This is one of a variety of improved (Ackley) designs based on the 375 H&H case, this version having a 40° shoulder.

This is another “improved” version of the 375 H&H Magnum  

The 375 Black Mesa Express was launched in 1993 by Ronald Brian McDaniels in Kenton, Oklahoma, who originally founded the Black Mesa Rifle Co. in 1992. It was named after Black Mesa, the highest point in Oklahoma.    Black Mesa range, OK

   Based on the 404 Jeffery case to make a good .375cal cartridge on a shorter action.

The 375 Canadian Magnum was developed by Aubrey White and Noburo Uno and is based on the .404 Jeffery cartridge but with a slightly rebated rim.   

Developed by Don Allen, owner of Dakota Arms in Sturgis, SD and was developed as an alternative to the 375 Holland & Holland but a rimless, shortened case that is based on the 404 Jeffery case, so as to fit in a standard length action. This is almost the same idea...

The following is from P.O. Ackley's "Handbook for Shooters and Reloaders", Volume One: "The .375 Durham Magnum is the .338 Win Mag case necked up to .375 with a 35 degree shoulder angle to provide a very fine short .375 Mag cartridge with an overall length suitable...

This is one of a number of versions of the 458 Win Mag case necked down to .375 or alternatively the 338 Win Mag case necked up to .375. See also 375/338 Win Mag.   

This is one of the various improved versions of the 375 Flanged Magnum   

The .375 Hawk/Scovill was designed by Bob Fulton and Dave Scovill and it is basically a .30-06 necked up to .375 inch with the Brown-Whelen shoulder configuration, meaning the shoulder is sharpened slightly and moved further forward, as opposed to the Ackley version...

The Heavy Express range of cartridges was developed by Jim Busha, from Colorado Springs CO, and was based on the 348 Winchester case with the rim removed. They came in a variety of calibers, ranging from .240 to .500 caliber and in 2 different versions, namely the...

The Heavy Express range of cartridges was developed by Jim Busha, from Colorado Springs CO, and was based on the 348 Winchester case with the rim removed. They came in a variety of calibers, ranging from .240 to .500 caliber and in 2 different versions, namely the...

Display Dummy Although listed separately, this is a normal 375 HOLLAND & HOLLAND but with the proprietary Hoffman headstamp. Hoffman Arms, in most cases, called the calibers by their (Hoffman's) own name but the only proprietary cartridges they actually had were...

One of a few ‘improved’ versions of the old 375 Holland & Holland case.   

The 375 ICL (Increased Case Load) was developed by Arnold & Vern Juenke, gunsmiths who owned Saturn Gun Works in Reno, Nevada and is based on the 375 Holland & Holland case. It resembles the earlier Ackley Improved version, but with slightly lower and slightly...

The 375 JDJ was designed and developed by J.D. Jones, from SSK Industries as part of a series of handgun and metallic silhouette cartridges around 1978. The purpose of these cartridges was to give added range and power to the Thompson - Center Contender pistol for...

The 375 Jensen is based on the 30-06 case necked up to .375 cal. and was developed by Stig Anders Jensen, owner of The Jensen Rifle Company Ltd., a Division of Baltimar Ltd. (Denmark) around May 2004.   

The 375 JRS was developed by John R. Sundra, who necked an 8mm Remington Magnum to 375 caliber. Its performance is almost identical to the 375 Weatherby.      

One of a series of cartridges designed by the Late Lee Jurras, one of the greats in handgun hunting. He was very interested in the exploits of the old hunters with their Howdah pistols and in the early 1970’s brought out his own versions chambered in 6 different...

   The 375 KO is, as its name suggest, a true knockout blow. It's ballistics are superior to any other suppressed round for the AR-15/MSR platform. It leaves the muzzle with 1050 fps and 857 fpe. While the 857 fpe is remarkable enough for a subsonic as it is...

The 375 Lethal Magnum was developed by Lethal Precision Arms to achieve extremely high ballistic performance in a portable package for long range shooting. By using an custom built LPA rifle, LPA owner Mitch Fitzpatrick took 1st place during the 2016 King of 2 Miles...

This is another design by Alaskan ELR shooter Pro Martusheff (aka Swamplord) from Precisioned Rifle Ordnance and dates from 2013 but was officially launched in August 2014. The original cases were made by Bertrams Australia, but current production is by RCC Brass in...

Remington introduced the .375 Remington Ultra Mag in the fall of 2000 by simply necking up its popular .300 Ultra Mag case — a case that is based on the beltless .404 Jeffery with a slightly rebated rim.   

Developed in a joint venture between Ruger and Hornady, the .375 Ruger was first introduced 2007. The idea was to create a cartridge similar in length to the .30-06 Springfield, but with a case capacity comparable to the .375 Holland & Holland. A major selling...

   The 375 Snipe Tac is an improved 408 Chey-Tac case necked down to .375cal and shoulder blown out to 35° and pushed forward about .050 inch 375 Snipe Tac by Black Diamond Rifles  

Developed by Ronald Strieby and based on the popular 348 Winchester case necked up.   

For all practical purposes the same as the 375/338 Win Mag, being a 338 Win Mag case necked up to .375 or a 458 Win Mag case necked down to .375. See also 375/338 Win Mag   

The 375 Viersco Magnum was developed by Dave Viers from Black Diamond Rifles as well as for the super long range "Hard Target Interdiction" rifles by Desert Tech from West Valley City, Utah. Specimen below loaded with the 414gr. GS Custom solid.   

   Developed by Ken Waters around 1968 and was based on the 44 Marlin case necked down.

Designed by Roy Weatherby as an early ‘improved’ version of the 375 H&H, it was obsolete for a long time before being re-introduced by Weatherby in 2001.

This is the improved version of the 375 Whelen that was developed in 1951 by L.R. "Bob" Wallack and named in honor of Colonel Townsend Whelen. The shoulder angle on the original Whelen retained the 17º 30’ shoulder angle whereas the improved version has a 40° shoulder...

According to the SSK website, a “Whisper®” cartridge must be capable of sub-sonic extreme accuracy with very heavy bullets for its caliber. The 375 Whisper is based on the 7mm Bench Rest case together with the 338 and 416 caliber to convert 308 case head size actions...

The .375 Winchester was introduced in 1978 in the Winchester Model 94 XTR Big Bore carbine as a modernized version of the old 38-55 Winchester. Against the hopes of Winchester, the 375 was not a success and was discontinued during the mid 90’s.   

This is the 300 Winchester Short Mag necked up to 375   

One of a series of cartridges by JD Jones based on the 30-06 case     

One of a series of cartridges that are based on the 284 Winchester case, this one necked up to .375 cal.   

          The specimen above was made in South Africa by OPM. It has a shorter neck than the Quality Cartridge version Also known as the 375/338 Chatfield-Taylor or the 375/338 Belted Newton. It was developed by RF Chatfield-Taylor...