I have a rant! Hopefully of general interest.

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Archie

Archie

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I recently bought a box of .22 long rifle ammo. It's for a .22 rifle I bought earlier this year. Chronographing the ammo in my rifle, it clocks about 1240 fps +/- a few. The box advertises 1235 fps velocity. Not a gripe.

Neither the box nor the website of the brand identify the arm used for testing, nor even the barrel length. One doesn't have an idea of what to expect. I shoot .22 LR pistol also. I know my four inch Ruger autopistol will not develop the same velocity (with the same ammo) as a twenty inch rifle. (That would be a pretty sad rifle, but that's not the ammunition's fault.)

I really have no reason to doubt the quality. The ammo shoots well out to fifty meters or so. Actually shoots about three to four inches at 100 yards, but I don't plan on attempting that much. I have no reason to doubt the velocity claimed in whatever rifle or testing device used. Or rather, the average of several shots, rounded off to the nearest five fps.

My gripe is I have nothing on which to base an expectation. Further casual investigation shows most all ammunition has a velocity shown, but no mention of the length of barrel. Nor am I expecting ammunition suppliers to test every conceivable arm so chambered and print that on the carton. But the addition of something like "... in a 24" barrel" would shed a ray of light for the user.

Or am I just too nit picky?
 
Archie said:
Or am I just too nit picky?
Click to expand...
Nah. I’ve often thought this.


For a 22lr or something like a 357, cartridges that get use in many different barrel lengths, it would be a very good bit of information to have on hand.
It isn’t often an issue for something like a .270, but even there would be beneficial.

A simple ‘/xx” barrel’ denotation could be instituted industry wide. They already have the information they need, it just needs to be printed on the box.:thumbup:

And you weren’t very ranty anyway. Not enough angst.;)
 
I think you're overthinking it.

A lot of factors can affect velocity, barrel length being only one.

Manufacturing tolerances in the barrel, manufacturing tolerances in the chamber, design of the barrel riflings, ammunition temperature, actoin design (bolt or semi-auto), etc. Even the chronograph itself is a factor.

Rifle A, made by one manufacturer, may produce slightly different velocities than Rifle B, made by another manufacturer, even though they may be the same model/design right down to the barrel length.

HOWEVER, to answer your implied question on barrel length used for testing, SAAMI sets the standards for ammunition manufacturing and testing in the United States. The SAAMI standard for most rifle barrels is 24 inches, though commercial lengths may range from 16 inches to 26 inches. The ammunition is also tested at 70 degrees F.

You can actually look up the SAAMI standards for velocity and pressure testing (second link below) for various cartridges. Be warned, though...there's a LOT more information there than the average person cares to know or understand.

The first three paragraphs on page 5 of the SAAMI link for rifle ammunition (a total of 375 pages of joy to read) has this to say:


Velocity recommendations are stated on the basis of a nominal lot mean velocity as measured using
equipment in accordance with the requirements of Section III and the procedures detailed in Section
II. Due to the fact that sporting firearms for general distribution are typically manufactured to
dimensional tolerances greater than those specified for test barrels, there should be no expectation
that these velocities can be duplicated from any test utilizing firearms. This situation is further
confounded by discrepancies in barrel length. Furthermore, once ammunition has left the control of
the manufacturer, storage conditions outside those recommended by the manufacturer may cause
variations in the velocity as measured using test equipment and procedures which conform to the
requirements of this Standard.

The values presented on pages 11 through 34 are recommended values for the use of ammunition
producers at the time of manufacture. It is the responsibility of the manufacturer to establish sample
sizes, sampling frequencies, and tolerances to ensure the performance of the ammunition obtained by
the ultimate user meets all applicable safety and functional standards. Of particular importance in
establishing velocity tolerances is the understanding that velocities significantly higher than the
nominal lot mean can cause actual maximum range performance to exceed expected values.

Ammunition tested subsequent to manufacture using equipment and procedures conforming to these
guidelines can be expected to produce velocities within a tolerance of ±90 fps of the tabulated
values.


Here are a couple interesting links read:

https://www.thefreelibrary.com/Velocity:+myths+vs.+facts:+chronographing+factory+ammo.-a0359731534

https://saami.org/technical-information/ansi-saami-standards/
 
It gives you a general idea of the power of the load and close enough for general shooting. If it's necessary to know a near exact velocity in needs to be cronied anyway to verify.
 
Archie said:
it clocks about 1240 fps +/- a few. The box advertises 1235 fps velocity.
Click to expand...

What length barrel are you using?

If - a few gets you to 1235 fps, I’d say both of you are using the same unknown barrel length.
 
Five feet per second ain't rant worthy. There's more variation shot to shot in a box of 22s. Heck, you'd get more than 5 difference from three identical guns off the rack.
 
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Archie said:
I recently bought a box of .22 long rifle ammo. It's for a .22 rifle I bought earlier this year. Chronographing the ammo in my rifle, it clocks about 1240 fps +/- a few. The box advertises 1235 fps velocity. Not a gripe.

Neither the box nor the website of the brand identify the arm used for testing, nor even the barrel length.
Click to expand...

What brand is your ammunition?

Archie said:
Further casual investigation shows most all ammunition has a velocity shown, but no mention of the length of barrel.
Click to expand...

Most all other ammo DOES show barrel length. Though some companies are not good at listing barrel length for rimfire ammo.
 
The numbers are just a guideline, at which point you need to try the ammo, yourself.

OTOH, yeah, would it kill them, to print "fired from a Marlin 60", or "fired from a Ruger 10/22" ?
 
fxvr5 said:
They are probably chronographed from a SAAMI spec (pressure) test barrel.
Click to expand...

Box velocity printed on the side flap is likely an retail packaging requirement and probably as reliable as gas milege estimates on your dashboard. Those who want known repeated and consistent performance handload and test with screens to get real world numbers.

If you drive up to a gas station and pull the nozzle out of the pump, look at the grades and have "Tula," "Remington," "Winchester," and "Hornady Critical Defense" on the pump, you make a choice which is relatively accurate. Cheap bulk .22 off the shelf isn't going to get any consideration for competition from me. It's dirt blaster ammo for a fun day at the range.
 
Keep Testing 22 LR and you are going to find quite a bit of velocity variation even within in same box of ammo. The same thing happens with centerfire too. Having ammo that shot the exact same velocity every time would be wonderful but it won't happen so get used to it.
 
Uh, to be brutally honest with everything going on in my life and the world a standard deviation of
+/- 5 fps in my .22 ammo is pretty low on my list of concerns........I salute you for your tenacity and seeking the answer though!
 
That squirrel can't tell the difference between 1100, 1150, 1200 or 1250 fps.

Wish I could find, way back when ( mid 80s, I think ), a gun mag had an article on the effect of barrel length on velocity. They took a rifle (.308, IIRC) and put a 30" barrel blank on.
They weren't interested in groups, but it would have been interesting to see his the harmonics were effected.

They shot 5 shots over a Chrono and recorded velocity.
They cut the barrel 1" at a time and repeated the 5 shots, down to 1" of barrel, beyond the chamber. They had to fire more more than 5 shots with the 1" barrel, to get the Chrono to read. I would imagine muzzle blast was impressive.

The thing I remember was, MAX velocity was 24" and 25" being almost identical. Longer and velocity actually dropped. Going down, velocity dropped about 100 fps with every inch, down to 16". Below that, things started getting squirrely.
 
I never pay attention to advertised velocity on the box when I buy it. I have my own chronograph so I can do my own testing, with my own firearms, with my own atmospheric conditions. If I even cared that much. The only velocities I pay strict attention to are my handloads.
 
doubleh said:
Keep Testing 22 LR and you are going to find quite a bit of velocity variation even within in same box of ammo. The same thing happens with centerfire too. Having ammo that shot the exact same velocity every time would be wonderful but it won't happen so get used to it.
Click to expand...
Yup. To further complicate the subject, a revolver will typically show a different average velocity - using the same ammunition - with each different chamber of the cylinder. Usually the range between chambers is not enough to make the arm totally unreliable.

Careful hand loading can cut the variance between shots to a bare minimum (in a single chamber), but 'factory' ammunition made to shoot in all the possible arms so chambered faces an uphill fight. I normally load all the ammunition I think I need to shoot well.
 
herrwalther said:
I never pay attention to advertised velocity on the box when I buy it. I have my own chronograph so I can do my own testing, with my own firearms, with my own atmospheric conditions. If I even cared that much. The only velocities I pay strict attention to are my handloads.
Click to expand...
No doubt the most effective manner. I hand load most rifle ammo, but use the advertised velocities as a rough estimation of results for which to look.
 
fxvr5 said:
Most all other ammo DOES show barrel length. Though some companies are not good at listing barrel length for rimfire ammo.
Click to expand...

I've never seen a barrel length listed on any ammo box - rimfire or centerfire. What companies list barrel length?

FWIW most people familiar with firearms know the listed velocity is for the best scenario possible. I always assume 20 to 24 inch for rifles, including rimfire, 5" for pistols and 8" for revolvers.
 
reddog81 said:
I've never seen a barrel length listed on any ammo box - rimfire or centerfire. What companies list barrel length?
Click to expand...
I don't recall any, either.
reddog81 said:
FWIW most people familiar with firearms know the listed velocity is for the best scenario possible.
Click to expand...
Without doubt.
reddog81 said:
I always assume 20 to 24 inch for rifles, including rimfire, 5" for pistols and 8" for revolvers.
Click to expand...
A requirement to assume is what my alleged mind refuses to accept. Probably a personal problem. And I resent all rimfire ammunition is tested and advertised from rifle use.
 
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