Has anyone loaded these bullets in a 44 magnum handgun? I have a 629-6 I hunt with sometimes. I was thinking of getting a box to try. A quick check on load data shows 10.0gr of Unique for around 1000fps.

Thinking it might make a good deer load.

Rifle or handgun cartridge?

Sorry 44 magnum. 629-6

Try it and as many other powders as you can. I don't load .44 Magnum anymore, just .44 Special, but my old notes indicate 10 grs. Unique and bullets cast from Lyman #429421 SWC (about 250 grs.) gave a MV of a little under 900 fps from a 6" Model 29. There are no notations beside this load in my notes, so it was probably a mediocre load for me from an accuracy perspective.

That means little, however. Your results may be entirely different. If I was to load .44 Magnum again, I'd go with #2400. A load below max will give you the velocity you seek. 18 grs. shows 1000 fps in my book in a 4" 29 and 1125 in a 6" 29.

Use standard or magnum primers. Try both if you have them from a benchrest at 25 yards. #2400 will leave some residue/ unburnt powder that many like to complain about but they likely won't complain about the accuracy (as long as the bullet is of the right diameter and the alloy is proper hardness for the load).

Crimp just enough to prevent bullet movement and no more. I've seen no evidence that a heavy crimp promotes complete powder burn but it can distort bullet diameter which may affect accuracy.

I had the RCBS mold for 270gr SWC type bullet. I loaded 20 and shot in
Ruger SBH, loaded around 900fps. They shot ok but I couldn’t see the reason for more than 240gr.

unique seems a less than optimum load for that weight.
I'd reach for 2400, Lil gun, H110, or similar.
Possibly something blue dot like.
I've bored a mold very similar to what you describe.
Certainly a worthy special collection round suitable for the upper range of 44 mag appropriate game.
For the whitetail you seek, I tend toward something 200 - 225 grain.

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it just needs more voltage

About 7 or 8 years ago Matt sold a 270 grain HPs with no gas check like them. And he said then as he does now to hold them down to 900-950 fps. I still have about 40 rounds loaded with 9 grains of Unique from back then. I don't have it written down but I'm pretty sure they were around 980 fps out of my 629. They mushroomed biggly.

How hard is the lead that Matt uses in his 44 caliber bullets?
Can't find anything on his website about it.
He has some great looking bullets. I'll probably be ordering some.

Another powder to try with that heavy bullet is IMR4227.
It's a slow powder but known for accuracy especially near top end loads (like 296/110).
Hodgdon's load data for a 270 suggests 20.5 - 22.5 grains for 1275-1425 fps from a 8.275" revolver.
Hodgdon's load data for a 280 suggests 20 - 22 grains for 1215-1373 fps.
I much prefer this powder to the ball 296/110.
It doesn't give the pressure spikes you can get from W296 and
won't congeal over time in storage leading to squibs.

However my best 44 magnum load is a (Cast Perf.) 260 WFNGC over 18-19gr. 2400 depending on the brass.
Super accurate in Redhawk and 629's and deadly if placed right.
Zips right thru animals around here.

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NEMO
"Everything 44"

IMR4227 has a great reputation for accuracy. Maybe not the highest velocities, but great accuracy combined with mild recoil.
Sounds like just the thing for handgun hunting where accuracy and quick follow-up shots are key factors.

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Thats is a soft bullet and he recommends not loading to full mag specs.

I loaded them with 17gr of IMR4227 for 900fps and 10.8gr of TrueBlue for 1070fps, preferred the TrueBlue load though the 4227 load should be fine for good expansion.
Matt casts all of his hp bullets with 20:1 alloy so they dont need high fos for good expansion.
Nice bullets though, I buy from him alot.