Ideal barrel length for a 22LR


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Frohickey
December 28, 2002, 07:54 PM
Anyone know what the ideal barrel length is for a 22LR before you start losing velocity from the bullet-barrel friction?

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444
December 28, 2002, 08:32 PM
I believe I remember reading 16" but it has been many years since I read that.

Dave Markowitz
December 28, 2002, 08:45 PM
444 is right. In general, it's about 16 inches.

Ledbetter
December 28, 2002, 09:20 PM
Correct. The shortest you can get is 16.5" I think. Laws.

Southla1
December 28, 2002, 09:39 PM
Maybe I am not as old as I thought LOL.................IIRC it WAS 16 inches before you begin to get a friction loss.

labgrade
December 28, 2002, 10:56 PM
Maybe a better question/answer would be "why would it matter?"

You got a ~40gr slug going at about 1200 FPS or so.

What real difference would a shade +/- make?

Nothing snide intended, but really.

Why even care?

& that's a serious question.

Frohickey
December 28, 2002, 11:09 PM
It matters because there are manufacturers out there that sell 16.5" barrels, 18" barrels, 21" barrels, and 24" barrels.

If the extra barrel length is not giving you added velocity why pay for it, unless you want it for the extra sight radius. But if you are using a scope anyway, might as well save the money.

labgrade
December 28, 2002, 11:54 PM
Yeah, I'll buy that, but far as anything pratical at all ... ?

a .22 rim fire goes through the sonic barrier "somewhere" & that appears to be a bad thing target-wise. Betcha velocities would matter within lots rather than barrel length moreso - maybe not.

Barrel length would matter quite a bit depending on what ammo you shot. Might have been a more definative question.

Not trying to ne smarmy, just my way of asking the question & learning a bit more about it all myself.

Understanding the why of the question is as important to me as the answer.

Frankly, for a .22LR-shooter, give me the shortest barrel, best accuracy. The bullet will do the rest.

Fact is, that'd go for anything I shoot.

[/smarm] ;)

cheygriz
December 29, 2002, 12:19 AM
Sixteen inches is optimum. It's a shame that ALL manufacturers of 22lr don't offer that length.

For my personal taste, a sixteen inch barrel is perfect for most calibers. (High velocity stuff excluded, of course.) They sure are handy. Try an old Colt "Colteer" carbine sometime. They were great. A Winchester Trapper .30-30 with sixteen incher is also very handy.

444
December 29, 2002, 01:04 AM
Years ago, I bought a book that had nothing but articles about .22s and I believe that I read in there that max velocity was obtained with a 16" barrel, but as I said, I could be wrong. There are a couple nice things about this IMO. First of all a 16" barreled long gun is a very handy package. That is certainly my faviorite in an AR15. I just seems to balance nice, it feels good in the hands, and does not get in the way. It is easy to manuver in and out of tight places whether it be through heavy brush or through thick trees, in and out of a vehicle or whatever. IThe thing I like best about it is that I can walk along holding the rifle in one hand, straight down at my side and the muzzle doesn't come anywhere near the ground and it is easy to control (where it is pointed). Secondly this also happens to be the minimum barrel length allowed by law without registering it as a SBR. So, it would seem that everything works out great; other than the fact that most .22 rifle barrels are longer than that.

labgrade
December 29, 2002, 02:04 AM
Sorta part of my question - perhaps & albeit ineptly put - was "who cares velocity as long as it still works really good."

I've a dandy 14" Contender-thing. It's a handgun, but would shoot just as well, likely a tad better, with a shoulder stock. Only difference is "somebody else's" rules.

Regardless, within the limitations of what a rim fire .22's for, you put the bullet where it's supposed to go & things get done.

Works the same for bigger stuff = adequate enough bullet in the right place ... "fast enough" is usually so much slower than anyone "knowledgeable" would even consider it to be a bullet.

JohnBT
December 29, 2002, 02:05 PM
Let's see if I can summarize some of what I've learned recently.

Supersonic speed is bad for .22 accuracy - if the bullet slows back below the speed of sound before it gets to the target (and it does) and is destabilized by the turbulence as it passes through the trans-sonic zone. So benchrest .22 target shooters shoot subsonic ammo. (Centerfire starts out supersonic and stays there.)

Target rifles don't have long barrels just because of sight radius. Slowing the bullet a little by using a long barrel helps guarantee that the bullet does not reach the speed of sound.

I just copied this definition and lost the URL, but a Google search will turn it up if you want to find a speed of sound calculator:

"Officially, the speed of sound is 331.3 meters per second (1,087 feet per second) in dry air at 0 degrees Celsius (32 degrees Fahrenheit). At a temperature like 28 degrees C (82 degrees F), the speed is 346 meters per second."

From what I've read, ammo that's rated at 1061 f.p.s. like this box of Eley TENEX Ultimate EPS I'm looking at, or Wolf MT at 1085, might be affected beginning at a speed as much as 10% under the speed of sound. So 1085 minus 11 = 1074...making the Wolf MT sort of iffy for BR depending on the barrel length, actual bore dimensions, elevation, temp and humidity.

Remember, the crack of a high speed .22 is a shock wave that can upset a bullet in flight.

John

DrDremel
December 29, 2002, 03:21 PM
Sound Technology, a Suppressor manufacturer tested this by cutting a barrel 1 inch at a time and recording velocities. 14" was the optimum. The 16 inch only slowed the bullet by 15-20 fps.

DMK
December 29, 2002, 09:39 PM
Assuming the same wall thickness, a shorter barrel should be relatively stiffer also.

Unless you are using open sights, I can't see any benefit to the "traditional" 24-26" barrel. Just use standard velocity ammo to keep it subsonic.

9mmepiphany
January 6, 2003, 06:46 PM
thank you drdremel...

i thought i was going crazy, i was about to post "14 inches", then started reading all the responses of 16", i was starting to doubt my memory.

so...the contender with a 14" bbl should better the velocity of a 16.5" rifle

Gewehr98
January 6, 2003, 08:50 PM
Stingers, Yellowjackets, Velocitors, etc? Still only 16 inches of optimal burn time in those loads?

BTW, centerfire rifles don't HAVE TO start out supersonic. 500gr .45-70 blackpowder loads start out relatively slow to begin with, and still do a fine job at Quigley-style steel buffalo matches way out there to 1000 yards. But then again, what's a little shock wave to a big honkin' slug even if it does transition from supersonic to subsonic? :D

Ledbetter
January 6, 2003, 10:44 PM
High velocity ammo does not slow past the sound barrier at distances of less than 25 yards from most barrels. At distances of 75 yards or more, the trans-sonic turbulance is more than made up for in accuracy by the higher velocity/momentum of the bullet.

This is my opinion only. See the attached photo of a group I shot at 100 yards with a factory-barrelled 10/22T and Winchester High Velocity Super-X.

Wolf MT shoots as well as any ammo I've tried in my 16" Magnum Research-barrelled 10/22. (But not at 100 yards.) I just bought two cases.

Ledbetter
January 6, 2003, 10:46 PM
oops. Is the file attached yet?

Gordon
January 7, 2003, 12:35 AM
The 26 to 28 inch barrels of match target rifles seemed to win most matches,maybe thats changed but I like their muffled discharge of subsonic bullets. Like a legal silencer IMHO.:D

firestar
January 7, 2003, 01:36 AM
I have a CZ-452 with a 24" (I think BBL) and it shoots PLENTY accurate for me. It is also a lot quieter than my Ruger 10/22.

JohnBT
January 7, 2003, 09:22 AM
Ledbetter,

Not a bad group for 100 yards, but not an inch group since a quarter is nearly an inch in diameter. I have never found an HV .22 that would shoot terribly accurately at 100 yards. Good enough for hunting, but not for trying to make all of the shots touch - not out of my rifles anyway.

We could expand the discussion of hypersonic vs. subsonic ammo to include factors such as actual bore diameter, actual bullet diameter, lube, humidity, temperature, barometric pressure and whether we're shooting into the wind or with it, but I'm a novice at this ultra accuracy stuff and would likely embarrass myself :)
I really need to stop reading Precision Shooting and lurking at benchrest.com and get out in the cold and shoot more.

I like the Wolf ammo too. I bought more than a case of WMT when it was going for $15 a brick and then a case of WME because I found it at the gun show for a reasonable price. So far so good, but I'm going to try some of the good Eley in my Finnfire when the weather warms. I only have one box left of the old Federal UMB1 and need to find something really good if I'm going to start shooting benchrest this year.

Oh, speaking of benchrest. Most of it is shot at 50 yards and that's what I think in terms of when talking ammo.

I'll check in later - time to work.

John

DMK
January 7, 2003, 09:57 AM
Please correct me if I'm wrong, but doesn't Hyper velocity 22 (like Velocitors and QuickShocks) stay above the sound barrier up to 50 or 75 yards, High velocity transition around 25 to 50 yards and Sub stay below from the start?

Ledbetter
January 7, 2003, 12:44 PM
Post corrected to state HIGH not HYPER velocity. BTW, seven (7) of those holes fit under the quarter. Seven.

Proudly:evil: ,

sasnofear
January 7, 2003, 02:46 PM
dont bother with .22LR get a .17 HMR, the ruger M77/17 sports 24" barrel with 1/4MOA @ 100 yrds!

JohnBT
January 8, 2003, 12:10 AM
You got a good .17. The two I've seen barely shot that well at 50 yards.

Ledbetter,

Yes, most of them are right there together, but the fliers ruined the roundness of it all. Hint: close-up lens :) Or trim the strays away and take a picture of what's left. Sort of like holding a fish at arm's length out in front of you to make it look a lot bigger.

I've got to stop reading all of this benchrest stuff. They don't care how good the first 24 shots are. It's only where the last one landed that matters.

John

ShaiVong
January 8, 2003, 09:42 PM
I bought a box of subsonic rounds for my 22lr just to give it a try. I was sighting in my Ruger 10/22 that i just bought, grouping pretty good at 50 yards. Maybe 1"-2" groups. I tried the subsonic rounds after my CCI rounds, and the group spread way out. I still have a box of 40 subsonic rounds, i think ill have that box for years :p

JohnBT
January 8, 2003, 10:15 PM
Unless you cleaned the barrel, that's to be expected when you change ammo. It could take anywhere up to 30 or 40 rounds for the new ammo to lay down a good layer of the new lube in the barrel. Could take 5, but you never know until you shoot them. Give them a chance. Why save them?

John

MacPelto
January 9, 2003, 09:33 AM
One trend in international 3 position smallbore is towards shorter barrel lengths with 'bloop tubes' attached. This allows a longer sight radius with the short barrel length. Velocity is not the reasoning behind this, however. The advantage is that the bullet spends less time in the barrel, being pushed off course by the body movements of the shooter. This may or may not be useful information, but it takes place in every rifle.

ShaiVong
January 9, 2003, 10:25 AM
I'm still trying to understand the relationship between barrel length and accuracy vs velocity, this thread is really helpfull.

Wouldnt you get more spin on your bullet if it traveled through a longer barrel? Isnt more spin better? Like a gyroscope?

Now that we have discussed the different properties, I have to ask:
Which is a more accurate barrel for a 22? 16" or X>16"

9mmepiphany
January 9, 2003, 12:25 PM
spin stabilizes the bullet... but once spin has been imparted, additional time in the barrel is a greater liability unless your followthru is perfect.

the real advantage of the longer barrel is balance and sight radius. the accaracy of a barrel has more it's chamber demensions, quality of the rifling and harmonics

444
January 9, 2003, 12:30 PM
ShaiVong
To sum up some of what has been said;
Velocity; In a .22LR there is a point where the maximum velocity is achieved. After that point the friction between the barrel and the bullet actually decreases velocity. Appearently the max velocity occurs at 14". In a rifle, a barrel this short requrires a federal tax stamp, so the best comprimise would be a 16" barrel. This would give you the most velocity for a non-NFA weapon.
Accuracy: The reason that a longer barrel is more "accurate" than a shorter barrel is simply because the sights are further apart which decreases the human error in sighting. Obviously this is only a factor with iron sights and only is a factor if the rifle utilizes the additional length. A rear sight mounted at the rear of the action is better than a rear sight mounted half way down the barrel as far as accuracy is concerned. With a scope, barrel length isn't a factor.
Spin: The amount of "spin" required is enough to stablize the bullet. This is determined by the length of the bullet. A given rifling twist will stablize a range of bullet lenths, deviate from that and you won't stablize the bullet. Once the bullet is stabilized, allowing it to "spin" in the barrel provides no benefit.

Please feel free to correct any errors I have made.

9mmepiphany
January 9, 2003, 12:43 PM
444 - a very nice summary

i remember an article awhile back in an annual (like gun digest) about the shape of the barrel, in cross-section affecting a barrel's potential. the optimum shape for the .22RF looked like a bell-shape with the opening facing downward

ShaiVong
January 9, 2003, 02:07 PM
Very nice 444.

Don't you want the bullet (in a 22) subsonic when it leaves the barrel though? I would think that a supersonic bullet that goes subsonic would be more accurate, especiallly on a breezy day, than a slower subsonic bullet which doesnt have nearly as flat a trajectory.

444
January 9, 2003, 02:25 PM
This I am not as well versed on, but to answer your question; No. It has to do with a turbulance that is created when the bullet goes from supersonic to subsonic. This creates some inaccuracy. How much, I don't know. Obviously if you are shooting inside the distance that it takes the bullet to go subsonic, it isn't an issue. I first learned of this when I dabbled in rimfire silhouette. I thought along the lines that you did. Since you shoot out to 100 meters, you would want the flattest shooting round you could get. But in reality, you make up for the greater trajectory by simply adding more windage to your sights, and the bullet is more accurate to boot.
So, the most accurate .22lr ammo made today is subsonic at the muzzle. However the difference is lost on mortals like me. But if you can shoot well enough to appreciate it, subsonic is the way to go in a .22lr.

twoblink
January 10, 2003, 01:19 AM
If you are using iron sights, then it's a great question..

You lose a lot of velocity out of a 24" barrel... But you gain quite a bit of sight radius..

I think 16" is great, but I like a good 22" sight radius...

ShaiVong
January 10, 2003, 09:09 AM
Sight radius doesnt really matter to me, atleast on my 22, because i use a scope.. My eyesight is bad enough that at less then 50 yards i cant really see the target anyway :mad:, if its smaller than a basketball that is.

Nematocyst
February 4, 2007, 01:05 AM
As a proud new owner of a Marlin 39A (http://www.marlinfirearms.com/Firearms/22Rifle/Golden39A.aspx) (with 24" barrel),
I'm subscribing to this information ladden thread.

Even before I bought this little sweet heart of a rifle,
I'd been thinking that once I got one,
I'd have the barrel cut down.

A 24" barrel, I thought,
would be just absurdly long
for a rimfire. What's the point?
(Yeah, yeah: sight radius. I'm going to scope it.)

Indeed, when today, I picked it up for the first time,
I said to myself, "Self, this is the right .22 rifle. Buy it."

and

"It's front end heavy. Get it cut down."

Now, the person who sold me this 39A, a gunsmith,
asserted that I can't cut it down much less than about 3"
because it has a magazine tube attached to the barrel
3.5" back from the end of the barrel.
If I cut it back more than that,
then re-attaching the magazine tube to the barrel
becomes very expensive. :eek:

Still, a 21" barrel seems more reasonable
(and no less accurate) than a 24" barrel.

Thus, I'm reading with interest.

Nem

Mal H
February 4, 2007, 10:59 AM
Ok, Nem, here are some facts as determined by me and my own chronograph. I set out to see if a longer barrel does indeed slow down a .22 bullet. I decided to use Colibri ammunition since it uses no powder, only priming compound, and therefore the friction aspects of the barrel would (should?) be greatly magnified.

The test firearms were the only ones I owned at the time in .22 LR: a 5 1/2" Ruger bull barrel, MK 512; a 20" 10-22T; and a 24" Marlin 39AS.

The results went against the conventional wisdom that a longer barrel will actually slow down a bullet since it has gone past the point of acceleration inside the barrel and is starting to slow down somewhere before exiting the muzzle. My experiment doesn't disprove that theory but it does show, for my ammunition choice and my guns, that the optimal length is at least 20" or longer.

The test results:

5 1/2" barrel
Avg vel = 405 fps
Std dev = 23.2

20" barrel
Avg vel = 418 fps
Std dev = 20.6

24" barrel
Avg vel = 426 fps
Std dev = 15.4

So, don't cut down that 39A barrel in order to gain velocity. (I think it would be a sin to cut it down anyway for any reason, but that's not my call.)

Now, the ideal experiment along these lines would use the same barrel, same lot of ammo, same environment conditions, etc. An inch would be cut off and the barrel recrowned for each run. Someone or some group has done that IIRC, but I don't know what the caliber was and what the findings were. I don't think it was .22 LR, however.

cheygriz
February 4, 2007, 11:10 AM
Mal,

IMHO, a chronograph test would only be valid if you used the same firearm, with the same barrel, and progressively cut off oone inch at a tims and chronogrqphed it. Different barrels from the same manufacturer will gove different velocities.

MY 20 inch barrel custom .30-06 consistently shoots 150 FPS faster than my 24 inch barrel 12903A3 Springfield.

Mal H
February 4, 2007, 01:08 PM
cheygriz, I believe that's what I said in my ending paragraph.

tubeshooter
February 4, 2007, 01:17 PM
Congrats Nem, I know you've been waiting patiently for that 39A. :)


I don't know if your mind is already made up.... but try giving it a spin as-is before you cut it. And let us know how it handles and performs if you *do* end up cutting it, please. Thanks....

Nematocyst
February 4, 2007, 02:18 PM
Mal & Cheygriz, thanks for the input. Even if it doesn't solve the issue definitively, it's still relevant.

I guess you're probably both right: same gun, same ammo, same conditions of temperature, etc, cut barrel one inch at a time and chrono it. (Nope, not me, but it is a valid experimental procedure. We'll have to see if we can find that paper that Mal spoke of where someone may have done just that.)

Anyway, this continues to be an interesting discussion. I hope we continue with it.

Tubeshooter, thanks. I'll definitely be shooting it for a while before cutting it down ... if I do cut it down. I haven't decided with certainty to do that. That's a big and irreversible decision. I'll take my time with it.

And finally, Mal, my decision is not really based so much on velocity decisions as on balance, pointability and length for carrying in thickets. I just have this thing for shorter long guns, as long as they get the job done. I'm not going to be punching paper at 100 m with this one, but mainly shooting squirrels at 10 - 50 m.

Still, I hear you about the "sin" part.

But then, I'm not a religious person. :evil:

Thanks all.

Nem

cheygriz
February 4, 2007, 04:59 PM
I think Nema has some valid points.

If you're gonna use a .22 for formal competition, then 22 or 24 inch "musket" barrel is the only way to go.

OTOH, if you want a fast handling, lighteight, easy to carry little trail and hunting rifle, a barrel of 16 inches, or 18 at the absolute max is the way to go.

IMHO, the finest little .22 hunting, plinking, and trail gun ever made was the old Marlin 39 "Mountie." Short, light, straight stock, lightning fast to shoulder,... in short, the nearly ideal .22. Just my $.02!:p

Nematocyst
February 4, 2007, 05:22 PM
I agree about the mountie for all reasons but one: I just don't like straight stocks.

All the long guns I've ever had have been (still are) pistol grips.
I've spent probably a few hours in gun shops over the years, just trying out straight grips.

For some (probably irrational) reason, they just don't melt my butter.
Every time I have the same response: put it back.

If the mountie was still made and with a pistol grip, I'd probably snap one up.

JustsayMo
February 7, 2007, 11:23 PM
Here's some comparitive data on barrel length/velocity that I did a while back. Except for the Aguila subsonic ammo the longer barrel always produced the highest average velocity though the difference was quite small.

Marlin 39A- 24" Barrel
Marlin 39A Mountie- 20" Barrel
Marlin 39TDS- 16" Barrel

The Ammo
Fedral 550 Bulk Pack ammo, 36 grains HP bullet, copper "plated"
39A : Average velocity 1263 fps (Highest was 1283, lowest was 1237)
Mountie Average 1254 fps (hi 1297, low 1230)
39TDS Average 1251 fps (high 1292, low 1216)

Notes: claimed velocity on box says 1280. This ammo shoots well in a wide variety of my rimfires, including autoloaders. The accuracy is very good in all of my Marlins.

Aguilla SE Subsonic 38grains lead hollow point
39A average 984 (high 1000, low 937.2)
Mountie average 994 (high 1023, low 984)
TDS average 1007 fps (high 1024, low 993)

Notes: This ammo has proven to be accurate in a wide variety of my rimfires. Only Match ammo has surpassed it in guns that shoot it well. It does NOT cycle any of my autoloaders. On most days this ammo will produce the best groups. Today it was true in my 39A and Mountie. Interestingly the 16" Barreled 39TDS produced the highest Velocity with this ammo.

CCI CB Longs 29g RN lead
39A (it was hard to tell these even when off in this gun) 677 avg (681 high, 668 Low)
Mountie 675 avg (720 high, 636 low)
TDS 668 average (674 high, 652 low)

Notes: Only the TDS (1/2" @ 25 yards) and my Single Six shoot this what I would consider "well". The Mountie shoots it OK (~1" at 25 yards). Most of my rimfires do NOT shoot this well. It is very quiet in long barrels.

CCI Mini Mag 40g copper coated, solids
39A 1255 avg (1272 high, 1230 low)
Mountie 1225 avg (1243 High, 1191 low)
TDS 1221 avg (1244 high, 1202 low)

Notes: Of my three 39's the Mountie shoots this the best. It is a little less accurate than the Fedral Bulk at more than twice the cost so I rarely use it.

Nematocyst
February 7, 2007, 11:25 PM
Related thread updated. (http://www.thehighroad.org/showthread.php?t=237498)

The 24" barrel on this Marlin 39A feels too heavy.
The rifle is definitely a keeper. (And haven't even shot it yet.)

But the barrel is too long and front-end heavy.
Beyond data, my intuition tells me so.

I've been doing some reading tonight about the importance of "balance" in rifles.

Not velocity as a function of barrel length, or hyper- v. sub-sonic ammo, but balance.

What I'm learning is that balance may be more important to accuracy than ... all that other stuff.

This 24" barrel doesn't balance well for me. YMMV.

I'm thinking 18" to 20" will balance better.

JustsayMo
February 7, 2007, 11:31 PM
Nema,
The original poster wrote;
"Anyone know what the ideal barrel length is for a 22LR before you start losing velocity from the bullet-barrel friction?"

Are you trying to hyjack his thread and make it a discussion about what balances? :neener: :D :p

Nematocyst
February 7, 2007, 11:43 PM
Just suggesting another dimension to the discussion, J'Mo.

;)

cheygriz
February 8, 2007, 12:15 AM
And, of course, the more dimensions a thread has, the threadier it becomes!:p :what:

And I hate hanging by a thread that isn't thready!:D

mp510
February 8, 2007, 01:07 AM
You'll get maximum velocity out of 16". If your shooting iron sights, the longer the better- simply because of the increased sighting radius. For some of the fancy olympic type rifles, they have 16" barrels and detachable false muzzles that are used to extend the sight radius.

Nematocyst
February 8, 2007, 01:28 AM
Now this thread is getting interesting.

Please pass the chocolate...

JustsayMo
February 8, 2007, 10:21 AM
MP510;
Where did you get your data that a 16" barrel maximizes velocity?

In chronograph tests with my own rifles* and handguns the longer barrel (up to 24")has always produced the highest average velocity in almost every ammo I've tried. Aguila Subsonic being the exception in the Marlin leverguns.

*Marlin 39's in 16", 20" & 24"
Bolt rimfires; CZ 452 in 20" & Remington 511P in 24"
Ruger Single Sixes in 4-5/8 & 5.5"
Auto's: Marlin Papoose 16" vs 18" 10/22

While not a perfectly controled study, it did convince me that there is more myth than fact in the 16" barrel is the ideal.

Mal H
February 8, 2007, 04:16 PM
... more myth than fact ...I wholeheartedly agree.

mp510
February 8, 2007, 04:25 PM
MP510;
Where did you get your data that a 16" barrel maximizes velocity?

That's what I recalled hearing after those expensive German made target rifles going to 16 or a little and using attachments for sighting radius. The claim at the time was that the long barrel were generally for sighting radius. Guess it was, as some poster said more myth than fact.

Carl N. Brown
February 8, 2007, 04:31 PM
What I have always heard is that Remington gave the
Nylon 66 a 19.5" barrel because that gives the maximum
velocity with Remington .22 lr ammo.

That said, tests by NRA showed that of .22 ammunition
only the CCI Stinger gave significant increase in velocity
from 20" to 26". Most .22 started losing velocity after
20" (not much, but it could be measured).

.22 lr must perform in both handguns and rifles, so the
typical powder load is a compromise.

As for balance, I have shot my cousin's 39A (24")
and my 39 Mountie (20") in the past two months.
The 39A seemed to hang well for offhand shooting.
Personally, I would like to see a M39 .22 balanced to
match the M336C centerfire rifle. Talk about thread drift.

-----------------
16" or 19.5" velocities are close, but a 16" bull barrel
is usually more accurate than a thinner 20" barrel
with the same overall weight.

Mal H
February 8, 2007, 05:02 PM
Ooh, ooh, Mr. Cotter! I just had an idea! If Nematocyst-870 does go ahead with his barrel cutting project, he can chrono the 39A before and after using the same batch of a standard velocity ammo. If there is any truth to the shorter=faster conjecture, he will be able to tell. If the bullet velocity goes down (as I fully expect it to), then we can call it a myth. That is unless someone here thinks a miracle is going to happen and the bullet would speed up to a velocity greater than in the first test if an additional 2 to 4 inches was cut off the barrel over the 4 to 6 he plans to cut off.

Nematocyst
February 8, 2007, 05:06 PM
Very interesting and informative thread.
Glad I'm here.

As for balance, I have shot my cousin's 39A (24")
and my 39 Mountie (20") in the past two months.
The 39A seemed to hang well for offhand shooting.
Personally, I would like to see a M39 .22 balanced to
match the M336C centerfire rifle. Talk about thread drift.Oooh, I'd drift with that tangent in a heartbeat. :D

In fact, if the original poster and mods don't mind, I'd very much like to hear some opinions about this concept "balance". (If either or both of you prefer not, I'd be happy to take this part of the discussion to a new thread.
It may deserve one anyway.)

"Balance" strikes me as one of those words that everybody uses, but not necessarily in the same way (or in some cases, not in a way that can even be described adequately with words in a rational way since it is mostly felt or intuitive, like riding a bike). Mea culpa.

I did some reading last night about "balance". In fact, I googled "rifle balance". Found a few pages, mostly related to formal target shooting techniques but some addressing carry issues (how it balances in the hand when carrying without a sling). They all used the word "balance", but none of them really explained explicitly what they meant by it.

So, for example, when shooting a rifle, when one says it's "balanced", does that mean that the rifle balances on the fore end hand (for me, that's left) without a tendency to tip forward or backwards? Or does it relate to some less tangible quality, like the distribution of the weight of the gun with relation to one's shoulder?

For me, "balance" has had more to do with the latter than the former. I like the barrel to be the "light end" of the gun, with more weight distributed towards the action and stock. My 870P is like that. The "balance point"(when carrying it in hand) is immediately in front of the trigger guard. When I shoulder it, my right arm is doing most of the weight bearing function, with my left hand mostly just steadying the barrel and pumping.

With my 39A, the balance point (now) is 2" in front of the trigger guard, under the rear sight. My left arm does more of the weight bearing function. That results in a different dynamic for me than if the balance was further back (as if the barrel was shorter). I'm not saying it's a worse dynamic; too early to say yet for me. I'm just saying it's different, and not something I'm used to yet.

Of course, with the lever gun, having more weight on the fore end hand may free up the rear hand for lever duty (the reverse situation from my pump shotgun).

I'm expecting my 336A any day now. (Hoping the gun shop will call today or tomorrow <no excitement to be read into that statement :what: :rolleyes: > ). I'll be really curious to compare it's "balance" (whatever that means) to the 39A.

Nem

Nematocyst
February 8, 2007, 05:08 PM
If Nematocyst-870 does go ahead with his barrel cutting project, he can chrono the 39A before and after using the same batch of a standard velocity ammo.You know, that's a great idea. I'd totally be down with doing it
(IF you guys don't talk me out of a barrel cut ... :uhoh: :scrutiny: :rolleyes: ).

Just in case, I'll start looking around for some one here with a chronograph.
I'll bet the folks over at the gun shop or at one of the local ranges can put me in touch with one ...

JustsayMo
February 8, 2007, 07:47 PM
GREAT idea Mal!

I'd almost be willing to drive my Chronograph down to Nema just to find out. Nema, do you ever get to the Seattle area? I range master at our club and can open it up for important scientific studies pert near any time there's daylight. Might even have to bring a milk carton or ten...:p

If so bring that 39 (and the 336A). We can test a bunch of varieties of ammo and see what it'll do. Science can be fun! :D :neener: :p

rangerruck
February 9, 2007, 12:08 AM
depending on the quality of ammo, the bbl, lapping , molyfusion, temps, altitude, hi velocity or hyper, it is going to be between 16 to 18 inches. you cannot say just one measurement. you cannot use just a chronograph, you have to use a computer program to input certain data strings, to find out where the velocity has it's 'smoothest' velocity gain point. And there are a few other factors, such as gas espansion ratio's, velocity blips, barrel balistics, etc. But those are more cumulative, and minor taken on singular points .
That being said, on average , with most 22lr ammo, it will be between 16 to 18 inches. 17m2, is 20 to 22 inches, as with a 22 mag, and a 17hmr i would do 22 to 24 inches.

Geno
February 9, 2007, 08:55 AM
This thread makes me wonder why T/C came out with a 28" .22LR barrel for the Pro Hunter if what has been alleged is accurate.

For my part, I seriously doubt that the added length would "significantly" decrease velocity. In fact, inasmuch as the barrel remains under preassure, I suspect that the velocity does not decrease between 16" and 28" (or other length).

The test is simple. Take a rifle with a 16" barrel, and a rifle with a 28" barrel (or other length). Clean both rifles. Buy 1 box of X-brand ammo. Fire 25 rounds from the box though each rifle through a chronograph. Put the data into ( Excel / SPSS / Minitab / http://www.physics.csbsju.edu/stats/t-test.html ). Note, use the link for "Are two sets of data really different?" Do NOT use the paired data option. That statistic is a for a test | re-test to see if the score-change is significant.

I suggest use Minitab or SPSS and run a 2-tailed, t-test checking to see if there is a statistically significant difference of mean group scores. (NOTE: verify appropriate critical-t per 1-tailed or 2-tailed t-test). Null-hypothesis: There is not a statistically significant difference of group means velocities for .22LRs fired through a 16" barrel versus those fired through a 28" barrel (or other length). Edit to add, these rifles should be the same make, and action-type. Do not use a microgroove Marlin and a deep-cut-rifled X rifle. Also, do not use one bolt-action and the other semi-automatic. We want to keep the only change (variable) being the barrels' length. To that same end, I strongly suggest using a professional, match-grade ammunition. (Of course we have the limitation that we cannot randomly sample 30 rifles of each length).

Someone with a chrono do the shots and send me the #s. I'll run the t-test for you all.

Doc2005

Nematocyst
February 9, 2007, 06:50 PM
J'Mo,

Thanks for the offer of help with chrono research. Unfortunately, I don't ever make it up to Seattle any more. I'm too poor right now in time and money; my business is eating my time, my diesel truck drinks fuel as fast some people drink beer :uhoh: , and I'm spending all my discretionary funds (that includes travel) on new rifles. :D

I'm going to explore finding a chrono here, though.

I also owe you a PM after this busy week is finished.
(Neat pack arrangement you mentioned...)

Nem

rangerruck
February 11, 2007, 12:10 AM
actually, speed starts to drop off fast, once 24 inches has been reached. the reasons for shooting 22's with longer bbls, are primarily, longer bbls are easier to stabilize, with a longer sighting radius for more accurate shooting. secondly and maybe more important, the longer bbl helps keep the extreme fps velocity spread down to a minimum, since there is better control over expansion of the gas, inside the bbl, for a round that may be loaded a teeny bit more or less powder grains.

xanderman
July 24, 2010, 12:39 PM
Hi there, I'm new to the forum but would like to throw in my two bits, the RUGER 10/22 is a semi-automatic rifle, part of the energy from combustion is used to propel the bullet, and part for cycling the breech block and carrier to load the next round into the chamber and cock the firing pin.
Changing the amount of powder will change the rate of cycling, reducing the powder will slow cycling, even prevent it from completing.
Any problems with jamming?
Approaching closely the amount of energy to overcome inertia of the block will sometimes cause increased back pressure, if it doesn't cycle some of this gas will be pushed back intot he chamber and increase bullet velocity, accompanied by a "jam"
or a soft cycle will just do it a bit.

xanderman
July 24, 2010, 12:54 PM
With low powder loads and quick burns propellants are exhausted before the bullet reaches the end of the barrel, so longer barrels will cause loss of velocity due to friction after the propellant is used up.
Using a bigger load of powder or slower burning powder (larger granules) will make a longer burn which will continue to burn as the bullet travels down the barrel, longer barrels will contain this expanding gas for longer and cause increased efficiency and increased velocity of the bullet.

Optimal barrel length is determined by multiple factors, including the powder load, specifically burn time and expansion rate (powder composition, granule size, absolute size, bore diameter), cooling rate of gases (bore diameter, barrel thickness, ambient temperature, coefficient of heat exchange of barrel material), time of projectile in the barrel (mass, length of barrel, friction (bore size))

There are so many variables that I can't list them all here, and the permutations of each of thise is extraordinary, but suffice to say, it is different for each ammunition and for each caliber.

Another factor is the need for spin to stabilize the bullt, in low velocity small powder charges a short barrel may be preferred, but is limited by the need for time to impart energy to the bulet and make it spin... can be overcome by choking down the barrel, increasing friction

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