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SA .284 Win - Range Report

 
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Old 09-18-2009, 08:24 PM
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SA .284 Win - Range Report

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.


Last edited by heikki02003; 09-18-2009 at 10:06 PM.
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  #2  
Old 09-20-2009, 02:02 AM
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Re: SA .284 Win - Range Report

Is this in the right forum????

Last edited by heikki02003; 09-20-2009 at 09:20 AM.
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  #3  
Old 09-20-2009, 06:17 PM
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Re: SA .284 Win - Range Report

2975 with a 160grain bullet is awesome! As you might be able to tell, I shoot a 280Rem. So please keep updating this thread as I will follow it closely.

What kind of barrel life might you expect with your 284Win? The 6.5x284 is a known 'barrel eater'
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Old 09-20-2009, 07:37 PM
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Join Date: Apr 2009
Location: Montana
Posts: 161
Re: SA .284 Win - Range Report

I also read your post as I just had a 284 built, it still has problems but we will get them worked out. your load with r17 seems a bit hot to me. in my gun I have shot 51 grns mith the 154 and get 3020 fps but I am having problems getting the gun to shoot well with anything. I start to get a sticky bolt with 52 grns and a 154 interbond and 53 grns shows extreme pressure signs. I would like to be kept posted on your progress.
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  #5  
Old 09-26-2009, 10:30 AM
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Re: SA .284 Win - Range Report

For a lot more information on this rifle see Gun of the Week over at 6mmbr.com: .284 Win Tactical Hunter

The barrel life of a .284 is very good relatively speaking. Yes, I know the 6.5 is a real barrel burner. I'm expecting comparatively similar barrel life to the .308, but maybe not quite as good.

Bud, hope the above article provides you with more informaion.
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  #6  
Old 09-26-2009, 03:54 PM
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Location: Oro Valley, Arizona
Posts: 127
Re: SA .284 Win - Range Report

Heikki,

Your article is very interesting. I've been toying with the idea of a similar rifle.

The only area where I differ with your approach is in the length of the action employed. Short actions (I use Winchester M-70, Tikka 595 and Remington 700) limit OAL to a maximum of 2.90, with my Remington action being limited to 2.820".

The use of standard length actions, at the added cost of about 4-6 ounces of added weight, really opens up the scope of whatever project one has in mind. Since most standard length actions will allow an OAL of 3.400", building a rifle on a .284 Winchester platform becomes a lot easier, due to the fact that 6.5 mm X .284 or straight .284 Win. chambers can be throated longer, allowing one to seat the bullets so that the base is aligned with the neck/shoulder transition of the case, thus maximizing powder capacity. This gives one more room to play with when developing loads for different bullet and powder combinations.

I currently use a 25-06 Ackley as my long range "death ray" for shots out to 500 meters, but realize that the effective range of .25 caliber cartridges is limited by the lower ballistic coefficients of available bullets, as compared to calibers of greater diameter. I will definitely check-out Surgeon's website to check the availability of standard length actions.

By the way, I use both Hornady A-Max 140 gr. and Sierra 142 gr. MK bullets on my silhouette rifles and I've found the Hornadys to be more consistent in length and weight than the Sierras. I've also found them to be less finnicky for load development in different rifles.

Regards,
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Last edited by Joaquin B; 09-26-2009 at 04:01 PM.
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  #7  
Old 10-14-2009, 07:43 PM
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Posts: 26
Re: SA .284 Win - Range Report

I'd like to think that my experiment proved that absolutely nothing is lost, nor is it a compromise, to build a .284win on a short action IF bullet weight is limited to 162gr's; especially using RL-17.

Also, the difference between a Surgeon SA and LA is not "about 4-6 ounces of added weight". My Surgeon SA weighs precisely 34.6oz's (2.1625lb's), and the Surgeon LA weighs 58oz's (3.625lb's). That's a difference of 23.4oz's (1.4625lbs).

Reference: http://www.surgeonrifles.com/sites/s...ion_specs2.xls (Surgeon Spreadsheet - Click Open)

Last edited by heikki02003; 10-14-2009 at 07:56 PM.
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