43 Mauser brass questions

[mazo kid]

I just got a 71/84 Mauser and have questions about forming the 43 caliber/11.15X60R brass: I have lots of 45-2.6" brass so I trimmed one to length, formed the brass in the sizing die and it functions nicely in the action. I know the case will have to be fireformed, but will I have any headspace issues using this formed brass? Can I seat a boolit out long and form the shoulder forward when fire formed, or should I do this procedure when forming the long neck? Will moving the shoulder forward eliminate headspace issues? Thanks for any insights.

[enfield]

the rims are about .010" too big around (for the 71/84) and need to be turned down , also the rims are a bit too thin and allow too much headspace, plus the bulge a bit ahead of the base. If it's all you can find they work fine.

[Green Lizzard]

mazo
i use 44-77 in mine also 44-90 with paper patched, but the 44-90 rim is a little thinner so i headspace on the shoulder

[mazo kid]

I fired (remotely) the 45-2.6 trimmed/formed brass today. Thought maybe everything was OK at first, but then spied a 1" long split ahead of the base. Primer was backed out a tiny bit as expected, but I wasn't expecting the split. Guess I need to try a couple more before giving up. This was a B.E.L.L. case.

[enfield]

the 45-2.4 and 45-2.6 I tried were both starline, and no splits so far.

[Good Cheer]

I fired (remotely) the 45-2.6 trimmed/formed brass today. Thought maybe everything was OK at first, but then spied a 1" long split ahead of the base. Primer was backed out a tiny bit as expected, but I wasn't expecting the split. Guess I need to try a couple more before giving up. This was a B.E.L.L. case.

I ran into the splits when trying to fire form 45-70 brass for a 9.5x52 bottle neck that originally used the "A" base. Wanted to figure out a pre-expander design than I could use to prep the cases for forming but never got my round tuit. Shouldn't be terribly hard to figger one out though.

[mikeym1a]

Would annealing the brass before fireforming help any?

[enfield]

always anneal

[justashooter]

i have used 45-90 brass with rims turned down to correct diameter and fire-formed with 12 grains unique and a 300 grain .452" casting from missouri bullet company that was run thru a homemade die and swaged to .446". rim thickness can be built up by adding a rubber o-ring to the case in front of rim. never had a split, but never loaded them to more than 1300 fps. if rim is turned to correct diameter concentrically the case will uniformly expand just forward of web by about 5 thou all around and be stable from that point on.

71 chambers, necks, and bores vary wildly in dimensions. 71/84 tend to be more uniform.

[Green Lizzard]

the first 50 cases we got (buffalo arms) were made from 348 win brass with the rims curled under by swaging to increase rim thickness, lost 5 on the first firing due to splits. we then annealed way down almost to the base and have not lost another. i suspect they were work hardened

[oilman041153]

i have fired 15 of the buffalo arms 43 mauser brass made form 348 brass at least 6 time and had no spliting. also have made my own cases using 348 bass and 45-70 and 45-90 and had no problem with them , i also have been using smokeless powder in them . i use 4198 powder 31 to 35 gn and a 370 gn cast bullet and to make up for the air gap in the shell i put half a one ply toilet paper under the cast bullet

[mazo kid]

"i have fired 15 of the buffalo arms 43 mauser brass made form 348 brass at least 6 time and had no spliting. also have made my own cases using 348 bass and 45-70 and 45-90 and had no problem with them , i also have been using smokeless powder in them . i use 4198 powder 31 to 35 gn and a 370 gn cast bullet and to make up for the air gap in the shell i put half a one ply toilet paper under the cast bullet"
oilman, did you turn down the base in order to run the brass into the FL sizer die for forming the bottle neck? That is what I have done to those few I have made. I haven't loaded or shot any yet. Those cases look good and are only about .100" too short.

[Safeshot]

When fire forming, you might try an "O" ring, of appropriate size, slipped over the cartridge case and back to the rim. This can provide a "tight" head space condition and keeps the cartridge case tight against the bolt face. After fire forming, neck size or 3/4 size in a full length sizing die (do not even touch the shoulder). Also, when forming the case do not form it all the way into the die. Leave the shoulder a little forward (long). Then my trial adjust the shoulder by subsequent trips through the siding die with small increments of adjustments, until the bolt will "just close" on the sized cartridge case. You should be able to definitely "feel" the bolt closing on the chambered case. Then load and fire form your sized case. Done this way you will not "need" the "0" ring. The brass should last a long time.