I would bypass even that. We use these in the N-SSA for ready loaded rounds-@pheenix99, I advise you to forego loading directly from the flask. You should always load from a volumetric measure. Use the smallest spout to pour powder into a volumetric measure. I only want to have one charge of powder being poured into the muzzle in case a lingering ember sets the powder charge off and I don't want to be holding a flask of powder if that happens. I am well aware that the likelihood of an ember setting off a charge of powder is rare but I would rather be loading powder with a one charge measure.
This flask from Midway has an attached volumetric measure.
https://www.midwayusa.com/product/1023140946?pid=637942
https://www.caplugs.com/search?query=rcl-6
Simply put a measured charge in the tube and use a minie, nose first, as a stopper. Then dip lube and head to the range. They'll end up looking similar to these. The ones in the pic are for 50cal. I use a color coding system for differing sizes/calibers. In my ammo box, red is for minies sized to .580, blue is for .576, black is for .69 and yellow is 50cal.