Sunday GunDay, July 30th 2023: Cartridges For F-Class Part II – Rise Of The MagnumsCartridges For F-Class Part II – Rise Of The MagnumsBy Emil Kovan READ Part I in this Series >>A few seasons back, I wrote an article on cartridge choices for F-Class shooters. CLICK HERE to read the article. Since I wrote my first article, F-Class continues to grow and push the limits for precision and accuracy. While the.284 Win cartridge and its variants remain the most popular F-Open cartridges for competitions, top F-Open shooters have been using magnum cartridges to win competitions. I will discuss the strengths and weaknesses for each of the most common magnum cartridges in this article. We will consider the following performance factors for magnum F-Open cartridges: 1.
2. Better ballistic performance
3. Case life is extended
4. Barrel lifeAccuracy potential of Magnum Cartridges in F-0pen CompetitionJohn M. Meyrs won four National Mid-Range Championships with the.300 WSM. Tim Vought won two Mid-Range Nationals with the same cartridge and a 7-6.5 PRC won the Long Range Nationals. Standard.437 or.437 Win? Standard.437? A.300 WSM, for example, is proportionally closer to the 6 Dasher, 6 PPC and 6 BRA than the.284 Winchester.
When magnums are mentioned, the first thing that comes into mind is power and speed. I believe that most shooters miss out on accuracy by pushing their magnums past the most accurate and stable nodes. I recently met my good friend, SFC Brandon Green from the Army Marksmanship Unit at a shooting contest. We talked about the latest and greatest developments in long-range firing. I knew the USAMU switched from 6.5-284 Norma cartridges to 7mm RSAUM a few years ago, but did not know what load was currently being used. Brandon told me the load was Berger 180gr hybrids with Nosler cases, at 2820 fps. SFC Green stated that we all know the 7 SAUM can reach much higher speeds. “But at around 2820 fps, the load/rifle combination will hammer any X-Ring in any condition” he said.
F-Open rifles at the Ben Avery Shooting Facility, Phoenix, Arizona.Most test shooters go straight to magnum speeds, ignoring the precision of standard chamber speeds. My 30 KMR can reach 2880 fps easily with 230gr hybrids and it shoots quite well. The same rifle, at around 2770 fps, will absolutely hammer any X-Ring anywhere in any conditions. F-Class is an extreme precision and accuracy long-range shooting event at a known range. It is not a race.IMPORTANT – Case-Head dimensions do make a difference
When both cartridges are loaded to around 2900 fps, a 7 SAUM case will outlast a.284 Win case. Magnum F-Open CartridgesThe biggest disadvantage of magnums may be the recoil. After shooting magnums for a while, some people complain of developing “gun shyness”. Magnums have a much more intense muzzle blast and recoil, but this can be easily controlled with a well-built rifle equipped to mitigate recoil with hardware like RAD or butt plates.
Barrel Life — “Barrels Are Expendable Components”.
It is true that some magnums can char a barrel within a few hundred shots. The barrel life of a 6BR can be significantly reduced when upgraded to a 6 Dasher, for example. After a certain number of rounds, more powder = increased heat = decreased accuracy. According to my experience, the barrel life of a F-Open is similar to that of high-performance standard cartridges like the.284 shehane or.284 kMR. I “retire”, my barrels after 1200 rounds, regardless of whether the cartridge is a magnum. After a certain number of rounds, barrels will still fire fine but copper up and you’ll start seeing those vertical 9s. Bottom line, barrels can be replaced just like brass. You can’t have the performance of the.300 Winchester Short Magnum and the barrel life the.308 win at the same time. Fuel mileage is not the most important factor when racing in NASCAR. Top Magnum Cartridges Used in F Class Open Division.300 Winchester Short Magnum
The.300 WSM is the most popular cartridge in the F-Class Open division. It has been used in numerous National Championships and has set National records. The short/fat case, minimal body taper, and 35-degree shoulder of the.300 WSM contribute greatly to its outstanding long range performance. Components are also readily available. The best brass is still Norma. ADG is also good, and some might even say better. However, it is more expensive at the moment and harder to obtain.
Berger makes the best bullets for the.30 caliber magnums in my opinion. If your rifle is not shooting 215gr, hybrids 230gr or 210gr VELDs well, it’s likely a rifle issue, NOT a problem with the bullet. The Berger 230gr Hybrid is my “go to” bullet. Hodgdon’s H4831SC or H4350 are the best powders for.300 WSM. There are many other powders that can be used for the.300 WSM, but none of them have been as consistent in my experience.
The 7mm RSAUM, also known as the 7 SAUM, used to be a favorite of F-Open. Its case size and shape are ideal for launching 180gr capsules with great precision and ballistics. Its popularity has waned a bit due to the lack good brass and the rise of improved versions of.284 win which can almost equal the RSAUM performance. Norma still produces 7 RSAUM Brass which is good but a little on the softside and difficult to find. ADG produces the best RSAUM right now. It is uniform, affordable, and holds up well, even when pushed to the limit. Berger makes the best bullets, which are the 180gr, 184gr, and 180grVLD. The best powders include H4831sc and H4350 as well as Alliant Reloder 16, Reloder 22, and Reloder 23.0-270 WSM and 7-300 WSM.
I personally prefer the first one since necking-up is easier than necking-down (with fewer doughnut issues). I prefer the first one because necking up is easier than necking down (with fewer issues with doughnuts). The WSM case-based sevenmms will give great velocity flexibility and superb precision when tuned properly. I was the scorer for a Canadian shooter of 7-270 WSM at the 2013 world championships in Raton NM. The wind was blowing hard that day. Just before he fired, the wind blew. I remember thinking it was going to be a line 8 for sure. The target was a line 10. After the match, I asked him what he shot and he said 180s at 3100fps. I believe that although such speeds are possible, it is possible to achieve more accurate results at slower speeds. Hodgdon powders and Berger bullets are the best. The best cases are made by Norma, ADG and Winchester.
The 7-6.5 PRC is our last but not least cartridge. This cartridge is a wildcat. It is a 6.5 PRC necked to 7mm. It is almost identical to the 7 RSAUM, with the only difference being a shorter body and.01-inch narrower neck. The 7-6.5 PRC cartridge is currently the most requested when I build new rifles. It seems to bridge the gap between.284 Win, and the larger magnums. It can reach 3000fps, but most shooters get their best results between 2920-2950fps. Brass is the biggest advantage to this wildcat. Lapua produces 6.5 PRC brass in high quality and is readily available. The best powders to use are H4831sc (H4350), Reloder 16, Vihtavuori 555, and H4831sc. The 180gr Berger is my favorite bullet. I have yet to hear of a bullet that performs better in this chamber.
Conclusion: magnums may not be perfect, but their performance advantages are worth considering when building a rifle to shoot at long ranges in the F-Class. In part three, I’ll list the most common wildcats and show you the KMR magnums that will convince you to buy a.338 magnum and build a magnum rifle for sure. Emil Kovan
Kovan Match Rifles LLC
www.matchrifles.com Emil Kovan Competition History: – 2014 F-Class Open National Champion
– 2015 F-Class Open National Championship Silver Medal
– F Class Open National Championship Teams 2015, 2014, 2013 Shooting Team Member
– More than 15 victories in Regional and State Championships at Palma, FTR, FOpen
– 2013 U.S. National Team member
– 2017 U.S. National Development Team member
Tags: 300 WSM, 6.5 PRC, 7 SAUM, 7 WSM, 7mm Magnum, Emil Kovan, F-Class, F-Open, Sunday Gunday, Winchester Short Magnum
