I have the now-discontinued 1100 Competition Master which has very similar specs to the Tac-4. I have shot it it 3 dram, 1 1/8 oz loads, but that is as low as I have gone. Usually I shoot 3 1/4 dr, 1 1/8 oz heavy dove loads for birdshot. The Remington reduced recoil slugs (1 oz at 1200fps) do not cycle reliably in cold weather (like, below 45 F or so); there is a Federal slug, 1 oz @ 1300fps that runs fine. Try it with your favorite target loads; if they do not cycle, you can open the gas system a little but that will pound the gun some if you run full power defensive loads.
The reliability issues in an 1100 are best addressed by keeping the gas system wet and replacing the seal (o-ring) often.
I use mine for 3-gun competitions, so I bang on the carrier assembly because we reload under the clock; mine has needed some carrier parts replaced lately after about 5 years of use.
Lee