Old Guys in the Know & Most would be Veterns

On this sight or another a person used a chronograph
and anything over a 16 inch and some fraction the FPS
declined.
I have 22 inch and shoot HV and a 16inc for standard and slower.
16 inch works very good with pistol match ammo.

FYI

 

I have been eyeing the CZ 457 AT-ONE in 22LR because the Boyds adjustable stock is a great feature. My primary use of the rifle is a trainer for longer range shooting. I see there is a model with a 24-inch barrel and a model with a 16.5-inch barrel. Some of the older guys at my range tell me that the longer barrel actually slows the 22LR bullet down (never heard that one before). I hope you guys can help me with some questions:

1. Do the barrel lengths of the AT-ONE result in a significant difference in velocity of the bullet?

A. Depends on how you personally measure "Significant" but a chronograph will pick up the velocity difference between a 16.5" and a 24.5" barrel.

2. Would barrel length be an important consideration taking into account my intended use?

A. Not really, powder in a .22lr gets full burn in a 16" barrel and 18" to 20" is pretty much recognized as optimum for gas expansion and bullet stability at best velocity.
Take into account that standard velocity or subsonic .22 ammunition is the ammo of choice for rimfire PRS/ELR shooters.
HV .22lr ammo is actually worse for long range shooting due to its BC at higher speed and stability degradation as it travels through the transonic barrier.

3. Is it true that the 24-inch barrel will degrade 22LR bullet velocity?

A. Yes, but again it takes a chronograph to measure the difference.
In some cases one might not have access to a wide range of subsonic ammunition and need the extra length 24"-29" to slow their perhaps more available HV ammo down as well as making it more hearing safe at the shooters ear.
But in most cases the longer barrels are for using iron sights to give the shooter a longer sight radius for increased accuracy.

 

My two most accurate .22LR rifles are a CZ 452 Scout with a 16.5" barrel and a CZ 452 UltraLux with its 28.5" barrel. They both like the legacy Wolf Match Target and Extra made by SK. With these loads, both consistently print under .5" groups at 50 yards and hover around an inch at 100. In my experience, barrel length itself doesn't appear to affect accuracy nearly as much as other factors, such as how well the inletting fits the receiver, barrel crown or even how much torque one puts on the action screws.

Edit to add: I have never shot these rifles over a chronograph so I have no comparison of their respective muzzle velocities.

 

If I had no intention of suppressing it a 24" would already be mine, but I will suppress it so a 24" plus a 6" suppressor gets a bit LOOOOONNNNGGG.

I'm waiting on a 16.5", YMMV and all that.

 

Don't know if this is a significant factor or not, but it seems to me that, especially for a HV round, the more time it spends in the barrel means the more chance there is for it to gain a nice stable spin from the rifling.

CZ's most accurate gun has a 20" bull barrel. Kidd advises their non-fluted, non-threaded 20" bull barrel as the best way to go for max accuracy. Shilen's sporter and bull barrels are 20", and their tapered one is 22", not 24. My 1996 10/22 Target model 1121 has a 20" bull barrel and is very accurate as well.

So with all that, even if we stipulate that the powder gets completely burned in 16" of barrel travel, it looks like 20" is the accuracy sweet spot--according to the experts.

 

The guys at Vudoo say they found 18" to be the sweet spot during their testing but they do sell 16.5 and 20" barreled guns as well.

These guys pretty much make the guns to beat in .22 ELR and NRL22 comps.
Left or Right-Handed MSRP $1770 V-22 BARRELED ACTION!

 

Perhaps a longer barrel slows down the bullet somewhat, but that is not an issue for you as a long range shooter. What you are trying to do is read and adjust for wind, calculate bullet drop, etc. As long as you are not switching back and forth between 16 inch and 24 inch barrels, you should be OK with either. Because there may me a few FPS difference between barrel lengths, you would run "your" calculations based on what you have. A few feet per second difference should not make one barrel length more "accurate" than the other. Just pick one and learn to shoot IT at long range. Remember, you are developing skills that can translate to high powered calibers, ie. read and adjust for wind, calculate bullet drop, etc. Burt

 

Anschutz's 54.30 (54 action) benchrest rifle comes with a a 26 inch heavy barrel. That's almost a $4000 rifle. They might be on to something. My most accurate CZ sports a 29.5 inch barrel. The majority of the powder might be burned in 16 inches (depending on the powder used and the load) but as long as the pressure inside the barrel exceeds ambient pressure and is sufficient to overcome friction, the bullet should continue to accelerate... In theory. But then I'm partial to 30+ inch center fire barrels for F Class. They continue to accelerate for each inch added to the barrel length. Most are running 32 inch barrels in that sport these days.

 

Those long heavy barrel guns are designed for bench rest shooters where the gun sits in big steel and aluminum carriage rests sitting on heavy vibration free concrete benches.
The long range rimfire guns are shot off bipods and bags in the field where a lower weight gun plays a more realistic role.

Bottom line with ELR is that you don’t want HV ammo for long distance shooting, which means you also don’t want your standard velocity ammo to ever go supersonic.
The key then is trying to loose as little velocity as possible from that ammo in the barrel length you choose.
18”~20” seems to be the most common with plenty of 16” barrels in NRL22 where distances are more in the 25~250 yard realm vs 300~600 yards.

 

Thanks to all for your input. A lot of good points to think about.

 

For what it's worth, I recently did some velocity tests on CCI Standard Velocity ammo. I fired 10 rounds through a 24" barrel and 10 rounds of that same ammo through a 16" barrel. The average velocity of the 24" barrel was 1,026 fps. The average velocity of the 16" barrel was 1,052 fps. The 24" barrel was, on average, 26 fps slower than the 16" barrel. Hmmm.

 

Thank you for the data! The velocity in the 16" barrel is more, but is it enough to make a big difference? It looks like it will be up to me, the potential owner of the rifle, to decide. Things line up very well with what prairie maggot posted.

 

I’ve read that a long Barrel is the choice of bench shooters because of the occasional hot round you might get , the longer barrel slows it down to hopefully stay subsonic.
I can understand that , but what about those under powered rounds that sometimes show up .
Just something to think about .
BTW , I own rifles with barrels from 16” to 24.8” . Including two of the heavy tapered 24” threaded CZ barrels . I like the long barrels in a bolt action , but prefer the shorter ones on my semiautos.
The thing I like most about the long barrel , is how much quieter they shoot .

 

MY RIFLE CHOICES ARE CZ VARMIT MTR 20" THE CZ457 VARMIT PRECISION CHASSIS MTR 16" OR THE CZ 457 VARMIT PRECISION TRAINER MTR 16" MY QUESTION IS WILL THE 16 "BARRELL SHOOT AS GOOD OF GROUPS AS PER SAY THE 20" BARRELL AT 200 AND 300 YARDS

 

Barrel testing by Gunsmith’s who build for NRL say 22”-24” barrels stabilize the bullet a little better which shows up as in increase in accuracy after you pass 100yds.

 

AT-1 24" and T1X 20" are my two ARA Factory Class shooters. Both super accurate with decent ammo.

 

First of all, listen to the old guys, they know stuff! They've already made the mistakes your about to make because they didn't listen to the old guys when they were younger, and yet, they somehow managed to survive to be old guys. This is why old guys are smarter; they have more experience. They also get crotchety from having to deal with younger people who don't listen.

I don't know what you consider "significant', but all things being equal, the round out of a 24" barrel will be a little slower than one that is 16." A .22 round will gain its maximum velocity somewhere between 16" to 19" of barrel length. After that approximate barrel length the expanding gas from the powder burn can't keep up with the increasing volume of the rifle bore behind the bullet, so the pressure drops, and the bullet begins to slow down due to bore friction. This reduction in velocity is a good thing, Why? A slower bullet, travelling below the speed of sound produces less aerodynamic drag than a bullet going faster. A slower bullet is less effected by wind drift than a faster bullet.

The speed of sound is not an exact number but is nominally given at 1120 fps. When fired, the .22 rimfire bullet spends it's "flight time" in what is known as the "transonic region", which begins at around 70% below the speed of sound and continues to around 20% above it. In this region, any nominal change in velocity is accompanied by an exponential change in drag. To say it another way, you double the velocity, you increase drag by 4 times. The opposite happens as the bullet slows down; drag is reduced which means wind drift is also reduced. Who would have thought that slower is more efficient?

What I've written about pertains to .22 rimfire primarily and only a very few centerfire rounds and the reason is again, the "transonic zone" of muzzle velocity as it pertains to the speed of sound. The vast majority of centerfire bullet are hypersonic when the leave the barrel and only way down range do their bullets slow down into the transonic zone.

Here's a link to an article that should be required reading of everyone on this forum. It was written by one of our members, "griecke,"(another old guy).

Wind Drift.indd (sagecreekgus.com)

And as far as using a .22 as a trainer for centerfire, it would be nice if the .22 was a close approximation of the centerfire, but it's not a requirement. More importantly, you could use the .22 to work on your fundamentals and wind calling ability; those assets should readily transfer over to centerfire.

 

I had a hard time locating a 24 a few months ago when I bought my 16.5. I am pleased with it though

 

I'm well pleased with my 24" at one. Most places don't have them in stock right now though.