trimming neck too short: implications?

I've trimmed one bottleneck rifle case 8 thou shorter than the manual's
1.902" trim-to length. This case is on it's fourth reload; the neck sized properly and will tightly hold/retain a bullet at its seated depth.

Wondering if there likely is enough neck length left to assure full obturation of gases/pressure?

Sure I could turf it, but the obturation question would remain.

Yes it is a bottleneck case.

Thanks for pointing out the safety implications wrt too-short cases that are designed to headspace on the mouth.