Take a look at .44 Special data. Whilst the .44 Magnum cartridge case is longer than .44 Special, the maximum overall length of the cartridge is the same. So the powder volume is the same for both, for a given bullet and given OAL.
Lyman 48th edition lists starting loads from 5.2 grains of Unique (1.570" OAL).
So you can be confident that there won't any ignition problems using this data in your firearm. (If that is what you mean by getting a squib load?).