates into 582-588 for a 60 shot match, which is what it usually is. Scatt has that percentage number displayed for every shot and then the average for every series and for the whole match.

[Rover]

I'm with you.

ALL I'm saying is that 1/100 second more barrel time is NOT going to affect your scores. I don't know where all this other stuff is coming from.

And Hougan, have your scores leapt upward yet?

[Houngan]

I'm with you.

ALL I'm saying is that 1/100 second more barrel time is NOT going to affect your scores. I don't know where all this other stuff is coming from.

And Hougan, have your scores leapt upward yet?

Ha, from what? The Izzy? Absolutely, but that could be a hundred factors, the most obvious of which is that I have 2500 rounds of practice beyond where I put it down. I've changed so many technique things in the last five weeks my current shooting bears very little resemblance to my old shooting form.

[Rover]

The way I calculated it was: barrel length 12"; pellet velocities 400fps for puny, 500fps for high. 1/400 sec for puny; 1/500 sec. for high. Difference: 1/100 sec.

I could be wrong.

Here's my back of the envelope maths:
1/400 = 0.0025
1/500 = 0.002
Difference = 0.0005 or half a millisecond.
Which is close enough but not totally correct because the pellets are accelerating from zero to muzzle velocity.

So in those measurements of the PCP rifles i'm guessing most of the difference must be in the firing mechanism.

You're right; your math is better than mine. Barrel times are much shorter than I said.

That makes my point even stronger.

[wasatch]

That makes my point even stronger.

It sure does.

The last bit of a SCATT trace before the click is 0.2 seconds or 200 ms. So half of 1ms would be the last 1/400th of that 0.2 second bit of the trace. Very small change in point of aim.

Difference in time of flight might make a difference. Assuming constant velocity from muzzle to target, there's 0.0165s difference in time of flight between 400fps and 500fps to hit the target at 10m. Angular motion of the barrel imparts lateral velocity to the pellet & there would be more time to deviate flying at 400fps.
Time of flight, at 500 fps = 0.066s & at 400 fps = 0.0825s.
If the SCATT trace speed is 200mm/s in the last 0.2s and
Wrist to muzzle is about 360mm and
Distance to target is about 10,000mm then
Lateral velocity at the muzzle is: 200 mm/s * (360/10,000) = 7.2mm/s (assuming all angular motion, no parallel)
Displacement at the target due to lateral speed @ 500 fps is: 7.2mm/s * 0.066s = 0.48mm.
Displacement at the target due to lateral speed @ 400 fps is: 7.2mm/s * 0.0825s = 0.59mm.

That was calculated with my SCATT trace speed of 200mm/s. A SCATT file for Gontcharov I downloaded shows his average trace speed in the last 0.2s is about 70mm/s. So the displacements would be about 1/3 those above, or 0.16mm @ 500fps. But the displacement SCATT shows for both me and Gontcharov are larger than what i've calculated here.... Maybe partly because the pellets loose speed. ChairGun says 10m time of flight for 500fps is 0.071 and speed at target is 439fps. But that is not enough of a difference to explain it.

BTW, Gontcharov uses an F Coefficient of 20.

With a compact barrel and 200mm/s trace speed the displacements would be roughly:
@500 fps = 0.41mm
@400 fps = 0.51mm

Even more impressive after looking at Vladimir Gontcharov SCATT data in many cases not only is his distance off center decreasing just prior to triggering but also the trace speed is near a minimum. He spent 76% time in 10 but 83% of his shots were 10 or better.

Edited: revised to correct calculations.

[emre-nur]

I finally went to a big boy gun this month, and after getting used to it my IZH sounds woefully underpowered. That might well be the various comps on the Steyr, but the target tears indicate it is definitely slower.

Question: is the IZH supposed to be in the neighborhood of a PCP gun, or might I need to do some maintenance?

Hi,
I had the same problem with a recently bought IZH46m. Comparing the target holes with other pistols, it seemed slow.

[northpaw]

So, I learnt a lesson.

Yes, you learned a lesson. That lesson teaches you to not buy a gun from less well reputed retailer/importer.
The Izzy comes cheap, but may be expensive i the long run. Stay away from that misery.

[william]

Lock times and barrel times are two VERY different things. The difference in BARREL times between low velocity and high velocity APs is around 1/100 of a second.

Assuming something like a properly functioning Izh-46M as "low" and a Steyr or Morini at factory setting as "high," I think you'll find that it's a fraction of that. Making it even less significant to the result downrange.

[northpaw]

We need to get the full picture here: lock time/does matter, or course.
Imagine what do you do wrong during that brief moment of extended barrel time? Wringing your gun out of line of sight? Probably yes. Imagine a gun of close to zero barrel time/ lock time: would it be beneficial to your scores? Yes,it would.

By denying the effects of increased locktime/barrel time you are talking contrary to common pfysics. Why? Do you not understand the fundamentals of physics?

[-TT-]

I dont have a chrono, but it stil seems slow, at least not consistent.
Not much to do.

The compression plunger is adjustable in the IZH46M, and it is often delivered de-tuned to comply with the destination market. At the higher pressures, you will not find it underpowered.

It's not very difficult to adjust, requiring only a small screwdriver. It's a little tricky to expose the necessary parts however.

[seamaster]

The IZH velocity is very easy to adjust.

Unscrew each compression hinge will give you about additional 15 FPS with each complete counterclock rotation.

It is fun to shoot at 515 FPS like a LP10, cutting super clean holes.

BUT, that high compression WILL destroy your compression lever.

Very soon.

My compression lever torn in half at the semicircle section just off the compression hinge.

I cried.

Not until my city STOP sign welder welded it back for me.

Now I am happy with 430, damned the holes. It is clean ENOUGH. I only need to know where I hit.