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Determine Correct Headspace

With the exception of the .240 Weatherby Magnum, most belted, magnum cartridges are based on the .375 H&H Magnum case. Therefore, they all use the same headspace gauges. The following is a partial listing of those cartridges which use the same Belted Magnum Headspace Gauges: .257 Weatherby Mag., 6.5 Rem. Mag., .264 Win. Mag., .270 Weatherby Mag., 7mm Rem. Mag., 7mm Weatherby Mag., 7mm STW, .300 H&H Mag., .300 Weatherby Mag., .300 Win. Mag., .30-.338 Win. Mag., .308 Norma Mag., 8mm Rem., .338 Win. Mag., .340 Weatherby Mag., .350 Rem. Mag., .358 Norma Mag., .375 H&H Mag., .416 Rem. Mag., .458 Win. Mag.

MIXING AND MATCHING BRANDS OF HEADSPACE GAUGES - Don't do it!! That's the short answer, here's why. It boils down to tolerance stacking. Each Headspace Gauge manufacturer works within a range specified by SAAMI. Manufacturer "A" may work at the high end of the range while Manufacturer "B's" gauges are in the middle of the tolerance range. Mixing the two could give an inaccurate reading. By sticking with one brand within a particular caliber, you will eliminate a variable. If you have a Forster, .308 GO gauge, get a Forster, .308 NO GO. Use Clymer with Clymer and Manson Precision with Manson Precision, etc. You can use any brand of headspace gauge with any other brand of chambering reamer. e.g. Forster Headspace Gauges with Clymer Reamers, Manson Precision Gauges with JGS Reamers, etc.


Big Book Catalog, Issue:67, Page:479
New Product Supplement, Issue:551, Page:006

MANSON PRECISION - BELTED MAGNUM CARTRIDGE HEADSPACE GAUGES

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3 Item(s)
.240 WEATHERBY MAG GO HEADSPACE GAUGE
513-000-041WB
GO GAUGE for .240 Weatherby Magnum
513000041GO GAUGE for .240 Weatherby Magnum

Mfr Part: G240WHB

$30.00

In Stock

Cartridge: 240 Weatherby Magnum

Style: Go Gauge

BELTED MAGNUM GO MANSON HS GAUGE
513-100-320WB
GO GAUGE for Belted Magnum Cartridges
513100320GO GAUGE for Belted Magnum Cartridges

Mfr Part: G0BLT

$30.00

In Stock

Style: Go Gauge

BELTED MAGNUM NO GO MANSON HS GAUGE
513-100-321WB
NO GO Headspace Gauge for Belted Magnum Cartridges
513100321NO GO Headspace Gauge for Belted Magnum Cartridges

Mfr Part: NGBLT

$30.00

In Stock

Style: Go Gauge

BELTED MAGNUM CARTRIDGE HEADSPACE GAUGES