Give them a try since you have them but first what gun do you have? Some Knights with the red disks will hang fire badly without a fairly strong primer and BH209....so knowing which gun could help.

They are not recommended but in some conditions they make work fine. Such as breach plug design and outside temps. Ive gotten them to work fine with some mods and accurately too but.......

I prefer plain Win209s usually and either the Fed or CCI mag primer should work fine but will leave more hard carbon in the flash hole and channel area. Its not a big deal unless you dont clean it well or have long range sessions. Sabotloader covered an important part too. Good snug seat on the powder and a good fitting sabot will help also with any primers.

So for me its..at the range Win209s and when hunting or cooler temps i go for the mags as a little insurance.