See 338 ARC velocity, energy, and bullet drop by grain weight and barrel length at real hunting distances. This guide breaks the topic down in plain language so you can make a confident decision for your build.
The 338 ARC pushes a .338-caliber bullet out of a standard AR-15 platform at over 2,500 fps from a 16-inch barrel. Here is what that actually means for velocity, retained energy, and drop at the distances you shoot.
What Makes 338 ARC Ballistics Different
The 338 ARC is built on the 6mm ARC case, necked up to accept a .338-inch projectile while keeping the rebated rim and overall length inside AR-15 magazine well limits. The bolt face and magazine well match what the 6.5 Grendel family already uses.
Sectional density is the reason the numbers behave the way they do. A .338-caliber bullet at 185 grains carries far higher sectional density than a 77-grain .224 or a 123-grain .264 projectile at comparable velocity, so it sheds speed and energy more slowly. A 77-grain 5.56 load loses terminal energy quickly past 400 yards. A 185-grain .338 load is still carrying useful energy well past 600.
Muzzle Velocity by Grain Weight
The 338 ARC was engineered specifically to perform from a 16-inch barrel. Most .338 cartridges need a 24-inch tube to hit their published numbers. This one gets there in a compact upper.
The 185-grain ELD Match is the speed leader. Step up to a 250-grain hunting projectile and you drop to around 2,100 fps. That 450 fps spread changes your drop chart significantly, so build your dope around the load you actually hunt with. The 250-grain entry is a handload scenario; verify against current published data before loading.
How Barrel Length Affects Velocity
Each inch of barrel is worth roughly 20 to 30 fps in either direction. A 16-inch barrel is the design baseline, an 18-inch adds about 50 to 75 fps, and a 20-inch squeezes out a bit more for dedicated distance work at the cost of handling.
Elevation and temperature also matter, though less than most shooters assume at typical hunting altitudes. Where it does show up is heat: a hot summer bench session can produce noticeably higher velocities than the same handload chronographed in cold weather.
Energy Retention at Distance
Velocity gets the bullet there. Energy is what does the work.
Most hunting authorities set 1,000 ft-lbs as the minimum threshold for ethical shots on deer-sized game. The 338 ARC clears that mark well past 500 yards with either load, which is the entire argument for the cartridge.
Energy on target, not muzzle velocity, is what decides whether a shot at distance is ethical.
Bullet Drop and Choosing a Zero
A 100-yard zero keeps things simple in tight cover, where most shots come inside 150 yards. Past 300 yards, holdover climbs fast and you need your numbers memorized or dialed.
A 200-yard zero is the better default for open country. With the 185-grain ELD Match you run roughly plus 1.4 inches at 100 yards and return to zero at 200, giving you a flat window from the muzzle to about 250 yards where you can hold center.
These inputs are replicable in JBM or Hornady 4DOF, so adjust for your actual barrel, elevation, and conditions rather than copying the table wholesale.
Build Notes That Affect Your Numbers
An adjustable gas block is worth the investment. The correct gas setting varies between 215-grain match loads and 250-grain hunting rounds, and a tunable block lets you cover both without swapping components. Check the set screw torque after your first couple hundred rounds, because vibration will move it.
The 338 ARC can also run subsonic loads in the 270 to 300 grain range at roughly 1,050 fps, which is a viable suppressed option inside 100 yards. Energy drops sharply below supersonic thresholds, so treat that as a separate configuration rather than a long-range one.
For more, read the long-range shooting guide or the hunting breakdown. When you are ready to build, browse complete AR uppers or contact the shop at ar15parts.com.
