does an improved case really improve

[ARlife4me]

For most they'll say "yes by far" for some known and unknown reason! As for now (the only info I can compare on) will be the AI (artificially maybe intelligent) versions. The case length being the same, increased shoulder angle and a tad bit more neck length and body length. With some boat-tails being long it uses the extra case body would-be powder storage unlike the longer shoulder area of the not so improved case. This isn't accounting for longer throated barrels, only saami coal lengths, actions restrictions and/or mag lengths. If you're loading where just the tail is past the neck (so to as having bearing surface to keep better neck tension) and no waste room in the case for more powder. What other possible gains are there from an improved case? Less stretch, more case life, better extractions and what else is there?

 

[Zen Archery]

Yes to the last 2 sentences. Any improvement is an improvement. Those who Acklys (minus 280AI) are throating for long/heavies to get the most out of their build.

Biggest negative is once you AI a caliber you're stuck with it unless you find other weirdos who like custom cals.

 

[Tiny Tim]

Even in SAAMI AI chamber, most parent cartridges shoot extremely accurate and drastically reduced case trimming on some after fire forming.

 

[can1010]

beyond all the normal reasons case stretch, case life, max velocity. one that isn't talked about much is performance with specific powders and bullets to get the best possible overall usage in a particular discipline. the 6GT is a prime example just enough case capacity for heavy 6mm bullets to get sufficient velocity with a full case of temp. stable powders with low ES at an OAL. that is mag friendly.

the 6GT started as a highly improved 6.5x47 lapua case that was good enough for brass makers to pick it up. they shortened the body, 35 degree shoulder and longer neck. classic reason to improve a case just make it better

 

[Mikecr]

Where the AIs really shine is when you plan/choose the best AI capacity for a given bullet -for accuracy.
This is like choosing a 6Dasher over a 243Win for 105-115gr bullets.
The Dasher (a 6BR improved) has more accuracy potential in the long haul, because you can push an improved case harder.
You can viably push a load into better efficiency.

This brings up another attribute of improved cases: better efficiency.
They keep more powder burning in the chamber instead of later down the barrel, or at the muzzle.

 

[Salmonhead]

The biggest improvement in velocity is simply running at higher pressure so you're not comparing apples to apples. Barsness details this well in his books and it makes total sense. If running at equal pressures, the gain is very minimal. Most hand loaders run higher than book pressure. No gains are free, it has to come from something and the nominal powder gain isn't enough to account for the velocity claims.

 

[Rick Richard]

I had one Improved cartridge and to me it was not worth the fire-forming process. So, to me not worth the minimal gain.

 

[ARlife4me]

The biggest improvement in velocity is simply running at higher pressure so you're not comparing apples to apples. Barsness details this well in his books and it makes total sense. If running at equal pressures, the gain is very minimal. Most hand loaders run higher than book pressure. No gains are free, it has to come from something and the nominal powder gain isn't enough to account for the velocity claims.

Then it's like comparing 6.5creed and 260rem. Though it's not an AI case, but still people compare. True you do need to use equal pressure to be fair! Not just the AI cartridges/cases, but any so-called improved case. Looking at the 22-250 case taper against the 22creed I can see where the creed is a winner for case life. With a more of a cone shape it would have more force toward the bolt, but others might disagree?

 

[Mikecr]

The biggest improvement in velocity is simply running at higher pressure so you're not comparing apples to apples.

Ackley did not improve cases for more MV. He knew, as everyone does, that you could always pick a larger case to get more MV.
His improvements are for case life, lower bolt thrust, and efficiency.

 

[Bob Wright]

The AI chambering was built around shooting the parent cartridge in it, if needed.
So, that's a nice side benefit.

 

[Lefty7mmstw]

Most ai cartridges are a joke. Even the 280ai gets most of the gain from a throating change. They aren't more efficient either. Efficiency drops off as capacity goes up. The two things they offer is lower case stretch and lower bolt thrust. I'll go to a bigger cartridge or bigger bore every time and not molest my chamber.
As far as efficiency, the most efficient cartridge I shoot is my 35 Whelen... I'm pushing 220's around 2700 fps from a 30-06 case necked up. It'll make a lot of rifles envious accuracy wise too; it's regularly 1/2 moa with screamer groups coming in as low as .15 moa..

 

[Koda_]

Biggest negative is once you AI a caliber you're stuck with it unless you find other weirdos who like custom cals.

True but probably only because most don't know they can still shoot the parent case in it. There's really no downside to the AI chamber and those that reload will appreciate having the AI chamber.

 

[wasskeet]

There's one thing that is just about guaranteed that an improved cartridge will improve - the life of your trimmer

 

[JSHKS]

30-06AI, took more powder to equal the parent case with a 165. 180's were a bit better. A200-220 there was a benefit.
I declared it a wash and sent it down the road.
Have a 6TCU now and a 22Clark in the works. The 6TCU I run 55-70 grain as hard as I can. The Clark. I am hoping to get a 75 grain bullet up to around 36-3800. Barrel is 24", the next one will be at least 28" maybe longer.