22lr Muzzle Velocity Relative to Barrel Length

[in2anity]

I'm trying to determine the muzzle velocity of my Lithgow la101 using match ammo (cci sv to be precise) without access to a chrono. So straight up, has anyone chronoed their 101 with match ammo?

If not, I believe there are other ways of calculating this. Match-ammo has an advertised velocity on the box, for example cci sv is rated at 1070 ft/sec. Generally, what barrel length are "official" advertised velocities (for given 22lr cartridges) relative to? Is the "standard" barrel length for a 22lr 16"?

If so, because the 101 has a 21" barrel, doesn't this mean that the muzzle velocity will be lower than the advertised velocity? (because 16" is optimal when it comes to velocity) Is there a way of calculating this value for varying barrel lengths?

I've done a few google searches and only found data related to HV ammo, none for match ammo

Any advice would be greatly appreciated?

[Bills Shed]

Why ? Shoot the rifle! Have fun.
Bill

[in2anity]

Why ? Shoot the rifle! Have fun.
Bill

Don't worry I do mate! I've plinked over 1500 rounds through her and loving every second of it

The reason I want this data is because my trajectory calculations for shots greater than 100m aren't quite right - 150m shots are a few inches lower than they should be

[albat]

Cci standard velocity is the round i normally use for general hunting and plinking as good as it is for the price it isnt a match round and that is reflected in the price i would suggest something from eley or lapua

[happyhunter]

Along the way to 150 meters the 22LR has lost a lot of velocity. It's quite a long way for a 22LR. A ballistics calculator that lets you input the B.C at different velocity points along the path might give a result closer to reality but then you need to know actual velocity at those points (real velocity, not calculated) to calculate the B.C. Best way is to shoot a target at that distance detail the shots on paper out to 200 yards and forget about using the calculator.

[bladeracer]

Why ? Shoot the rifle! Have fun.
Bill

Don't worry I do mate! I've plinked over 1500 rounds through her and loving every second of it

The reason I want this data is because my trajectory calculations for shots greater than 100m aren't quite right - 150m shots are a few inches lower than they should be

Use the true drop to adjust your BC when calculating your trajectory.

EDIT: I just realised you aren't using a chronograph.
In that case you can calculate your muzzle velocity from the true drop you're seeing.

[in2anity]

Along the way to 150 meters the 22LR has lost a lot of velocity. It's quite a long way for a 22LR. A ballistics calculator that lets you input the B.C at different velocity points along the path might give a result closer to reality but then you need to know actual velocity at those points (real velocity, not calculated) to calculate the B.C. Best way is to shoot a target at that distance detail the shots on paper out to 200 yards and forget about using the calculator.

Yes perhaps extrapolating the data is the best way - it feels a bit brute-forcish though. It'd be nice if I had a nice round formula that would be applicable to any ranges between 100m and 200m

[GLS_1956]

Every gun and every batch of ammunition is different. You've said you enjoy firing the gun, so the best thing to do is take her out and record the actual adjustment needed as determined by firing that batch of ammo through your rifle.

Next batch of ammo may shoot damn close to the one you used, or it may be off by a fair margin, so after you have shot and recorded the actual adjustments needed, go and buy hellacious amounts of that batch. .

[Title_II]

I love this stuff. It is silent out of M16 with Gemtech HALO and conversion kit. The loudest noise (other than bullet impact) is actually the hammer cocking, not the bolt. It is very consistent which is necessary for .22 full auto conversions since .22 has so little energy that tuning can be tricky. Too much spring no ejecty, too little spring no feedy, .22 crud starts to build up and the balance changes. Unfortunately my HALO has been gaining weight from shooting .22.

[in2anity]

Every gun and every batch of ammunition is different. You've said you enjoy firing the gun, so the best thing to do is take her out and record the actual adjustment needed as determined by firing that batch of ammo through your rifle.

Next batch of ammo may shoot damn close to the one you used, or it may be off by a fair margin, so after you have shot and recorded the actual adjustments needed, go and buy hellacious amounts of that batch. .

Is there really that much deviation between batches? Wouldn't that destroy accuracy when target shooting? (Yet they are fairly accurate)

[happyhunter]

Sometimes there is a big difference. Consistency within the batch and batch to batch consistency costs the manufacturer more money which they pass on to us.

[<<Genesis93>>]

I wouldnt worry about the barrel length, apparently 22rimfire requires 10" of barrel to reach 'peak' velocity...after that it maintain that velocity +/- up to at least 22inch,

an article in Shooters Bible provided this and showed barrel length-Velocity from 22 inch down to 1inch...same for both Shorts and LR-HV.

[bladeracer]

I wouldnt worry about the barrel length, apparently 22rimfire requires 10" of barrel to reach 'peak' velocity...after that it maintain that velocity +/- up to at least 22inch,

an article in Shooters Bible provided this and showed barrel length-Velocity from 22 inch down to 1inch...same for both Shorts and LR-HV.

I don't think 22" is correct. Most .22LR starts slowing down around 16-18" of barrel length.

http://www.ballisticsbytheinch.com/22.html

[<<Genesis93>>]

I wouldnt worry about the barrel length, apparently 22rimfire requires 10" of barrel to reach 'peak' velocity...after that it maintain that velocity +/- up to at least 22inch,

an article in Shooters Bible provided this and showed barrel length-Velocity from 22 inch down to 1inch...same for both Shorts and LR-HV.

I don't think 22" is correct. Most .22LR starts slowing down around 16-18" of barrel length.

http://www.ballisticsbytheinch.com/22.html

Maybe this calls for a stern email from you to Shooter's Bible for spreading disinfo ...

[bladeracer]

Maybe this calls for a stern email from you to Shooter's Bible for spreading disinfo ...

Maybe, but I've never heard of Shooter's Bible so I probably won't bother.

[in2anity]

I wouldnt worry about the barrel length, apparently 22rimfire requires 10" of barrel to reach 'peak' velocity...after that it maintain that velocity +/- up to at least 22inch,

an article in Shooters Bible provided this and showed barrel length-Velocity from 22 inch down to 1inch...same for both Shorts and LR-HV.

I don't think 22" is correct. Most .22LR starts slowing down around 16-18" of barrel length.

http://www.ballisticsbytheinch.com/22.html

Yes this is my understanding - you only need around 16" of barrel to achieve peak velocity, after that you start to trade velocity for accuracy. Thinking back, I remember years ago my coach telling me that so long as the harmonic wave was optimized, you can incrementally cut down a 22 to around 16" and still achieve very good accuracy.

But getting back to my original question, I wonder if published velocities for 22lr ammo is usually relative to a 16" barrel? That link doesn't detail anything about subsonic ammo, so its hard to guess what the muzzle velocity difference would be between 16"and 21" (for subs)

[bladeracer]

But getting back to my original question, I wonder if published velocities for 22lr ammo is usually relative to a 16" barrel? That link doesn't detail anything about subsonic ammo, so its hard to guess what the muzzle velocity difference would be between 16"and 21" (for subs)

I've chronographed several types through four rifles of varying age and barrel lengths.
New Ruger American Compact 18" barrel
1940 Remington 510 25" very poor barrel
1930's Cooey Ace-1 17" barrel
1950 BSA Sportsman 5 25"(?) very good barrel

From CCI Quiet 710fps through to CCI stingers at 1650fps the differences were not huge, within a few percent.
I think it might make more difference in how clean and tight the bore is than its length. And cartridges primarily designed for use in pistols are likely to achieve peak velocity in shorter barrels.

It requires around 100fps lower muzzle velocity for a subsonic to drop an additional three-inches at 150m.

[pomemax]

Why ? Shoot the rifle! Have fun.
Bill

Don't worry I do mate! I've plinked over 1500 rounds through her and loving every second of it

The reason I want this data is because my trajectory calculations for shots greater than 100m aren't quite right - 150m shots are a few inches lower than they should be

15oo rounds what did you do the next time at the range,
The trick is not to calculate it but shoot it and get to know what you will be doing at different distancesand the only way to do that is put 1500 throught it a few times
Have a look at how ammo is made
https://www.youtube.com/watch?v=_rCZHG_eEak&t=401s there are so many variables

[happyhunter]

Stingers are designed to work best in a 22 inch barrel. Slower powder, more of it.

Anyway, back to the original topic.

It'd be nice if I had a nice round formula that would be applicable to any ranges between 100m and 200m

Unfortunately there isn't one
You would have to accurately measure the velocity at 100m and 200m and calculate the B.C from those numbers and use. have a read of what is published on the Hornady website and some good stuff here. www.snipercountry.com/ballistics/index.html

Also check out the JBM website and there is some stuff at Sellier and Bellot that might give you an idea of what is needed to get more realistic results from ballistic calculators.

[in2anity]

Ha so I figured out why they were hitting low - my range finder was set to meters yet I was still calculating based on yards herp derp! So in reality I had only adjusted for 137m (instead of 150m). Whoops - new range finder for Chrissy, don't I feel stupid! This almost exactly describes the discrepancy!

I think what I can take away from this however is that generally the muzzle velocity difference for a 16" vs a 21" is pretty negligible - and indeed there are other variables at play (like manufacturing deviations and differences between rifles).

I still would like to know what the published velocity is relative to however...

Thanks to all for your inputs.

[SendIt]

I still would like to know what the published velocity is relative to however...

I can only surmise that the majority of the brands don't published actual tested data, they just use a sensible average.

Look at the MV numbers from Federal, SK, CCI and plenty of others. Across the rate you'll see certain numbers repeated in all the brands 1250, 1200, 1080, 1050, 1040.

No velocities like 1252, 1204, 1086... You're telling me everyone's making a dozen types of different ammo, testing them on different platforms, and all are getting velocities to a neat 10 fps on everything? I think not.

They're just indicative figures to get you in the ball park you want to be in. Sub-sonic or super-sonic, and how slow or fast you want on either side of the fence. Understandable considering that unless you're using their testing platform (which we're not) the numbers won't be correct anyway.

Sellier & Bellot and RWS are the only 2 brands I can think of that state velocities with the variance you'd expect. As examples RWS states 1082 fps for their club ammo, S&B say 1066 fps for theirs. But again, once it goes through your or mine or anyone else's rifle those numbers aren't going to be spot on.

If you want truly accurate numbers you need to run the loads through your own setup work it out yourself. You should still be able to get a somewhat accurate figure without a chrono though.

Try this... Zero for 50 metres, shoot a 10-shot group at 25m, 50m, 75m, 100m and 150m without change the zero and record the average rise/drop.

Put the projectile weight, BC and claimed MV of the ammo into a trajectory calculator and see what the calculated arc looks like compared to the results you've recorded.

From there increase or decrease the MV figure entered in the calculator as required incrementally and refresh the results, comparing the calculated arc to your recorded results.

When they match you've got you've got your actual (close enough) MV.

[in2anity]

I still would like to know what the published velocity is relative to however...

I can only surmise that the majority of the brands don't published actual tested data, they just use a sensible average.

Look at the MV numbers from Federal, SK, CCI and plenty of others. Across the rate you'll see certain numbers repeated in all the brands 1250, 1200, 1080, 1050, 1040.

No velocities like 1252, 1204, 1086... You're telling me everyone's making a dozen types of different ammo, testing them on different platforms, and all are getting velocities to a neat 10 fps on everything? I think not.

They're just indicative figures to get you in the ball park you want to be in. Sub-sonic or super-sonic, and how slow or fast you want on either side of the fence. Understandable considering that unless you're using their testing platform (which we're not) the numbers won't be correct anyway.

Sellier & Bellot and RWS are the only 2 brands I can think of that state velocities with the variance you'd expect. As examples RWS states 1082 fps for their club ammo, S&B say 1066 fps for theirs. But again, once it goes through your or mine or anyone else's rifle those numbers aren't going to be spot on.

If you want truly accurate numbers you need to run the loads through your own setup work it out yourself. You should still be able to get a somewhat accurate figure without a chrono though.

Try this... Zero for 50 metres, shoot a 10-shot group at 25m, 50m, 75m, 100m and 150m without change the zero and record the average rise/drop.

Put the projectile weight, BC and claimed MV of the ammo into a trajectory calculator and see what the calculated arc looks like compared to the results you've recorded.

From there increase or decrease the MV figure entered in the calculator as required incrementally and refresh the results, comparing the calculated arc to your recorded results.

When they match you've got you've got your actual (close enough) MV.

Good advice thanks

[straightshooter]

I still would like to know what the published velocity is relative to however...

I can only surmise that the majority of the brands don't published actual tested data, they just use a sensible average.

Look at the MV numbers from Federal, SK, CCI and plenty of others. Across the rate you'll see certain numbers repeated in all the brands 1250, 1200, 1080, 1050, 1040.

No velocities like 1252, 1204, 1086... You're telling me everyone's making a dozen types of different ammo, testing them on different platforms, and all are getting velocities to a neat 10 fps on everything? I think not.

They're just indicative figures to get you in the ball park you want to be in. Sub-sonic or super-sonic, and how slow or fast you want on either side of the fence. Understandable considering that unless you're using their testing platform (which we're not) the numbers won't be correct anyway.

Sellier & Bellot and RWS are the only 2 brands I can think of that state velocities with the variance you'd expect. As examples RWS states 1082 fps for their club ammo, S&B say 1066 fps for theirs. But again, once it goes through your or mine or anyone else's rifle those numbers aren't going to be spot on.

If you want truly accurate numbers you need to run the loads through your own setup work it out yourself. You should still be able to get a somewhat accurate figure without a chrono though.

Try this... Zero for 50 metres, shoot a 10-shot group at 25m, 50m, 75m, 100m and 150m without change the zero and record the average rise/drop.

Put the projectile weight, BC and claimed MV of the ammo into a trajectory calculator and see what the calculated arc looks like compared to the results you've recorded.

From there increase or decrease the MV figure entered in the calculator as required incrementally and refresh the results, comparing the calculated arc to your recorded results.

When they match you've got you've got your actual (close enough) MV.

Well put sendit.
To my way of thinking however, if you have generated a trajectory table, why would you care any longer about the muzzle velocity.
I would like to add that all standard velocity target ammo is generally made for use in standard smallbore target rifles to produce subsonic velocities within the normally encountered range of elevations (height above sea level), temperatures and atmospheric pressures at any likely smallbore competition. The aim is to keep the projectile out of the transonic range of velocities, about 1100 to 1200 FPS, where inconsistent accuracy is the result.
Generally smallbore rifles have a 26 inch barrel.

[in2anity]

To my way of thinking however, if you have generated a trajectory table, why would you care any longer about the muzzle velocity.

For some of us (suburbanites) who only have limited places to shoot, this may be difficult to generate, so we have to go off the published velocities