Safe Pressures In the Cadet Martini
Q: I seek your advice on a series of reloading problems. I have several rifles built on small Martini actions and am having trouble reconciling advice from several sources - SAAMI, ADI, and your reloading manual 5th edition. SAAMI lists the maximum pressure for the Cadet Martini as 40,000 c.u.p I have used Winchester 46gn factory cartridges for years with no ill effects. Do you know the what their velocity and pressure is? I want to reload with the Hornady 40gn V-Max and 40gn Speer Varmint using AR2207 powder for about 2600-2800fps. ADI lists loads generating about 38,000 cup, but none for AR2207. You list 15gn of AR2207 for 2820fps maximum with no warning about the starting load "not to be exceeded in Martinis". So is this load safe in a Martini? Could you suggest a safe load for then .218 Mashburn Bee with the same powder and projectiles for about 2800-3000fps? Does this still have the same pressure limits as the standard .218 Bee? For the .17 Ackley Bee in a Martini ADI lists maximum loads at 45,300 cup - a tad high for my liking. Would a starting load of 12.5gn of AR2207 developing 2976fps at 32,400 cup suit my Martini better? Or could I go a little higher? Rifle has a 500mm barrel. A Martini .222 Rimmed using the same powder and projectile: ADI lists a starting load of 19gn of AR2207 at 26,100 psi for 3020fps while your manual says not to exceed 19.5gn in a Martini for 30350fps. Why is the starting load so much lower in pressure than for the standard .218 Bee? What am I missing? If the .218 Bee case can withstand 40,000 cup, why is the .222 Rimmed rated so far below? I also own a Marlin 1895 in .45-70 for which I have Hornady 325gn FTX bullets. Can you suggest a load using AR2207 to duplicate or slightly better the 2050fps of the Leverevolution cartridge? I have shortened cases (and crimping die) to accommodate this. ADI doesn't list a load using AR2207 which is what I intend using on sambar.
A: Sorry to say, I have no idea what pressure level Winchester loads .218 Bee ammo to. If you look at the data in my Practical Reloading Manual for the .218 Bee, you'll see that it was developed in the strong Sako L46 bolt action. I would certainly not recommend using the maximum loads in a Martini and be content to use the starting loads. The .218 Mashburn Bee chambered in a Martini would have the same pressure limitations as the standard .218 Bee. I cannot comment on the ADI data; you'll have to ask them about that. Again I cannot comment on ADI loads for the .222 Rimmed. All I can say is that it is not simply a matter of the .218 Bee case withstanding 40,000 cup, rather what amount of pressure the Martini action can stand. The small diameter of the barrel shank in these rifles is a limiting factor. I sure wouldn't like to risk loading to 40,000 cup in a Martini. A charge of 58gn of AR2207 behind the Hornady 325gn FTX should give you about 2150fps.