Chronograph Procedure — Help?

[Koda_]

Copy that.

Final question..

When I go to re-chrono, should I wait enough time between each individual shot to allow for the barrel to cool?

Thank you for all of your insight.

yes.

Point of aim/impact and velocity usually change as barrel heats up, some rifles can shoot 2 to 4 rounds between cooling with the last shot having a slightly different POI, thats your temp limit... my guess is a 300WM heats up pretty fast.
If for hunting you want a cold bore zero and chrono readings for best ballistic estimations. Do the work up front and you'll have more precise ballistic data to use in the field past your zero distance. After that you'll learn what your rifle gives in changes in point of impact after 2 or 3 consecutive rounds so you know in the field what practical results you will get in the (hopefully) rare chance you need more than 2 rounds to fill a tag.

 

[Brydawg512]

Also be sure that the temperature of your ammo is closely managed for consistency. Here are things that can affect temperature of ammo which can affect velocity, depending on powder:
1. As mentioned above, loading a round in the chamber and leaving it in there for more than the amount of time it takes to get in target and pull the trigger.
2. Loading from a magazine when the rifle is hot. Ammo hests up by convection/proximity to heat from barrel. I always single feed when doing load development. I recommend you do this.
3. Letting ammo sit in the sun. Keep it in the shade or covered.
4. Differences in powders and powder lots within the same powder type. You never said what powder the cartridges were loaded with that would be good to know.

Good news is you are already in the 'pretty darn good range' for velocity with a 215, ES, and accuracy. Practice with technique and some of the other things above, including reloading fireformed brass might really get your into the sweet spot without much more effort.

Keep us posted.

Thank you very much. It is H1000

 

[Brydawg512]

So did you reload the ones you shot or did the builder?

I had them loaded by Unknown Munitions.