Magazine Fed SA 284 Win. A long range Surgeon The goal was to build a long range hunting rifle for whitetail deer, moose, and elk. The criteria were superb 7mm ballistics in a medium weight carry rifle, weighing no more than 10lbs with scope. The rifle needed to have a detachable box magazine (DBM), must feed smoothly and reliably, and be equipped with a light weight medium power scope for shots out to 600 yards. Premium components where to be used such as a Surgeon SA repeater action, Jewel HVR trigger, Krieger barrel, McMillan A3 stock, and Leopold VX-3 6.5-20X40 LR scope. Rifle Specifications – All the Hardware The receiver is a Surgeon SA repeater with integral recoil lug and scope rail. The lug and rail are machined into the body of the action, with the integral rail helping to maintain rigidity in the hollow bottom repeater action. The bottom metal is manufactured by Badger Ordnance and utilizes a 5 shot Accuracy International magazine with a maximum COAL of 2.90. This action and bottom metal set up was chosen for their tight machining tolerances and reputation for reliable feeding. An Arnold Jewel trigger set at 2lbs was utilized with top safety; because this is a hunting rifle a safety was an absolute necessity. The trigger does not have a bolt stop as the Surgeon action is outfitted with one. The barrel is manufactured by Krieger in a 7mm #5 contour with a 1:9” twist that finished at 25 inches. The #5 contour is the smallest Krieger will machine a 7mm stainless steel barrel. A 25” barrel was selected as a compromise between velocity and weight. Dave Kiff at Pacific Tool and Gauge supplied the reamer and Grant Schick smithed the rifle. I turned my Winchester brass necks down to .313 for the .317 neck reamer, giving me 2 thou clearance per side. Dave made my reamer with .090 freebore for mag length COAL. The barrelled action was skim bedded with Devcon to a McMillan A3 stock in 40% olive drab, 30% black, and 30% light tan swirl. The A3 was chosen for the shallow forend which contributes to a lighter stock, I did not want the butt hook found on the A5 and A4 in order to make it an easier stock to carry. Also, a fixed length of pull was selected as oppose to the adjustable version to further save on weight. All metal was finished in matte black Ceracote. A Leopold VX-3 6.5-20X40 with fine duplex reticle sits in Leopold Mark IV 30mm aluminum rings. Odd History The .284 Winchester has a very odd history. It was first developed by Winchester in 1963 to fit their short action Model 100 autoloader and Model 88 lever action rifles. The idea then was to compete with and rival the ballistics of the 280 Remington. In order to do so in a short action rifle the case needed greater powder capacity than was previously available in any short action rifle. The case has an expanded width of .500” at the web while maintaining the .308 Win bolt face diameter of .473”, creating what is refered to as a rebated rim. The near absence of case taper, along with a very steep 35 degree shoulder produces 66 grains of powder capacity. This approaches the 68.6 grain capacity of the 280 Remington, the 67.4 grain capacity of the 270 Winchester, and the 68 grain capacity of the 30-06. The .284 Winchester fell by the way side shorty after its inception along with the model 88 and model 100. That is however, until wildcaters realized its potential and began both necking up, and necking down the short, fat, sharp shouldered case. Recently the 6.5X284 Winchester has gained much popularity with long range benchrest and F-class shooters. So much so that Lapua is now manufacturing high quality 6.5X284 brass. Caliber Selection; many nay-sayers With Charles Ballard’s National 1000-yard F-class victory with a “strait” .284 Winchester, there has been renewed interest in the original .284. See his Purple Haze: Record-Setting .284 Win F-Classer. A .284 single shot on a long action throated for long VLD bullets is an extremely efficient and accurate cartridge, as Ballard and others have demonstrated. People are now actually necking up 6.5X284 Lapua brass for 7mm projectiles; oh the irony. However, there are many perceived negatives towards a .284 built on a short action receiver, as it was initially designed. To begin, even relatively light 140gr bullets, seated to a maximum 2.80 COAL, have bases that project below the base of the case shoulder by approximately 1/8”, reducing available case capacity. A 160gr Nosler Accubond’s base sits a full 1/4” below the base of the case shoulder. When bullets are seated to the maximum COAL of 2.80, the bullets ogive is actually below the case neck, which makes measuring cartridge length from base to ogive impossible. Furthermore, many people believe the sharp 35 degree shouldered case poses feeding problems. This is the steepest shoulder ever produced by an American manufacturer. Secondly, the rebated rim is thought to be difficult to feed from a magazine that is designed for the narrower .308 cartridges. Cartridge Feeding I am only able to get 4 .284 Win cases into the 5 shot .308 Win Accuracy International magazine. Maximum COAL is 2.90”. When the rifle was first assembled the bolt would grab the cartridge from the mag and then quickly jam as the bolt slipped over the case. The magazine feed lips needed to be bent open in order to raise the height of the case in the action. Once the feed lips where opened enough the action fed very smoothly. Load development When the maximum COAL of 2.80 is adhered to, and possibly extended to 2.90 which is the max cartridge length of an Accuracy International magazine, I was unsure if I would reach acceptable velocities due to the limited case capacity. More on this in a bit. When it came time to choose a none VLD hunting bullet, Nosler’s 160gr Accubond appeared to be a great candidate. It has a very impressive BC of .531. It just so happens that 7mm bullets ideally suited for hunting in the 140gr to 160gr range have very high BC’s, with the 160gr Accubond being the highest. A couple of other characteristics I really like about the Accubonds are the solid base design jacket which acts as a platform for a large diameter mushroom, and the pointed polymer tip that will resist deformation feeding from my magazine. One of the initial strategies I used in developing a load for the 160gr Accubonds was to use small grain powders such as and Hodgdon’s H4831SC, H4350, and of course Alliant’s new Reloader 17. First up was H4831SC. My worst nightmares came true as I sat down to load my first set of cases after fire forming. My maximum powder charge that would fit in the case with a 2.90 COAL was 53gr’s. 53gr’s of H4831SC was such a compressed load that I could not maintain a consistent 2.90 COAL. Many of the cases would come out 5 to 10 thou longer. This was discouraging because Hodgdon lists 55.5 as being the max non-compressed charge with a 2.87 COAL. To simplify matters, it turns out that 53gr’s plus/minus 1gr was all the powder I could fit in the case with a 160gr bullet and a COAL of 2.90 for all powders tested. RL17 however was the least compressed charge and I think next time I will get a full 54gr’s. After fire forming the cases with a mild load of 49gr’s of H4350, the first step in my load development is testing for max pressure and velocities. I load up each powder starting with a mild charge and increasing the powder until signs of pressure occur. This is when I know to stop. I then work backward from this max load looking for an accuracy node. This is basically an OCW method of load development. Although some of the loads I list are above max, I encountered no pressures signs at all. However, I can’t physically get any more powder into the cases, except for RL17. Load: Winchester case, Winchester Large Primer, .310 neck bushing, 2.165 case length, loaded with Redding FL die and Competition seater. Here are my findings. Tested at 10ft from muzzle with a Chrony Beta Master. 77F/25C, 55% RH. H4831SC 49.0 – 2433 50.0 – 2489 51.0 – 2573 52.0 – 2595 53.0 – 2670 H4350 47.0 – 2633 48.0 – 2751 49.0 – 2781 50.0 – 2792 51.0 – 2805 52.0 – 2871 52.5 – 2895 53.0 – 2902 RL17 48.0 – 2669 49.0 – 2749 50.0 – 2800 51.0 – 2849 52.0 – 2902 52.5 – 2928 52.7 – 2938 53.0 – 2975 53.2 – 2980 53.4 – 2991 Conclusion Reloader 17 has given new life to the short action .284 Winchester. 53gr’s of powder is the maximum allowable powder charge due to compressed loads. Of the three powders tested I was able to get more RL17 into the case than H4831SC, and H4350. H4831SC was the bulkiest and was the most compressed charge. All else being equal, RL17 is 73fps faster than H4350 and an amazing 305fps faster than H4831SC. H4831SC: 53.0 – 2670 H4350: 53.0 – 2902 Reloader17: 53.0 - 2975 I am positive that a half grain more powder will get me to 3000fps with RL17. I will test and see if my gun will handle the pressure before accuracy testing. I still have not mentioned accuracy or other bullets. I am also going to try 162gr Hornady a-max's. Up till now the testing has only been to determine which powder will get me into an acceptable velocity range with a short action magazine length COAL. I am now going to do some accuracy testing with Reloader 17 between 2800fps and 3000fps with the Nosler 160's and Hornady 162's. While testing velocity and pressure at 50yards with a ladder test between 48gr to 53.4gr, all 10 charges went into one large hole. Things are looking promising. I'll keep you updated as I perform more tests and find the accuracy node for each bullet. Any comments or questions greatly appreciated.