Bowling ball core · Roto Grip

Roto Grip Caliber Core

Symmetric Roto Grip core

A symmetric core with later rev-up, more length and medium flare, built for heavy oil. Balls with this core are no longer available at BowlersMart.

  • Symmetric
  • RG 2.570
  • Diff 0.048

Specs

RG AT 15 LB

2.570

Later rev-up, more length

Revs soonerRevs later

92% of the reactive and urethane balls we stock have a lower RG.

DIFFERENTIAL AT 15 LB

0.048

Medium flare

Less flareMore flare

52% of the reactive and urethane balls we stock have a lower differential.

MASS BIAS AT 15 LB

None

Symmetric core

Symmetric cores have no mass bias marker to place when drilling.

RG How soon the ball revs up.Differential How much the ball can flare.Mass bias How asymmetric the core is.
Roto Grip Caliber Core specs by ball weight
Weight RG DifferentialDiff Mass biasMB
16 lb 2.540 0.051 None
15 lbUsed on this page 2.570 0.048 None
14 lb 2.600 0.044 None
13 lb 2.590 0.045 None
12 lb 2.650 0.035 None

Source: Roto Grip published specs, as shown on BowlersMart’s original Roto Grip Caliber core page (2022). 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.

Looking for a ball like your Roto Grip Caliber?

Balls with the Roto Grip Caliber Core are no longer available at BowlersMart. These in-stock balls have the closest RG and differential.

Storm Hy-Road Bowling Ball

Storm Hy-Road

Storm R2S Hybrid Reactive

Medium oil

Sale price $139.95 Regular price $229.95In stock
Hammer Anger Solid Bowling Ball

Hammer Anger Solid

Hammer Semtex Solid Reactive

Medium oil

Sale price $99.95 Regular price $249.95In stock
Storm Next Factor Bowling Ball

Storm Next Factor

Storm R3S Pearl Reactive

Medium oil

Sale price $119.95 Regular price $289.95In stock
900 Global Portal Bowling Ball

900 Global Portal

900 Global RB 92 Solid Reactive

Heavy oil, medium to heavy oil

Sale price $209.95 Regular price $299.95In stock
Motiv Primal Ghost Bowling Ball

Motiv Primal Ghost

Motiv Coercion HFS (High Friction Solid) Reactive

Medium oil

Sale price $169.95 Regular price $259.95In stock
Hammer Red Pearl Urethane Asym Overseas Bowling Ball

Hammer Red Pearl Urethane Asym Overseas

Hammer Pearl Urethane

Dry to medium oil

See priceIn stock

Balls with the Roto Grip Caliber Core

None of the 3 balls with the Roto Grip Caliber Core are in stock at BowlersMart right now.

Show 3 balls no longer available at BowlersMart
More bowling balls with the Roto Grip Caliber Core
Ball Cover First seen
Roto Grip Berserk Bowling Ball Roto Grip 65MH Hybrid Reactive March 2012
Roto Grip Outlaw Bowling Ball Roto Grip Inception Solid Reactive March 2011
Roto Grip Bandit Bowling Ball Roto Grip Inception Pearl Reactive March 2011

Where the Roto Grip Caliber sits

Each dot is a core in balls we stock. Cores close together roll alike; the cover and layout decide the rest.

DV8 Larceny Core, RG 2.471, diff 0.028DV8 Renegade Core, RG 2.499, diff 0.040Track I-Core Gen4, RG 2.480, diff 0.053Brunswick Vintage Light Bulb Low RG Core, RG 2.568, diff 0.032Brunswick Dual Centric Core, RG 2.509, diff 0.047Ebonite Big Time Core, RG 2.500, diff 0.054Hammer Stacked LED Core, RG 2.545, diff 0.047Hammer Vindicator Core, RG 2.474, diff 0.053Radical Vexed Variant Asymmetric Core, RG 2.490, diff 0.045Radical Modified Intel Symmetric Core, RG 2.483, diff 0.032Motiv Affliction V2 Core, RG 2.480, diff 0.055Roto Grip GEM A.I. Core, RG 2.490, diff 0.057Hammer Obsession Tour, RG 2.469, diff 0.034Hammer Super Offset Core, RG 2.524, diff 0.053Hammer Gas Mask Core, RG 2.500, diff 0.058Ebonite Turbo Core, RG 2.510, diff 0.040Ebonite Centrex Symmetrical Mass Bias, RG 2.460, diff 0.056Motiv Excel Core, RG 2.550, diff 0.030Motiv Detonator Core, RG 2.470, diff 0.055Storm Solarion AI Core, RG 2.480, diff 0.054SWAG Insanity Symmetric Core, RG 2.520, diff 0.034SWAG Fusion Symmetric Core, RG 2.540, diff 0.036SWAG Watcher Symmetric Core, RG 2.510, diff 0.048SWAG Dragon Asymmetric Core, RG 2.480, diff 0.054SWAG Executioner Asymmetric Core, RG 2.500, diff 0.051Motiv Predator V2 Core, RG 2.470, diff 0.054Storm C3 Centripetal Control Core, RG 2.490, diff 0.029Roto Grip Rondure MaxD Core, RG 2.500, diff 0.058Hammer Vibe Core, RG 2.510, diff 0.042Hammer Aftermath Core, RG 2.520, diff 0.052Brunswick Alert Core, RG 2.478, diff 0.037Brunswick Rampart Core, RG 2.502, diff 0.051DV8 Collision Core, RG 2.462, diff 0.052Track MC2 Asym Core, RG 2.470, diff 0.046Radical Evil Eye Symmetric Core, RG 2.490, diff 0.046Ebonite Iron Fist V2 Core, RG 2.470, diff 0.053Radical No Doubt Symmetric Core, RG 2.480, diff 0.051Storm Surge Core, RG 2.580, diff 0.024Roto Grip Hyped UP Core, RG 2.500, diff 0.042Roto Grip Morph-Wing Core, RG 2.510, diff 0.051Brunswick Fury Core, RG 2.524, diff 0.038Motiv Sigma Core, RG 2.470, diff 0.047Roto Grip Hustle Core, RG 2.530, diff 0.030900 Global Blast AI Core, RG 2.470, diff 0.055900 Global Strobe AI Core, RG 2.510, diff 0.052Radical Guru Core, RG 2.500, diff 0.044Track I-CORE 3.0, RG 2.480, diff 0.056DV8 Unholy Core, RG 2.500, diff 0.051Brunswick Infinity Core, RG 2.521, diff 0.051Storm Catalyst Core, RG 2.500, diff 0.052Hammer Gauntlet Core, RG 2.501, diff 0.050Hammer Raw Hammer Core, RG 2.537, diff 0.038Storm Atmos A.I. Core, RG 2.530, diff 0.042Storm Booster Core, RG 2.540, diff 0.046Track Shuttle Core, RG 2.490, diff 0.038Brunswick Light Bulb Core, RG 2.524, diff 0.030Radical Sneak Attack Core, RG 2.540, diff 0.036Motiv Gear Core, RG 2.480, diff 0.034Hammer Huntsman Core, RG 2.470, diff 0.050Hammer Super LED Core, RG 2.632, diff 0.034Ebonite Enhanced V2 Core, RG 2.480, diff 0.048DV8 Dualistic Core, RG 2.490, diff 0.045Radical Vexed Asymmetric Core, RG 2.490, diff 0.036Motiv Quadfire Core, RG 2.550, diff 0.043Track Stealth Core, RG 2.480, diff 0.056Brunswick Tiered Hexagon Core, RG 2.540, diff 0.045Columbia 300 Piranha Core, RG 2.550, diff 0.043Storm Torsion AI Core, RG 2.470, diff 0.050Storm Element Max AI Core, RG 2.470, diff 0.055Storm Radius Core, RG 2.610, diff 0.020Roto Grip Rondure Tour X Core, RG 2.480, diff 0.034SWAG Unreal Core, RG 2.510, diff 0.047SWAG Craze Core, RG 2.520, diff 0.030SWAG Serpent Asymmetric Core, RG 2.510, diff 0.048Radical Torpedo Asymmetric Core, RG 2.480, diff 0.054Motiv Overload, RG 2.480, diff 0.050DV8 Duality Core, RG 2.480, diff 0.036Hammer Spheroid Core, RG 2.480, diff 0.048Radical Outer Limits Asymmetric, RG 2.490, diff 0.051Motiv Apex Predator Core, RG 2.520, diff 0.055Brunswick Danger Zone Core, RG 2.501, diff 0.048Storm Velocity Core, RG 2.480, diff 0.051Hammer LED Resin Bowling Ball Core, RG 2.586, diff 0.027Epic Spark Core, RG 2.540, diff 0.049Motiv Hadron Dual Density Core, RG 2.500, diff 0.045Track Criterion ID Core, RG 2.490, diff 0.047Brunswick Zone Asymmetric Core, RG 2.478, diff 0.048Ebonite Entity Core, RG 2.510, diff 0.052Roto Grip Rocker AI Core, RG 2.480, diff 0.050Motiv Flux Core, RG 2.570, diff 0.015DV8 Mantra Core, RG 2.490, diff 0.047Hammer Gas Mask Low Diff Core, RG 2.500, diff 0.034Roto Grip RST Core + AI, RG 2.520, diff 0.055SWAG APX V1 Core, RG 2.500, diff 0.042SWAG Fusion Core, RG 2.540, diff 0.036SWAG Judge Core, RG 2.490, diff 0.052900 Global Magna AI Core, RG 2.490, diff 0.044Roto Grip Rondure Core, RG 2.490, diff 0.052Columbia 300 Pulse PowerCOR, RG 2.460, diff 0.045Storm Element Tour A.I. Core, RG 2.470, diff 0.035KR Strikeforce KR Launch Core, RG 2.530, diff 0.047900 Global Ellipse Asymmetric A.I. Core, RG 2.480, diff 0.050Motiv Halogen Core, RG 2.550, diff 0.037Storm C3 + AI Core, RG 2.480, diff 0.031Motiv Gear APG, RG 2.470, diff 0.036Radical Snapshot Symmetric Core, RG 2.520, diff 0.050Hammer High Rev Offset Core, RG 2.489, diff 0.053Hammer Huntsman Tour Core, RG 2.472, diff 0.036Hammer LED Core, RG 2.650, diff 0.015Storm Capacitor Core, RG 2.570, diff 0.022Storm Velocity A.I. Core, RG 2.470, diff 0.053Storm Atomic Core, RG 2.480, diff 0.053Storm RAD-X Asymmetric, RG 2.480, diff 0.054Storm ID AI Core, RG 2.510, diff 0.055Columbia 300 Shifter Core, RG 2.470, diff 0.050Radical Modified Intel Symmetric, RG 2.480, diff 0.032Columbia 300 Columbia Ricochet Core, RG 2.480, diff 0.054Roto Grip Defense AI Core, RG 2.490, diff 0.053Storm Supercoil Core, RG 2.470, diff 0.053Storm Centripetal HD A.I. Core, RG 2.460, diff 0.056Brunswick Ethos Core, RG 2.480, diff 0.053Hammer Hazmat Core, RG 2.470, diff 0.055Track Criterion MD Core, RG 2.500, diff 0.052Storm Ignition Core, RG 2.490, diff 0.052Roto Grip Momentous A.I. Core, RG 2.480, diff 0.049Brunswick Portal X Core, RG 2.473, diff 0.054Ebonite Emerge Core, RG 2.510, diff 0.053Radical Katana Core, RG 2.500, diff 0.050900 Global Meditate LD Symmetric Core, RG 2.560, diff 0.027Columbia 300 Movement Core, RG 2.510, diff 0.053Hammer Modified Infamous Core (pictured: Hammer Anger Solid Bowling Ball)1Storm Inverted Fe2 Core (pictured: Storm Hy-Road Bowling Ball)2Storm RAD-TQ Core (pictured: Storm Next Factor Bowling Ball)3Motiv Impulse V2 Core (pictured: Motiv Primal Ghost Bowling Ball)4900 Global Conduit A.I. Core (pictured: 900 Global Portal Bowling Ball)5Hammer FAB Asymmetric (pictured: Hammer Red Pearl Urethane Asym Overseas Bowling Ball)6Roto Grip Caliber Core (pictured: Roto Grip Berserk Bowling Ball)EARLY REV-UPMID-LANELATER REV-UPHIGH FLAREMEDIUMLOW FLARE2.442.482.522.562.602.642.680.0100.0200.0300.0400.0500.060RG at 15 lbDifferential at 15 lb← Revs up soonerRevs up later →More flare ↑Less flare ↓

Nearest cores, zoomed in

Hover or tap a dot for that core’s numbers. Click a dot to open its page. Drag to move around when zoomed in. The same RG and differential do not guarantee the same ball motion.

This core 1 Nearest cores Other cores

Nearest cores to the Roto Grip Caliber Core
Core Brand Shape RG Diff vs this core
Hammer Anger Solid Bowling Ball1Hammer Modified Infamous CorePictured: Hammer Anger Solid
 Hammer Symmetric 2.567 0.049 RG −0.003 · Diff +0.001
Storm Hy-Road Bowling Ball2Storm Inverted Fe2 CorePictured: Storm Hy-Road
 Storm Symmetric 2.570 0.046 RG 0.000 · Diff −0.002
Storm Next Factor Bowling Ball3Storm RAD-TQ CorePictured: Storm Next Factor
 Storm Asymmetric 2.560 0.051 RG −0.010 · Diff +0.003
Motiv Primal Ghost Bowling Ball4Motiv Impulse V2 CorePictured: Motiv Primal Ghost
 Motiv Symmetric 2.550 0.050 RG −0.020 · Diff +0.002
900 Global Portal Bowling Ball5900 Global Conduit A.I. CorePictured: 900 Global Portal
 900 Global Asymmetric 2.590 0.050 RG +0.020 · Diff +0.002
Hammer Red Pearl Urethane Asym Overseas Bowling Ball6Hammer FAB AsymmetricPictured: Hammer Red Pearl Urethane Asym Overseas
 Hammer Asymmetric 2.550 0.051 RG −0.020 · Diff +0.003

Matches use 15 lb RG and differential.

Drilling and tools

Drilling layoutsLayout guides for symmetric and asymmetric ballsDual angle converterTurn a pin to PAP layout into a dual angle layout

The smooth-rolling Caliber core utilizes increased energy transfer to create maximum pin action for both rev-dominant and speed-dominant players.  

From Roto Grip’s description

Questions bowlers ask

What is the RG of the Roto Grip Caliber Core?

At 15 lb the Roto Grip Caliber Core has an RG of 2.570. It ranges from 2.540 to 2.650 across the listed weights.

What is the 14 lb RG of the Roto Grip Caliber Core?

At 14 lb the RG is 2.600.

What is the differential of the Roto Grip Caliber Core?

At 15 lb the differential is 0.048. This is a symmetric core, so mass bias is not applicable.

Which bowling balls use the Roto Grip Caliber Core?

Roto Grip Berserk Bowling Ball, Roto Grip Outlaw Bowling Ball, Roto Grip Bandit Bowling Ball. 0 are in stock now.

Can I still buy a ball with the Roto Grip Caliber Core?

Balls with this core are currently unavailable at BowlersMart. Closest in-stock alternatives by RG and differential include Storm Hy-Road Bowling Ball, Hammer Anger Solid Bowling Ball, Storm Next Factor Bowling Ball, 900 Global Portal Bowling Ball, Motiv Primal Ghost Bowling Ball, Hammer Red Pearl Urethane Asym Overseas Bowling Ball.

How do the Roto Grip Caliber Core specs change by weight?

At 16 lb: RG 2.540, differential 0.051. At 12 lb: RG 2.650, differential 0.035.

How does the Roto Grip Caliber 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. Roto Grip published specs, as shown on BowlersMart’s original Roto Grip Caliber core page (2022), as published by the manufacturer.

Baseline. The baseline is 265 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.

Next lesson

Compare cores by RGEvery in-stock ball from lowest to highest RGCompare cores by differentialEvery in-stock ball from lowest to highest differentialAll bowling ball coresCore libraries for every brand we carryRoto Grip core libraryEvery Roto Grip core we have specs for