We've been making our rifles, specifically the Overwatch™ model, in the 300 Norma Magnum for a little over two years now. Believe me when I tell you that this caliber is an absolute blast to shoot! For those of you not in the know, the 300 Norma is actually based on the 338 Norma Magnum case, which is based on the 416 Rigby case, which is what the 338 Lapua Magnum is based on. At the end of the day, the 300 Norma is a shorter, necked down 338 Lapua case. The beauty of the cartridge is that it's not nearly as punishing on the shooter as the Lapua and that it uses a wide variety of 30cal projectiles.
Our most common variant has a 26", 1:10" twist, Proof Research carbon fiber wrapped barrel seated in an ESS chassis from Modular Driven Technologies ("MDT"). And, typically, we put a Hellfire™ brake from Area419 on the end. This combination, unloaded, typically weighs in around 10.5 pounds. To some, that might seem a little light in terms of recoil absorption. For any other magnum caliber, it might be. However, this combination feels like a light hitting 300 Winchester Magnum. It can easily shoot 100 rounds in a day without the shooter needing to ice his/her shoulder down overnight. In fact, during Range Day at the 2018 SHOT Show, we had a 60 year old lady shoot it. She had the biggest smile on her face and never complained about the recoil.
More recently, during our #12HundoInHondo match, we had two pro-shooters, Josh Reeves and Nico Detour, shoot the rifle at the ELR range which went from 1 mile out to 2 miles.
We started at 1 mile. With a 225gr Hornday ELD-M projectile, sitting in Peterson brass, filled with 88.0gr of Hodgdon Retumbo, we averaged 2970fps with an SD of 4 and KE equalling 1730 ft-lbs at our 1000 yard zero. On that particular day, we dialed up 53.25moa and held left 17moa for the wind. Easy day. Then, once we were comfortable with that dope's consistency, we started pushing out to farther targets.
At the end of our ammo supply, we were working on the 1.6 mile target. Here's what we took away from that - and it was an important lesson learned for the upcoming 2-mile competitions. First, while the 3-port Hellfire™ brake did it's job with no complaints, we believe that the 4-port Sidewinder™ brake would offer just enough to tame the minute (pronounced "my-knute") muzzle flip that needed to go away for such a long shot. The chassis did it's job in keeping the rifle very secure and locked into place - no complaint there, no changes needed. The big take-away was that 26" of barrel is not enough to keep the projectile up to speed and prevent tumbling at 1.6 miles or more. After running the numbers, we're replacing it with a 30" barrel which should garner another 120fps, on average; plus, give a little more stability to the 0.777 G1 BC projectile. Going that long in barrel length will mean that we'll either have to special order another barrel from Proof Research, or we'll have to swap over to one of our cryo-treated 416 stainless steel barrels. Either way, we feel like this combination will further continue to be the death of the 338 Lapua Magnum's many people use for such activities. Though the trajectory curve of the 300 Norma is almost parallel with that of the 375 CheyTac to the same distances, it doesn't quite meet the performance level of the CheyTac. But it's a whole lot cheaper to shoot than the CheyTac and not nearly as painful at the end of the day. Next up is a performance comparison of the 300 Norma to the 300 PRC.
Summary of thoughts:
> this particular set-up in 300 Norma is the caliber of choice for anyone who needs a magnum caliber to reach targets from 1000 - 2800 yards. Be that for competition, hunting, or military operations.
> For no added cost, the 4-port Sidewinder™ brake from Area419 needs to be used in order to maintain the best sight picture upon firing.
> If you don't plan to exceed 2800 yards, the 26" barrel is plenty of length to achieve your goals.
> As far as magnum calibers go, throat erosion on such a heavy caliber is comparable to the life expectancy of a 30-06 or 300 Win Mag - meaning the barrel will most likely outlive most recreational shooters.
> Retumbo, from Hodgdon powder, appears to be the best choice for this particular set-up. We didn't nearly come close to the max load; whereas, we were more interested in finding the most accurate load. SPEED KILLS!
> The Calvin Elite Custom trigger from Timney provided the short-stroke, predictable crisp break needed to perform at these distances. They're the only triggers we use because of their performance standard.
> At roughly 10.5 pounds, and an overall length of about 52", this rifle is easily humped around all day if needed.