Barrel length and .22 Long Rifle

[Vern Humphrey]

We've recently discussed the effect of barrel length in .22 Long Rifle. I knew I had slomething in my packrat stack of gun magazines, and I came across an article on the Taurus 62 clone of the old Winchester Model 62 pump. This is from "A Model 62 Winchester for Today's Shooters" in the November 2000 edition of Shooting Times:

Taurus Model 62 .22 LR 16.5 inch barrel
Load muzzle velocity SD 25-yard accuracy
Federal 32 gr Hyper Velocity HP 1431 27 0.75
CCI 36 gr Mini-Mag HP 1179 28 0.68
Remington 38 gr high Velocity HP 1147 20 0.75
Eley 40 gr Tenex solid 1096 8 0.4
Federal 40 gr Gold Medal Match solid 1049 6 0.48
PMC 40 gr ScoreMaster Solid 1093 3 0.5
Winchester 40 gr T22 Solid 1124 24 1
Overall accuracy 0.65

Taurus Model 62 .22 LR 23 inch barrel
Load muzzle velocity SD 25-yard accuracy
Federal 32 gr Hyper Velocity HP 1421 17 0.83
CCI 36 gr Mini-Mag HP 1170 23 0.75
Remington 38 gr high Velocity HP 1134 32 0.5
Eley 40 gr Tenex solid 1080 11 0.44
Federal 40 gr Gold Medal Match solid 1028 14 0.38
PMC 40 gr ScoreMaster Solid 1064 7 0.63
Winchester 40 gr T22 Solid 1091 14 0.88
Overall accuracy 0.63


Note that barrel length had no appreciable effect on accuracy, and that the 23-inch barrel showed a decrease in velocity in six out of seven loads compared to the 16.5 inch barrel

My apologies for the jumbled appearence of this table -- it was perfectly lined up in the draft, but apparently the final version wipes out the spaces and tabs.

 

[Father Knows Best]

Interesting.

I've always known that longer barrels are not inherently more accurate. The advantages of longer barrels are primarily: (1) greater velocity; and (2) on an iron-sighted gun, longer sight radius. Of course, there are diminishing returns in terms of velocity gains. Once the bullet reaches max velocity, any additional barrel length will actually cause it to slow down.

It might be that you would get maximum velocity from most of those rounds out of a barrel that is somewhere between 16.5 and 23 inches in length -- say around 20 inches. If so, then anything over 20 inches gives you additional sight radius with iron sights, but no other advantage.

I do know that competitors in rimfire silhouette competitions use rifles with quite short barrels. Those short barrels, however, have long extensions on them (sort of like those fake suppressors). The purpose of the long extension is to give you the sight radius of a long barrel, without having the long barrel. It's also been explained to me that the shorter barrels are more accurate because they get the bullet out of the gun quicker, and are therefore less susceptible to being pulled off target. Another way to put it is that the gun can move between the time of primer ignition and the point when the bullet exits the muzzle. The bullet will go wherever the muzzle is pointed when the bullet exits. Therefore, you want to minimize the time between the shooter pulling the trigger and the bullet exiting the muzzle, because that reduces the likelihood of pulling the shot off target after the shooter has made the decision to fire. You can shorten that time by reducing the lock time of the action, and by reducing the time it takes to get the bullet out of the gun. Thus, especially with low velocity rounds like the .22LR, a shorter barrel can be more accurate despite the shorter sight radius.

 

[MTMilitiaman]

Hmm. That is interesting. Now I would be curious to chrono some loads through my 10/22. I recently put a 20" heavy barrel and laminate stock on it. It would be a fun learning experience to see how velocity compared to shorter barreled .22 rifles in our family or even the original barrel, which I still have laying around.

 

[Sheldon]

I have seen the "tube extensions" called bloop tubes??? Not sure how they came up with that term.

 

[pbhome71]

A bloop tube is used to increase a rifle sight radius. The only use that I see is in competition.

 

[Sleeping Dog]

I seem to remember that some rifles used in the Olympics have about a 10" barrel. A permanently attached bloop tube gives it a sight radius as well as making the "barrel" a legal length. Theory is that the shorter the barrel, the quicker the bullet is flying free, no influenced by a wavering shooter.


"Bloop" I think is the sound they make.

 

[Bottom Gun]

I think the chamber is also a factor in velocity. My Anschutz 1416 has a tighter chamber than my other .22 rifles do. It won't chamber Stingers because of the slight difference in brass.
Because of this, it consistently chronos approx 100 fps faster than any other .22 rifle we have compared it to (several Remingtons, Marlin, Sako, Ruger, etc) regardless of barrel length or brand of ammo.
I think the brass may seal better in the tighter chamber.

 

[GunGoBoom]

Interesting. I'm actually surprised that the vels from the longer bbl, though lower, weren't signficantly lower - instead, they are only slightly lower. I like short .22s - my 16" cutdown Win 69A, my 19" Marlin 60, my 18.5" Henry pump, and 16.5" Rossi single shot.

 

[Bottom Gun]

I remember reading an article by a gun writer who started with a long barrel and cut it down 1" at a time while chronographing the results. In his particular barrel, 16" gave the highest velocity.
However, I've found that other factors influence velocity as well such as chamber like I mentioned above, the type of action, and the tolerance of the bore & chamber.

Some of my longer barrels shoot faster then my shorter barrels and vice versa. Apparently the other factors infulence the velocity more than barrel length.

I have two identical Remington Nylon 66 rifles. One will consistently shoot about 60 fps faster than the other with all but two brands of ammo.
I've compared at least 2 dozen different types of ammo in them and all but two types show a 60 FPS difference. Those two types shoot consistently within 5-15 fps of each other. That still has me puzzled. I have no idea why.

 

[OldWolf]

Over at rimfirecentral it is common knowledge that a 16" barrel is optimum for 22LR velocity. Increasing the length helps with sight radius though.

 

[Jim Watson]

It has long been known that a 16-18 inch barrel gives highest velocity with .22lr... if that is all you want.

It would be interesting to run the hacksaw experiment on accuracy, machine rest, bench rest, and prone to see what effects were present and how they balanced out.
Short barrel = short barrel time with subsonic .22 match for easier followthrough.
Long barrel = lower muzzle pressure, cleaner shot exit for mechanical accuracy.

 

[Vern Humphrey]

It would be interesting to run the hacksaw experiment on accuracy, machine rest, bench rest, and prone to see what effects were present and how they balanced out.
Short barrel = short barrel time with subsonic .22 match for easier followthrough.
Long barrel = lower muzzle pressure, cleaner shot exit for mechanical accuracy.

The advantage of short barrel time won't show up from a machine rest or a bench rest. The advantage is dependent on getting the bullet away from an unsteady position -- such as offhand.

 

[Jim Watson]

I know that, machine rest shooting is to isolate the effect of muzzle blast from user wobble and followthrough.

I have been told that a GOOD prone smallbore shooter can beat benchrest results.

 

[Vern Humphrey]

I know that, machine rest shooting is to isolate the effect of muzzle blast from user wobble and followthrough.

The point is, reduced dwell time is an advantage only if you have user wobble.

I have been told that a GOOD prone smallbore shooter can beat benchrest results.

He can certainly equal them.