first ask yourself if the bullet you are looking at is made to use gas checks.
You don't just put gas checks on any ol' bullet.
If so , there may be a reason.
But for your typical Handgun mag loads with a somewhat hard bullet , you most likely do NOT need them.
But if a speed is what you want , I will say 1400fps just for arguements sake.
Not a single one of my 44 loads use gas checks , and a few of them are as hot as you should be going.
All are hard casts.
Alot of gas checks come in to play with cast rifle loads.
Don't over complicate your 41 mag pistol.