1000 with 250s in a 45 Colt revolver isn't necessarily a very stout load. Hodgdon shows several mid-900 loads in it's sub-14,000 CUP loads for original Colts. 800-X, HS-6, or Universal are all good ways to load "fast" and still keep your pressures within the old-Colt data.

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Or you could just get a M-94 and shoot 320s at 1550. grin

Sometimes, the air you 'let in'matters less than the air you 'let out'.