Home Forums Hunting & Shooting Custom Rifles & Wildcats great explanation of the Ackley Chamber

or if you wanted it explained more better..you could call Roger. He worked with P.O. for years...

Pert near as good as if you heard it from the horses mouth so to speak.

jus sayin

or read it in ackley's handbook and get is straight from the horses mouth.

Cat's explanation is better than Ackley's...more advanced.

Compelling but somewhere around his 2nd post he was wrong, no need to read any further.

He is right on the money when he explains why .004 crush is not enough.

Ackley did a lot as a marketing ploy and the way he set up chambers to fit the guy that wants to shoot factory ammo in his chamber...really bad idea...good for selling guns, bad for wild catters.

If you read further in to Catshooter's explanation, AI shooters will learn a lot.

Cat shooter knows his way around a lathe building guns, and also a pro in the ammunition business.

I'm afraid CatShooter is correct and incorrect. The correct headspace is .004" shorter(they actually do make headspace guages for Ackley cartridges). When you chamber for an Ackley cartridge the juction of the neck and shoulder becomes the pinch point because you are changing the shoulder angle, so the reality is you may in fact have .030-.040" crush at that point(of the neck and shoulder), but the guage is only .004" short. He is overstating the case head separating issue, the real issue is misfiring while case forming. When fireforming an Ackley cartridge the point of the neck and shoulder is the only support the cartride has - if you don't have some difficulty closing the bolt you will have a misfire because when that firing pin smacks the back of the case it's only supported on a corner rather than a nice wide shoulder.

As far as the 280 Ackley is concerned, I believe Dave Kiff told me that Nosler was forced to change the dimension because Remington had produced some custom shop rifles with a shorter headspace dimension before it was SAAMI approved. He also told me the old reamers would work fine, the only thing that changed was the new Nosler 280 Ackley headspace guage.

Dale

OK ,since it is on the internet and a guy who is a good machineist says so it must be true.... Wow....

I have been building and shooting AI'ed cartridges since WAY before there even WAS an internet and I think PO Ackley knew what the ever luvin hail an Ackley Improved cartridge was!!!! Sheesh, if you want to do it some other way, great, but an AI'ed round does not have to be a hard fit with factory ammo. That is just plain ridiculous. It surely CAN be made that way, and some gunsmiths might insist on such to make themselves seem or feel better than others for no good reason but it sure don't havta and really shouldn't be that way at all.

There is quite a bit of difference in headspace just between variations and manufaturerers of even SAAMI spec ammo, and we ALL stretch the cases a little when we fire a round for the first time and begin to intruduce initial incipient head separation. Some of these guys, thoguh have seemingly already had thier heads separate.....

How much we stretch a case out in firing it is subject to a number of varialbles not limited to just the chamber and headspace but can include such things as action springiness (See SMLE and Savage 99 for details here) and the makeup/hardness of the brass.

"Substaintial set back" is used to make some gunsmiths feel and market themselves as 'super special better than the others' gunsmiths and THEY are the ones I would be wary of. There are a number of ways to fireform the brass to one's chamber, AI'ed or not, and then use a minimalist approach to re sizing the cases from there on out so as not to over work the brass whether AI'ed or not.

We have been over this stuff and doing it since the 40's, folks. There is no need to re invent the wheel or make it harder than it is. One of the STATED advatnages of the AI'ed case, in ACKLEYS OWN damn BOOK for crying out loud is the ability to safely and easily use factory ammo in said chamber! And, it WORKS and works really, really well. Has been for quite a few decades now and counting.

I know my way around some wildcats and AI's, too and have been at this game for a few decades now. Long enough to see and smell and hear zebrapoop when I see it and call it just that. Crush fit of tens of thou on an AI'ed case is just that.

lathedog/dale

what you have said makes more sense than 99% of the stuff I have read of late on the internet. Well stated. A small amount of crush at that juncture would make some sense. Still could easily use factory spec ammo without needing a hammer to close the bolt on the round. We used to make a lot of chambers without even that much setback however and just used bullets set into the lands a bit for a temporary headspaceing or pre fireform with fast burning powder topped with some kind of filler. Then, set our loading dies to not push the shoulders back too far. not all that hard to figure out.

I wish I had the means to show the two chamber prints superimposed on each other. They say a picture is worth a thousand words, in this case a picture would be worth a hundred thousand words.

That's right......you're the guy who rechambers these things by hand, with the barrel still screwed on.

I Did that once, with a pilot for the receiver to help keep the reamer and handle straight and the job was little more than a chamber cleanup going form 300 Win to 300WBY. Would not try such as a whole chambering job with a barrel blank. Worked just fine, rifle shot terrific and is still in use today almost 20 years after. Been playing with stuff like the 22K (Kilbourne)Hornet and 220 Weatherby rocket (an early 220 Swift improved) since the 70's. Not as long as some here, but a pretty long time.

And once again, if anyone knows what an ACKLEY improved cartridge should work like, do and be, that person would be Parker O. Ackley himself. His works and writing are still with us for reference.

That and 60 or so years of Ackley Improved cartridge collective experience before all of the internet guru's were chucking up baby formula, let alone a lathe.

Didn't know Catshooter was still around.
Always got a kick out him.
Ask him why there is more power available in 89 octane gas than 87.

Last year an old timer horseshoer who is still shoeing in the same town as me told me I was making a big mistake utilizing any of the new technology. After all....he'd been shoeing when I was still in diapers. I'm not sure if my first, second, and third place horses in state this year mean squat or that I'm still part of the new and upcoming crowd of diaper kids. Heck.....his closest horse in state was more than a second slower than my slowest runner at state this year. I will readily admit I learned a huge amount about horseshoeing from a couple oldtimers but had I listened to masses of old shoers out there I'd of been steered straight to the mentality of an old dog can't learn new tricks. Then your just done learning period.

Shod

Yep, a big difference between a guy with 50 years of experience and one with 1 year of experience 50 times.

Or in the case of a certain poster, one year of experience fifty years ago.

I wish my smith had read something about Ackley chambers.The 25-06AI chamber he cut in a virgin .25 cal. barrel will not give me any kind of crush fit from factory ammo,and I'm getting case stretch in front of the web.I guess I'll have to oil my fireform rounds.He says all is fine but it's the only one of 4 Ackleys I own that does not give me crush on factory rounds and I don't like it. Monashee

Monashee, forming a false shoulder will be easier and will net you the same results as oiling but won't stress your bolt nearly as much.

your shoeing made your horses faster than his..???????

I think you've mixed peaches and nectarines here....

You're overly magnanimous today, Don will appreciate it.