This is a Dirty Harry era gun with oversize throats and questionable timing.   When I first aquired the gun, I attempted to work up a load for an NEI 240 Keith bullet but the gun refused to shoot the Keith cleanly and accurately, despite trying numerous powders and alloys.   Firelapping did not help, though it did make the barrel easier to clean.   In retrospect, the bullet diameter may have been too small, dropping out of the mold at 0.430" - 0.432" depending on alloy.    The throats currently run 0.4334" - 0.4336" as measured by an expanding ball gauge (as a side note, an oversize bullet driven through the throats measures 0.4330".   I place more faith in an expanding ball gauge).
The cylinder sometimes fails to turn far enough to engage the cylinder stop, especially when the hammer is cocked slowly and deliberately.   Neither the hand or the cylinder star showed significant wear, so the timing has probably been like that since day one.   I tried lengthening the hand but it did not help.   For now, I just try to remember to cock the hammer quickly, giving the cylinder enough inertia to keep spinning until the bolt engages.   Remind me to become a Smith and Wesson fan.
This gun has been known to unlock the cylinder with hard kicking loads.   Smith seems to be in total denial about the problem.   During the 80's they claimed it was fixed by lengthing the notch on the cylinder.   Surprise, surprise, people continued to report problems with unlocking.   Smith recently started blaming the problem on the shooter, claiming the shooter was re-pulling the trigger as the gun recoiled.   Oh, gimme a break -- the cylinder unlocks because the bolt has a wimpy spring that lets the bolt move around as the gun recoils.   Somewhere along the way I replaced the factory bolt spring with a Wolff spring, and it seemed to help a little, but the gun would still unlock with max loads.   So I rummaged through my spring collection and found a spring that was the same size but made of thicker wire.   It remains to be seen if the newest spring will be stout enough to do the job.   The problem is, there isn't enough room inside the gun to install a substantially larger spring.
I bought a Brownell's 5° forcing cone reamer for this gun, but when I got to looking closely at the forcing cone it was big enough to allow a 45 caliber bullet to enter.   That seems excessive, but the barrel would need to be set back about 1/8" to allow recutting the cone correctly.   I went ahead and made a light pass with the 5° reamer, not enough to touch the opening, but only shaving a little off the rifling.   I made a brass pilot for the reamer so there was no chatter and the cut turned out nicely if I do say so.
A scaled up version of the deep-seated truncated cone that my Ruger 357 likes seemed to be a likely candidate.   0.434" would appear to be the likely diameter, but as it turned out the bullets fell out of the mold at about 0.433".   The 0.433" bullets would barely fit in the chamber owing to a tight spot at the case mouth OD.
25 gr 296, 250 gr. deep-seated truncated cone   9.4", 1358 fps, 76 ES.   Quickload estimate 1370 fps at 33351 psi.   Bad leading.   The forcing cone was fairly clean but there was a lot of leading toward the muzzle.   The cases were difficult to eject even though the pressure was supposed to be reasonable.
Conclusions   This load kicked about as much as any 44 load kicks, yet the cylinder did not skip, so maybe the stiffer bolt spring helped.   It doesn't look like this gun is going to be happy with a plain base bullet, so I'll try again with a gas check.
5.1", 1297 fps, 42 ES.   Quickload predicted 1266 fps at 33411 psi.   This is pretty much the same bullet and load that I have been shooting for a while, the only thing different is 296 powder and the experimental lube #2.   It seems to shoot well and I was impressed with the velocities and the ES.   This will be my standard load, and maybe I'll get lucky and tag an elk with it someday
Since I am kinda bogged down on the '06 I decided to spend the day breaking in the barrel.   I am not a big believer in the break-in ritual but I figured it couldn't hurt.  Then I did this little experiment with empty lube grooves.   The bullet was a 180 TC loverin that had been tried before and did not shoot well, so I was not expecting it to shoot well today.   I was just trying to see if the empty lube grooves would effect the gas seal.
60 gr. Ramshot Hunter, 180 gr.TC, lube in bottom 3 grooves   2758 fps, 32 ES, 6.0".   A little leading.
60 gr. Ramshot Hunter, 180 gr.TC, lube in top 3 grooves   2742 fps, 61 ES, 7.9".   A little leading.
60 gr. Ramshot Hunter, 180 gr.TC, lube in all grooves   2743 fps, 28 ES, 3.8".   A little leading.
Conclusions   Filling all the grooves gave the best accuracy (or least worst accuracy) but had little effect on velocity.