Testing the 166 A-Tip in the 7mm SAW

Measurements and test rifle data

Bullet OAL: 1.503”
Base to Ogive, measured on Forster Datum Dial tool: 0.778”
Ogive to nose: .725”

Test Rifle
Bighorn Arms TL-3 SA #1717, Kahles K525i SKMR3, 28″ Broughton 8.5″ twist 5C rifled barrel. This barrel was chambered with our 7mm SAW II reamer, and at time of testing has had approximately 350 rounds fired since new.

Max seating depth measurements

Cartridge OAL: 2.988”

Cartridge BTO: 2.263″

Given that the maximum OAL/BTO falls slightly outside of magazine length(2.965″ max in our MDT non-binder plate mags), we opted to begin our loading .030″ off the lands. We chose to use H4350 powder for our initial work up, as it has proven very accurate with all bullets tested in this cartridge from 160 up to 185 grains. A go-to match load for the 160gr Sierra Tipped MatchKing has been 46.6gr H4350 across multiple 7mm SAW barrels, so we began slightly below that in hopes of finding a similarly good node without much trouble. We started at 45.6gr, and decided to also test down to 45.3 as well once we saw that our starting load was already producing velocity above 2800 FPS.

100 yard beginning OCW test groups, 45.3-46.2gr H4350

Our original intent was to do a standard 100 yard OCW test, with 5 shot total groups fired in a round robin sequence. However, after getting through three rounds per charge weight and seeing all four charges test produce sub .5MOA groups, we decided to move out to 500 yards and begin looking for vertical dispersion.

Here is the velocity data for each charge weight tested:

All loads on 3x fired WTO/Alpha Munitions 7mm SAW brass
2.233”BTO, CCI450 Primer
45.3: 2836/4.3SD, .210” group. 2823/7.8 when shot on brand new brass
45.6: 2842/10.4SD, 442” group
45.9: 2865/6.9, .510” group. Possible flyer induced by heavy mirage. Shot 2852/8.6SD on brand new brass.
46.2: 2879/5.9SD, .411” group, established max for this barrel. Bolt lift easy, primer looks fine, but click at top of bolt lift stroke. Slight ejector cutout mark on case head.

Since the 46.2gr charge was borderlining max pressure in our test rifle, we fired round robin sequence groups at 500 yards with 45.3, 45.6, and 45.9. Both 45.3 and 45.9 produced less than 2″ of vertical dispersion, with 45.9 producing less than 1″ of vertical. If not for a blown wind call, 45.9 would have produced a fantastic group measuring just under 1.5″ total. Wind on test day was moving at 13-18MPH full value, with some very significant mirage also to contend with. We opted to cease testing for the day so as not to build skewed results based on conditions.

The next morning, we shot the 45.3 and 45.9 grain charge weights at 850 yards, with no load producing a clear advantage. Both loads showed very little vertical dispersion, and Hornady’s published BC of .332 matched up well. The farthest distance available on the test range is 1090 yards, and here the 45.9 grain charge showed itself as the true winner.

1090 yard group, just under 4.5″ total

A sub .4 MOA group at almost 1100 yards is a keeper from any rifle and load combination. This was in line with previous accuracy benchmarks set for the cartridge and other bullets, and once again the Doppler tested .332 G7 BC worked out to an accurate firing solution with no additional tweaking.

Final Observations and thoughts

1. In our opinion, the Hornady 166gr A-tip is exactly what it claims to be. It is a highly accurate, premium consistency level projectile for producing utmost uniformity in precision rifle shooting. The bullet’s weight and BC combination are as close to ideal as is currently available for a mid-capacity, do-all cartridge like the 7mm SAW.

2. More testing is needed to confirm this, but in this trial the A-Tip did not appear to be sensitive to seating depth. The Redding micrometer seating stem in our Type S 7mm SAW die set seated the bullet perfectly, and did not effect the tip of the projectile.

3. The bullet produced very similar velocities to the 162gr ELD-M, which would lend itself well to possibly using the ELD-M as a short range practice/club match bullet, and the A-Tip as a more intense competition projectile.

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