277 I.C.L. Flying Saucer

[CaptainMal]

Fellow let me hunt boar hogs on his property. Now it looks like I will repay with a project.



Mauser action - he said he has dies, gave me some ammo with two fired cases, a few loaded that are like the fired cases and most look like 277 bullets into 7 X 57 Mauser cases.

I have put tape behind one of each type of case and there is a close headspace on them all. It also looks like the 7 X 57 case necked to 277 will headspace on the shoulder and probably blow out. This "Flying Saucer" has a 45 degree shoulder and literally no body taper.

Did an internet search. Quality Cartridge does not show it with a headstamped case. The case was designed by Arnold and Verne Juenke in the early 60's. I.C.L. stands for "Increased Case Load", RCBS does list it as a die set and the owner of this thing said he had a set of dies he could not find just yet.

Owner has never shot it. He wants me to deal with it. Gun cleaned up fine. Looks safe. Only data I can find is for the .270-.257 Improved with the 40 degree shoulder. That should be fine but what about forming cases?

Do I need to jam? It seems like there is shoulder contact with the Mauser case necked to 277.

Here's a formed cartridge, fired case and one in 277 - 7 x 57 Mauser.



Have any information for me?

 

[Witchhunter]

The ICL cartridges were popular around here like you say. The Juenke's developed them and a line of rifles called Saturn. Both were great gunsmiths. Vern is now selling comparators. Nice ones...

 

[wapiti25]

I think that cartridge may be listed in P.O. Ackley's book.

 

[CaptainMal]

Thanks for the comments. I checked my P.O. Ackley pocket handbook and it's not in there. An old Speer Wildcat book from 1960 does have the 270-257 Improved. That will help on loads.
Really curious about measurements of the shoulder, neck, oal for this case.

If the guy shows up with the dies, that will be helpful as I can run some 6mm or 257 Roberts cases in it. Probably could contact RCBS for die reamer specs. Pretty much exhausted my internet research.
Without some feedback on case formation I'm gonna pull some of the loaded/unformed cartridges he gave me, load my own (tough without the dies), load a moderate load and then just jam .030 and go for it.

Thanks for keeping this up. Somebody reading just might have some experience or an information source on this "flying saucer" cartridge.

 

[MrMajestic]

I think that cartridge may be listed in P.O. Ackley's book.

I think that cartridge may be listed in P.O. Ackley's book.

Capt., Volume #1

 

[CaptainMal]

Had spotted that on some internet site but did not pay attention to the loading because of the 110 gr. (light) bullet) . Reading the text now I see it says the data would be IDENTICAL to the 270-257 Improved that I have in my 1960 Speer Wildcat Manual. Great. That takes up one issue.

That case has a 40 degree shoulder angle and some body taper. Gonna' figure the 2.253" case length would be correct or close. Then compare the shoulder and neck lengths to what I see to that little bit of old, reloaded ammo I have.

Hoping to get away without finding someone to do a chamber cast and just doing a successful and safe fireforming.

Here I had some of the answers right before me and didn't recognize it. Thanks.

 

[MrMajestic]

Capt., You can do chamber cast. It's so easy a "Caveman" could do it. ;D

 

[CaptainMal]

Yeah right...

Just got a neat tip from "gotcha" Dale in a PM. It should make any fireforming easier if the chamber is cut properly.

 

[Witchhunter]

Vern used to live in Verdi, Nv. his shop was the Accuracy Den. I heard Arnold is gone, but if you call Marty, Dave or Todd Puccininni at Mark, Fore and Strike in Reno, they could probably steer you to someone that can help with the Saturn/ICL stuff, PM me if I can help....

 

[CJ6]

Handloaders Manual of Cartridge Conversions has specs as follows: Case length=2.23, Head dia= .471, Rim dia= .473, Neck dia= .310, Neck length= .364, Shoulder length=.046, Body angle(DEG's/SIDE).495, Case Cap (CC's) 3.79, Loaded length=2.93, Rim thickness=.049, Shoulder dia.=.443, Shoulder length=.046, Length to shoulder=1.82, Shoulder angle (DEG'S/SIDE)=55.32, Primer=Large Rifle, Case Cap (grs. water)=58.58. Fireform notes: Taper expand 257 Roberts to .277 and fireform in 277 ICL chamber. Load included is 110gr bullet, 48grs/4831, 2631 fps. EDIT to CORRECT Shoulder length .046 and ADD Length to shoulder 1.82.

 

[CaptainMal]

CJ...Looks like you nailed it. I'm writing it all down and if the info. is good ...job done.

Thanks.

 

[gotcha]

Excellent info from CJ6 ! Expect that MV will be noticeably higher after fire forming even with same powder charge. I'd expect 150 to 200 FPS. Don't trim new brass as it will shorten considerably on fire forming. I'd expect about .010" to .012".......... This based on my experience with .257, 6 Rem. & 250-3000 AI's. You'll probably only need to trim once (to even up lengths) through the life of the cases. Have fun. I wish it was my new toy Dale

 

[CaptainMal]

FYI...IT SHOOTS!

Chronographed in the mid 2700's with the fire-forming ammo I had. Looks like the cases formed fine. The few formed pieces I had, shot in the mid-2800's and seemed to group under 2 MOA with two different unknown bullets. Not great accuracy but this rifle has scope and bedding issues that I will soon resolve.

Again, thanks for all the help.