A Little Confused

[Dark Horse]

Took my TRG-42 to the range tonight for the first time since receiving back from APA, which did a stellar job on the rebarrel. I had put several rds through it to chronograph some Corbon 300 grain loads that came out at 2775 avg. A quick JBM calculation at 600 yards called for 3.5 mils of elevation from a 100 yard zero.

Now I don't pretend to be the smartest guy in the world, but shooting tonight has me a little confused. I actually started with 4 mils just to be safe with 2 rds and the impacts were 24" low. Scope is a 3.2-17 with a 1/10 mil Erek. I dialed up to 5.2 mils thinking that would cover it and fired 2 more. Impacts were still 12" low or half of what I thought I dialed. Increased to 6.4 mils and had some fun in the X-ring for the rest of the night.

Questions are, why is JBM so far off, and why did I have to dial double the elevation to move 24"? Am I doing the math wrong?

 

[flyboy]

Re: A Little Confused

Cronny May not have read right. Slight missalingment can cause wild readings in my expierance. That might answer your question about JBM

 

[264Charlie]

Re: A Little Confused

Incorrect Velocity
Incorrect BC -Use G7-
Incorrect sight hight
Broker Scope
Incorrect yardage
Target angle
Incorrect DA

one, two, or three above combined.

 

[Lindy]

Re: A Little Confused

If you dialed up 2.4 mils at 600 yards, that should have been 52 inches.

If that's really what you dialed to move the POI 24 inches, your scope is probably defective.

I assume that you checked your 100 yard zero before starting.