Nosler'™s RDF bullet - A new option for long range competition shooters
September 11, 2017
Nosler has entered the long-range match-bullet fray. Named the RDF for Reduced Drag Factor, the company's new bullet features refinements engineered to combat air friction. Yes, Nosler already makes match bullets, but building an accurate match bullet and building an accurate long-range match bullet are two entirely different things because aerodynamic-enhancing features are often at odds with accuracy-enhancing features.
Long, sleek boattails exacerbate muzzle crown inconsistencies. Secant ogives provide low drag but are picky about seating depth. Long bullets with high ballistic coefficients are harder to stabilize. In short, building an accurate, forgiving long-range bullet is challenging, but the burgeoning popularity of Precision Rifle Series and sniper-style competitions is pushing bullet companies to get into the game.
Driven by the slogan "The Point is The Point," the RDF claims to have the highest BC of any hollowpoint match bullet currently available, courtesy of a tightly closed point and tiny meplat. A long, aggressive boattail and a hybrid ogive contribute to the RDF's high advertised BC.
To promote optimum accuracy, the RDF employs a marriage of both tangent and secant ogives at the point where the bullet takes the rifling. The short, secant-like portion takes the rifling leade willingly and provides seating-depth forgiveness, and the long tangent portion of the ogive provides the needed aerodynamics.
Nosler's initial offerings will include .224, 6mm, 6.5mm and .308. Time was too short to test fire all four, so I chose the 6mm and 6.5mm. What with Hornady's legitimization of the popular, competitive 6mm Creedmoor wildcat — a favorite among obsessive PRS shooters — bullet companies are vying to produce the best heavy, sleek 6mm bullet available. Nosler's 105-grain 6mm RDF projectile offers a higher BC (.571) than Berger's 105-grain Target Hybrid (.536 BC) — a bullet it's almost certainly designed to compete with.
I don't have a 6mm rifle capable of getting the best out of the 105-grain RDF, so I asked good friend and competitive shooting partner Paul Dallin to test it in his custom 6mm Creedmoor. With no load development at all, the bullets averaged 0.56 inch for three three-shot groups. Average velocity was 3,047 fps, with a standard deviation of 12. Paul thought that with a little work, the RDF would shoot right with the Bergers he uses in the rifle, a load that shoots 0.3-inch groups.
As for the 140-grain, 6.5mm version, its .658 advertised G1 BC is one of the best around. As far as I'm aware, only Hornady's tipped 147-grain ELD Match bullet has a higher BC (.697 G1) among 6.5mm bullets, and it can't be driven quite as fast.
To test the 140-grain 6.5mm RDF, I loaded two test batches of 6.5 Creedmoor handloads for my Ruger Precision Rifle — a half-m.o.a. gun with ammo it likes. One test batch featured Reloder 17 powder, the other H4350, both in neck-turned Hornady cases.
Because the Ruger rifle uses either AR-10 Magpul or Accuracy International-type magazines, I typically limit cartridge overall length to 2.825 inches so my ammo will function either magazine. However, the Nosler RDF touched the rifling at 2.910 inches. Clearly, unless I was willing to single load, the RDF bullets would have quite a jump — 0.085 inch — to the rifling.
Since the rifle is a workingman's practical precision tool, and single-loading it doesn't make much sense, I decided to seat the bullets in the RL-17 load to a 2.820-inch OAL and the H4350 load to a 2.885-inch OAL.
The RL-17 handload provided much the best velocity (2,753 fps average over nine shots in subzero temps) and averaged an acceptable 0.83 inch over three three-shot groups. The standard deviation was only 10 fps.
The H4350 load halved the group size, turning in an honest 0.38-inch average group. At 2,653 fps, muzzle velocity was 100 fps slower than the RL-17 load, but standard deviation was tight at eight fps. It's worth noting that this was the load with the bullets seated long, to 2.885 O.A.L.
As for the new .224 RDF, Nosler's Zach Waterman suggests shooters use the Nosler manual's data and OAL spec for the company's 69-grain HPBT Custom Competition bullet. In other words, it's a .416-BC bullet that can be pushed as fast as common 69-grainers and is compatible in AR-15 magazines.
Presuming it actually does have the ballistic coefficient Nosler claims, the zippy little 70-grainer will edge out every other high-BC magazine-compatible bullet currently available. Every other mag-compatible projectile with a BC over 0.400 is much heavier. Pair the Nosler RDF's .416 BC with an additional 100 fps in velocity and you've got a winner.
While the .308 version of the RDF is good, it doesn't stand out from the crowd like the other three do. Its decent BC of .536 (G1) just doesn't raise eyebrows. That aerodynamic spec is equaled or exceeded by a crowd of similar-weight .308 bullets.
However, it's superb in one critical way. I weighed 20 bullets of each RDF version and noted the extreme spread and standard deviation of the 20 weight measurements. I also measured the base to ogive length and ran the same calculations. As diameter increased, discrepancies decreased. The 105-grain 6mm version was consistent enough to suggest good performance, but the 140-grain 6.5mm version was better. The 20 different .308 RDF bullets varied only 0.1 grain, and as for length, there wasn't even 0.001 inch of measureable difference in the base-to-ogive length across all 20.
I think Nosler's new RDF bullet is going to be a serious player on the long-range scene, and I'm anxiously awaiting the potential addition of a 7mm to the lineup.