I was sighting in a new 450 I put together. I'm using a Trident barrel and bolt and a 3-9x nikon scope. I was having trouble dialing in the elevation at 150yds so I got out the chronograph and got these numbers:

I was shooting Hornady 250gr ftx #82244
1943
1990
1943
2164
1907
2032
1943
2089
2008
2126
2023
2070
1996
2008
2123
2113

Is it normal to have this big of changes in velocity with factory ammo? I could also tell when it was going to be a faster shot by the sound.  It was around 20 degrees out, and the ammo was in the truck overnight. Would the cold weather explain this?

I was shooting wolf gold out of another upper and the difference from shot to shot was only 20-30 fps.  I think I'm going to call hornady monday, but was wondering what other people's experiences were with this stuff.

What length barrel speeds seem slow ?  This is from a 24" barrel 450 bolt gun
Attached File

17 3/4" Ported barrel with carbine gas system.  Barrel length shouldn't affect the standard deviation should it? I think maybe I got a bad lot of ammo.

I have a 18in Tromix 450bm barrel on an ar and it's very consistent at 2260fps with factory hornady 250ftx. And extremely accurate.

No but you speeds are way down that's why I asked .