Quickload has two entries for that bullet, it probably has two cannelures. That is an assumption on my part because the bullets are listed at different lengths, which would not be right, but the same part number. Possibly there is one flat point and one hollow point version which would account for the difference? But that would imply two different part numbers, I would think. If I understand the database correctly, the deeper seating depth ends up at about 47,000 PSI and the shallower one at about 43,000 PSI.
Pretty hot for Unique...... treat this info with caution, because something isn't quite 100% correct here.
Well I don't think 60,000 is reasonable in either case. And 'speculate' was a good word to describe the estimate. Then again, predictive software models aren't always 100% accurate at the extremes. But I think that Quickload is probably much closer to the truth.
Even with the longer OAL provided by the second cannelure, I'd have worked that up, very carefully, maybe in a Redhawk, if I was to do that at all. Probably get 1100-1200fps with a typical revolver.
Please note that upon reviewing my Quickload input, somehow the first time through I put 10.0 grains of Unique, instead of 10.6. The pressures go up a significant amount with that extra .6 grains of powder and I have edited the first post.
This would imply that the load is quite sensitive to case capacity, so it is possible the pressures could vary a fair amount depending on the brass used. Then again, Quickload also has a standard disclaimer that it doesn't always get the correct numbers with straight-walled cases and especially in revolvers. Usually, you have to adjust the case capacity upwards (up to 10%) to match the actual muzzle velocities, or fiddle with the burn rate numbers. But that would mean real-world pressures are probably lower than what is first predicted. Bumping the case capacity 10% or so drops the max pressures to around 35,000-37,000PSI, so the truth is probably somewhere in between. If we think about a revolver having freebore (due to the cylinder throats) this makes sense.
It's a hot load for sure and I really don't see the point of trying to do that with Unique. Trouble brewing, I'd say. Throw in the usual disclaimer that powder burn rates vary per lot, etc., and there's even more confusion. Bottom line: That heavy of a bullet with that fast of a powder is going to be a very touchy combination at the top end.
I asked Hornady about this bullet last year. They told me the correct length is 0.860" +/- 0.005". The nose to the front cannelure is 0.310" +/- 0.005" (due to the length variance). That is for nominally seating it to 1.600" COL. The cannelures are 0.025" wide. The bottom cannelure is 0.45" +/- 0.005" from the nose for seating to a nominal 1.740" COL in long cylinder revolvers to get more powder capacity. They list no load data for that, however.
I get 48,500 psi and 35,600 psi, for 1.600" and 1.740" COL, respectively, using QuickLOAD's defaults. Bear in mind that QuickLOAD is really better geared toward bottleneck rifle cases than handgun cartridges. Revolver loads, in particular, are subject to barrel cylinder gap bleed down and other issues that the program can't account for. Nonetheless, I would be working up toward 10.6 grains with extreme caution from about 8 grains in .3 grain steps. Especially given Unique's tendency toward erratic metering in many powder measures.
As a side comment, I really don't see a good reason to run such a hot Unique load. You could get the same velocity in the shorter load from about 11 grains of Power Pistol, but do it at the pressure of the longer load, above.
The thing that occurred to me was that 10gr Unique is pretty snappy under a 240gr Cast SWC, and even loaded out, 10.6 would be pretty scary to me with a 300gr bullet. It's worth considering that Hornady lists 10.7gr as Max with a 240gr bullet in their 8th Edition. And there's not any loads for Unique and a 300gr bullet, in any of the manuals I have, which covers several editions from Speer, Hornady, and Nosler, three generations of Lyman, and Lee. That's what I consider "a sign".
For many years my standard 'reduced load' for both the 44 Magnum and 45 Colt has been a 240gr, LSWC & 255gr. LSWC over 10 grs. Unique, respectively. My 41 Magnum reduced load has been a 215gr. LSWC over 9gr. Unique. Have I been pushing any pressure limits with these loads?
Load Data has no listing for JHP/JSP 300 grain .44 mag. They do list 10.0 grains max for 300 grain RCBS SWC for 1,098 out of a 7 1/2" Blackhawk. If it were me I would not go over 10 grains, max with the XTP and at that velocity I would not expect reliable expansion with the "magnum" XTPs but obviously I could be wrong about the expansion part. That is the beauty of the LBT designs that do not need expansion.
P.S. By mistake, I did first search for .45 Colt and came up with this: Sierra Bullets Edition V lists 10.5 grains max for 300 JHP out of 7 1/2" Blackhawk for 1,000 fps "Ruger Only" load. Load Data/Handloader Magazine lists 10.5 grains max out of an 8" Dan Wesson LBT LFN for 1,068 fps and indicates suitable for Blackhawk. For me, 10 grains would be the sweet spot for Unique and 300 grain bullets in a Blackhawk. I do not see any good reason to run it out to 10.5 as you will get around 950 FPS.
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