What I've learned so far

[Halftime]

Hi Veral,
 Maybe I should have said I hope I've learned something - please tell me if I'm starting to catch on.

 Been through your book 3 times and I think I understand the things that seem most confusing about casting bullets. Obviously, I'm new, but here's the best summary of the basic things I need to understand.

 Bullet fit is most important for accuracy and not leading.

 Bullet strength (higher BHN) is most important for accuracy and killing power. While the alloy is important mostly for the bullet's purpose - if some expansion is wanted, especially in under 35 caliber, and at longer range (200 yds.+), then a softer alloy or softnose welded on a hard shank. Actually, the whole bullet could be softer with a gas check to get expansion but with a copper base to handle obturation pressure. All this assumer a good lube.

 The lube grooves(s) is basically a reservoir. Under hydraulic pressure the lube leeches out reduces friction.

 So far, am I thinking right?

 This part is a little jump - just trying to be systematic. I want to standardize for sixgun and levergun on 180 FN @ about 1300+ fps from a 4" barrel, giving about 1800 fps from a 20" Rossi carbine. The best way to figure the max would be to duplicate a standard max load with AA#9 using 180 XTP following Accurate's info for COL, primer & case and get the average case head size after firing.

 My handgun cylinder will take 1.675" so would it be better to get the .4 nose for lower pressures? I believe this length would also work in the carbine. Then it would be a matter of working up loads approaching the case dimensions of the standard.

 Thanks!
James P.

[Veral]

  You have things pretty close, but are technically off about lubrication.  The lube doesn't just leach out, but upon being engraved by the rifling and sized down a bit on entering the barrel, the 'sizing' deformation causes hydrolic pressure on the lube contained the the grooves, thus applying it with considerable force against the barrel.  Under heavy chamber pressure and bullet obturation in the base area, this hydrolic pressure come up pretty close to chamber pressure, which at max in the magnum handguns is pushing 40,000 psi.    Compare that to standard operating pressure for the hydrolics in most heavy equipment, which is 2,500 psi, and you'll understand that bullet lubricant needs to be some heavy duty stuff!

  Your thoughts of working up a jacketed bullet load to find maximum pressure are correct, but only if you want to get maximum power from your cast bullets, which you don't if wanting 1300 fps from a 4 inch revolver.  I'm assuming you are talking about my 180 gr FN 38 caliber bullet, gas checked, and with LBT lubricant.  If so, just load it to your desired 1300 fps from the revolver and set the sights on your rifle to where the group lands with the same load.  The Rossi will handle anything the revolver will, but a 1300 fps revolver load will probably not give quite 1800 fps in the longer barrel.  Don't hang your hat on a preconcieved optimum velocity from the rifle.  No deer will stand up against a 1600 fps load with that bullet.  It kills great at 1200 fps, and very well at your desired 1300 fps revolver speed..

  If you intend to use any other, bullet design, or lubricant, by all means develop a pressure standard as you describe and stay within that limit with the cast bullet you choose, but also be forwarned.  You won't get 1800 fps from the Rossi with any other 180 gr cast bullet design that I'm aware of, nor with any other lube than LBT, without getting excessive pressures.

  Accurate 9 will give a bit quieter loads in the revolver than 296 or H110, but the latter will give the highest velocity at equal pressure, and with this near magnum velocity, the difference in sound isn't important, as either load will damage your hearing without ear protection, with extensive shooting.  This last tidbit of sound information pertains to the revolver.  My wife calls her 357 Marlin the 'quiet gun'.  She thinks she can kill anything up to elk with it, and hasn't been proven wrong yet!.