cukrus

To clean a .357 mag cylinder after shooting shorter cases: working a slightly flared .357 case back and forth in each chamber seems to do a better job than brushes. Don't wait a decade or two to clean the chambers either or you may notice permanent changes in the cylinder. Leading may be a problem at higher (>900 fps) velocities - watch for it. I've had luck with 3.5 gr HP38/W231 under a 144 - 150 gr cast RN for a lite load; HS6 up to 8 gr for a moderate load. I like Lee's 158 gr RF cast at 153 gr with 8 gr HS6 or 9 gr HS7 for my comfortable max. (My preferred powder is AL7 at 8.7 gr - or AL8 at 10.4 gr if you don't have AL7 lying about.)

chrono this one: 125 gr jacketed bullet in 38 Super, WWSP starting with 7.2 gr HS-6 col 1.220" Hogdon has listed 8.2 gr HS-6 as max with a 124 fmj in 38 Super. Maas has listed a stiffer load than that, but you shouldn't have trouble getting what you've asked for.

George D., pure soft lead has a higher melting point than hard linotype and other lead alloys. Leading with a hard alloy is thought to be due to "gas cutting" as it blows past the bullet. Obduration was the term used by the source of the formula I quoted, but the correct term may be obturation or sealing of the bore by the bullet. As noted above a larger bullet may be used to do that, and the lube used may act as an "O" ring as well. cukrus

kaiserb, the formula I have is for hardness vs pressure not hardness vs velocity: minimum pressure (psi) for obduration = brinnel hardness x 480 x 3; the maximum pressure to avoid leading = brinnell hardness x 480 x 4. George D, the hardcast bullet does not obdurate at lower chamber pressure while the softcast does; expect the leading near the chamber with the hard cast. At higher chamber pressure the hardcast will obdurate and not lead but the softcast will lead - expect the leading toward the muzzle. E.g. A bullet with a bh of 12 would have a calculated minimum chamber pressure of 17 280 psi for obduration and a max chamber pressure of 23 040 psi to avoid distal leading. A bullet with a bh of 22 would have min ad max chamber pressures of 31 680 psi and 42 240 psi (respectively.) Now where did I get this? cukrus

Consider, too, that large pistol primers are useful with reduced rifle loads (cast bullet loads) to reduce case set-back (and possibly enhace accuracy.) Large pistol primers seat deeper and a more suceptible to pressure, having a softer cup.

My wife has a Mohawk 600 in .308 Win with a shortened stock. She doesn't even like 38 grains of 748 under a 150 gr. jacketed bullet. A light accurate load she does like is about 8 grains of PB under 140 - 150 gr. cast lead bullet out to 100+ yds. I like 16 - 20 grains of 2400 under 165 - 180 gr. cast lead bullet for 200 yds or more.

4. The purpose of nickle plating is corrosion resistance (sweat protection) for carry ammo.

"Lube" is a misnomer but easier to say than "anti-tining" or "anti-leading" compound, acting as the opposite of a "tining" compound used in soldering. Bullet "lube" may also have a mechanical function like and O ring. You may want to investigate Lee bullet molds designed with micro grooves for tumbling in their Liquid Alox. (Edited by cukrus at 6:10 pm on Aug. 31, 2002)

I've used HS6 4.5 gr under a 158 gr swchp at 1.14"col. Hodgdon Data Manual #23 lists max of 4.8 gr of HS6 for 160 gr lead bullet, (also listing 3.3 gr max of HP38 for a few hundred fps less.)

Clark, right on! Something else to consider is the concept of "nominal" i.e. so-called, bullet diameter. A nominal .357" jacketed bullet usually mics .356" but any particular batch may mic from .355" to .357" in my limited experience. Cast bullets from the same mold will vary enough in size due to changes in alloy composition and casting temperature to be evident when sizing and lubing let alone with a mic. I don't notice any difference or worry about this when shooting, but I will tend to load the smaller bullets for the 9mm's and the larger bullets in the .38 Supers and appropriate revolvers. By the way, my S&W Model 52 (.38 Special) slugs smaller than my .38 Supers. The pressure needed to swage a lead bullet through a tight barrel is way less than "8,000 pounds", less than 5% of that, or you'd have a hard time slugging a barrel. (Edited by cukrus at 11:09 am on April 30, 2002)

From Cast Bullets an NRA publication written by Col. E.H.Harrison, I quote "Lead alloys do harden considerably for a time after casting ." (Pure lead won't.) Most of the hardening occurs within 10 days. I have found changes from 12 Brinell hardness to 16 BH on my wheel weight alloys. Heat treating can raise the hardness considerably. Specifics can be found in the same publication or a web search of the subject. The trick is rapid quenching after 50-60 min of heating the bullets of an appropriate alloy to just below melting (slumping) point; these will work soften.