Here is another option for "standard" length M98 actions.



This is a wildcat formed from necking down the 9.3x64 to 8mm. Brass can also be formed from 338 Win Mag, but case capacity will be reduced slightly. Maximum loads for the 338 formed cases will be obout 1 1/2gr less with a decrease of 10-15 fps @ 63000psi



This cartridge is called the 8mm Mazon and the case drawings were posted on the "376 Steyr as a Basis For Wildcat Cartridges" thread by Daniel M



Parameters are similar to the other cartridges listed. The COL will be 3.34" ("06" length) for the 180gr Nosler Ballistic tip, 3.315" for the 200gr Nosler Partition. Maximum pressure will be 63000psi (816psi less than the maximum pressure for the 9.3x64)



Although the performance is for all practical purposes equal to the 8mm Steyr Improved, case forming should be easier and perhaps this cartridge will be a little more flexible with longer (heavier) bullets.



All calculations are for 23 1/2" barrel length.





8mm Mazon 180gr Nosler Ballistic Tip

• Win 760 96.8% load den. 70.0gr 3064fps 98.5% prop burn 63000psi
• IMR 4350 106.4% load den. 70.8gr 3061fps 98.1% prop burn 63000psi
• Vv N550 99.7% load den. 69.2gr 3055fps 99.8% prop burn 63000psi
• IMR 4895 93.5% load den. 62.2gr 3027fps 100% prop burn 63000psi
• Hodgdon H380 105.5% load den. 71.0gr 3024fps 96.0% prop burn 63000psi

8mm Mazon 200gr Nosler Partition, 63000psi

• Vv N560 106.5% load den. 74.3gr 2950fps 96.8% prop burn 63000psi
• Norma 204 106.3% load den. 71.7gr 2950fps 99.4% prop burn 63000psi
• Acc. Arms XMR4350 106.7% load den. 69.6gr 2929fps 100% prop burn 63000psi
• Win 760 94.2% load den. 68.3gr 2923fps 99.3% prop burn 63000psi
• IMR 4350 103.6% load den. 68.3gr 2920fps 99.0% prop burn 63000psi

Again, these are only "Quickload" predictions and are not to be used as load data, but as an indication of the performance level that can be expected @ a pressure ceiling of 63000psi.

That 4895 load with the 180 grainer is really efficient at 33027 FPS.

W.J.

Is the 8mm Steyr AI based on the sweet 375 Steyr case? If so, then which chambering would require more metal alteration, the 8mm Steyr AI or the 8mm wsm? Seems to me that there wouldnt be much difference.

Hola, Wildcat Junkie

here are some real life loads of my 8mm MAZON as compared to quickload's guesstimates, which appear in brackets:

BalTip 180gr 3.37" 72.1gr/N204 RWS5341 3,084fps (2,979 at 3,612bar) 1.0moa

BalTip 180gr 3.38" 75.0gr/R905 RWS5333 3,067fps (3,103 at 4,133bar) 1.0moa

RWS KS 181gr 3.25" 73.5gr/N204 RWS5341 3,103fps (3,025 at 3,806bar) 0.6moa

Woodl. 196gr 3.35" 77.5gr/MRP CCI250 2,903fps (2,995 at 3,828bar) 0.8moa

RWS TIG 198g 3.37" 77.5gr/MRP CCI250 2,913FPS (3,015 at 3959bar) 0.9 moa


RWS KS 224gr 3.29" 73.5gr/MRP RWS5333 2,825fps (2,831 at 3,946bar) 1.1 moa

here is a link to a web page hosted by my good friend Mr. Lutz M�eller which includes more information about the 8mm MAZON and the rifle in which I had it built:

http://home.snafu.de/l.moeller/8-9,3x64S-Brenneke-Mazon.htm


here is a picture of the cartridge flanked by a 7x65R and a 30'06


this is my rifle


and now to show that the thing works... the proof is in the pudding







Alvaro MAZON, known here as "montero"

Thank you montero, I invited Daniel M to post the data he had, but he declined. As usual "Quickload" is somewhere in the "ballpark", sometimes astonishingly close.

Actually I discovered an error in my case length dimensions as I was going from reamer dimensions and forgot to allow .126" from the bolt face to the chamber.

Max loads @ 63000psi allowed about 2.5gr more powder with perhaps 20-30fps increase in MV. Not enough to quibble about.

Again thank you for the "real world" data.