Originally Posted by melloyello
...Your other option is to put up a large target and shoot at it until you have dialed your rifle in for that particular load at all distances that you will shoot. You can write down your dope and use it for future engagements.
A chrono is rarely better at giving your velocity than the guide on the side of the box or a reloading manual.
I don't even use it anymore...ever.
As stated. Put up a target that is big enough that you can print a group at 400 or 500 yards. Use a 4'x4' or bigger target if you need to.
Make sure you have a good aiming reference point and dial to an elevation that will at least get you on target.
Judging by where your group impacts, in relation to where your aiming point is...you can calculate your TRUE velocity, based on the BC of your factory ammo and current atmospheric conditions.
It's best to use a good ballistic program for this, so you don't have to worry about keeping a data book, but a data book is a good thing to learn anyway.
If the ammo shoots well at 100, then the only reason it won't shoot at 4-500 is shooter or equipment error. As said, it's pretty likely that the 26" barrel is giving you a little velocity boost, but it's not going to be an insane amount.