How to use load data with an unknown bullet and reduced case capacity

From the formula I provided, your bullet is actually seated 0.374" into the case and not 0.31", so something went awry with your original calculation. This solves the length discrepancy, though. I am guessing you have something close to a Wide Flat Nose style bullet, as when Beartooth Bullets was still in business, their 240-grain WFN was 0.665" long, which isn't far from your length. And that Lyman #428667 you got load data from is also 0.68" long, having a fairly wide 0.31" meplat. Your bullet's design may be that same Lyman profile but with the crimp groove moved forward for the 44 Remington Magnum case (see below).

The Lyman bullet #429667 that is mentioned in the Lyman data, when you look it up, turns out to be designed for 44 S&W Special rather than for 44 Remington Magnum. The Special has a SAAMI and CIP max COL of 1.615", while the Mag has a slightly shorter Max COL of 1.610". However, the Special case is 0.115" shorter than the Magnum case, so Special bullets have their crimp grooves further down from the nose than Magnum bullets of the same profile and weight, and as a result, they stick out beyond SAAMI and CIP max COL when crimped into the crimp groove in a Magnum case. This is why you sometimes see 44 bullet designs with two crimp grooves 0.12" apart, the upper one being for the Magnum case and the lower one for the Special case.

The above is also why Lyman has that 1.645" length when that Special bullet is put into the Magnum case. If this bullet had been designed long enough that it seated to 1.615" COL in the Special case, using its crimp groove would make a cartridge 1.730" in the Magnum case. However, it has a shorter nose than that, which you can see in the Lyman manual where it is also listed among 44 Special loads at 1.5" COL (calculation says it should be 1.53", and I can't account for that discrepancy). But the reason they chose this bullet for the 44 Mag is that at 1.645", it will still, just barely, fit in S&W m.27 cylinders.

The SAAMI standard Pressure and Velocity test barrel that is vented to mimic a revolver barrel/cylinder gap has a chamber throat 1.755" long, while the carbine and single-shot pistols P&V barrel has a throat 1.763" long. Since Lyman used a SAAMI P&V barrel in a Universal Receiver for their testing, it explains why they could ignore the extra length.

Here are the main takeaways: First, if I put a 0.68" lead bullet into a magnum case with 1.645" COL in QuickLOAD or GRT and then shorten the COL to 1.581", the pressure difference with Unique is about 10.5%, and I would need to reduce charges about 5.6% to get a pressure match. In other words, multiply the Lyman loads by 0.944 to get a pressure match.

Second, a load like 8.5 grains of Unique is operating way below maximum pressure in the magnum. You need, based on Lyman's data, adjusted down for a 1.581" COL with a 0.68" bullet, as described above, 11.05 grains to get to maximum peak pressure. You would not expect any pressure signs below that number, though you would still approach it no closer than 10 grains and with caution, watching for leading effects from the pressure on the bullet base.

If your 8.5 gr load of unique is leaving the fired cases covered in soot that is telling you your charge is too light. Increase 0.2 grains at a time until only the last 1/8" of the case at the mouth is sooty, or if the last 1/4" of the case is sooty only on one side of the case and all clean on the other, those will still be a somewhat reduced load. When charges are finally high enough to generate normal working pressures the cases will inflate to fully seal the chamber and the fired cases will come out of the chamber clean on the outside with the possible exception of the last 1/16" where the crimp was which might still be sooty. If you have been going up 0.2gr at a time this appearance indicates you are approaching a max load. In no case would you exceed any published data for 240-250 grain cast bullets. My personal go to 44 RMag load with whatever 240+/- cast bullet is on hand is 10 gr. Unique or H-Universal seated to and crimped into whatever groove is offered, some are crimped over the front driving band if no groove is present. Many M of them have gone down the tubes both handgun and rifle. This is a solid load, not a stout load, pressures are far-far below max jacketed pressures. Chances are you will experience severe leading well before you reach max pressures with cast in the 44RM using Unique. Now on the other hand, if you run out of Unique and can only find Bullseye or its ilk you can easily go over pressure before getting leading. Bottom line, don't sweat those 0.070" in that big case using Unique and cast. It doesn't play by the same rules as a low capacity 9mm or 380 where 0.010" deeper seating can put you over the top in a heartbeat with some faster powders.

avesteve said:

If your 8.5 gr load of unique is leaving the fired cases covered in soot that is telling you your charge is too light. Increase 0.2 grains at a time until only the last 1/8" of the case at the mouth is sooty, or if the last 1/4" of the case is sooty only on one side of the case and all clean on the other, those will still be a somewhat reduced load. When charges are finally high enough to generate normal working pressures the cases will inflate to fully seal the chamber and the fired cases will come out of the chamber clean on the outside with the possible exception of the last 1/16" where the crimp was which might still be sooty. If you have been going up 0.2gr at a time this appearance indicates you are approaching a max load. In no case would you exceed any published data for 240-250 grain cast bullets. My personal go to 44 RMag load with whatever 240+/- cast bullet is on hand is 10 gr. Unique or H-Universal seated to and crimped into whatever groove is offered, some are crimped over the front driving band if no groove is present. Many M of them have gone down the tubes both handgun and rifle. This is a solid load, not a stout load, pressures are far-far below max jacketed pressures. Chances are you will experience severe leading well before you reach max pressures with cast in the 44RM using Unique. Now on the other hand, if you run out of Unique and can only find Bullseye or its ilk you can easily go over pressure before getting leading. Bottom line, don't sweat those 0.070" in that big case using Unique and cast. It doesn't play by the same rules as a low capacity 9mm or 380 where 0.010" deeper seating can put you over the top in a heartbeat with some faster powders.

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Hi Steve
Apologies if you have already seen my reply, I had an issue logging in and had to reset my password after trying to send the reply so I may have sent two replies. Anyway, you were right, I worked up from 8.5 gns to 9.8-0 gns. Both of those loads were accurate , no issues with flattened primers, cases were clean. I have some 2400 to play with and some XTP heads and managed to find a tub of tin star but there is no data available so that will be another project!
I will check out the Bullseye situation but I think that like a lot of US made powders the EU banned most of them. It's very difficult at the moment to get anything here so I just grab what I can when I see it and I am in the trade in a small way and still struggle To find stuff. Many thanks for taking the time to respond and for the great information, very kind of you to do so and much appreciated,
Trevor