Forming .348 WCF brass into .348 Ackley Improved

[cspook01]

I have a Mod. 71 re-chambered to .348 Ackley Improved. If any of you are familiar with Ackley's books, he gives significant coverage to the concept of "bolt thrust" (See: P.O.Ackley, Vol I/Handbook for Shooters & Reloaders, pp. 140, 465). Of the three Mod. 71's I have owned over the years, two of them would actually open the action and eject the fired case if not tightly held shut! My present Mod. 71, re-chambered to Ackley Improved has demonstrated the advantage of improved chamberings in that my reloads (with close to maximum charges) do not "unlock" and cycle the rifle.
The information I am seeking is concerning the forming of additional improved cases. I have only a 120 formed cases on hand, and given the panic concerning brass availability, I want to acquire and form an additional 100 cases (to leave as part of my legacy to my sons).
Conventional fire forming with strong loads and bullet seated to touch the lands is a concern because (1) it really raps my fingers/hand to have to hold the action shut during the fire forming as the bolt thrust is as described above; and, (2) because so much brass has to be stretched to fill that large chamber, the necks are shortened to less than minimum trim length and no longer true. (square).
I have read about the Hornady hydraulic forming die set, but am not excited about spending the better part of $200.00 given the probability that the brass I will have on hand will last me all of my life and well into my sons' lives if they choose to keep and shoot this old smoke pole.
The other option I am aware of is the use of cream of wheat/corn meal and such to fire form. I can find no data on how to load such a concoction for a case this large.
Any thoughts or suggestions would be most appreciated before I just give up and beat my poor old fingers into hamburger!!!

[BigSky56]

Tip from Beartooth bullets on fire forming. danny
http://www.beartoothbullets.com/tips/ar ... ips.htm/17

[flatnose]

cspook, hello and welcome.
What year is your 71? It is interesting why 2 of your previous 3 m71's exhibited the unlocking problem and 1 did not. I have the browning m71 from around 1986, and although it gives a healthy kick, I have not experienced unlocking. I have noticed that with my m71 the length of pull of the stock is much shorter than the 1886 winchesters, and the felt recoil is much more. The unlocking of your action may be attributed to this, and your lever/ trigger hand maybe jarring the lever forward.
Try using a shoulder pad or packing between you and the butstock, maybe 1'' or 2''.
Of the 120 fireformed brass that you already have, how many did you lose during the fireforming process? I have split a couple of new standard cases on the first firing in a stock 348 chamber. Some of the brass productions are a bit on the brittle side, and you may have to anneal the case down into the neck a bit to prevent splitting and to assist in forming the shoulder.
You dont need full power loads or bullets even to fireform the cases. Full loads with bullet seating into the lands may cause pressure spikes, and you dont want the action springing open, which may lead to a cartridge length that is too long, which is a posibility worth considering.
I would use 10g of unique, then fill the case up to the base of the neck with cream of wheat, and top it off with a piece of toilet paper to hold it all in place. You wont perfectly fireform the case with sharp shoulders, but subsequent ackley loads will take care of the rest. Also check for splits on the first firing.
The A.I. case will now hold more powder, and you will get more recoil. It will be interesting to see if the action stays locked, or if the length of pull and recoil is causing is causing the unlocking problem.
if you dont have any Unique powder, try starting loads of the powder that you are using, although a bit wasteful these days, that should work.
Keep us posted....all the best.

[flatnose]

I should add,
Your case necks will be shorter, and need trimming back to square them up.
If you are getting splits, anneal the brass and use the cream of wheat method....trying to seat a bullet in a case with a soft shoulder may cause the shoulder to deform and collapse.

[Terry Murbach]

THE NEW BOOK " METALLIC CARTRIDGE HANDLOADING " BY MIC MCPHERSON HAS DETAILED INSTRUCTIONS ON FIREFORMING CARTRIDGE CASES USING NO PROJECTILE AND GIVING NO SHORTENING OF THE CASE.

[JerryB]

Welcome to the forum, hope you stay around after you get some help. I don't own a 348 but I have fire formed 38-55 from 30-30 cases, with Unique and cream of wheat with a small piece of paper towel folded in the case mouth.