Why not that much interest in the .270 Ackley Improved?

[Alibiiv]

I keep asking myself the same question, curious if the readers on the forum would provide some answers. I am a fan of the .270 Ackley Improved. From my stand point it is a great cartridge that is a great round for hunting whitetail deer and game of the same size and category. I always look for any information/articles referencing this cartridge, yet there really is not too much information relating to the cartridge. I recently contacted the folks at HANDLOADER Ammunition and Reloading Journal. When I asked the personnel there about any articles relative to the .270 Ackley the representative said he would look into past articles. He came back only to tell me that they only made reference, way back in 1990, to the .270 Ackley Improved "magnum", and no articles "at all" in reference to the .270 Ackley Improved. This cartridge bridges a number of cartridges, including the high-speed 26 and 27 Noslers, runs along the same ballistics of the 7mm RemMag and the .270 Weatherby magnum or better, only using a lot less powder. Yet... none of the big-gun manufacturers have given it any interest of mention. I have experience with two rifles that we had made a number of years ago using 26 inch, 1:10 Lilja barrels. I know there are some hard-core followers of the .270 AI who have rifles with 1:8 twist barrels who are hurling the heavy, high BC bullets and who are very happy with the round. We get between 3100-3300fps with 150gr Nosler ABLRs, and the rifles are tack drivers. The 3100fps seems to be in the node for our particular rifles, and... the brass seems to hold up better than the 3300fps load. I consider this round to be like a .270 WSM/6.8 Western on steroids. Although these rifles have been around for a number of years now, we have only now started to play with the 130gr and 140gr bullets. From what I remember P.O. Ackley stated that the .270 Winchester cartridge was already too overbored to bother improving, but...that was many years ago and there has been a tremendous amount of improvement to the many powders that are out there and available. I am just curious about what other readers thoughts are on this subject? I have posted an older photo that I have posted on the forum before just for reference. We call our rifles "two shot" rifles because the barrels are profiled after the original Ruger 77 barrel contour. After two shots the shots start to open up, so we stick to the two-shot groups.

 

[Bghunter338]

Thank you for sharing, I two have q love for the 270. We've had 3 270wins, 270wsm, and now I've been working with the 27 Sherman mag. With a fast twist barrel and heavy for caliber bullets they have now makes it a wildcater's dream.
Always thought about a 270ai way back in my teens and now I'm 50

 

[338 dude]

I like my Tikka 270 very much!

 

[nhenry]

280 AI's the reason it never became a popular wildcat. Same ballistic potential with more bullet options. It's also a huge improvement over the standard 280 Rem in factory configurations, whereas the 270's pressure is already spec'd at 65k. The 270 AI is great, don't get me wrong. It just doesn't do anything that the much more successful wildcat-now-standardized cartridge didn't already do.

And before anyone calls me out as "wrong," there is no way on God's green earth that a 270 AI can beat the velocity of a 280 AI using same-weight bullets at the 65k psi threshold. Same thing with 25-06 and 6.5-06 (and their AI's). You may be able to go over that at a higher pressure, but I won't.

 

[MagnumManiac]

runs along the same ballistics of the 7mm RemMag and the .270 Weatherby magnum or better, only using a lot less powder

This right here I have to totally disagree with.
I have had most of the Ackley cartridges based off the '06 cartridge, and having my Pressure Trace II, I can assure you most people running these are running north of 75,000psi to achieve the velocities they are quoting. Not once did the 270AI come within 150fps of the 270 Weatherby, using pressures within norms. It is true that an AI case will hide excessive pressure very well, and it is an unknown until something nasty occurs.
After saying all that, the 270AI is a great cartridge, but you can easily boost performance with quite a few cartridges today that leaves the 270AI way behind.
Improved cartridges definitely have their place, which is why I designed my own on 416 Rigby Improved cases in 30 cal, 33 cal & 375 cal. Looked at 41 cal, but the OAL is way passed 4.1".
Of all the AI cartridges I've had, only 2 are still in the stable, my 22-250AI, 1:7" 30" barrel and my 257AI. Both of these give the best improvement that I have seen. The worse improvement for me was a 35 Whelen, less than 100fps and most bullet weights only achieved about 60fps.
Another great case is my 375 Weatherby, instant 200fps gain, but it does use 10+ grains more powder.

Cheers.

 

[buckbrush]

This right here I have to totally disagree with.
I have had most of the Ackley cartridges based off the '06 cartridge, and having my Pressure Trace II, I can assure you most people running these are running north of 75,000psi to achieve the velocities they are quoting. Not once did the 270AI come within 150fps of the 270 Weatherby, using pressures within norms. It is true that an AI case will hide excessive pressure very well, and it is an unknown until something nasty occurs.

You're not the only one who disagrees. Nothing but fuddlore with the blanket less powder more/equal velocity statements (and safe pressures).

 

[comfisherman]

You're not the only one who disagrees. Nothing but fuddlore with the blanket less powder more/equal velocity statements (and safe pressures).

The safe pressure issue is the sticking point. There is absolutely no magic potion of less powder more velocity, without an accompanying pressure. Case dimensions and modern brass seem to cover what would have been a multitude of pressure sins.

Have buddies convinced they found the mythical ackley that does... ya know the ones that run two or three case clases below and "equal" velocity. Can't really apply 1950s brass wives tales with modern primers, brass and actions. Doesn't take away from the fact that lapua and adg brass appears to be able to last even at elevated pressure settings. Wildcats and "safe" in the modern context are a tough one, just so much saftey in a modern action and components.

3300 would be hauling for a 270 wsm, that runs at a higher established pressure with 8 grains more case capacity on the 270 ai. 3100 is still pretty fast, having shot out a couple 270 wsm barrels that would be scooting for a consistent all weather 150 load. Brisk load would be my thoughts.

 

[FEENIX]

Raoul (@Alibiiv), IIRC, we had this conversation before.

Q: Why not that much interest in the .270 Ackley Improved?

A: When I did my research, the overwhelming information available was bullet choices and barrel twist rate. I built mine to propel the 165/175 Matrix and a 30" Lilja 3G 1:8", so neither was a factor for me. It propels the 175 Matrix at 2996 FPS, which is not too shabby, IMHO. I reached near 3100 FPS with H4831SC, but the group opened up, and unwanted pressure signs started showing. Others are reporting 100 FPS with RL-26, but I did not explore it.

I have no issue with the lack of interest. I believe only a handful of us are here, and that's how I like it.

 

[Buffalobwana]

When did Ackley start making his wildcats?

Back in the 50's Verne Junke at Saturn Arms in Reno was chambering the 270 AI, but he was calling it the 270 ICL.

My dad had one built off a Mauser action. Very snazzy rifle for the times.

It shoots great, extremely accurate. 1/4" groups were possible if you did your part.

I still have a box of original ammo from the 50's.

 

[Buffalobwana]

From Wikipedia on the 270 ICL.

"ICL cartridges are wildcats based on conventional cases in use at the time. They feature a 45 degree shoulder[3] and the sides are straightened out compared to the parent cartridge. Most of the cartridges are considered improved cartridgessince they simply create more powder space while maintaining the same caliber as the parent cartridge."

Is AI a 40 degree shoulder and sides straightened out? ICL appears to be a 45 degree shoulder.

 

[FEENIX]

When did Ackley start making his wildcats?

Back in the 50's Verne Junke at Saturn Arms in Reno was chambering the 270 AI, but he was calling it the 270 ICL.

My dad had one built off a Mauser action. Very snazzy rifle for the times.

It shoots great, extremely accurate. 1/4" groups were possible if you did your part.

I still have a box of original ammo from the 50's.

IIRC, hopefully, others more knowledgeable will chime; I do not think Ackley explored the .270. Not that it matters in my decision-making.

From Wikipedia on the 270 ICL.

"ICL cartridges are wildcats based on conventional cases in use at the time. They feature a 45 degree shoulder[3] and the sides are straightened out compared to the parent cartridge. Most of the cartridges are considered improved cartridgessince they simply create more powder space while maintaining the same caliber as the parent cartridge."

Is AI a 40 degree shoulder and sides straightened out? ICL appears to be a 45 degree shoulder.

I considered the .270 ICL in 2012 before deciding on the .270 AI. I went the easier route because the AI makes reamers and dies more available.

I went with the 45-degree shoulder with my .338 Thor (NMI).

 

[7mm man]

270 AI would be great

 

[CogburnR]

I have possibly the first 270 Sherman. It basically does what a 270WSM does, which is great. The one thing about it in my humble opinion is that traditional pressure signs don't show up until it is well over pressure. Same thing happens with my 300RUM. Watch the case head expansion, everything looks good then a new primer falls out.

 

[P7M13]

I have three Ackleys, two 6.5 BJAIs and a 6mm Rem. A fourth one, I shot out.
I didn't build them for speed, though there was a time I chased that Holy Grail.
I could never achieve the velocities that some shooters claimed without venturing into high pressures. Somewhere along the way, I learned the value of "one hole" and I stopped chasing velocity around a decade ago.
Now I enjoy long brass life and small groups.