Yes, that is a pretty good analogy. Transonic flight through air is often described as "turbulent" for planes as well as bullets. Long-nosed supersonic rifle bullets tend to become unstable when they fall into the transonic speed range even though their gyroscopic stability is very high (Sg > 5.0) at that point in their flight. Air drag shifts from being proportional to the 1.5 power of airspeed in supersonic flight to being proportional to the square of subsonic airspeed. This is similar to planing over the water surface versus plowing at hull displacement speeds through the water. The stern wave swamping your transom causes the instability. I suppose that hypersonic flight above about Mach 5 could be analogous to hydrofoiling with the hull above the water surface. Those transitions with speed changes are much more gradual and stable, however.
Yes popular, but that doesn't equate to optimum speed generated for the barrel length. My sons rimx with a 22" green mtn barrel exceeds manufactures stated velocity by a bit, and a friend of his that has the same setup is fast also, both 1:16", Barrel length is not the only thing that affects velocity. You really don't know until you do some shooting.Yeah 16” - 18” are the most common numbers thrown out there.
AgreedYes popular, but that doesn't equate to optimum speed generated for the barrel length. My sons rimx with a 22" green mtn barrel exceeds manufactures stated velocity by a bit, and a friend of his that has the same setup is fast also, both 1:16", Barrel length is not the only thing that affects velocity. You really don't know until you do some shooting.
Got me wondering is there is a correlation between good or bad accuracy and whether the slug has passed Mach 1 and slowed back below Mach 1 before exiting the muzzle? (Thinking my old prone rifles w/28” barrels).Some notes on crosswind sensitivity for 22LR rimfire:
As was formulated by DeDion in 1859, air drag causes wind drift "downwind" across the target which is proportional to the actual time-of-flight with air drag minus the hypothetical time-of-flight to the target at the undiminished launch speed. Rimfire match 22LR bullets have very low ballistic coefficients (i.e., high coefficients of drag) relative to Very Low Drag (VLD) rifle bullets. The coefficient of air drag is greatest in the transonic speed range for all bullets, especially for 22LR match bullets. The transonic speed range is from Mach 0.8 to Mach 1.2 for any non-VLD bullets. The "speed of sound," Mach 1.0, is 1116.45 fps for sea-level ICAO-standard air at 59 degrees Fahrenheit and varies primarily with the square root of the absolute temperature (T + 459.67 degrees F) of the ambient air. Thus, Mach 0.8 is 893 fps at 59 degrees F in that standard atmosphere, and 911 fps at 80 degrees, etc.
Actually, the highest airspeed at which no "sonic crack" will be heard from firing a 22LR match bullet is at about Mach 0.75. That "crack" indicates that some portion of the airflow around the rather blunt 22LR bullet exceeds Mach 1.0. That Mach 0.75 airspeed would be 837 fps at 59 degrees. As airspeed falls below this critical transonic value, the subsonic coefficient of drag drops dramatically from about 0.4 (+) down to about 0.1 at Mach 0.70. [The lowest possible subsonic drag coefficient is about 0.03 for an elongated "teardrop" shape.] The 22LR match bullet is an excellent subsonic bullet design and flies serenely to great distance with very little loss in forward speed (and very little crosswind sensitivity). The whole trick is firing them below Mach 0.75 in that day's ambient air temperature. Available 22LR match ammo needs at least a 30-inch barrel to approach this low muzzle speed, and still needs a hot summer day when the speed of sound is relatively high. Perhaps a shorter barrel could be made to accomplish this feat reliably by venting some of the propellant gasses away within the first 10 inches of bullet travel.
I totally agree. What's the big deal with maximum mv. So what if you loose a few feet per second. Maximum mv doesn't translate into maximum accuracy. It is consistency you need for accuracy no matter what speed. If I had to choose between a 16.5 in barrel and a 30 in " actually I don't like either lengths" I would choose the 30. 16.5 is barely long enough for a complete powder burn and with a 16t you barely have one revolution of the bullet before it exits the crown. There is something to be said for stabilizing a bullet before it exits the barrel.With the 22lr, my only worry about muzzle velocity, is how much it differs shot by shot.
It can be 1052 fps, or 1300 fps, as long as it's consistent. It's mv spread that burns my biscuits.
The greater the difference in mv, the worse the the vertical difference in point of impact.
I don't care if it's with an 18 inch barrel or 28 inch barrel, mv spread ruins results.
Spend a few years shooting every box of rimfire across a chronograph, recording the data,
it gets real easy to correlate point of impact to the displayed muzzle velocity.
From my experience(2 Green Mountain’s on my RimX and a friends on a CZ457) Green Mountain barrels are on the fast side. Mines a 22” now and really contemplating going to a 24” GM for better balance and see if I can squeeze a tad bit more accuracy out of it. My 22” shoots most Center X 1090fps-1105fps depending on lot and time of year.Yes popular, but that doesn't equate to optimum speed generated for the barrel length. My sons rimx with a 22" green mtn barrel exceeds manufactures stated velocity by a bit, and a friend of his that has the same setup is fast also, both 1:16", Barrel length is not the only thing that affects velocity. You really don't know until you do some shooting.
I would like some details/info on your m12Long barrels… I too feel as if they work best, my best shooters are long barreled rifles. I own/have owned several Winchester model 52’s. Pre A’s, B’s, C’s and a D. All that I currently own wil shoot sub 1” at 100 on a 6x5. The Bull Barrel and the cut down C (24”) will shoot .7-.75 on low wind days. My Mark Penrod H&R model 12 is a .6-.75” rifle. I’m pretty sure it’s 28” (I’m away from the rifle for the moment sorry) and it has a tuner. My Vudoo (22”) is a bit finicky on ammo but is a .75-.85 rifle when I find the right ammo. Once found, it is consistent, but doesn’t come close to the Model 12.
All of this to say, if you’re trying for the best accuracy, long barrels are the place to start.
I would like some details/info on your m12
I have three Kenyon worked triggers. My two 52 C rifles and my 52E all have Kenyon worked triggers. He would tell you a trigger he worked the pin re-location on was just as smooth as the complete triggers he turned out. I had the privilege of talking to him a couple of times.Nice , people have done or have had done the pin relocation like the win52 c/d kenyon mod , where the pivot pin on the trigger is moved up giving better mechanical advantage and lowering trigger pull