Ballistics for Excel Forum

BfX => General discussion => Topic started by: admin on January 15, 2011, 10:40:43 PM

Title: The strategy of a Match ....
Post by: admin on January 15, 2011, 10:40:43 PM
I found on the website of the South Australian F-Class the following (part of) an interview with Brian Litz http://www.safclass.com.au/celebrity3.html (http://www.safclass.com.au/celebrity3.html) The reasoning might be explored with the WhatDoIShootToday spreadsheet I released lately...

You're eluding to the development of higher BC .30 caliber bullets which are currently under development (no timeline yet on release dates).  The new .30 caliber bullets will have much higher BC's than any existing line of bullets.  Since they're basically scaled up copies of the new 7mm Hybrid, the BC's on the new .30 cal Hybrids will be higher than the 7mm's.  Will they be favored over the 7mm's?  That's a question I think will be governed by each individuals thoughts/feelings about recoil.  Consider the 6.5mm vs 7mm debate.  The consensus seems to be that the 6.5mm is inherently more precise than the 7mm's, probably due to the effects of recoil on the platform and shooter.  However the 7mm is a better ballistic performer, so there's a trade-off.  The introduction of high BC .30 caliber bullets is simply an extension of that same trade off.  Rifles built to shoot the new .30 caliber heavies (~230 grain range) will probably be capable of less inherent precision than the 6.5mm's and 7mm's, but will be even better ballistic performers than the 7mm's.
For those seeking advice regarding the trade-off between precision and ballistics, I'll offer the following.  Consider the scores and standings during a long tournament or season aggregate.  On the relays/days/matches where the conditions are good (this is where the smaller, more precise calibers do well) the point spread in the standings is very small.  In other words, the top twenty places are only separated by a couple points.  For example, the 200's, 199's, and 198's might be fired with the 6mm's and 6.5mm's because they tend to be more precise, and the 197's, 196's, and 195's are shot by the 7mm's and .30 cals.  Now if the event is long enough, there is going to be at least one, likely several relays/days/matches where the conditions are horrible.  On those inevitable days, the point spread is greater, and the larger calibers have the advantage.  Now the larger calibers (better ballistics) are shooting 195's, 193's, and 191's, while the smaller calibers are getting all blown around in the wind and shooting in the 180's.  Here's the important conclusion to draw from the above analysis: It's better to optimize your equipment for the situations when the point spreads are large.  Imagine you're shooting a 7mm in a 3-day tournament.  It's calm the first two days and you're a couple points and a bunch of X's behind the smaller calibers.  Now the last day comes, and with it, the inevitable wind.  You can make up more on a windy day with superior ballistics than you're likely to lose in two days to slightly compromised precision.
Of course things don't always play out as described above.  There are exceptionally precise large caliber rifles, and exceptionally talented wind readers shooting small caliber rifles.  However as an analysis of general trends, I've participated in the scenario above many times.