I was wondering how many of you guys have chrono'd factory ammo and checked how badly it was overrated on advertised velocity? I know from readin a lot of books that most say it is overrated...I'm sure of this is due to factory using longest barrel they could find but I wonder if any calibers really stand out a sbeing overrated in factory trim according as opposed to real world numbers. Thanks in advance...

The only factory loads I've ever chronographed was the Winchester 45 grain JHP .22-250 load, which is advertised to reach 4000fps. Out of my Ruger M77VT with it's 26" barrel, this load clocked and average of 4016fps, with an SD, if I recall correctly, was right at 10fps. So yes, this load, in my gun, lived up the the advertised velocity, but I will tell you that it is a very hot load, and I've had several rounds show mild pressure signs.

Mike

I have chrono'd Remington factory stuff in 300RUM and it was right on target believe it or not. But hornady light mag stuff is BS.

I can see the ammo manfactures point however. For example, my 300RUM in remington 700 factory barrel shot 180gr nosler partitions 3180fps and in my krieger barrel it shoots em almost 3280fps.

I haven't chrono'd much rifle ammo but I've done a decent amount of handgun ammo and almost without exception, factory numbers are inflated. Sometimes considerably.

They do not seem to be as far off as they used to be. I think now that more people have chronographs, that they don't inflate it as much. I have chronographed quite a bit of Federal ammo and found them pretty close. What suprises me is how low some of the velocities are on ammo that does not claim any velocity on paper. I have tested 250-3000 ammo from WW. Their 100 grain silvertips average 2600 fps. That was picking a few from several different boxes. My first chronograph used the old paper screens. Good machine but those screens were a little spendy plus I always had to remember to order new ones.

I've chrono'd Winchester Supreme extended velocity, .270 WIN, 130 gr. Power Point. It is published at 3060 fps, I got nearly 3100 out of my 22" Ruger MKII.