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Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/16/2014 at 18:20
ugapaul View Drop Down
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I guess I'm in a stink stirring mood, so forgive me. I tend to get better info sometimes though, when you push a few buttons.

I have a 280 ackly and enjoy tinkering with it. That said, I usually tell people that the performance "gains" are mostly a gimmick. There is more case capacity than the parent case but if you generate the same pressure on the parent case with the same powder, the velocity is essentially the same between the ackly and the pArent. Almost all of the "benefit" can be attributed to higher loading pressures in the ackly. Standard 280 is usually loaded under 60,000 psi at around 58,000. I load my ackly in the 63-65,000 psi range. If you load a 280, assuming a strong action, you can achieve very similar results.

What say you? But remember, we must talk the same powder in equivalent pressures!
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/16/2014 at 19:47
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One of the biggest benefits to the Ackley is longer case life. My 280 Ackley started life as such, so I really can't speak about higher velocities over the standard 280. From what I gather though, the realistic gain is probably in the neighborhood of 100 fps or slightly less.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/16/2014 at 21:16
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4 gr powder is 4 gr powder, all else being equal, the 280AI will push a bullet faster.  That is at equal pressure.

Most often the advantage comes when you can put more of a slower burning powder in and gain velocity.  For example with RL22 you CAN get close to max with a 280AI by loading 62 gr where with a 280 rem you would not be able to get that much powder into the case and seat a bullet.  Probably closer to 58gr.

Are you saying that 62 gr RL22 will not shoot a 160 gr Accubond faster than 58 gr RL22??  Again same pressure because the larger combustion chamber of the AI will take more of the same powder to achieve the same pressure as a smaller chamber.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 05:30
ugapaul View Drop Down
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Based on every comparison in reloading manuals I can gather, yes the 280 essentially drives the same bullet, with the same type of powder, at the same pressure, with less powder, the same velocity. Whether it is attributed to differences in case geometry, I don't know.

I have compared till I'm blue in the face. The only thing you have to work through is different maximum load postings because the 280 numbers generally stop at 58,000 psi or so.

Yes, technically you would think that all things being equal 4 extra grains of rl 22 would prove beneficial. I just haven't been able to find that. I want that to be the result, that's why I own an ackly 280.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 08:11
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I have a Nosler 280AI and love it..
3150 FPS with the 140AB is what I can safely get
My pet load is 59g of IMR 4831 at 3060 FPS into one hole.

I like the rifle itself as much as the cartridge.
I know a deer at 300 yards isn't going to care 100, even 200 FPS difference.
I got it to satisfy a curiosity itch and really liked the overall package.

I can also run factory 280 ammo and just got a few boxes from Barnes to test the factory 140TTSX load.  If it shoots well I wouldn't feel undergunned with anything in the lower 48
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 09:46
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I don't see what's so great about Porsche 911 Turbos.  I mean, hell, compared to a horse-drawn carriage, limiting them both to the same speed, they do the same damn thing.  The carriage even holds more stuff, and is WAY cheaper.
 
Now let's talk about why air conditioning is such a waste of money.  Limiting the inside air temperature to exactly match the outside air temperature, why spend all that money on the AC unit in the first place!
 
And don't even get me started on these new-fangled calculators and my old-faithful abacus - limiting the discussion to only addition and subtraction problems.
 
Same powder? Seriously?
 
I think you miss the entire point, intentionally or otherwise.
 
If you would like to talk bullet selection, barrel life, case life, or case-prep time, I'd be happy to discuss; otherwise, it's a bait-n-switch.
 
Do you vote Democrat?
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 09:48
Dale Clifford View Drop Down
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4 grs. of powder isn't going to make as much difference as the relative smoothness between the sample barrels you are using as comparison. If your interested in going to the edge like this, use a 7 mag.

I have used a 7x64 in a Steyr Luxus for 30 years and in the last 10 yr a 280 in a TI Rem. The velocities in any common bullet wt. run 100 to 200 fps difference. that's pretty good.

I don't think I want to go that high on the pressure end however. different cases benefit more from the Ackley Improved modification than others.

All things being equal, equal pressure will shoot the same wt, the same velocity.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 09:58
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Originally posted by Rancid Coolaid Rancid Coolaid wrote:

I don't see what's so great about Porsche 911 Turbos.  I mean, hell, compared to a horse-drawn carriage, limiting them both to the same speed, they do the same damn thing.  The carriage even holds more stuff, and is WAY cheaper.
 
Now let's talk about why air conditioning is such a waste of money.  Limiting the inside air temperature to exactly match the outside air temperature, why spend all that money on the AC unit in the first place!
 
And don't even get me started on these new-fangled calculators and my old-faithful abacus - limiting the discussion to only addition and subtraction problems.
 
Same powder? Seriously?
 
I think you miss the entire point, intentionally or otherwise.
 
If you would like to talk bullet selection, barrel life, case life, or case-prep time, I'd be happy to discuss; otherwise, it's a bait-n-switch.




 
Do you vote Democrat?


Roll on Floor Laughing
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 10:53
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Originally posted by Dale Clifford Dale Clifford wrote:



All things being equal, equal pressure will shoot the same wt, the same velocity.



Therein lies the confusion. It is obvious that a 300 win mag will not shoot a 180 gr bullet the same velocity as a 300RUM albeit at the SAME PRESSURE. The difference is in the size of the combustion chamber and the amount of powder.

If you are relying on manuals for safe max loads in the 280SO then you are sucking gas. I rely on pressure signs and life of primer pockets. Book loads don't cut it
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 11:00
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AI not SO

Hard to post on mobile and even harder to edit     
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 12:21
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While it's true that the large velocity delta between .280 and .280 AI is mostly attributed to the fact the latter is loaded to much higher pressure, still, when loaded TO THE SAME PRESSURE and fired from the same barrel length, .280 AI will provide 50 - 75 FPS advantage over .280. Who cares what powder you're using? The fact is, any cartridge with greater case capacity will yield higher velocity using the same bullet at the same pressure as a same caliber cartridge with less case capacity.

When comparing like pressures, one can reasonably argue that going the AI route isn't worth it based on velocity alone. If AI'ing a chamber was a huge hassle and added expense, I would agree. However, it really isn't. There are several factory rifles chambered in .280 AI now that it has been made a commercial SAAMI cartridge. If you're building a custom rifle or rebarreling an existing factory rifle, it takes no more effort nor cost to ream an AI chamber than it does a standard chamber. While .280 AI factory ammo is likely to be more expensive due to less selection and availability, if you reload, there's no additional ammo expense. .280 AI dies cost about $30 more than standard .280 dies, but that's a one-time expense. There's no "hassle" associated with fire-forming and case prep, since you can shoot the standard vanilla cartridges in the AI chambers. Consider that EVERY time you ignite a primer, regardless of what you're shooting, you're fire-forming to your chamber anyway. After the first firing of virgin brass, you're in AI mode from then on, and that never changes because you're reloading with AI dies. So, from the standpoint of feeding an AI chambered rifle, the difference in expense and "hassle" is negligible at best.

The real advantage to AI chambers vs. standard to my way of thinking is improved brass life. Because the AI case has less body taper, under firing pressure, it exerts greater grip on chamber walls and stretches less longitudinally. That fact alone makes going AI worth it to me, and the improvement in brass life soon pays for that whopping $30 increase in reloading die cost, if you shoot much at all. Even if the AI chamber yielded no velocity increase whatsoever, I'll take a superior chamber design that works my brass less any day, especially when I still have the option of shooting standard, "non-AI" factory ammo in the same chamber, with no penalty.

So, let's assume for argument's sake that one doesn't choose to load to max pressure and the real world velocity difference is only 50 FPS. What's the disadvantage to gaining "only" 50 more FPS when there's no additional hassle and minimal additional cost involved? Who among us wouldn't take that?

I'm personally not going to bother reaming most standard factory rifle barrels in standard chamberings out to AI, especially if the rifle shoots well. However, if I'm building a custom rifle or I'm rebarreling a factory rifle and considering a standard chamber... why not AI?


Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 12:51
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Originally posted by Dale Clifford Dale Clifford wrote:

All things being equal, equal pressure will shoot the same wt, the same velocity.



Not so!

7mm-08 has the exact same max SAAMI spec pressure as 7mm Rem Mag (61000 psi), yet 7RM will always shoot the same bullet (weight and design) about 300 fps faster with the same bbl length.

.308 Win has 2000 psi greater max SAAMI pressure than .30-06 (62K vs. 60K), yet .30-06 will always outrun .308 by 200 fps or so with the same bullet.

There are numerous other comparisons that refute your statement.

It's all a matter of peak pressure/time. Larger cases hold a larger volume of slower burning powder, so the pressure builds more gradually over a longer time, yielding greater velocity even if the peak pressure is less.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 13:28
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I can concur on case life, the Nosler brass I have been using has held up under many reloadings.

I also neck size only unless I encounter brass that is hard to chamber.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 14:44
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Somebody articulate expound on classic pressure sign differences when loading Ackley Imp. ammo, please RE if you see the classic pressure signs [ hard bolt lift, ejector marks, etc.] you are WAAAAY over pressure. Due to better chamber wall grip by the Ackley case. 
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 15:17
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I wouldn't use flattened primers as any indicator of excess pressure. If you have a chrono, that is probably the best indicator (outside of real pressure testing equipment naturally) and watch your velocity compared to what a modern load manual states as max velocity for a given load with the same components. Sure, a hard bolt lift is an indicator too, but again, like with flattened primers, you are really just guessing.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 15:24
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Have you seen catastrophic case failures with blow back without first seeing signs like sticky bolts and flattened primers.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 15:27
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I pushed pretty hard on my last 280 loading but didn't see any of the visual warning signs. I was 2 grains over the Hogdon manual but .5 grains lower than the nosler manual.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 15:36
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Originally posted by ugapaul ugapaul wrote:

Have you seen catastrophic case failures with blow back without first seeing signs like sticky bolts and flattened primers.

Excessive headspace can cause catastrophic case failure with blowback with no such prior warnings. If headspace is excessive enough to cause case rupture/head separation, it's gonna bite you immediately, without the benefit of warning of impending danger.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 15:41
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Good to know. I assume that if there was a defect in the original head spacing, I would already know, and as long as my brass is correctly sized and seating depth is ok - I'm good.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 15:42
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Originally posted by ugapaul ugapaul wrote:

Have you seen catastrophic case failures with blow back without first seeing signs like sticky bolts and flattened primers.

I haven't experienced a catastrophic case failure so I can't answer that. I don't try to make any specific round into something it is not, such as making a 30/06 into a 300 WM. Flattened primers can also be a sign of excess headspace and not necessarily excess pressure.

Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 15:48
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Originally posted by ugapaul ugapaul wrote:

I pushed pretty hard on my last 280 loading but didn't see any of the visual warning signs. I was 2 grains over the Hogdon manual but .5 grains lower than the nosler manual.


You have to keep in mind and I said this before, that you have to use the same components that the manual you are using as a guideline. Don't assume that because one manual states that 58 grs of say IMR-4831 with a 140 Nosler BT is safe to use if you switch to a 140 Barnes TSX that may have a longer bearing surface, harder or softer copper jackets etc. etc....Lots of guys make that mistake.

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Originally posted by ugapaul ugapaul wrote:

Good to know. I assume that if there was a defect in the original head spacing, I would already know, and as long as my brass is correctly sized and seating depth is ok - I'm good.


That's an incorrect assumption. Yes, you would know very soon after loading for that rifle. It's possible the mfg cut the chamber outside SAAMI tolerances (too deep). You could have out of spec sizing dies. More than likely, you will be within spec on both, but it's not a certainty. Mistakes can and do happen. The only way to know for absolute certain is to check headspace beforehand. There are sizing tricks you can use (i.e. creating a "false shoulder" on the base of the neck during sizing) when handloading that will enable you to know by feel that you have tight headspace.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 16:16
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To check for excess headspace can I compare a fire formed case against a nosler 280 ai case and an unused 280 round? Also could I check a resized case in the same way?
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 16:20
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Unused nosler brass and a factory loaded 280 round. I keep both.
Post Options Post Options   Thanks (0) Thanks(0)     Back to Top Direct Link To This Post Posted: February/17/2014 at 16:24
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Not sure that you could just measure a fired case due to the fact that there is a certain amount of spring back when a case is fired in a chamber. How much I don't know. Using "virgin" brass wouldn't tell me much of anything. Probably the only way to really determine if you have proper headspace would be to have a gunsmith measure it with the proper gauge. All factory virgin brass will be undersized for obvious reasons.
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