I have several rifles with the same chambering, some even cut with the same reamer. I don't always see exact copies of velocity in them when sharing ammo.
Lot to lot ammo variation, barrel difference, chamber difference....altitude, pressure, temp.... it all plays a part.
My advice if you do not have a chrono is to take the printed velocity and use it as a baseline. Take the rifle to 3,6 and 900 and see what it tells you. If you do this, you can back feed your ballistic program and get a corrected velocity.
If you're vertically stringing at long range you'll know the spread is not good.
Guys often balk at this method due to ammo cost, but the only way to get good at range is to shoot accurate rifles at range.
Barrel variance (fast vs slow, bore diameter, etc), bore condition and break in status, chamber spec, temperature, lot to lot powder burn rate variance, brass case capacity variance (fireformed vs virgin, lot to lot variance, brand differences) all plays a part.
Most rifle velocities are for a 24" barrel. I only have one rifle with a 24" barrel, everything else is shorter. I use the printed velocity as a reference point (sanity check) when initially working up a load with my chronograph.
I bought a chronograph long ago and I can't imagine doing load workup without one.