Accubond BC correction

[tirednlost]

Hey all, curious if anyone has verified actual b.c. Vs. manufacturer listed b.c. I was out with a friend the other day who is shooting 200gr accubonds out of his 300 RUM. Instead of adjusting is muzzle velocity to validate his dope he wanted to see how it would work adjusting the b.c. To get the correct dial at 800 yds it was what I felt insanely lower than posted by nosler. Posted is .588 and we end up around .460 if I remember to get the right correction. Anyone else see this? Thoughts?

 

[Dusty Stevens]

Ive seen it but not near that bad. Have you double checked that chronograph?

 

[tirednlost]

Haven’t double checked the chrono. Hopefully get out tomorrow and do some rechecking of data and double check against some of my rifles that I know are correct. Seemed pretty crazy to have that much of a difference.

 

[INTJ]

Also, measured BC can vary based on barrel twist, groove diameter, etc. Even with that, .128 is a lot of difference. I wouldn't be surprised by .2 or .3 though, and it's not always worse either.

 

[Park ranger]

Is the G7 a better model?

 

[tirednlost]

Applied Ballistics shows G1 .524 G7 .268
Different rifles are typically showing G7 variations of less than .010 with various bullets.

thanks for the info. Hopefully can get out soon and do some re checking. I might take a peek at his app and make sure he has all his info in correctly. Just didn’t seem right to have to make that big of an adjustment

 

[FeMan]

You absolutley need to know the excact MV and atmospheric conditoins or you aren't getting usefule data. As stated above, twist rate (stability) can have an effect. The farther you do the test the better. Most hunting bullets I have shot trued at 5% to 10% under advertised ay 1K. I haven't seen anything that low though. Its probably a combination of things. Check his density altiuide input into his program. That and MV will have a significant affect on the accuracy of your results.

 

[tirednlost]

I sure will FeMan! Thanks everyone for the responses. Tons of help. Just joined this forum a couple weeks ago. It’s been pretty awesome so far. You can actually ask a question, have a conversation, get some help and don’t have to deal with all the smart a$$ comments.