Short barrel 16.5 inch 308 Winchester load development

In my opinion, there aren’t many guns cooler than a short bolt action rifle.  I think my fascination started back in the 90s, before the proliferation of precision rifles, with an advertisement in the Shotgun News showing a Steyr SSG69 PIV with its 16.1″ barrel.  I wanted one bad.  Fast forward a couple decades and I’ve almost fallen off the wagon in my pursuit of short precision rifles.  I’ve built 16″ 308s, a 6.5 Creedmoor, and a 300 Win Mag!  I’ve even cut a 308 Winchester down to 6″ (pistol)!

I’ve written a few posts about 16″ 308 Winchester bolt action rifles including; Short and Loud: the 16 inch 308 precision rifle,  Super Short Precision Rifles: Is there such thing as a 16.5″ .308 Tactical Bolt Action Rifle?,  Short Rifle, Long Range: Testing our 16.5″ 308 Remington 700 out to 635 yards and 16.5 Inch 308 Winchester Precision Rifle: Summary of a Short Rifle.  All these posts and I’ve never presented load development for this cartridge and barrel length combination. This is because the majority of testing was with a few select loads.

In this post we’ll explore load development for a 16.5″, 1:10″ twist, 308 Winchester bolt action rifle.

I selected the same bullets I like in my longer barrel rifles, the 168 gr. Sierra MatchKing (SMK), 175 gr. SMK, 175 gr. Tipped MatchKing (TMK), 190 gr. SMK, and 195 gr. TMK.  For powder, I’ve selected my two favorites for 308 Winchester, Varget and IMR 4064.  

Our test rifle is a custom 308 Winchester built with the following parts from Brownells:

WARNING: The loads shown are for informational purposes only.  They are only safe in the rifle shown and may not be safe in yours.  Consult appropriate load manuals prior to developing your own handloads. and its authors, do not assume any responsibility, directly or indirectly for the safety of the readers attempting to follow any instructions or perform any of the tasks shown, or the use or misuse of any information contained herein, on this website.

All loads shown use Norma brass and a Wolf large rifle primer.  All rounds were fired prone, from a bipod with a rear bag.  Target distance was 100 yards.

I chose to increase the powder charges in .5 grain intervals.  While this is fairly coarse (I’ll typically tuned loads in .3 grain intervals, and if I find a couple loads that are promising, split those charges again), it does allow coverage of a broader spectrum of powder charges with a given number of loads.

Velocity data was recorded with a MagnetoSpeed barrel mounted ballistic chronograph.

Since a short 308 is anything but a match rifle, I decided to maintain an overall length for all load rounds below 2.880″ to allow for feeding in an AICS style magazine.  Overall length for each load is shown on the table below.

Results are shown below:

For all bullets tested, at least one load was able to achieve precision of sub 3/4 MOA with at least one powder and bullet combination.  The 168 gr SMK was able to achieve sub 1/2 MOA, while the 175 SMK went sub 1/4 MOA.  Pretty impressive results for such a stubby little rifle.

The magic load in terms of precision was a 175 gr SMK over 44.5 grains of IMR 4064- a bug hole group that made my day!

To see how these bullets in a 16.5″ 308 Win would work at longer ranges, I modeled one load for each bullet with the maximum velocity I recorded in the table above.  For each load, drop and drift are shown in MRAD for 200 yard increments from 200-1,000 yards.  This table assumes a 1.75″ optic over bore height, the shooter is at sea level and temperature is 59F.  The lowest value(s) for each given range is highlighted in bold.  The red font indicates the round went transonic prior to reaching the given distance.

For comparison purposes, I included the load I use in my 22″ 308 Winchester, as well as the published velocities for Federal Gold Medal 168 and 175 gr SMK loads.

The results of these runs are shown in the table below:

As you can see in the table above, bullet choice matters.  By tailoring a load to a specific rifle, you can maximize velocities and downrange performance.  In the case of the 168 SMK, the hand load shown is only 24 feet/second slower than the factory 168 Gold Medal publish velocity.  For the 175 SMK, the hand load was actually 24 feet/second faster!

While I shot my best group at 100 yards with the 175 gr SMK, the big winners here seem to be the 175 TMK, 190 SMK and 195 TMK.  Velocity isn’t everything, when switching to heavier (190 SMK, 195 TMK) or longer (175 TMK) bullets performance will actually match or beat shooters using lighter bullets loaded in factory ammunition in longer barrels.  The 195 TMK has the wind drift advantage at every distance shown, impressive.  At 1,000 yards the 190 SMK gives up 0.4 MRAD of drift to 195 TMK with similar drop.  At 1,000 yards the 175 TMK gives up 0.3 MRAD drift to the 195 TMK but has  0.5 MRAD less drop.  Not too shabby!

Is a 16.5″ 308 Winchester a purpose built match rifle?  Absolutely not.  But it is a compact rifle capable of putting rounds on target at loner ranges provided the shooter does his part.

For information on how barrel length effects velocity in the 308 Winchester, please see 308 Winchester / 7.62x51mm NATO: Barrel Length versus Velocity (28″ to 16.5″) and 308 Winchester/ 7.62x51mm NATO Short barrel length and velocity- A six inch 308 bolt gun?

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