ackley improved- to do or not to do?

[Toddco]

I have been shooting the guts out of my rem .243 and the barrell is nearing its appointment with the crematorium. I am happy with the caliber and have all of the reloading equipment for it. I plan to rebarrell the rifle and I was also toying with the idea of redoing it as an ackley. Thoughts on the pros and cons of this?

Thanks,

Toddco

[steve4102]

OK, if you are going to re-barrel, why wouldn't you chamber in the Ackley? Better brass life, increased performance and the KOOOL Factor. Some will argue that it's not worth the effort due to the HIGH cost of Ackley dies. This is simply not true. In the 243 and other 308 based cartridges the dies are inexpensive. The standard Lee Collet neck die will work in the 243 AI. The standard seating die (RCBS) will also work with the 243 AI. When it's time to bump the shoulder back a $30 Redding body die in 243 AI is all you need.

I just had my son's Savage 7MM-08 chambered in 7MM-08 AI. Nice, easy on the brass and excellent performance. here are some of my Chrony numbers from a few weeks ago.

160gr Nosler Partitions.

Hunter.
48gr---2705fps
48.5gr-2724
49gr---2766
49.5gr-2797
50gr---2820
50.5gr-2850
51gr---2884
51.5gr-2893
52gr---2894


MRP
47gr---2626
47.5gr-2722
48gr-error
48.5gr-error
49gr-error
49.5gr-error
Replace battery
50gr---2704
50.5gr-2744
51gr---2781
51.5gr-2803
52gr---2833


DP-86
47gr---2667
47.5gr-2710
48gr---2742
48.5gr-2746
49gr---2781
49.5gr-2833
50gr---2843
50.5gr-2869
51gr---2888
51.5gr-2910

[t45]

I love my 243ack. It holds a few grains more powder that the standard 243. I set my 17lbs rifle up for 1000yd benchrest and chose the ackley over some of the other 6mm's. My favorite load is a Berger 105gr VLD over H1000 or H4831SC. I do not think you will be disapointed. Remember you can still shoot regular 243 Winchesters through it in a pinch.

[woods]

OK, if you are going to re-barrel, why wouldn't you chamber in the Ackley? Better brass life, increased performance and the KOOOL Factor. Some will argue that it's not worth the effort due to the HIGH cost of Ackley dies. This is simply not true. In the 243 and other 308 based cartridges the dies are inexpensive. The standard Lee Collet neck die will work in the 243 AI. The standard seating die (RCBS) will also work with the 243 AI. When it's time to bump the shoulder back a $30 Redding body die in 243 AI is all you need.

Did it again! Nothing left to say.

[Loader9]

If you ever followed any of Parkers readings, he always stated that for every bore diameter there is an optimum bullet weight. That's a bullet weight that carries the most weight but does not sacrifice speed. In a .243 bore you have 60 gr bullets that can fly at the speed of light but don't carry much weight and has less energy at distance. You can shoot the heavier bullets like a 105 gr and carry more energy but not at the same speed as the 60. His opinion was that the 87 gr bullet was the optimum weight for the .243 bore, bullet construction not considered. Going to an Ackley chambering will net you about 200'ps more over a standard 243 chambering for the 87 gr bullets, per Ackley data. But you will burn 5 grs more powder to get it. Is it worth it to you? Is velocity the prime reason for wanting an Ackley chambering. If so, the 6mm/284 is eons ahead of the Ackley chambering pushing 100 gr bullets faster than an Ackley can push an 87gr. If you just want something exotic, Ackley is a good choice as is the Nieomiller where the shoulder is slightly pushed back yielding the sharper shoulder with the sides blown out to give more case capacity. You also get a longer neck which is suppose to help with holding the bullet straighter in the case for less bullet yawl. But ultimately you need to decide what it is you're looking to achieve by going the different road. If accuracy is the quest, consider a 6BR chambering. The guys are now shooting prairie dogs (targets) reliably at 1 mile with this chambering with 95gr Bergers at 3100'ps. So consider what you are trying to achieve and then pick a chambering. There is no right or wrong answer by the way.

[Doyle]

In .260, you can get an extra 200fps easily out of switching to AI.

[tulsamal]

The best of the AI's is the .257 Roberts AI. I've got one and it can approach 25/06 loads while using less powder. Very mild mannered and easy to shoot rifle. And _so far_ I haven't had any big problems forming AI cases.

Gregg

[Zak Smith]

In .260, you can get an extra 200fps easily out of switching to AI.

With about ten guys shooting .260 Rem locally, and one shooting the Ackley version, this is not our experience at all.

Prior to Reloder 17, the two most common .260 Rem loads for long range were a 139 or 142 using H4350 or H4831SC at 2830 - 2860 fps. The one guy shooting .260AI got about 2950 fps on his first barrel. Second barrel was 2900-2930.

With Reloder 17, the standard .260 Rem shooters are now getting 2900-2975 fps. The .260 Ackley guy is still using H4831SC.

I am loading a 139gr Scenar at 2900 fps using RL17 in my AI-AW.

[t45]

Im happy with my 243ack. I dont see myself changing anytime soon.

[Nomadicone]

What Steve4102 said. I don't have a 243 AI but I do have a 280 AI. The entire range of the AI calibers is great. Too bad they never caught on better. If it were me I'd send it to Hart and have a Hart barrel screwed on it. Of course there are many great custom barrel makers I am just partial to Hart from my old benchrest days.

[GeauxTide]

To amplify Zak's comments, the 260 has a perfect expansion ratio - the bore to capacity. Most of the AI calibers on the 2 inch(308) case don't gain any marked improvement. If you shoot standard stuff in an AI, you'll have some accuracy/velocity challenges.

PS. Just thought of one other thing you might consider. When I had my .338-06 built, I had it throated for 250 Partitions. For most hunting, I use 200 Hornady or Speer. In a 22" barrel, I'm getting 2810 over the chrony. I had the same thing done with my 6.5-06, throated for 140 SierraBT. The 6.5 gives 3200 with 120s, 3100 with 125s, and 2935 with 140 Hornady - in a 24" barrel. That is 264Win territory.

[SL1]

so there is little increase in velocity FROM THE CAPACITY INCREASE. However, by making it impossible to fit a standard chamber, the AI case shape change makes it "safe" for handloads to exceed the SAAMI pressure limits in strong modern bolt actions for some of the older cartridges like the .257 Roberts. Going to the higher pressure can substantially increase velocity.

SL1

[Zak Smith]

Handloads generally shouldn't be swapped rifle to rifle without testing anyway.