If you’ve been following Super Short Precision Rifles: Is there such thing as a 16.5″ .308 Tactical Bolt Action Rifle? and Short Rifle, Long Range: Testing our 16.5″ 308 Remington 700 out to 635 yards, you’re well aware of the custom 16.5″ 308 Winchester I built on an M700 action with parts from Brownells. If not, take a look at both posts, the rifle is a pretty neat little package.
Optics have been upgraded to a Leupold Mark 6 3-18X44mm scope in a Spuhr mount. With a front focal plane reticle, compact size and zero stop, the Mark 6 is a solid improvement over the tried and true Mark 4.
I’ve been running a 175 Sierra MatchKing (SMK) over a Tula Large Rifle Primer, Norma brass and Reloader 15. Unfortunately, last time I was at the range, I shot my MagnetoSpeed chronograph (mounting the MagnetoSpeed on such a short rifle is difficult, because the chronograph has to be mounted directly to the brake since the barrel isn’t exposed). Today I was able to get some data on the load (and not shoot my chronograph). Average velocity was 2387 FPS with a SD of 11.2. Not too shabby considering I got lucky with the load for this rifle (first one I tried worked well).
I use the same load in my 22″ 308 and 16.5″ 308 except for the brass. I use Norma brass in 16.5″ and Lapua brass in the 22″ to avoid confusion. Shockingly, the load is 283 feet-per-second (FPS) slower in the shorter barrel, an average loss of 51 FPS per inch of barrel length. This was especially interesting since the factory Federal Gold Medal 168 grain load lost about 17 FPS per inch of barrel length.
The table below compares the drop in mils of the 16.5″ and 22″ 308 with 175 SMKs out to 1,000 yards.
|16.5” 308 175 SMK 2387 FPS (mils)||0||0.7||1.8||2.9||4.3||5.9||7.6||9.7||12.0||14.7|
|22” 308 175 SMK 2670 FPS (mils)||0||0.5||1.5||2.3||3.3||4.5||5.8||7.4||9.2||11.2|
The 16.5″ rifle goes subsonic around 900 yards, but has significantly more drop than the longer barrel gun at intermediate to long range. While I don’t think a 16.5″ 308 Winchester is the best package for long range shooting, it can certainly hold its own at shorter distances. Fast handling and quick to deploy, I would envision this rifle as ideal for most law enforcement (police sniper) applications as well as shorter range (sub 700 yard) unknown distance shooting. For general purpose use, I would suggest a 18-22″ 308 Winchester (interesting, 20″ splits the difference…).