One for MB , Vics vapour rub

[Mortblanc]

Over here it is not unusual for 22lr ammo to be all over the place, especially when you own a chrono and actually measure a few rounds.

I shoot a lot of Eley and SK ammo and find that it is very consistent, hovering around the 1050 mark you have mentioned. Much of our hi-speed stuff goes faster then the 1250 mentioned. Some approaches 1400-1500fps with the 38 grain bullet.

I also shoot a bit of Fiocchi subsonic which starts out just below 1000fps and shoots a 40 grain bullet.

Federal ammo company came out with a 60 grain sub-sonic load some years back but it will not stabilize in the standard twist barrel. It is specifically made for best energy transfer from suppressed barrels.

There is also the situation where many 22 pistols will not get more than 1000fps from that 1250 rated rifle ammo.

With 22lr the max velocity is usually obtained out of a 13" barrel! That was a shock to me, but true. Some loads even slow down when fired from a longer barrel due to friction.

There is a lot written about ammo becoming unstable when it crosses the sound barrier, but at .22 ranges that is usually not an issue. If it starts below the SB it stays there and if it starts above the SB it is usually going to end its flight before it falls below that speed.

That is one of the limiting range factors for many center-fire rifles. They are accurate out to their trans-SB limit and scatter their groups after that mark, be it 800/1000/1200 meters. That is where ballistic coefficient and other math heavy factors enter the marksmanship craft.

The Enfield .303 is a good example of that. The 175 grain slug has such a solid BC that it carries farther than many rounds that start at higher velocities using 150 grain bullets. The 7x57 Mauser in the military 175 grain load is much the same.