Bowling ball core · Hammer
Hammer Gas Mask Low Diff Core
Asymmetric Hammer core
An asymmetric core with mid-lane rev-up and low flare, built for medium to heavy oil. 1 of the 1 balls with this core are in stock at BowlersMart.
- Asymmetric
- RG 2.500
- Diff 0.034
- MB 0.016

Specs
RG AT 15 LB
2.500
Mid-lane rev-up
40% of the reactive and urethane balls we stock have a lower RG.
DIFFERENTIAL AT 15 LB
0.034
Low flare
17% of the reactive and urethane balls we stock have a lower differential.
MASS BIAS AT 15 LB
0.016
Mild asymmetry
33% of the asymmetric reactive and urethane balls we stock have a lower mass bias.
| Weight | RG | DifferentialDiff | Mass biasMB |
|---|---|---|---|
| 16 lb | 2.510 | 0.030 | 0.015 |
| 15 lbUsed on this page | 2.500 | 0.034 | 0.016 |
| 14 lb | 2.517 | 0.034 | 0.016 |
| 13 lb | 2.589 | 0.043 | 0.011 |
| 12 lb | 2.612 | 0.043 | 0.011 |
Source: Hammer published specs, as listed on the Black Widow Tour V1 product page. RG and differential change with ball weight; use the row for the weight you throw. The highlighted 15 lb row is the one used on this page.
Balls with the Hammer Gas Mask Low Diff Core
1 of the 1 balls with the Hammer Gas Mask Low Diff Core are in stock at BowlersMart. Same core, different covers: pick the cover for the lanes you bowl on.

Hammer HK22 Aggression Hybrid Reactive
Medium to heavy oil
Where the Hammer Gas Mask Low Diff sits
Each dot is a core in balls we stock. Cores close together roll alike; the cover and layout decide the rest.
Navy ring = a ball in your bag. Dashed ring = off this chart, or this same core.
Nearest cores, zoomed in
Navy ring = a ball in your bag. Dashed ring = off this chart, or this same core.
Same family: Hammer Gas Mask Core
This core 1 Nearest cores Other cores
| Core | Brand | Shape | RG | Diff | vs this core |
|---|---|---|---|---|---|
|
|
Radical | Asymmetric | 2.498 | 0.036 | RG −0.002 · Diff +0.002 |
|
|
Roto Grip | Asymmetric | 2.480 | 0.034 | RG −0.020 · Diff 0.000 |
|
|
DV8 | Asymmetric | 2.499 | 0.040 | RG −0.001 · Diff +0.006 |
|
|
Radical | Symmetric | 2.483 | 0.032 | RG −0.017 · Diff −0.002 |
|
|
Motiv | Symmetric | 2.480 | 0.034 | RG −0.020 · Diff 0.000 |
|
|
SWAG | Symmetric | 2.520 | 0.034 | RG +0.020 · Diff 0.000 |
Matches use 15 lb RG and differential.
Drilling and tools
Turn on JavaScript to compare with your ball.Balls with the Hammer Gas Mask Low Diff Core1 of the 1 balls with the Hammer Gas Mask Low Diff Core are in stock at BowlersMart. Same core, different covers: pick the cover for the lanes you bowl on.
Questions bowlers ask
What is the RG of the Hammer Gas Mask Low Diff Core?
At 15 lb the Hammer Gas Mask Low Diff Core has an RG of 2.500. It ranges from 2.500 to 2.612 across the listed weights.
What is the 14 lb RG of the Hammer Gas Mask Low Diff Core?
At 14 lb the RG is 2.517.
What is the differential of the Hammer Gas Mask Low Diff Core?
At 15 lb the differential is 0.034. The mass bias is 0.016.
Which bowling balls use the Hammer Gas Mask Low Diff Core?
Hammer Black Widow Tour V1 Bowling Ball. 1 are in stock now.
How do the Hammer Gas Mask Low Diff Core specs change by weight?
At 16 lb: RG 2.510, differential 0.030, mass bias 0.015. At 12 lb: RG 2.612, differential 0.043, mass bias 0.011.
How does the Hammer Gas Mask Low Diff Core compare with my ball?
Type the ball you throw into the Compare with your ball box on this page. It shows the RG and differential side by side and saves your bag for every core page.
Sources and method
Specs. Hammer published specs, as listed on the Black Widow Tour V1 product page, as published by the manufacturer.
Baseline. The baseline is 212 in-stock, published reactive and urethane balls. Plastic and polyester covers, 2-piece, 3-piece and pancake cores, missing covers and missing RG or differential values are excluded.
Percentiles. Percentiles are the share of baseline balls with a strictly lower or higher value; ties are not counted.
Nearest cores. Nearest cores are ranked by distance on standardized 15 lb RG and differential, with the same symmetric or asymmetric shape preferred among near ties (distance bands of 0.1).
Mass bias. Mass bias is compared among asymmetric balls with numeric mass bias only.
Updated. Catalog and page updated 2026-10-16.


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