Optimum barrel length for .22LR

[rg1911]

I'm getting ready to buy a Kidd barrel and notice that it's available in a couple lengths for my 10/22.

Some time back, I recall reading that a .22LR has burned all its powder and actually starts losing velocity past about 16 inches. So it would seem that a 20-inch barrel would not be necessary, unless you were using iron sights and wanted the extra sight radius.

Has anyone else read this about the .22LR?

Thank you,
Richard

 

[wigwamitus]

Right, my reading on the .22LR indicates between 16 and 16.5 you will achieve max muzzle velocity, so if "optimmum" means the length at which you acheive max MV, then I agree with the 16-16.5 length, for .22LR. Of course there is more than one .22LR cartridge. And subsonic might be different from super sonic.

I've been shooting Federal AM22, 40gr, 1200fps and getting it for between 8 and 14 cents per round. I'm now switching to Eley match subsonic, which looks like it will be running between 24 and 34 cents per round. I finally realized that subsonic will do a better job of meeting my goals. I shoot out to 325yds with .22LR at the maximum distance, to better simulate wind and drop issues. Checking the numbers, I now realize the subs can get out there (just barely) with my scopes, though the droppage will be more like 150 inches versus the 115 inches with the supersonic. The benefit is that the round will come out of the barrel already being below the transonic barrier and hence avoid the instability induced by flying through that barrier. Hence the subs should be more accurate. The trade off of needing more elevation can be managed at my max range, hence the only big trade off is the cost. But I've decided to do it. My 5.56 rounds are running about 40 to 45 cents per round (Lake City green tip) so the .22LR rounds are still cheaper, but not by as much as I would like. That is the main downside of switching to subs.

 

[Frank Green]

Going totally off of memory one of the gun manufacturers did a big test on this and if I remember correctly it was around 18" or 19" for the most velocity gain. Anything past and your not gaining anything.

The only reason to run a longer barrel length is for the sight radius if your shooting iron open/match sights etc....

I'm getting ready to start rebuilding another Winchester 52 International type match rifle but instead of running a 28" barrel I'm going to finish it at 21" (I can always cut a little more off) and for the iron sights I'm going to run a bloop tube to give me the extra length for the sight radius.

With the shorter barrel length the bullet is in the barrel for a lesser amount of time and usually shooters will see there average for scores (not they're highest score) go up because of a less of a tendency to push the shot etc...

The only other reason in my opinion for a long barrel in .22RF is if you want to duplicate a contour/finish length etc...for restoration.

Funny though the Saami spec. for test barrels for .22rf for ballistic testing is 24". Think they would change it but what ever.

Later, Frank
Bartlein Barrels

 

[1SMALLJOHNSON]

Hey RG,

Yes, the propellant is actually almost all burned out in the first inch, depending upon any cylinder gap or throat. Now, the "push" continues after max pressure, so just because all the powder's burned out, it does not mean that the GAS is not still working on the base of the projectile.

There are a bunch of variables that determine how long it takes for the projectile to "outrun" the pressure generated. Chamber diameter, throat, lead, primer composition, and charge weight. All sorts of stuff.

I went down the path you describe. Many shooters did, especially in the "accuracy" game of Olympic prone and 3-position. We'd shoot a short barrel, then put a "bloop tube" on the end, to extend our sight radius. It was all the rage for a while. Here's what I can undeniably tell you: At one point, there was a "study" commissioned of barrel lengths and barrel makers. All rimfire, all shot from a 2013 action, all shot out of the stock. Various ammunitions of "match grade". IIRC, there were about 40 different barrels in this study. When it was all said and done, the three top barrels were of "German manufacture", all the same manufacture, all "Long", full-length, (maybe 24 or 26"?). I don't believe there was a single "short" barrel which made the top-10 cut. Why? Probably has something to do with the variation in the acceleration of gravity or something....

I will make an assumption that both the "short barrels" and "Long barrels" supplied by one German manufacturer used the same match reamer.

As to the rest of the barrels, both long and short, I cannot attest to the reamer dimensions, nor throats.

Food for thought,

1smalljohnson

 

[MarkCO]

I spent a good deal of time testing various load, lengths and materials for the .22LR barrels in auto-loaders. Based on that, it did seem that anything beyond 19" offered no benefits. From about 10" to 19", there was velocity gain, and with supersonic, a slightly different yardage for transonic, but no real change in accuracy inside the transonic ranges. Below 10" accuracy and velocity waned, but not uniformly. The best overall performance across the widest window of loads was from about 13 to 18".

 

[Victor Co Heather]

I like 18" barrels on my .22s.

 

[Victor Co Heather]

For me, the goal is fire a round as close to the sound barrier without breaking it.

Keep in mind, the speed of sound changes with altitude.

 

[ivanthesane]

BBTI - Ballistics by the Inch :: .22 Results

Unfortunately, the subsonic stuff isn't represented beyond the 60grn SSS load.

On that note, I pick for balance and "rightness".

 

[BERTMAN77MK2]

+1 for Dfooskiing!! I can shoot a 16" as well as a 26 off a bench rest
at 100 yds. But I like the long heavy barrels for off-hand as that is how
I shoot most of the time and I can do so much better.

 

[Fotheringill]

There is no set answer. A great deal depends on the whip of the barrel. That is why most target shooters have tuners on their barrels.

It is true that after 16" max velocity is reached, but that is only the beginning of the story.

 

[rg1911]

Many thanks for the thoughtful responses and sharing real-life experiences. It looks as though the longer Kidd barrel is the one I want. Depending on how well it works, I may check into a tuner.

Richard

 

[Kid_Lefty]

Many thanks for the thoughtful responses and sharing real-life experiences. It looks as though the longer Kidd barrel is the one I want. Depending on how well it works, I may check into a tuner.

Richard

Check this out ->PDT Partical Dampened Tuner - Range Report

-Kid

 

[Corpsie]

Friedrich's Record-Setting Rimfires

I found this small article to be a good reference point for optimizing a 22LR. This guy was able to shoot perfect scores with a 16.5" barrel.

 

[Badshot308]

16.5" was the twist rate, not the length.

 

[TOP PREDATOR]

i don't know if it is optimal, but i have not seen a big difference (in a bad way) going down to 17" from 20"

i had more chrony data per the inch, but i think that thread was lost in the site switchover.

but there's this one: http://www.snipershide.com/shooting/snipers-hide-rimfire-section/65127-shortening-barrel-length.html

an initial drop of velocity by about 20 FPS with SV and HV, then it seemed to not make much of a difference.

accuracy actually seemed to increase slightly (whip / harmonics etc.)

i'm under the impression, other than open sight shooting, anything past 18" is more weight and space taken up, and like the 16-17" range the best.

 

[RFMan]

Longer, as in 24" to 28", barrels are definitely quieter, especially with subsonic ammo.

 

[ivanthesane]

More than likely due to the powder being completely burned up, the blast being farther from your ears, and the speed being reduced by drag on the rifling.

Noting to do with speed of projectile, unless you go from super sonic to sub sonic - it is the gasses being less compressed so the sudden escape at the end is less violent. Just like a suppressor works by somewhat controlling the sudden release of gasses when the bullet exits the barrel.

 

[justin amateur]

Best length for 22lr accuracy? No idea.
But I'm having fun searching for the answer.

The Truth About Barrel Length, Muzzle Velocity and Accuracy | The Truth About Guns

SWAT Article BARREL LENGTH

http://www.accurateshooter.com/technical-articles/barrel-faq/

http://www.chuckhawks.com/rifle_barrel.htm

http://www.6mmbr.com/barrelfaq.html

 

[hatidua]

I've not tried every length that Kidd makes but I've owned two of their 16.5"s that were far more accurate that I was, -they were very impressive.

 

[repiv]

I asked this same question some time back and a member named Larry in SD provided me some data to help test with. He had tested the Kidd 20" and Kidd 18" with several ammo types he was getting faster FPS with the 18". I also had gotten some info from another shooter that the 16.5 was going to be even faster so I got a 16.5" Kidd barrel and ran a chronograph test with Wolf Match Target (same as one of Larrys tests) and my FPS was faster than his 18" or 20". I had my chrono at the same distance as his. Of course we were not in the same location and the guns were 3 different guns but as you can see the differences were enough to make the difference clear for me. With match ammo going lower than the sound barrier I think you get more FPS with a Kidd 16.5" barrel than the 18" or 20".

http://www.snipershide.com/shooting...arrel-length-new-10-22-build.html#post1747895

hope this helps

 

[Corpsie]

16.5" was the twist rate, not the length.

Ack. I reed gud oops

 

[Charger442]

Keep in mind, the speed of sound changes with altitude.

FYI, the speed of sound does not depend on altitude or atmospheric pressure. that is an often repeated falsehood. Speed of sound calculation is only dependent upon temperature, and temperature only. People like to say altitude but usually at higher altitude temperature is lower. The speed of sound at 80 degrees where i am at 850 feet above sea level is the same speed that it is at 3000 feet when its 80 degrees.

This corn shit'n flatlander doesn't see much altitude changes anymore.

I see more shift off of temp and even then I don't get miss much on the area raccoons and gophers.

yes, its dependent on temp.

 

[hatidua]

Keep in mind, the speed of sound changes with altitude.

Altitude (elevation)? -no.

 

[Greg Langelius *]

Stop and think a minute.

"Standard" (Subsonic) velocity ammunition is often treated as a premium commodity, with the accompanying scarcity and higher prices, and I'm talking about a world where such distinctions are easy choices.

Having a longer barrel that can tame the higher velocity brands down to a subsonic status could be even more optimal than the basic 16-16.5" standard so many of us embrace.

You can't go shorter than 16 and still be legal, so the next logical option could be to go longer.

Greg

 

[Charger442]

I have a 22lr rifle with a 4.5" barrel and it's perfectly legal. Keeps bulk pack subsonic.

 

[Badshot308]

I have a 22lr rifle with a 4.5" barrel and it's perfectly legal. Keeps bulk pack subsonic.

You live in a free state that allows NFA firearms. New York is not a free state...