Advanced Marksmanship Truing BC'S

[rybe390]

Hey folks!

Question here for you guys who have been around longer than me.

When you true data by truing BC, how far or what % variance from the original BC are you willing to go before you begin to question? And, do you see consistencies in how your barrel effects BC ie it always produces a worse or better bc?

Reason I ask, is that my Bergara drops the BC of a 140 bthp down by 4% and of a 140eldm by down 2%. This results in a .2-.4 mil difference of truing at 1,000 yards.

I want to take my trued data(which has been confirmed now at a mile and in) and print out other environmental cards, and I want to be sure the data will jive in other environments. I just want to be sure my BC Truing is as good as can be so it will hold true at other environmental conditions.

Assume that the shooter has tall target tested and just used a magnetospeed(because I do this).

How far are you willing to slide BC to true data before you begin to wonder what's going on?

 

[_Windrider_]

If I know my MV is spot on I’ll adjust the BC till it lines up with real world data within a .1 average across the ranges.

but remember as your amV varies in different temps so will the BC but it will take a 50 FPS change or so to see it

 

[rybe390]

If I know my MV is spot on I’ll adjust the BC till it lines up with real world data within a .1 average across the ranges.

but remember as your amV varies in different temps so will the BC but it will take a 50 FPS change or so to see it

Sounds good. I verify after truing bc and have found myself to be waterline within 1,000 as well as beyond.

Good point in MV changing with temp. I try to use temp stable powders to minimize this, but good info to have nonetheless that your bc may change if MV changes a bit.