Sheister,

My 375 Improved barrel was prechambered by Douglas. I have had the rifle for about 30 years and it's very accurate as yours is.

What I don't understand is how my chamber will stretch webs and have short case life and yours may not. While my chamber may not be perfect to me it's the faulty design of the improved chamber that allows the case to stretch on the first firing. I don't see how an 300 AI could be any different.

The way mine is throated I may be able to chamber and safely fire the .375 Weatherby. But the ammo is so expensive and so is the brass.

Sam Taylor,

I am sure your discussing only rimless improved rounds. Just try a belted or rimmed cartridge and you will be shaking your head.

A friend has had a 6mm Krag Improved in a nice High Wall for a long time. He says that there is no way to get more than 6 shots from a case. That they separate at the heads.

I don't buy the longer case life with improved rimless cartridges either. Would somebody post the facts of how many times say a 30-06 case was reloaded vrs the same lot of brass from an improved chamber?

There is data on the web by Fred Huntington on case life. I will look for it later.

Case "life" has too many variables outside the control of the individual for me. I will vouch for less case stretching with conventional dies, though. As for the original question, I like the 250-3000 AI best though my 375 H&H AI was the easiest to work with. Others I have or have had are the K-Hornet, 280 AI, 6MM AI, and 338-06 AI. All worked well enough.

Savage 99,

You are correct. I have no experience with improved cartridges based on either belted or rimmed rounds, nor do I have any interest in doing so. I'm still trying to figure out the true reason for the original post.



For the most part, if someone wants more velocity than a standard cartridge can provide, it usually makes more sense to simply move up to a bigger case. There are noteworthy exceptions, of course. I have no valid excuse for jumping into the world of Ackley Improved cartridges, other than just being a gun nut. I'm the only one in our hunting party each deer season that doesn't use a vanilla factory offering. I usually take a buck and two does each fall, and they don't seem to be any deader than everybody else's deer. I have to admit, though, that I really like mine.

I've never had a problem with Ackley imps stretching as you say you do. Have you ever had the headspace checked? Douglas does very good work, but the installing gunsmith has to do the final headspacing on a deep-chambered barrel. I have a new 7x57 Ackley imp deep chambered from Douglas, so I am very familiar with this requirement. I have Ackley imps in 6mm Remington, .257 Roberts, .280 Remington, 8mm-06, 35 Whelen, 375-06 and .375 H@H. My most user friendly has to be the 6mm Ackley which has furnished some of the highest velocity gains and is the most accurate rifle I've ever owned. It is a factory sporter barrel with a standard
twist and it will handle bullet weights from 58g V-max to 100g of several makes and will shoot any of them into 1/2" groups or less. My smallest group was last Thursday with the 50g IMR4350 and 70g ballistic tip load going into .078 for a 3 shot group. There have been two loads with the 58g V-max which shot in the .15 range. There is much more to the Ackley designs than velocity increase...

Nothing really missing in my rifle battery, just looking for something to tinker with!

Hey Smokn-- i like that WWIII comment-- purdy good. You know-- considering the extreme taper in the parent case-- i bet if a guy AI'd the Swift with a faster twist for the VLD's and A-Max, and a 26-28" barrel, i bet you'd see a real long-range varminter close enuf to the now popular 22-243/6mm's to have some noticeable increase in effectiveness over the parent case. There's some info. floating around on the Swift Improved and variations, but not a lot about its varminting application with the higher BC bullets. There's some info on it though in some of the back issues of TVHM, and Steve Hanson wrote about it some in his book Varmint Hunter's Odyssey. BUT, maybe the 223 WSSM will put it out of business, ehhh???

You are a jackass on the campfire and just as big of one here. change your posting id to DFC-II.

savage99; If you would oil the case for the first firing it wouldn't stretch.
Good Luck!

"savage99; If you would oil the case for the first firing it wouldn't stretch"

Irv,
If he did anything to help the process along what would he have to bitch about? What were you thinking? Jim

Oiling the cases does help. I have done that on the .219 Improved since the 1960's as I mentioned above.



What is the specific case life improvement with fireformed or improved chambers vrs conventional? If you don't mind lets keep the 30-06 as an expample but if anyone has any data go ahead.



Where does a 30-06 case fail in reloading in a normal chamber? Does it fail from weakening at the web? I don't find that they do, not at all in fact. Do they fail at the neck by spliting? Of course they do but so do all other rounds wether they are fireformed or not. How could an improved chamber help the necks unless it was cut with less expansion of course. But that could be done with any conventional standard chamber.



What is the case life improvment? Be specific.

Jim White,

Please read page #1 of this topic. You will find that I mentioned oiling cases before anyone else did! It does help as the case does not stick to the chamber as much and it forms better with less stress to it.

The problem with oiling the brass is that it's just a pain.

tiggergate,

How can one have less case stretching with a fireformed case and also have less bolt thrust?

The only way I can think of is that if the recut chamber is tighter or the dies fit better. That could be done with any chamber.

Which is it or neither?

I dont oil cases because it can potentially hamper the seal between the brass and chamber resulting in excessive bolt thrust. This is especially true during fireforming. Clean brass and a clean chamber should be all you need. If your getting excessive stretch at the webbing then you either have a bad chamber, really bad brass or are loading too hot. Do you get a crush fit with factory cases?

Western,

You can't get a crush fit with a belted improved chamber as they fireform way out on the neck. One could design such a chamber however. Ackley's design here is really faulty. It's the same on the rimmed designs. Not good at all.

I get good sealing on fireforming with oil. Why not?

Moreover the correctly designed improved cartridges were not started by Ackley at all but made by Lysle Kilbourn.

My comment is based only upon my own experience. I simply do not have to trim the Ackleys I have had and I cannot say that about standard rounds. The worst have been 220 Swift and the Hornet. Brass is obviously flowing toward the necks in these and I will leave the reason "why" to more educated people than me.

wstrnhunter: The idea is to break the "seal" between the case & the chamber. With the case stuck
forward it expands to the rear at the "stretch" line. Bolt thrust is the same oiled or not. At around 40 KPSI
the case comes back in a dry chamber."Improved" cases have the same "thrust " as conventional cases.
Good luck!

Stepchild,

The really really bad so called improved cartridges are the rimmed and belted ones. The experimenters of the past should never have used belted cases for magnums. Rimless cases should have been used. We went over this and the belt is a useless and troublesome appendage except of course for cases with no or inadequate shoulders. We would not have cartridges like the 458 Win for instance and in that application for a magazine rifle they are a good idea.

Kilbourn did it right and Ackley copied him. Then Powell Miller, Ackley, Hutton and others got lazy and just blew out belted cases willy nilly. Not a good idea.

What they should have done is just to use the 404 Jeffrey case or maybe the 8-68 and set the barrels back like Kilbourn did.

Oh well, it's all a lot of fun anyway as there is that miracle of the fireformed case and they look cool.

Don,
This thread has been beat to death. I'm ready to leave it lay. There's no point to continue with it.
Stepchild

Savage99,
In your last post you said that "Ackley copied Kilbourn"
What is your source for that statement? Seems to me they were both very active at about the same time and I am curious how you came to the conclusion that Ackley copied anybody. Jim

stepchild2 and others,

Good has come of this discussion as now we are talking to each other. I hope it keeps on this way.

Jim White,

I read that Kilbourn was the first to cut an improved chamber. Lysle D. Kilbourn was a NY state gunsmith who came to work at Lyman's in the early 1950's as their reloading technician.

I am looking for the reference but I did not find it in an old Ideal handbook as I expected.

Don,
I said I was going to let this lay but I just can't do it.(caught my second wind) You claim to be a friend of Lysle Kilbourn, I would say probably more of a worshiper. All of your negative posts about Parker Ackley are in defence of Lysle Kilbourn, aren't they? No answer required.
With out knowing all the history, my guess would be that Lysle was envious of Parker Ackley, after all, who wouldn't be. He was(St. Ackley, I mean) an accomplished gunsmith, taught gunsmithing at Trinidad State Junior College, and an innovator extrordinaire.
Did you ever wonder why all the reamer makers have most of Mr. Ackley's creations on the shelf and the same applies to the die makers, why, because they are popular and they sell.
Nothing that I say is going to change your opinion(notice I didn't say thinking) and your not going to change mine or that of anyone that has an open mind.
No offence intended here, just say a prayer and ask forgiveness of St. Parker.
Stepchild

Don,
Not to degrade Lysle Kilbourn, but what did he accomplish other than the K Hornet? Are there any other cartridges that he can lay claim to? I live in a small NE Michigan township and I can't find anything on their(library) shelves about Lysle Kilbourn. Fill me in on what I might have missed. Thanks.
Stepchild

Stepchild2,



This is from "Twenty-Two Caliber Varmint Rifles" by Charles Landis (1947) "Lysle D. Kilbourn of Whitesboro, N.Y. is a woodchuck shooting gunsmith who prices his services in line with the quaint idea there are many more men prepared to spend a moderate amount of money to convert his favorite rifle into a .22 high velocity wildcat that are in a position to spend much greater sums. This is so unusual amoung custom gunsmiths that the author felt that it merited special announcement at the head of this chapter. There are today many who need better rifles but many less who are prepared to pay enough to purchase them. Kilbourn's rechambering will help some, for this reason."



Landis lists seven cartridges such as the .22 K-Hornet Jr., .22 K-Lovell, .22 K-Zipper etc.



In a later Ideal manual they show data for the K-222 and the K-220 Swift.



I met Kilbourn and he showed me how to set up dies back in the early 50's when he worked at Lymans. I never met Ackley but I like Parker very much. He is one of the all time great gun writers and experimenters.



I wish that someone like Ken Waters could write a book of biographies with maybe a chapter on some of the the riflemen of the past. Waters may be one of the few still around that may have known Kilbourn, Floyd Butler and others like Landis himself.

I would like to see a book like that also. I know that Ackley was Teaching returning GIs gunsmithing after the war and in 1947 he entered a collaboration with Trinidad Jr college and opened their gunsmithing school at that time as the instructor. The only thing I'm sure of about Kilbourn is that somewhere around 1940 he did the K-Hornet. Does anybody know if there is anything in print about some of the great old gunsmiths? The only ones I can find anything about is Harry Pope and Harvey Donaldson. I just got my hands on a book written by Donaldson called "Yours Truly" Very interesting reading. Jim