In a double, where two constrictions are available, improved cylinder and modified are a good pairing, especially in fixed-choke guns. If screw-in chokes are an option, try a more forgiving match, like skeet and light modified. Shoot the more open barrel first on the covey rise, then the tighter barrel as the birds make their escape.
The CD and DVD have a single track of data in the form of a spiral, which starts as the center going outwards. The data is stored on the bumps or pits which are then read by the CD/DVD layer. The bumps/pits on a DVD are much smaller than on CD, allowing the DVD to store more data.
CDs and DVDs are not the same format. A CD drive can only read CD discs. A DVD drive can read both DVD and CD discs. Additionally, Blu-Ray movies requires a Blu-Ray drive which can also read DVD and CD discs. #2 - You need a program to play back the DVD movie. I prefer using Media Player Classic (Google it). CD drive can only read CD discs. A DVD drive can read both DVD and CD discs. Additionally, Blu-Ray movies requires a Blu-Ray drive which can also read DVD and CD discs. #2 - You need a program to play back the DVD movie.