Bowler Ratings


Bowler ratings are from 1 to 10 in order of Stroker (ST), Tweener (TW), Cranker (CR)

Note: Ratings are only available to our premium members.

General Info

Reviewed:March 2024
Coverstock Specs
Name:HK22 – Cohesion Pearl
Type:Reactive Pearl
Box Finish:500 / 1000 / 1500 SiaAir / Factory Compound
Color:Maroon / Blue / Black / Purple
Core Specs
Int. Diff:0.017

For details on our standard test layouts, please click here.

The Effect introduces another high-flaring asymmetrical option into Hammer’s High Performance price point. This ball uses the new Huntsman core design, which features a lower RG (2.470″), a lower differential (0.050″), and a slightly higher intermediate differential (0.017″) than the Gas Mask core from the Black Widow series. The Effect is the first four-color bowling ball on the market, and it features the new HK22-based Cohesion Pearl coverstock that comes from the factory finished at 500/1000/1500 SiaAir plus Factory Compound. The box finish and new pearl cover made the Effect very clean through the front of the lane during our testing, and it was very quick off the dry when it got to the friction.


Stroker had the best reaction out of our three bowlers on the medium oil pattern. He could play a small swing from just outside the second arrow out to about board six downlane. He had room for error to the outside, but he sometimes saw too much skid and ended up half-pocket on his misses to the inside. While throwing this ball by itself, he saw very little transition and could stay in the same part of the lane for a while. Once duller balls started breaking down the track area, he needed to start moving farther inside. He needed to get pretty steep with his launch angles to get it to the friction, which is not his most comfortable shot. His ball reaction was fine, but his execution wasn’t as good due to being a bit outside of

Additional Hammer Effect Resources

Click here to visit Hammer's website to read the manufacturer-supplied information on this ball. Also, see below for the manufacturer-produced promotional video for this ball.

Please remember that our reviews are solely based on our own testing and that you may sometimes find differences between our comments and ratings and the manufacturer's claims. Links to these manufacturer resources are provided here strictly for convenience purposes.

The BTM Ball Testing Team

About The BTM Ball Testing Team

The BTM Ball Testing Team is led by Eric Martinez. Our team of three testers has thrown and reviewed hundreds of bowling balls for Bowling This Month. When not testing balls for BTM, Eric owns and operates University Pro Shop in San Antonio, TX and he is an avid competitive bowler. Click here to learn more about how we test and review bowling balls.