Technical Newsletter From Your Ballistic TechniciansVolume 3, Issue 3
|Take Your Best Shot
by Rich Machholz
"What bullet should I use for...?" This is the standard beginning of many of the questions we field in the Technical department here at Sierra. This time of year it usually pertains to big game applications. Obviously there isn't one answer for all questions. Generally, however, if you're going to error, error on the big side. For instance, let's say you're shooting a 7mm Rem. Mag. for deer. Usually your shots are inside 100 yards but there are opportunities that may exist at 250 to 350 yards across a clear cut field or utility right of way. Popular writings suggest that a 140 grain SBT at high velocity to reduce drop would be appropriate. Not so - the high incidence of a close shot and the effects of wind on the long shots preclude the light bullet and favor the heavier 160 grain SBT. Close shots can require less than ideal placement and angles. This coupled with high impact velocities of the light bullet can produce premature expansion, lack of penetration, and lots of ruined meat.
At long range, wind is an unseen adversary that affects light bullets to a greater extent than heavier bullets, making shots difficult at best. By using a heavier bullet you get the best of both worlds. Great penetration and adequate expansion, coupled with enhanced wind resistance give the hunter an even better chance for success at all ranges. All this with very little real difference in trajectory under field conditions.
|Surfing Sierra III:
Zero Range and Increment Range
By Rich Machholz
If you own Sierra III, our Exterior Ballistic Computer Program, we want to share a little insight to working with the zero range and increment range. When exploring Zero Calculations, don't overlook (D) program defaults. (I) Increment Range must match up with (Z) Zero Range. Example: a 175 yard zero (Z) will not work with increments (I) of 50 or 100 yards but will perform perfectly with 25 yard (I) Increments. (Zero range must be evenly divisible by Increment range) The tip here is to use the longest increment practical when printing to conserve paper.
Bill Shehane (left) and his gunsmith Dave Tooley with Bill's 40X Remington 6-284 used to set both group and score records for 1000 yard Benchrest in the light gun class at Hawks Ridge Gun Club, Ferguson, NC. Bill's group was 3.1" and his score was a perfect 50. Bill used Sierra's #1570, 6mm 107 grain HPBT MatchKings in his 8" twist Hart barrel.