Home Forums Reloading Big Game Rifles Load Data 280 Ackley

I have been using the RL22 loads that JD338 put me on to for several years.Excellent accuracy with both the 140 and 160AB. Monashee

Men,
Certainly did not mean to get you guys into a whizzing contest. Like I said I would be pleasantly surprised if my 280AI would perform with a 140 at those velocities. Bob I have strong doubts and tend to agree that it would be tough to do.
I (in other rifles) learned my lesson a long time ago when it came to burning what turned out to be too much gunpowder to achieve velocities that are more than a guy can find published anywhere or possibly in only one publication.
Case in point 300 Win Mag burning 76g of IMR 4350 and shoving a 150 @ 3375. Mine will do it but the rifle I was abusing went thru 3 barrels before I wised up. (long time ago)The deal as all of us know is to know the ballistics and the necessary elevation compensation adjustment.
A 12" AR500 plate will ding with no audible difference to my ear when hit by a Berger 140 VLD @ 3000, 3100, 3200, or 3300 at any distance the shooter can hit the plate at or at least at any distance I can hit it at and any animal would never be able to tell the difference.
Bottom line do I think my ULA will spit any 140 out at over 3300? Like I said I would be pleasantly surprised but I have no unreasonable expectations and that is a good thing in this case IMHO.

Dave

Sure it can but the question remains, how do you have any idea of the actual pressure once you exceed those published and pressure tested 61K loads printed by the folks who make reloading manuals?

The real real question is: How does ANYBODY have any idea? You and I both know that every rifle barrel is different... they tell you as much in your "reloading manuals". So, how close are they? 2%.... 4%.... 15%? I'll trust my eyes, ears, and the empirical evidence before I trust the data shot in ONE BARREL as gospel. You gotta use your coconut.... even within 'book data', cause you ain't shooting their barrel.

You are, however, correct. Once you leave book data, you're on your own.... so yeah, I don't really KNOW.

I do know:

A. I've actually seen 7 Mag shot in the Nosler Ballistic Lab at 65K PSI out of the same barrel they shot the book data with.... with my own eyes. You can add about 100-150fps across the board... even Steven... in the same lab... with the same f'n barrel.

B. I've actually rolled around a few 7 mags... as have you... and have determined a comfortable operating range for a variety of pills.

Last.... but not least.... I find it a bit interesting that your arguing SAAMI data for a cartridge that is probably the biggest whore in the entire Wildcat Ranch. There have got to be more different .280 AI chambers floating around than all the rest of POs finest combined.

In a pure SAAMI world though... the .280AI can tickle the 7RMs arse....

You have quite a way with words Dog! I like it.

There are a bunch of different .280AI chambers but there is only one which has the SAAMI stamp of approval.

You're right about each barrel being an entity unto itself. Precisely why a guy doesn't just start out with the max book load and run with it.

There are ways to REALLY know what pressures you're running and the price is not crazy high either.
Pressure Trace. I have one but haven't run it through the paces yet. Will be interesting to see what's up.

n,
No way to know unless the correct equipment is employed.Otherwise those of us without the equipment have to rely on the signs all of us rely on to determine when too much is in fact too much. From my experience as I articulated in my previous post I pushed a rifle past what is considered safe and reasonable by every manual except one and did not know I was killing the barrels (or at least none of the tell tale signs were there)until I replaced barrel #3.
Bolt did not lift hard, brass base not burnished by the ejector, no split cases, and it shot under !/2 minute but in less than 400 rounds one of the barrels (the last one I replaced)was bead blasted from the breech 8" forward.
Many years ago I went thru this process because of a chronograph, my desire to have a 300 WM that would shoot faster and flatter and because the Lyman Manual (if memory serves me correctly) said a guy could drop 76g of IMR 4350 in a 300 WM case and shoot it. Well I could but it got pretty expensive.
I guess that's how I figured out there was too much pressure. My bet with the 280AI is that as one of the posters said you can stuff all the double based powder in the case (as long as it will hold it) you want until the chrony tells you what you want to see. Might work for some but I learned my lesson a long time ago.

Dave

RaceTire, I am loading right at max. as shown in Nosler #6, using IMR 4831. I have also worked with RL 22 and IMR 4350. At this point I have not experienced any signs of excessive pressure HOWEVER, I will not go beyond what is noted as MAX in this manual.

Actually as is almost always the case I have found the sweet spot with a 150 BT and the 160 AB about 1 grain under max. and that is a comfortable place to be.

Randy

I personally believe anything over 3200 with 140's is over pressure, and those that claim 3300 and above are living on borrowed time,the 280AI is a great cartridge but some expect it to be more than it safely can be!

Randy,
If it satisfies you with the way it shoots and you are a grain under that's what matters. A 140 @ 3300 in a 280 AI anyone who owns one would be real impressed with that velocity especially if accuracy was good.
The 280AI may in some rifles reach that number with a 140 but the potential consequences are more than I want to deal with. Barrels are pretty expensive.
The difference between 3300 and 3100fps using a Berger 140 VLD @500 using a 300 yard -0- is 3 clicks. The diff in energy is 230 ft lb. 1769/1539. Doubt any animal would know the difference.

Dave

I should also concede the fact that the 7RM ain't exactly the Virgin Mary.... it's a know chamber floozie too. So with these two cartridges in particular... it's pretty easy to get lost in the forest, cause people just keep planting more trees.

That's kind of what I'm getting at here.... as is Bob and Dober. Guys who run .280AIs.... generally speaking... are guys who are going to MAKE them run as close to a 7RM as possible. You did.... I did too... twice. Otherwise... why would you build one? With the 7RM most folks run it pretty easy.... and the guys who do lean on them... are the same guys (or type of guy) who floor the AI.

Pick one... and clobber stuff with it. I can't think of a critter that'd know the difference on one end.... and 99 out of 100 shooters wouldn't know the difference on the other. Hell... I bet half the guys who've read this post have actually had to Google "SAAMI"....

What if some or all the normal pressure signs are in some ways masked by the shape of the 280ai case?

With a 26" tube I can see flinging 140's at 3250-3280. In a 24" tube I'd also agree that 3200 is about tops.

Dog,
You are funny. Great post!

Dave

AF,
I guess he finds out when he runs a brush thru the barrel and pulls it back toward the breech and one day the rifling is missing 8" out.
No doubt in some cases the signs don't show up as in the case I cited in one of my previous posts. No signs. The quality of the Sako AV action on the particular rifle (in my case) must have masked the signs.
There was no masking the barrel issue when it showed up. Good discussion. Heading over to the Orange County (Florida) Convention Center this morning. Exhibiting at the PRI (Performance Racing Industry Trade Show) Hope all have a blessed day today.

Dave

Have a good time!

Precisely...and these differences can never be underestimated.And also why we really don't know when we use data from the manuals that we are blissfully operating at or in excess of SAAMI specs, and conversely we could still be within those specs even if we do exceed manual data.

This is precisely why a chronograph is so essential,and while not perfect as a means of measuring pressures, it should at least serve to tell us when we are over the top.

it isn't always enough to say...Well I stuck to manual loads and got 3300 fps and the SAAMAI data says I am at 65,000 psi so everything is OK...

No not always.I recall one 7 mag with a Krieger barrel that gave 3080 or so with a 160 and manual load;and a second 7 mag with a Douglas tube that gave over 200 fps more velocity with the same ammo.

But the velocity of well in excess of 3200 fps was too much velocity for that case, which I knew,and backed down accordingly with that rifle.

And before someone starts thinking the 7 Rem Mag is the only cartridge afflicted this way, forget it because I have seen precisely the same thing in 270's, 280's, 300Win and Weatherby,and a host of others.And I have also seen factory ammo for the 7mm WSM give velocities that a 7mm Mashburn tops out to meet,and had ejector slots ironed into the brass....I am sure the stuff was supposed to be within SAAMI spec,but not in that barrel that day.Per Federal,It was loaded to 65,000psi too.But I did not let that serve as tacit license to chase those velocities and frankly could not come close with my hand loads.

So when you see your rifle give extraordinary velocities with stock manual loads it isn't always carte blanche to assume everything is OK and you just have a fast barrel...it may be a warning to back down.

Like dogshooter says you gotta use your noodle with this stuff.

Another thing besides the obvious issues associated with custom tubes, trued actions and straight taper cases which all conspire to hide traditional pressure signs, is what Bob Hagel noticed adn wrote of years ago, but which rarely gets mentioned anymore, and that is the smaller area of the case head on an 06-based case will tend to show pressures signs less quickly than the larger case head area of the belted magnums.

Add all these little things up and it is not hard to understand why some are running velocities off the chart but think everything is completely OK because they are religiously sticking to tested manual data;well maybe so but there is just as good a chance that the extra velocity you are getting is not free,and is an indication that you are already off the charts or close to it.

Seeing all this stuff over many years is why I eventually got to the larger 7mm cases like the Dakota and Mashburn....not always for the extra velocity they are capable of, but also because when I see 3200-3300 fps from a 140 gr bullet I know I have lots of slack and safety margin in my loads.

I got precisely the predicted speed with one grain less Magpro than Accurate predicted I'd need.
I'd say those loads were safe (and under 65K) in my rifle.

Well reading all this .280 Ackley stuff got me sorta horned up...so beautiful warm day with NO WIND I dusted the ackley off and rounded up 3 powders, and 2 different 140's (Sierra & Nosler BT's)
My rifle is a 24" Nula with a chrome moly barrel.

first N165 and the campfire load of 63.5 gr and the 140 BT..Great accuracy about 3/8" but velocity of just 3000.

Increased 1 gr. and 3060

One more grain and 3100, but sl ejector mark on the nosler brass and the primers were dead flat..group opened up to 1 1/2"

A long way from 3300 and 7 mag territory!

R22 same bullet, went up to 64 gr. & slight ejector mark 3120. borderline too hot IMOP

R17 same bullet up to 59 gr. Too hot ejector mark -2" group and 3140 vel.

So the Ackley is a neat round certainly effective with 140's but IMOP is NOT a 7mm Mag. At least not with anything I am comfortable shooting out of it.

Lefty C

If you'd have gotten precisely the predicted speed with one grain more Magpro than Accurate predicted you'd need.... would you say those loads were "over max pressure"? How do you know?

Just askin.... seriously....

I wouldn't go over the max listed Magpro load. When I did go to max I had slightly sticky bolt lift so I went back to the load which produced 3050 with the 162 Amax in my 26" tube.

Now I have a much better capability than most to measure ACTUAL pressure since I got the Pressure Trace system.

I need to wring that out thoroughly very soon.