257 Roberts AI FL die problem

[roysha]

I recently finished building a 257 AI. This was done using the correct gauges (AI) and a new Shilen barrel. Fired formed the cases the usual way. I purchased a set of Bonanza dies (FL). When I went to resize the cases, I could not touch the shoulder before I ran into the shell holder. I can chamber the resized cases but it is very snug, about the way I like my varmint rounds to fit. Since this is a hunting rifle, I want a small amount of shoulder relief so I can freely chamber under hunting conditions. If a granule of powder or a tiny bit of anything got on a round or into the chamber I'm not sure I could get the bolt closed.
Sent size die to Bonanza and was told it is in spec. OK.
I am pretty sure I know what I'm going to do but I would like to know some of you folks would do.

[cutter10]

try some different shell holder had a similar problem with my 257 had to shorting the top of a shell holder.

[Ozark Howler]

I would suggest that you invest in a (RCBS) 257 Ackley Improved neck sizing die, since you're fire forming brass to your actual chamber specs, you only need to neck size after that. Also during fire forming the 257 I use a pretty stiff load to form new improved case. Even under the best of conditions though, you may lose some brass after re-reloading the Improved case. Some cases just seem to stretch too much and may experience case separation.

The 257 Roberts Improved is about the best of the 25's and has an ideal bore to powder ratio, it should have been adopted by the factory chamberings years ago (like the 22-250).

Good luck..

[Dale53]

The "general" rule is the change the least expensive item (if you spoil it the cost is less). You have two choices here, either remove a few thousandths from the bottom of the die or the top of the shell holder.

I would do as is suggested above - remove a few thousandths from the top of the shell holder and mark it so it is a "dedicated" shell holder only used for this purpose.

Dale53

[Lloyd Smale]

Ive never had luck with milling the top of shell holders. Everyone ive tried has broke and left brass stuck in the die. Anymore i just take some off the bottom of the die.

[Bret4207]

I've seen similar issues before. Anytime you get into a "wildcat" that doens't have the dimensions carved in stone you can hit this problem. We used to see it all the time with so-called "22-250's" built in the late 40's and 50's. They were all over the place on dimensions.

Relieve the bottom of the die.

[Ozark Howler]

I recently finished building a 257 AI. This was done using the correct gauges (AI) and a new Shilen barrel. Fired formed the cases the usual way. I purchased a set of Bonanza dies (FL). When I went to resize the cases, I could not touch the shoulder before I ran into the shell holder. I can chamber the resized cases but it is very snug, about the way I like my varmint rounds to fit. Since this is a hunting rifle, I want a small amount of shoulder relief so I can freely chamber under hunting conditions. If a granule of powder or a tiny bit of anything got on a round or into the chamber I'm not sure I could get the bolt closed.
Sent size die to Bonanza and was told it is in spec. OK.
I am pretty sure I know what I'm going to do but I would like to know some of you folks would do.

Allowing a small amount of shoulder relief in the improved case is going to shorten up the expected life of the brass considerably, as it stands, the factory case is stretched to about maximum in the fireforming process, continuing to move the shoulder back and reforming the brass will result in case separation (about 1/2" from the base), basically what happens is that the case stretches to move the shoulder forward, a nice close fit on the improved cases is actually best in my experience.

[roysha]

First a short rant: This was brought on by the use of this term on several other sites I visited in search of load data.

The "Improved" type of chamber or cartridge is NOT, let me repeat NOT a "wildcat"! The definition of a "wildcat" is a cartridge that must be made by the loader/shooter because NO FACTORY cartridge can be fit and fired in the chamber. You are entirely correct using the pre-Remington 22-250 as an example. Also the 25-06, 22-243, 25-284, etc.

The "improved" case/cartridge on the other hand, allows the firing of the parent cartridge in the "improved" chamber to either fire form the brass or as an emergency expedient, albeit with a small loss of performance, if the handloaded "improved" ammo is unavailable.

In regard to the dimensions not being chiseled in stone, this is probably quite true in many instances, however the Ackley Improved series were drawn up and the dimensions were/are standardized and available to anyone. The reamers, GO/NO-GO gauges are standard as are the reloading dies. The die set I purchased was a standard stock item. In this instance, I just happened to end up with a combination of manufacturing tolerances that created this particular situation. I have had this happen with standard factory rifles and ammo also. There are several die sets in the drawer that have had several thousandths removed from the bottom of the size die.

And yes, that is what I am going to do. Remove material from the die. I have tried the shellholder modification and although have never pulled one apart, I am always thinking it might happen.

"Allowing a small amount of shoulder relief in the improved case is going to shorten up the expected life of the brass considerably,"

I am fully aware of this and if this was a "varmint" round where I would expect to shoot several 100 rounds, or more, a year then case life might be an issue. However, this is for my purposes, a hunting rifle which I suspect will barely shoot 100 rounds in a year, more realistically, 50-60. It is much more important to me to be able to freely chamber a round in hunting conditions than to gain 2-3 extra reloads. I'm not suggesting setting the shoulder back several thousandths, just a light bump of perhaps .0005/.001.

In fact when I have this project completed to my satisfaction the rifle will more than likely end up in the safe while I finish the .358 Norma Mag and 25-35 M-99 Savage I'm building and who knows what else I will come up with between now and then.

Now before someone jumps me about not spending all that shooting time with only that rifle, let me say I believe that "trigger time" is more important than just limiting myself to that rifle. I wholeheartedly agree that one must familiarize oneself with the rifle he/she is going to shoot, however the very act of shooting anything regularly is very important. Some years ago I became heavily involved in air rifle shooting. Although the air rifles had very little, if any, resemblance to any of my powder guns, I firmly believe just the amount of shooting, (average 500 shots a week) is what helped me qualify for Expert in NRA High Power. Life intervened and a lot of this went by the wayside.

[swheeler]

Are your dies set up deep enough so the press has to cam over, die touching the shell holder plus 1/4 turn more, it makes a difference. If so, take the shell holder and lap it down on a whet stone until you can just bump the shoulder when sizing, .0005" is plenty. That AI case with it's minimum taper won't stretch/flow brass much at all, all the Ack Imp I load for almost never need trimmed 257,7x57,06 and 450 Watts, never had a head seperation.