God I wish I remembered the name of the article but YES you do lose some velocity with the semi 22 vs. bolt action. Test was done with 2 Marlins, I beleive, one semi and one bolt with the same barrel lenght. Semi averaged about 20 fps slower than the bolt; not enough to worry about.
How much power is lost by S/A Marlins .22lr
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I can't say I've ever seen a .22 semi with really good reliability, although Marlin model 60's probably come close. I think it's just a problem of a very short, rimmed cartridge. They just don't do very well when they're stacked on top of each other.
RCModel is now selling the "Overdrive Kit" for all .22LR Semi Auto's.
The instruction manual will contain several "Mental Images"
Left handed model is still in testing phase.
"Not enough to worry about" Agreed, I got bigger problems! The Rem bulk packs are a roll of the dice at farther ranges for sure.
The instruction manual will contain several "Mental Images"
Left handed model is still in testing phase.
"Not enough to worry about" Agreed, I got bigger problems! The Rem bulk packs are a roll of the dice at farther ranges for sure.
As far as the bullet clearing the barrel before the bolt starts to move backwards, I just don't think that stands up to reason. You can cut the barrel on a 10/22 down to just a couple of inches and they will still cycle. If the bolt weren't beginning to cycle until it had cleared a standard 18.5" barrel, then imagine the situation with a 6" barrel. By the time the bullet has left the 6" barrel and traveled another foot there would be no pressure left to cycle the action, yet chopped down 10/22 pistols and SBR's still do function.
I always knew that one of the advantages of the blowback design is that you have virtually no power loss compared to a gas system.
In a blowback firearm, bolt and bullet start moving at exactly the same time once you fire....there is no way around physics.
However, to keep things working and avoid a nice burst of hot gases in the shooter's face the bolt has to be much much more heavy than the bullet and calibrated to the cartridge performance as well, one of the reason that the blowback system is usually limited up to cartridges in the same power class as the 380 Auto.
If you want to keep using the blowback architecture with more powerful rounds you have two choices:
1) Some sort of delayed mechanism (typical example the rollers in the CETME semi auto assault rifle in 7,62 X 51 NATO and civilian versions in 308 Winchester) to supplement the "natural" cycle delaying action offered by the temporary bulging under pressure of the case walls against the chamber
2) a very very big and heavy mass for your bolt...ever wondered why Hi-Point pistols are so big, unwieldy, heavy and ugly??? Because they use a blowback system for full power pistol rounds (9 mm, 40 S&W and 45 ACP) so they need an oversize slide mass.
So, as we said, the much heavier bolt start moving at the same time as the bullet.
However, because its sheer mass, the recoil spring and the pressure that keeps the case walls tight against the chamber walls, the bolt moves with a velocity which is a minimal fraction compared to the speed of the bullet.
To be fair and precise, the bullet, despite being very light, has to win the friction of the rifling which increases in a non linear fascion as the speed increases, a problem that our lubricated bolt doesn't have.
In practice when the bullet start leaving the muzzle, the bolt has yes moved backward but not in an amount which allows noticeable gas escape and we still have the bulged case walls from the pressure which form some sort of a gas seal with the chamber.
With the bullet out the pressure drops and the case walls "retreat" from their pressure against the chamber..the bolt (and the recoil spring), because of its sizeable mass has acquired enough momentum to complete the cycle and lo longer has to "fight" the bulged case under pressure.
As you may suspect, one of the critical aspect of a blowback design reliability is the use of good quality cases and carefully refined chamber tolerances.
A well designed and calibrated blowback system is insensitive to barrel lenght for a given caliber.
Interesting enough, in the artillery field, where the aestethical appearance and weight is not a factor, the blowback design is being used....these are really big guns
In a blowback firearm, bolt and bullet start moving at exactly the same time once you fire....there is no way around physics.
However, to keep things working and avoid a nice burst of hot gases in the shooter's face the bolt has to be much much more heavy than the bullet and calibrated to the cartridge performance as well, one of the reason that the blowback system is usually limited up to cartridges in the same power class as the 380 Auto.
If you want to keep using the blowback architecture with more powerful rounds you have two choices:
1) Some sort of delayed mechanism (typical example the rollers in the CETME semi auto assault rifle in 7,62 X 51 NATO and civilian versions in 308 Winchester) to supplement the "natural" cycle delaying action offered by the temporary bulging under pressure of the case walls against the chamber
2) a very very big and heavy mass for your bolt...ever wondered why Hi-Point pistols are so big, unwieldy, heavy and ugly??? Because they use a blowback system for full power pistol rounds (9 mm, 40 S&W and 45 ACP) so they need an oversize slide mass.
So, as we said, the much heavier bolt start moving at the same time as the bullet.
However, because its sheer mass, the recoil spring and the pressure that keeps the case walls tight against the chamber walls, the bolt moves with a velocity which is a minimal fraction compared to the speed of the bullet.
To be fair and precise, the bullet, despite being very light, has to win the friction of the rifling which increases in a non linear fascion as the speed increases, a problem that our lubricated bolt doesn't have.
In practice when the bullet start leaving the muzzle, the bolt has yes moved backward but not in an amount which allows noticeable gas escape and we still have the bulged case walls from the pressure which form some sort of a gas seal with the chamber.
With the bullet out the pressure drops and the case walls "retreat" from their pressure against the chamber..the bolt (and the recoil spring), because of its sizeable mass has acquired enough momentum to complete the cycle and lo longer has to "fight" the bulged case under pressure.
As you may suspect, one of the critical aspect of a blowback design reliability is the use of good quality cases and carefully refined chamber tolerances.
A well designed and calibrated blowback system is insensitive to barrel lenght for a given caliber.
Interesting enough, in the artillery field, where the aestethical appearance and weight is not a factor, the blowback design is being used....these are really big guns
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czarjl
Member
That makes sense to me and explained better than I could have.
waterhouse
Member
Not a very conclusive test. You could probably find 2 bolt action marlins with the same barrel length that showed a 20 fps average difference between each other.
I'm not saying that test results aren't valid, but the only way I can think of to prove the theory is to use the same exact barrel with both action types.
Thanks to the OP for bringing the topic up, interesting question and I certainly have learned a bit about the blow backs.
Dr. Tad Hussein Winslow
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I don't think ANY; and surely not much. The bullet has already left the muzzle before the the casing clears the chamber mouth, IINM. Who's gonna do the controlled experiment, though?
The Rem 552 speedmaster is very very reliable.
The Rem 552 speedmaster is very very reliable.
rcmodel
Member in memoriam
Totally invalid test.
Any two barrels, even installed on the same receiver, could easily have more velocity variation then that.
But comparing two different rifles, off two different production lines, and built months or years apart?
No way the test means anything at all, except one rifle had a "faster" barrel then the other.
rc
Funderb
Member
Come on, guys, you are ignoring physics here, there HAS to be an energy loss, because energy is being diverted to operate the bolt. There is no way on earth or in heaven that there is no energy loss from the bullet involved in this process.
Vern Humphrey
Member
Try this experiment. Shoot your Ruger automatic, 10/22, or whatever and pick up the fired case. Try to put it back in the chamber.
If there was any significant gas pressure remaining when the breech block started back, the fired case would be swollen and would not fit.
Pressure doesn't get that low until the bullet is gone.
If there was any significant gas pressure remaining when the breech block started back, the fired case would be swollen and would not fit.
Pressure doesn't get that low until the bullet is gone.
czarjl
Member
I still like my test idea of using a semi-auto with the bolt locked and then letting it cycle. If there is a measureable difference this should show it… I think it will be a few Feet per second but not much in the grand schema of things.
Whatever energy loss you may have because of the bolt going backward is totally negligible and hardly measurable with our home grade equipment (Chrono)
This hypothetical "loss" is way way less than a gas operated system firing the same cartridge with the same barrel.
Vern Humphrey
Member
If it were done with a bolt action rifle, energy would be "diverted" to move the bolt. In fact, energy (actually momentum) would be "diverted" to move the whole gun.
As I said, fire your semi-auto blowback .22, pick up the case and see if it will go back into the chamber -- if it's swelled or blown out to the point that you can't get it back in, that will indicate high pressure after the bolt started moving.
But if it slips back in like it came out, then clearly there was very little pressure at the time of extraction, and hence the bullet was gone before the bolt opened.
Dr. Tad Hussein Winslow
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Or like someone said, using the same semi-auto rifle, just manually holding the bolt closed with the bolt handle in the second part of the test. Shoot 10 rounds each way; average them - who can do it this weekend and has a chrony?
Vern Humphrey
Member
I've done it -- or something close.
I shot a .22 pistol (in this case an M1911 with a Ciener conversion kit) both as-is, and with lead weights clamped to the slide -- to the point where the slide no longer cycled.
The results were that 30-round strings fired with the basic pistol, with a 1-lb weight, a 2-lb weight, and a 5-lb weight were statistically the same.
I shot a .22 pistol (in this case an M1911 with a Ciener conversion kit) both as-is, and with lead weights clamped to the slide -- to the point where the slide no longer cycled.
The results were that 30-round strings fired with the basic pistol, with a 1-lb weight, a 2-lb weight, and a 5-lb weight were statistically the same.
gvnwst
Member
Okay, this is coming with the knowledge that i know very little about pistols, but aren't almost all pistols blowback? The 1911, glock, SA XD, H&K USP, ect? I have always read about them being this...they don't use a gas system, that is for sure.
Other than that, they are right, while the bolt does move back at firing, by the time it goes anywhere far (more than a few thousandths of a inch) the bullet is gone out of the barrel. There is no power loss, because the energy is simply put into making the bolt go back faster than the gun normally would, and the gun just goes back a bit less.
rcmodel
Member in memoriam
All semi-auto .22 RF pistols & rifles, and most all .25, .32, and .380 ACP pistols are blow-back operated. In other words, at no time is the slide or bolt connected to the barrel.
Almost all center-fire pistols are Browning locked-breach, short-recoil operated.
The slide & barrel are locked together long enough for the bullet to clear the barrel and pressure to drop to near nothing.
rc
Almost all center-fire pistols are Browning locked-breach, short-recoil operated.
The slide & barrel are locked together long enough for the bullet to clear the barrel and pressure to drop to near nothing.
rc
Vern Humphrey
Member
No. Most centerfire pistols are locked-breech, short recoil actions.
The classic is the M1911. The barrel is locked to the slide (which includes the breech) by horizontal lugs which mate with transverse grooves in the slide. When the gun is fired, the barrel and slide recoil as a unit.
There is a swinging link on the bottom of the barrel, near the breech, and a pin (the slide stop pin) runs through the frame of the pistol and through the link. As slide and barrel continue backward, the link pulls the rear end of the barrel down and out of engagement, and brings the barrel to a stop. The slide continues rearward, extracting and ejecting the case and over-riding the hammer to re-cock the gun.
The recoil spring, which has been compressed by the slide coming back, now expands and drives the slide forward. The slide strips a fresh cartridge out of the magzine, chambers it, and hits the breech.
At this point barrel and slide continue forward, and the link forces the barrel up so the lugs re-engage the grooves.
Vern
You nailed it perfectly....even in a bolt action rifle the bolt is "moved" backward....the entire rifle is moved backward for that matter because the bolt is locked in place....this is one of the reason that the recoil of a semi-auto rifle is milder compared to a bolt action chambered in the same caliber.
The only hypothetical insignificant energy loss I was talking about and that I can imagine on a blowback system is the extremely minuscole increase in the chamber volume created by the beginning of the backward movement of the bolt as the bullet proceed through the barrel compared to exactly the same barrel on a bolt action rifle (same charge acting on a bigger volume = less pressure).
On top of that whatever little gas can escape from the seal formed by the bulged case under pressure.
But this "loss" is absolutely and totally insignificant, other factors such as the outside temperature, bore tolerances, barrel temperature, rifling design, etc... have a much much more bigger impact on performance.
Comparing the muzzle velocity of a blowback semi auto 22 LR rifle with an other 22 bolt action of the same barrel length is absolutely without merit. Any meaningful and measurable velocity differences are due to the other factors already mentioned...the same rifle can have much more than 20 fps of differences between shots during the same session
You nailed it perfectly....even in a bolt action rifle the bolt is "moved" backward....the entire rifle is moved backward for that matter because the bolt is locked in place....this is one of the reason that the recoil of a semi-auto rifle is milder compared to a bolt action chambered in the same caliber.
The only hypothetical insignificant energy loss I was talking about and that I can imagine on a blowback system is the extremely minuscole increase in the chamber volume created by the beginning of the backward movement of the bolt as the bullet proceed through the barrel compared to exactly the same barrel on a bolt action rifle (same charge acting on a bigger volume = less pressure).
On top of that whatever little gas can escape from the seal formed by the bulged case under pressure.
But this "loss" is absolutely and totally insignificant, other factors such as the outside temperature, bore tolerances, barrel temperature, rifling design, etc... have a much much more bigger impact on performance.
Comparing the muzzle velocity of a blowback semi auto 22 LR rifle with an other 22 bolt action of the same barrel length is absolutely without merit. Any meaningful and measurable velocity differences are due to the other factors already mentioned...the same rifle can have much more than 20 fps of differences between shots during the same session
gvnwst
Member
Hmm...this is intresting. I was shooting a 1911 for my first time on sunday (yay!) and i didn't notice tha barrel move at all. Cool.
rcmodel and Vern, thanks for the explanation.
rcmodel and Vern, thanks for the explanation.
Vern Humphrey
Member
Take that .45, being very sure it's unloaded, and wrap your strong hand around the grip, and use your weak hand to move the slide slightly backward, a quarter of an inch or so, while you look at the breech. You will see it drop down as you press the slide back.
gvnwst
Take your 1911, make sure it's unloaded and pull back the slide very very slowly and you will notice that at the beginning, for a very short distance, barrel and slide go back together....if you keep pulling back at some point the barrel will stop going backward and it is pulled down while the slide keep going back.
If you have or you can put your hands on a small semi-auto in .380 or less do the same thing (make sure it's unloaded) and you will notice that the barrel will not move back at all.
Take your 1911, make sure it's unloaded and pull back the slide very very slowly and you will notice that at the beginning, for a very short distance, barrel and slide go back together....if you keep pulling back at some point the barrel will stop going backward and it is pulled down while the slide keep going back.
If you have or you can put your hands on a small semi-auto in .380 or less do the same thing (make sure it's unloaded) and you will notice that the barrel will not move back at all.
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