PCC Not PC

Varmint/Target – Part 2: Tack Driver Fun (with Colonel Smoothbore)
By angelamontana


In a recent post I described the varmint/target rifle that I assembled over the winter. The rifle started as a Savage® Model 12 FCV chambered in .204 Ruger. I replaced the stock with a Boyd’s laminate thumbhole design and mounted a Weaver® Super Slam 4-20×50 Side Focus scope in Burris® rings. The following is how I worked up some loads for this gun which you will find is a real “tack driver.”

tack4I finished the barrel break-in procedures recommended by Savage® and zeroed the scope to the point where only fine adjustments might be needed in the future. I have been experimenting with three different loads; a 32 grain Hornady VMax bullet, a 32 grain Hornady ZMax bullet, and a 40 grain Hornady VMax bullet. Both 32 grain bullets use the same loading data and have the sametack7 ballistic coefficient.

tack5I started with new unfired Hornady brass which I full-length resized. I did not trim the cases as they were in the proper length range for .204. I will trim them to equal length after the first firing. The cases were primed with Federal® Match (GM205M) small rifle primers and Hodgdon® CFE223 powder was used in all loads. I consulted the Hornady®, Hodgdon®, and Nosler® manuals for starting and maximum loads. The starting loads in all three manuals are similar; however, the maximum loads differ greatly between the three. I found that being slightly below the maximums gave the best results. All shots were fired from 100 yards.

tack8

tack11First, let’s look at the two 32 grain loads. The VMax and ZMax bullets are very similar in performance. Both have a .210 B.C., bothtack10 have polymer tips (VMax-Red, ZMax-Lime). Hornady® does not describe the difference in construction on their website, but I believe the ZMax is a plated bullet, while the VMax has a swaged lead core. Both bullets have flat bases; ZMax bullets are less expensive. I found no performance differences between the two and neither showed any pressure problems with the same powder charges as I worked up from the minimums.

tack9The 40 grain VMax bullet has a .275 B.C. and is a boat tail design. Powder charges are smaller than the 32 grain offerings and velocities are a bit lower, yet still impressive. To measure velocities I used my Caldwell® ballistic chronograph placed 12 feet from the muzzle. All shooting was done off very stable sandbags. The only weak link in the set-up was my aged eyes. Here are the results.

tack2Starting with the 32 grain ZMax. I fired a four shot group from a clean barrel and the results were a .920 group measured center to center (c-c) group. I then fired 5 four shot groups, the best of which was .401 inch group c-c. I kept all 20 shots in the same data group on my chronograph. Two of the shots showed velocities over 4200 fps, one at 3990 fps, and some just over 4000 fps. After editing out those extremes I was left with 14 shots giving the following results; Average velocity-4079.29 fps, Standard Deviation-36.25, Min. 4043 fps and Max. 4162 fps, Spread-119, and True velocity-4105.81 fps.

tack3I then set up to fire the 40 grain VMax load. I fired 11 shots; the first two to test the chono, and then 3 three shot groups. I used all 11 shots to determine velocity averages. Earlier groups showed me that this gun really likes the 40 grain bullet. The final group was the smallest I have ever fired with any gun at any time. It measured .194 inches c-c. It’s better to be lucky than good and in my case I think I’ll frame that target, my only regret is that I didn’t use a new target, dumb cheapskate. Both of the other groups measured under half an inch. The velocity figures for this load were quite consistent: Average-3755.45 fps, SD-21.75, Min. 3726 fps and Max. 3794 fps, Spread-68, and True Velocity-3774.09.tack1

tack6I’ll run both sets of numbers through a ballistic calculator to get MOA suggestions for various ranges. Then more testing and more fun. CFE223 is a bit sooty when fired, but the extra cleaning time is worth the results I got with my “tack driver” rifle. I may experiment with bullet seating (bullets were seated at the recommended 2.25” COL), but I doubt I can shoot any better results than what I already have. This project has resulted in a fun, extremely accurate rifle that is inexpensive to shoot and will be hell on coyotes.

Be safe and good shooting.

Colonel Smoothbore

www.guncoach.net






test