OTOH we have this....down loaded from another site as well.I'm not sure if this guy is a thoughtful, reasoned handloader or a dangerous nut,and is one reason I regard some 280AI handloaders as a bunch of riverboat gamblers willing to dangle by threads on the brink of imminent disaster....notice the warnings and constant reference to loose primer pockets.
I am caused some doubt about his intelligence and experiences,however, when I see the references to the 280AI being the "perfect" case capcity for the 7mm, and anything from the 7 Rem Mag on up being "overbore"....clearly another guy on a mission.
I know from my own experiences that a standard 280 in a 22"-24" barrel is hard [ressed to hit 3100 fps with a 140 gr bullet....how it is that you can add 300 fps to that velocity and get 3400 fps from it by increasing case capacity to only 67.6 gr in the 280AI has me completely flumouxed(that is stretching the limit for a 7mm Dakota,STW or Mashburn)...and another reason I consider the cartridge to be nothing more than a lot of overblown hype hawked by guys living on the ragged edge of disaster.
Everytime I see one of these 280AI threads I think I should get one;then reason prevails and I know I will simply piss $2k down the toilet and the thing will be down the road in 6 months.
I'm through with this stupid [bleep] topic...and the fools who want to believe this shidt,which is all it is.....
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Ackley Improved User
New Member
USA
11 Posts
Posted - Mar 01 2005 : 15:26:46
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This is my 280 AI Oehler-chronographed data with 140 grain Sierra flat-base bullets and a 26" barrel - THEY ARE HOT, SO BE CAREFULL AND WORK-UP THEM FROM 3 GRAINS BELOW MAX IN 0.5 GR. INCREMENTS. STOP! when you see pressure signs.
140 Sierra FB - Alliant Reloader 25
66.0 grs. - 3234
66.5 grs. - 3271
67.0 grs. - 3322
67.5 grs. - 3430 (Maximum!)
140 Sierra FB - IMR 4350
60.0 grs. - 3304 (Maximum!)
140 Sierra FB - Alliant Reloader 22
63.0 grs. - 3241
64.0 grs. - 3300
64.5 grs. - 3318
65.0 grs. - 3342 (Maximum!)
~3400 fps velocity is achievable with a 26" barrel and Reloader 25. But, go no higher and use only first-rate modern bolt action rifles in perfect condition. Subtract ~25 fps for each inch less than 26 inches.
Ackley Improved User
New Member
USA
11 Posts
Posted - Mar 01 2005 : 15:30:08
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This post is relevant to Ackley Improved users or proposed users. This post was originally stimulated by a question on another form of "how does Hornady get enhanced performance from their Light Magnum ammunition" - that is, what's their process. Below was my response, but I'd like to get feed-back from the reloaders posting here. What do you think? Besides, I though the individual interested in getting a 280 Ackley Improved might appreciate this post.
I don't know what factory process is used for the Hornady Light Magnum ammunition, but you can equal or exceed their velocities without excessive pressures, if you're willing to tap in powder and use compressed loads.
I have a .257 Ackley Improved (AI), .25-06 AI, .280 AI, and 30-06 AI. All guns are custom made bolt-action rifles (Rem M700 or Win M70) with match-grade 26" barrels. I have developed loads for all by experimenting with almost all available modern powders and by chronographing every test firing (Oehler with three screens). I've developed these loads in conjunction with the NECO Internal Ballistic Program. I have reams of data.
The best performance - at a given pressure for a given weight bullet - is almost always obtained with the slowest burning powder that will fill the case and bring the maximum pressure to the desired level. For example, consider Reloader 25 in a 30-06 using 165 or 180 grain bullets with no higher than 65,000 psi. A standard Winchester 30-06 case will roughly hold 66 grains of R25, when tapped in and the powder compressed by the bullet. Reloader 25 compresses nicely, and with tight case necks the bullet will not be pushed back out by the compressed powder. With a 24 inch barrel, maximum velocity with a 180 bullet will be right at ~3000 fps, and with a 165 grain bullet right at ~3100 fps.
I would NEVER recommend starting with this load, but rather recommend working up to it by starting from 62 grains of R25 - then incrementally increasing the charge by 0.5 grain increments until serious pressure signs develop or you achieve 66 grains.
I'm willing to tolerate "significant" pressure - that is, pressures often used when loading the .270 or some of the newer magnums. (These new magnums look good, because they're being loaded to pressures significantly higher than the older calibers - well over 60,000 psi � even close to 64,000 psi. Hence, the comparisons to the �old� are not fair; remember, the companies want to sell new guns.)
A standard modern bolt-action rifle will tolerate pressures in excess of 150,000 psi; hence, you're not in danger of bursting the gun � not even close. But, you don't want to load beyond 65-70,000 psi, because beyond that pressure you can get a sticky bolt or even a frozen case in the chamber - a disaster, if you need a second shot at the trophy of a lifetime. Loading to 65,000 psi will loosen those primer pockets fairly quickly � although I�ve read that brass cases will �take� up to 80,000 psi without overt failure. (By the way, converting CUP pressure to other measures of PSI is a vague and unclear process, without clear conversion tables or rules.)
To test for loose primer pockets, I hand prime all cases and "feel" the primer into the pocket - indeed, you can consider your brass case a type of "copper crusher" pressure gauge. I don't care too much about multiple reloadings of a single case, because cases are cheap, expendable, and very easy to replace.
Finally, I�ve found that Reloader 25 is the single best slow-burning powder on the market. I routinely get the best performance � both accuracy and velocity � with the lowest pressures. Yet, you must load a relatively heavy bullet. When you go to lighter bullets (e.g., 150 or 130 grain for the 30-06), you�ll may need to use R22 or R19 to achieve maximum desired pressure.
Please keep in mind that the 30-06 AI is only a small improvement over the regular 30-06 - that is, ~7% increase in case capacity. For example, with Alliant Reloader 25, I can tap in ~66 grains in a Winchester case, for a 30-06 AI case I can tap in ~71 grains - both filled just below the top. Then you compress those super charges with a 180 grain Nosler BT, and you'll get ~3000 fps with the regular 30-06 and ~3100 fps with the 30-06 AI. Pressure will be ~65,000 psi, and primer pockets will loosen fairly quickly - maybe only after a few loads. Is this worth it? For me, the fun figuring this out was worth it. But, maybe not for you.
The 280 AI and 30-06 AI are essentially identical in performance - get one but no need for both. When worked-up, as described above, the best load I have for the 280 AI is 67 grs. of Reloader 25 with a 150 gr. Nosler BT, which will produce ~3250 fps in a 26� barrel.
The 25-06 AI is over bore and not much of an improvement over the 257 Roberts AI. Of all of them, the 257 Roberts AI is probably the best - just about perfect bore for the .25 caliber - that is, given modern powders.
Actually, the 280 AI is just about perfect bore for 7 mm caliber - the 7 mm Rem Mag and equivalents are all over bore, in my opinion. The 30-06 AI is under bore for .308 caliber - I believe the 30-338 is just about perfect bore for 30 caliber - that is, until high-energy slower burning powders are developed. I find that Reloader 25 is the best high-energy slow burner out there. I know of slower burning powders, such as H870, but they don't seem to have the energy content.
As a final note, IT IS VERY IMPORTANT THAT I USE ONLY THE BEST COMPONENTS, WEIGH EVERY CHARGE, CHRONOGRAPH EVERY LOAD, ANALYZE MY FINDINGS IN CONJUNCTION WITH THE NECO INTERNAL BALLISTICS PROGRAM, AND SHOOT WITH CUSTOM-MADE BOLT-ACTION RIFLES OF THE ABSOLUTE HIGHEST QUALITY! If you plan to do why I�m doing, you should do the same � compromise nothing.
Regards, Ackley Improved User
CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer nor the staff of this forum assume any liability for any damage or injury resulting from use of this information.
Ackley Improved
