MODULAR HEADSPACE COMPARATOR INSERTS 

NEW MODULAR DESIGN FOR THE MOST ACCURATE CARTRIDGE HEADSPACE AND BULLET MEASUREMENTS AVAILABLE!

THE MODULAR HEADSPACE BODY MUST BE PURCHASED SEPARATELY AND CAN BE FOUND AT THE MODULAR HEADSPACE COMPARATOR BODY PAGE.

https://shortactioncustoms.com/product/modular-headspace-comparator-body/

OUR SHOULDER INSERTS OUR DESIGNED TO MEASURE RELATIVE HEADSPACE.  THEY ARE NOT DESIGNED TO MEASURE HEADSPACE OFF OF A REAMER PRINT.  IF YOU ARE LOOKING TO MEASURE HEADSPACE FROM A REAMER PRINT PLEASE PURCHASE OUR DATUM GAUGES.  SEE LIST BELOW FOR COMPATIBILITY.  IF UNSURE OF WHAT INSERT TO CHOOSE PLEASE CLICK TO LINK BELOW TO CHECK YOUR SHOULDER ANGLE OR DATUM SIZE FROM SAAMI.ORG

https://saami.org/technical-information/cartridge-chamber-drawings/

Newly designed Modular Headspace Comparator (MHC) is an updated version of our highly successful dedicated Headspace Comparator that we previously made out of 6061 aluminum.  We improved on its design allowing the new MHC to be used with cartridges up to 338 Lapua Magnum and more.

 Each bullet and headspace insert is precision machined out of 17-4 Stainless Steel for increased durability and corrosion resistance.

Modular Headspace Comparators will ship with your headspace comparator insert of choice by selecting the correct insert from the drop down menu.

PLEASE USE THIS COMPATIBILITY LIST TO DETERMINE WHICH HEADSPACE COMPARATOR IS RIGHT FOR YOU. THE HEADSPACE COMPARATOR MODEL IS LISTED FIRST, THE COMPATIBLE CARTRIDGE IS LISTED AFTER.

204 Ruger

•  204 Ruger

223 Model

• 223 Remington and 5.56mm NATO

• 222 Remington

• Wildcat Cartridges necked down from the 223 Remington

22 Cal x 28°

• 22-250 Remington

• Wildcat Cartridges necked down from the 22-250 Remington

22 Cal x 30°

•  22 Creedmoor
• 224 Valkyrie

22 Cal x 35°

• 22 GT (6GT necked down to 22 caliber)

22 Cal x 40°

• 22 Dasher (Non-Alpha Chamber)
• 22 BRA
• 22-250 Ackley Improved

• 223 Ackley Improved

22 Alpha Dasher

• .22 Cal Dasher with an Alpha Legacy Reamed Chamber

6mm x 20°

• 243 Winchester

• Wildcat Cartridges necked down from the 243 Winchester

6mm x 26°

• 6mm Remington

6mm x 30°

• 6mm Creedmoor

• 6 x 47 Lapua

• 6BR

• 6BRX

• 6mm Super LR

• 6 ARC
• 6 PRC
• 6 XC

6mm x 35°

• 6GT

• 6mm x 284 Winchester

6mm x 40° 273” Neck, .060” Neck Shoulder Radius

• 6mm Dasher

• 6BRA (6mm BR Ackley Improved)

• 243 Ackley Improved

• Any 6mm Cartridge with 40° Shoulder and a neck smaller than .273”

6mm x 40° .275” Neck, .060” Neck Shoulder Radius

• 6mm Dasher

• 6BRA (6mm BR Ackley Improved)

• 243 Ackley Improved

• Any 6mm Cartridge with 40° Shoulder and a neck smaller than .275”

6mm x 40° 279″ neck

• 6mm Ackley Improved cartridges with a fired neck diameter over .275″

6mm Alpha Dasher

• 6mm Dasher  with an Alpha Legacy Reamed Chamber

25 Cal x 30°

• 25 Creedmoor

• 25 x 47 Lapua

• 25 PRC

• 25 SAUM

• 25 SST

25-06 Springfield

• 25-06 Springfield

6.5mm x 20°

• 260 Remington

6.5mm x 25°

• 264 Winchester Magnum

6.5mm x 30°

• 6.5 Creedmoor

• 6.5 x 47 Lapua

• 6.5 PRC

• 6.5 SAUM

• 6.5 Grendel

6.5mm x 35°

• 6.5 Winchester Short Magnum

• 6.5 x 284 Winchester

• 26 Nosler

6.5mm x 40°

• 260 Ackley Improved

• 6.5mm Wildcat cartridges with a 40 degree shoulder

6.5-06 Springfield

• 6.5-06 Springfield

6.5mm x 55mm Swedish

• 6.5mm x 55mm Swedish

270 Winchester

• 270 Winchester

280 Remington

• 280 Remington

7mm x 20°

• 7mm-08

7mm x 25°

• 7mm Remington Magnum
• 7mm STW

7mm x 30°

• 7mm SAUM

• 7mm Creedmoor

• 7mm LRM

• 7mm PRC

7mm x 35°

• 28 Nosler

• 284 Winchester

• 7mm WSM

• 7mm/300 WSM

7mm x 40°

• 7mm-08 Ackley Improved

• 280 Ackley Improved

• 7mm Wildcat cartridges with a 40 degree shoulder

7mm Sherman Short

• 7mm Sherman Short, 40° Shoulder, .125” Neck/Shoulder Radius

.30 Cal x 20°

• 308 Winchester

• Wildcat Cartridges necked down from the 308 Winchester

.30 Cal x 30°

• 300 Remington Ultra Mag

• 300 SAUM

• 300 PRC

.30 Cal x 35°

• 300 Winchester Short Magnum

.30 Cal x 40°

• 300 Norma Magnum Ackley Improved

• .30 Caliber Wildcat cartridges with a 40 degree shoulder

300 Blackout

• 300 AAC Blackout

30-06 Springfield

• 30-06 Springfield

300 Winchester Magnum

• 300 Winchester Magnum

300 Norma Magnum

• 300 Norma Magnum

338 Cal x 20°

• 338 Federal

338 Cal x 25°

• 338 Winchester Magnum

338 Cal x 35°

• 33 Nosler

338 Cal x 40°

• 338 Lapua Magnum Ackley Improved

• 338 Norma Ackley Improved

• 300 Norma Ackley Improved

338 Lapua Magnum

• 338 Lapua Magnum

• Wildcat Cartridges necked down from the 338 Lapua Magnum

338 Norma Magnum

• 338 Norma Magnum

• Wildcat Cartridges necked down from the 338 Norma Magnum

33XC

• 33XC

37XC

• 37XC

375 Cheytac

• 375 Cheytac

375 Enabler

• 375 Enabler

Simply put, these are the highest quality headspace and bullet measuring tools available.