CZ American 20 vs 24 inch

[grauhanen]

All the data I have seen shows the opposite. anything beyond 16-18" shows a reduction in FPS. You can only put so much powder in a .22 RF. In centerfire shooting, with a longer barrel, you can often get more velocity by putting more slower burning powder in the cartridge.

In the .22, the only way you can get more velocity is use faster burning powder with a lighter projectile. Lighter projectile as less weight therefore less force is required to get it moving, so the faster burning powder will not overpressure and blow the case out. End result is a bit more speed.

For readers in general, the assumption that there's a certain barrel length beyond which .22LR bullets must slow down is an idea that's not necessarily correct. It's repetition on rimfire forum posts doesn't make it a rule.

Barrel length is only one of two important factors that helps determine .22LR MV. The other is bore condition, including how smooth, concentric, and tight the bore itself is.

There are studies that are more scientific and more reliable than internet lore (including the "Ballistics by the Inch" website) and anecdotal reports that shorter .22LR barrels are invariably "faster" than longer ones. In one such study, the same rifle was used with its initially 24.25" barrel progressively cut shorter inch-by-inch. A number of different kinds of .22LR ammo was tested as each inch was cut off, including various match ammos. The results showed that there was not a consistent relationship between barrel length an average ammo MV. As the tester observed at the end of the testing, "Amazing is in it? With center fire each inch means something, here [with .22LR] not so much."

For the data developed from this testing, see https://forums.accuratereloading.com/eve/forums/a/tpc/f/8711043/m/4871072832/p/1

 

[Vzduchovka]

I have the 20 inch; my brother went with the 24. I prefer the 20 inch in the woods.

 

[ntaylo48]

What are your guys thoughts on barrel length for shooting offhand? Is the longer 24 inch barrel going to be more stable or result in a more front heavy rifle than the 20 incher? Deciding what barrel length to consider when picking a CZ for silhouette shooting.

 

[Suther]

All the data I have seen shows the opposite. anything beyond 16-18" shows a reduction in FPS. You can only put so much powder in a .22 RF. In centerfire shooting, with a longer barrel, you can often get more velocity by putting more slower burning powder in the cartridge.

In the .22, the only way you can get more velocity is use faster burning powder with a lighter projectile. Lighter projectile as less weight therefore less force is required to get it moving, so the faster burning powder will not overpressure and blow the case out. End result is a bit more speed.

I suggest you reread my post as you've completely misunderstood me if you think I'm claiming 24" barrels are generally faster.

Also, slower powder in a centerfire DOES NOT get you higher velocity in a longer barrel. Powder hits peak pressure within the first few inches of barrel. Peak velocity is reached when you find the right burn rate for your case size, bore diameter, and bullet weight, too fast of a powder and you'll go too high in pressure or leave a bunch of empty space in the case (thus less powder to burn and expand) too slow of a powder and you never reach the peak pressure you're after even with a compressed load. Most of the time the best powder at 16" is also going to be the best powder at 26".

 

[OkayShooter]

What are your guys thoughts on barrel length for shooting offhand? Is the longer 24 inch barrel going to be more stable or result in a more front heavy rifle than the 20 incher? Deciding what barrel length to consider when picking a CZ for silhouette shooting.

I run 22s with 26-27" barrels off hand without issues. My Anschutz 64 Silhouette has a 21.5" barrel.

 

[Great North Guns]

I like long barrels for farm work. With standard velocity rounds the sound is quite tolerable.

 

[Meroh]

I suggest you reread my post as you've completely misunderstood me if you think I'm claiming 24" barrels are generally faster.

Also, slower powder in a centerfire DOES NOT get you higher velocity in a longer barrel. Powder hits peak pressure within the first few inches of barrel. Peak velocity is reached when you find the right burn rate for your case size, bore diameter, and bullet weight, too fast of a powder and you'll go too high in pressure or leave a bunch of empty space in the case (thus less powder to burn and expand) too slow of a powder and you never reach the peak pressure you're after even with a compressed load. Most of the time the best powder at 16" is also going to be the best powder at 26".

55 years experience disagrees.

 

[grauhanen]

See more data regarding MV and .22LR barrel length. The fact is that despite what is repeated on forum posts, there isn't a reliable relationship between barrel length and .22LR MV. In short, barrel length doesn't determine .22LR MV.

 

[waldo54]

You'd have to WANT the 24" for some reason (balance, looks, sight radius, etc). There won't be any real accuracy difference, but that extra length slows your bullet down a couple hundred fps - something to keep in mind.

I don't think the American comes with irons (CZ must think Americans all use scopes), so I can't think of any practical reason to get the 24.

Sorry no where near a couple hundred feet per second, I just completed a test of 11 different brands of 22 LR for accuracy and velocity, shot 3 groups of 5 shots each and took the average recorded on a Garmin Xero C1 pro chronograph, the 2 rifles used were a CZ 457 with 24" sporter barrel and a Christensen Arms Ranger with an 18" carbon fiber barrel, so 15 rounds of 11 different brands of ammo came to 165 rounds out of each gun, when totaled up and averaged out the 18" barrel produced 7 FPS more than the 24" barrel and that could be just attributed to the barrel and chamber itself, conclusion is 6" more barrel makes no noticeable difference in velocity.

 

[grauhanen]

the 18" barrel produced 7 FPS more than the 24" barrel and that could be just attributed to the barrel and chamber itself, conclusion is 6" more barrel makes no noticeable difference in velocity.

A good point. It's shortsighted to say that barrel length dictates ammo velocity. The fact is that barrel length in .22LR does not have a consistent relationship to average ammo MV. The average MV depends more on a particular bore's characteristics. The same lot of consistent ammo can have different average MVs from two barrels that are the same make and length.

There are several factors other than barrel length that determine MV with .22LR. Among these are bore smoothness (some bores are less smooth than others), bore diameter size and variation (diameter will vary through the length of the bore), and bore diameter concentricity (how close to perfectly round the bore is, which can also vary).

 

[TheCoyoteHunter]

Do the 457s come with an all metal bottom?
I was under the impression that the 2 piece bottom was all metal.
I recently got a 457 American Beech. It has a 20" barrel with beech wood stock.
I was surprised to find that the trigger guard was plastic. The flat part of the 2 piece bottom is metal, but the trigger guard part is definitely plastic.
I know the synthetic stock version has a plastic trigger guard, but I thought the wood stocked models had an all metal bottom. The beech wood American is cheaper than the walnut wood American, by $100 - $150.

 

[Meroh]

Do the 457s come with an all metal bottom?
I was under the impression that the 2 piece bottom was all metal.
I recently got a 457 American Beech. It has a 20" barrel with beech wood stock.
I was surprised to find that the trigger guard was plastic. The flat part of the 2 piece bottom is metal, but the trigger guard part is definitely plastic.
I know the synthetic stock version has a plastic trigger guard, but I thought the wood stocked models had an all metal bottom. The beech wood American is cheaper than the walnut wood American, by $100 - $150.

This is a bit off topic to this thread, but I have a .455; mag well and spacer are plastic. Only plastic parts on it. My 452 and the older Mod 4 I owned were all steel. No mag well spacer as they calibers were not interchangeable.

 

[MilitaryCollectorMark]

I have a LH 457 american with the 20" barrel.

 

[a j cave]

I like the longer barrel. I shoot a 452 Lux mostly on gophers and the feel is great. Ask around the gun club to see if you can handle both.

 

[Butcherbill]

You’ll probably only notice a difference in sound, I have 20” & 24” .22’s and with the same ammo the 24” barrel is a lot quieter. Having tinnitus the 20” is uncomfortable to shoot without ear pro while the 24” I’m fine without it.