280 Ackley Chamber

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I think what Shep is getting at, is that reamers don't cut chambers to the print depth. The chamber is cut to the depth of the headspace gauge. As shown in his example, the headspace gauges are the same. Therefore it's doesn't matter what the length is on the reamer print.
 
Spot on Tim. I don't know one Smith that says where is that Reamer print so I can cut this chamber to the proper depth. They say where is my go and no go guage. I built them with both guages and they end up the same. The problem is you can't just measure the guages because they hit the chamber in different spots. The Sammi guage with the 40 shoulder hits the full shoulder but a regular go guage hits the neck shoulder junction. So you really can't measure them against each other. But dropped into a cartridge head space tool they both sit flush. Or on a complete chamber both guages show the same amount of bolt close on them. If the Sammi chamber was really .014 shorter the bolt wouldn't even begin to close on the standard guage. Or if the Ackley chamber was .014 deeper then the Sammi no go guage would just let the bolt cam over easy and still have play. But this is not what happens. I do 5 different AI Chambers and use the standard go as a no go on all of them. Got the Sammi guage for 280AI and was a waste of money because it shows the same as the standard go. I just ask other Smith's to try both guages and see what they show. I know what it will show because I've done checked at least the last dozen or so I built the last couple yrs. The proof is the guage in the chamber not the numbers on the Reamer print.
Shep
 
I not arguing just stating facts that are true. I've been doing Ackley Chambers for over 30 yrs. Besides your the one saying it's wrong. I have physical proof and I've showed you 2 references that physically sHow you they are the same. I know for a fact that if you chamber a barrel with the Sammi guage and another with the standard go as a no go that those Chambers are in fact the same. How many of each have you chambered and measured. How many Ackley Reamers and guages do you own. How many different Chambers have you measured of each. Obviously none. It's ok to think your right. You looked at a print comparing an apple to an orange and your right. They are both fruit. But in the real hands on physical world they are the same depth. The only way they could be slightly off is if you use a no go on a Reamer with a different neck diameter. And that would only change it a thou of 2. Be glad to have you come to the shop and you bring your Reamer and guage and I will do 2 chambers. Sammi and an original AI. Actually I can show you 4 280ai rifles done to PO spec. What's really weird is nosler 280ai brass fits them all perfectly. They should absolutely be .014 short and then grow .014 when fired. They do not.
Really it can't get any simpler than dropping both guages into a case headspace tool and see if one is .014 different. Hard physical proof. They are not different as shown in the article and video. Wonder how they got that solid steel guage to go in that hole .014 deeper. Explain that. But your right. I'm wrong. Oh well I can't win them all. And yet you probably have never even measured one or 50 of them. Or have the tools to do so.
Shep
Some other sources and references for you to argue with. Besides me...





 
The proof is the guage in the chamber not the numbers on the Reamer print.
Shep
So if the headspace dimension as you cut it with your tools and machines doesn't comply with the numbers on the design Reamer print, the Reamer print is wrong, and your chamber is correct? If your chamber doesn't comply with the numbers on a SAAMI chamber print, the SAAMI chamber print is flawed.

Now it's clear why we'll never come to a common consensus.
 
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I've been doing Ackley Chambers for over 30 yrs.

"Since 1946 Redding has provided the reloading marketplace with innovative, American Made products of the highest quality."

2021 - 1946 = 75 years. Not that math counts for anything. Maybe I got the math wrong. I give Redding at least 40 years over you. Could be as many as 45 years extra experience by Redding.

 
I have read the posts and there is in-depth conclusions made. I have what I assume is the traditional 40 since it was chambered in 94. I have fire formed using 280 rem shells some I just bought the 280 and shot them to fire form. I have formed with wads to not use rounds down the bore. So far after fire forming and with 160 Noslers using Rl 19 no more than a cup of coffee I have still grouped under 1/2 inch. My take from all this is that I can use nosler shells and load and shoot them and they will fire form to my chamber with a shorter neck?? At some point I will shoot out this barrel (maybe not) I carry a Medicare card now and then I will deal with the madness that was made when 280 AI was designated Saami. Sometimes people can be to smart for their own good!!
 
As per post 48. Redding is saying their 280ai is different than a 280rem imp. 2 different cartridges. An improved can be any length you want. An AI is specifically made .004 short of parent cartridge. Post 49. I never said any Reamer prints we're wrong. I said gunsmiths don't chamber to the numbers on them. We use Sammi spec guages to make a chamber the correct depth. So if I'm using a Sammi spec 280ai guage and a standard 280 go guage as a no go and they both give me the same depth than I conclude it's the same chamber. The Reamer is cut the same and it's the same depth in the barrel. The intent of making the chamber .004 shorter from Ackley was so parent brass would have a crush fit and be easier to fireform. Now if nosler made the chamber another .014 shorter that's .018 shorter than parent brass. A standard 280 brass would never fit in a nosler chamber. Yet they do fit with a slight crush fit. Just like the Ackley is supposed to.
Shep
 
A worthwhile read: "Handbook for Shooters and Reloaders", consists of 2 books written by P.O. Ackley. It doesn't address the new SAAMI spec .280AI, but it is "the" reference when it comes to all the other Ackley Improved cartridges. Here's another read; https://www.redding-reloading.com/tech-line-a-tips-faqs/133-280-changes I normally don't go to places like reamer rental companies when I need to compare prints. Those may be correct, but to be honest I didn't even look at 'um. I go to www.saami.org for industry standards. The 'traditional' .280 Ackley won't be listed there as it is a 'wildcat'. If I need a print of a 'wildcat' I go to JGS or Dave Manson. PTGs' customer service is so poor I'd trust nothing provided by them. With the current unavailability of all things related to reloading I would opt for the SAAMI unless you are willing to spend for a custom made die set. By the way, there is no 'factory' .280 Remington on the shelf, either,,, to fire form in a 'traditional' chamber. I'm done here, done all I can do on this subject.....
Good luck trying to find those books. I bought mine back in the late 80's. I tried to find some a friend a few years ago with no luck.
 
Good luck trying to find those books. I bought mine back in the late 80's. I tried to find some a friend a few years ago with no luck.
I stand corrected. Amazon seems to have some. It seems that some were reprinted in 2013 and it is also available on kindle, but I don't know if it has both volumes. Oh, modern marvels.
 
As far as Redding having more experience. How many chambers in actual rifles do you think Redding has done? Half the dies I get from them won't set the shoulder back on a perfectly cut chamber. Meaning minimum headspace. I routinely have to put their sizing dies in the lathe and cut .005 to .010 off the bottom to get set back. Every custom Smith I know has had to do this. Or grind the top of a shell holder down. I choose to shorten the did so any shell holder works. I use almost exclusively Redding s type dies for everything I own. I reccomrnd them to my customers too and fix half of them for my customers. I love my Redding dies but it seems no 2 are the same. I have 3 sets for 300wsm and every one of those sizers give me a different result.
Shep
 
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