The small 4.5” Ace Sniper Search Coil performs well in high trash areas where the highest level of target separation is required. It is more sensitive to smaller jewelry items than the larger coils and is more maneuverable around playground poles. However, the small size of the sniper coil results in less depth and covers areas at a slower pace. This is not my coil of choice for metal detecting most park and open field locations unless the areas are extremely trashy. It is, however, a good little coil for tot lots.
The Stock 6.5×9” Ace 250 Search Coil is a good all-around coil. The length of the coil allows for a moderate coverage speed, while maintaining good separation in low to moderate trashy sites. This is also a good coil for searching tot lots and works well in the turf.
The 9×12” Ace Proformance Search Coil can quickly cover a lot of ground due to its sheer size. It adds some depth over the stock coil but the large concentric coil suffers in moderate to high trash locations and is my least favorite of the Garrett search coils, especially after the release of the newer DD coil.
The 8.5×11” DD Proformance Search Coil provides excellent coverage, but with the advantage of having a narrower strip of sensitivity down the center of the coil due to the DD design. This results in better target separation between adjacent items and the DD also provides a little performance boost in areas with more mineralization. Because this coil is a DD, pinpointing can be a little more challenging for some detectorists as the side to side front to back method is more difficult. With this coil, it is easier to do a side to side followed by a 90 degree turn of your body and another side to side motion.
The Garrett 8.5×11 DD coil and 6.5×9 concentric coils are my favorites followed by the sniper coil and then the 9×12 concentric coil. Each search coil has its place, but if money is an issue, it is not necessary to purchase extra coils to be successful. The stock coil is adequate for most metal detecting situations. I like to buy my coils used to save extra money as it is common to find like new coils selling at a steep discount.