280AI

[roper]

Got alittle chronographing in with my new 280AI has a Kreiger barrel .  1gr under max using R-22 with 150gr bullets velocity is 3110fps.  So for about a 10% increase in powder over the 280 get appr 7/8% increase in velocity not bad.  I think I'll just stay with that load and after hunting season may play with it some more.

[quickdtoo]

I'm considering a rechamber to .280AI, one of my questions is on powder choice, I've read several complaints of RL22 being very temp sensitive, but it also gives great velocities and accuracy, have you experienced temp issues?

Thx,

Tim

[roper]

Tim, I've also shot R-19 in the 280AI and have used both powders in other calibers and haven't had a temp  problem yet.  Wish I could be of more help. 

[Graybeard]

The problem with your analogy is that when you increase the 280 to a 280AI you DON'T gain 10% in case capacity. Load both to equal pressures and you "might" gain 100 fps. Anymore than that you're gaining based on increased pressure.

[roper]

The problem with your analogy is that when you increase the 280 to a 280AI you DON'T gain 10% in case capacity. Load both to equal pressures and you "might" gain 100 fps. Anymore than that you're gaining based on increased pressure.

      Graybeard, I've heard the same thing before  and fully understand what your saying, I just don't agree with it.  Shooters who don't like the Ackley use the same arguement equal pressure I guess that how some look at it myself since I don't have pressure testing equipment the real gain should be if the 280 can equal 280AI pressure so the only choice for some is to take the 280AI down to the 280 pressure levels and call that the gain as the max loads for the 280 are the appr starting load for the 280AI. 
What would be the pressure of a 280 if you loaded 60gr/R19with a 150gr bullet your appr 5 grs over max but you can shoot that load in a 280AI.  Thats the real world gain to me over the 280.

[Graybeard]

To each his own but you are running pressures considerably over SAAMI for the parent case. IF you chose to operate at those same pressure levels with the parent case then you'd be within 100 fps of the same velocity and using less powder.

John Barsness did a bunch of manual studying and playing around and wrote up his results some while ago. His conclusion was you can get about a 1% velocity increase for every 4% increase in case capacity using equal pressures. My real world experimentation tends to agree with that. It's not really a hard and fast rule but it seems to hold up in the real world.

That's one problem I have with ALL the various AI and other wild cat rounds, there is just no good reliable source of pressure tested data so folks go wild over their loads and run the pressures up too high for safety. Without pressure testing your loads there is absolutely no way to know what pressures you're running. Modern rifles are perfectly safe up to about 65,000 psi generally altho that's a wee bit more than most factory level loads run and a bit over SAAMI level. Still as long as one's loads don't exceed that for a maximum average then they aren't likely to blow up a modern bolt action rifle.

BUT you can load the standard rounds to that same pressure just as safely as the improved or wildcat rounds. When/IF you do then you'll be mightly lucky to gain more than 100 fps with any AI round in existence. The primary advantage they offer is the sharper shoulder and reduced case taper resulting in longer case life. Anyone who uses them for their supposed greater velocity is kidding themselves. Now if you wish to kid yourself that's fine, I care not, it's none of my business BUT posting unsafe load data here would be my business.

[roper]

Graybeard,  Sierra has puiblished data for the 280AI,22-250AI,6mmAI 25-06AI plus many others so there is some guide lines for those rounds and maybe with Nosler making 280AI brass who know.   

The  first wildcat manual I got was made in 1959 plublished by Speers called Reloading Manual for Wildcat Cartridges they had a 25 Neidner other name was 25-06 and they had another called 7mmx06 was later called a 280.
 
As to posting unsafe load or as you say kidding myself I used Noslers or Sierra reloading manual data for my 280AI  so if that data is unsafe how is the other data considered safe?  I can only assume you don't agree with the reloading data that is published in those manuals for the 280AI or another Ackley/Wildcat they have data published for?  For some reason their data supports the greater velocity I got with my 280AI and the amount of powder I used, and I cann't seem to find any mention of equal pressure maybe they are looking at something different they do mention the pro and cons on doing that certain caliber.      Doesn't Jarrett sell loaded 280AI ammo.

Graybeard, I'm sorry that I gave published data for my 280AI but since this is a wildcat forum didn't understand your rules, won't happen again.

[Graybeard]

I did not say you gave unsafe data. I merely said that IF unsafe data is given that concerns me. There is a difference. Yes some manuals do have data for the .280 AI as it is perhaps the most popular of all the AIs and the .257 Roberts AI isn't far behind in popularity.

BUT there is no SAAMI standards for ANY of the AIs, therefore many load them to higher pressures than the parent round. Add to that the fact that Remington planned the .280 for use in the pumps and semiautos of the day so the SAAMI specs on it are set well below such other rounds as the .270 Win. and .30-06.

So yeah you can gain a bit with the AI over the standard .280 if using SAAMI pressure in the standard and the non standard higher pressures in the AI. That doesn't alter the fact that there is but about 100 fps to be safely gained in the AI if identical pressures are used. The Hornady Light Mag .280 ammo will reach all the AI can safely reach in standard chambers.

[roper]

It's funny but in the Speer wildcat manual I have dated 19589 they list the 7mmx06(280),35 Whelen and 25 Neidner(25-06) all the test they did was with bolt action rifles and of the powder they used back then that are still being made today those  loads are used in present day reloading manuals. 
The good thing about the shooting world is the many calibers one can choice from.  I happen to like the odd calibers and I appreicate what they have contributed to the shooting world.  Back in 1959 was afew shooter liked the wildcat 7.mmx06,25 Neidner and 35 Whelen and it forced the manufactors into making them standard calibers. 
 Rem didn't follow your equal pressure when they made the 40x in 30-338mag,6x47,6BR, and 22 BR and they made the X-P in 7BR and 6x45 you couldn't buy factory ammo for those calibers wasn't any SAAMI spec either, you being a Rem guy should of know about those wildcats.  The equal pressure thing just doesn't hold up in the real shooting world only does for guys who don't like wildcats and I understand that.  I'd be dollars ahead if I just stuck to factory chambers but what fun would that be.  Look at all the work Tubb's has done on his 6xc.  Their wildcating the new 6.5x47 case up to 30 cal and down to 6mm.  Let's see wasn't the 6 Dasher set a small group record at 1000yds for light gun I forget how long Sierra ran ads on that.  Let see don't you have to fireform the Lapa 220 russian case to make the  6ppc case where the SAAMI spec on that case. 

[Graybeard]

Rem didn't follow your equal pressure when they made the 40x in 30-338mag,6x47,6BR, and 22 BR and they made the X-P in 7BR and 6x45 you couldn't buy factory ammo for those calibers wasn't any SAAMI spec either, you being a Rem guy should of know about those wildcats.  The equal pressure thing just doesn't hold up in the real shooting world only does for guys who don't like wildcats and I understand that.

I honestly don't have a clue what that's supposed to mean.

But you misjudge me really. I love the .280 Rem and would dearly love to have a .280 AI. I've never managed to find the right rifle in either but have come close a time or two to having one made, still might some day and it will likely be the AI. But not for the supposed extra performance of it.