RCBS APS Unprimed Primer Strips do not come with any primers so you can fill them however you choose. If you prefer to choose the type of primer you use these RCBS APS Unprimed Primer Strips are an excellent option.RCBS APS Unprimed Primer Strips are coded by color to make it simple to identify the type of primer you are using and each unprimed strip can hold up to 25 primers. This particular set of primer strips is white which means that they work with large pistol and small pistol primers.