I experimented with a couple of loads today by utilizing QuickLoad (QL) and a number of parameters including OBT.

I had by a previous load knew my 9.3 Husky would shoot cloverleafs with the Mt Baldy cast bullets over 24 grains of AA5744, but the load printed slow and low of POA with the Husky's iron sights at 100 yds.

So I calculated the chamber pressure from QL for that load to be 21.8 ksi, a "safe" pressure for that bullet to maintain accuracy.  To get a bit more speed, energy, and POI to match better to POA, I selected AA4064, a medium speed powder to try.  And to expand the pressure enevolpe a bit more I took the Mt Baldy alloy at their advertised 18 BHN and multiplied it by 1280 (I believe this is a Lee guideline for pressure on lead) and got 23 ksi.

I measured my cases for actual water capacity and weighed my bullets and ran with actual numbers in QL along with AA4064 to see what velocities I could get.  Once I had some ballpark velocities, I checked the OBTs for a 24 inch barrel and came up with 1.846 and 1.929 ms nodes.  Then I went back and cranked QL to obtain a load that would acheive those barrel resident times and checked pressure limitations.  A load of 40.1 grains would give me the 1.929 node at 21.6 ksi and 41.4 grains would give me the 1.846 node at 24 ksi, one ksi over the 23 ksi limit.  I decided it was close 'nuff and loaded up both sets and went off to the range.



The first 5 shots of the 40.1 grain charge printed just where I wanted 'em but #6 through #8 fell down.  The 41.4 grain charges scatter gunned so I stopped.  Sure 'nuff my barrel leaded, mostly towards the muzzle end.:o   I'm guessing something about cartridge #6 wasn't right, left lead in the barrel, and everything afterward was downhill.


The Mt Baldy bullet is the 2nd from the left and has such a big meplet that  when feeding from the magazine the meplet strikes the barrel and doesn't enter the chamber.  I took a Lee chamfer tool for case mouths and trimmed the meplet edge down to get these bullets to feed reliably.  Easy fix, it removes very little lead from the bullet.

I think I've got a winner in that 40.1 load, just need to shore up what's giving me the leading.

Nels

Outstanding! Your procedure with QL is precisely what I try to do. So far, I've had both good and bad results. I was reading through the QL PDF of the manual today, and that may have provided some answers for the failures.
 
Can you - or would you - "temper" the Mount Baldy bullets in hopes of hardening them a bit? Maybe that would be just enough to keep the lead from the muzzle. I'm just thinking out loud here.
 
Armed with the "new" info from QL and some new ideas, I'm going to try some of my cast bullets in my .45-70s again. I'm also going to just 'bite the bullet' and fire-lap a couple of barrels.
 
Looking forward to seeing the next round of 9.3 targets.
 
Paul
 
PS - You know, if you put the pointy end of the Mount Baldy on the rear of the bullet also, it'd look a lot like the FBK... Oh yeah, one more question; I forgot what you said the groove and bore diameter was on the 9.3.

If I can, I'd like to stick with the 18 BHN to enable some expansion on terminal performance.  That's not much harder than the Lyman #2 alloy at 16 BHN that's a standard of sorts for being a tough hunting bullet.

I  may have been a little excited firing the first set going too fast and getting the barrel hot.  Maybe the difference too in powder with the AA4064 having a longer burn and hence, more heat.  The lube on this set of bullets was also a bit spotty in some of the grooves and I'm going to pay closer attention to ensure future bullets grooves are uniformly filled.

This Husky barrel is a 6 groove 14 twist, grooves are .366, the bullets .367.  That's something else to check on from now on too; check bullet OD to ensure an undersized one doesn't slip through.

Nels

Interesting as I am considering a cast load for my 9.3

Miner,

I highly recommend using AA4064 for cast in the 9.3.  QL predicts it is slow enough that the pressure peak occurs after the point the bullet is fully engraved but burns well enough (94%) to transmit most of its energy to the bullet.  That and this combination regulates pretty well with the fixed iron sights.

This bullet alloy seems to like 21.6 ksi, but I do want to try again the higher load and see what happens with better lube at 24 ksi.

Nels