Success Comes from the Details

By Philip H. Dater, MD

Evaluation of the S&H Arms of OK Model 30 Integral Blackout AR-Platform Upper Receivers

For the past 30-plus years, the name Curtis Higgins and S&H Arms of Oklahoma, Inc., have been at the forefront of quality machine gun conversions of Heckler & Koch (HK) semi-auto rifles and carbines. The business started in 1986 manufacturing thousands of registered HK autosears prior to the May 19, 1986, ban on new machine guns and conversions. Since the 5/19/86 Day of Infamy, Curtis and his company have converted innumerable HK 93, 91 and 94 rifles into fully transferrable select fire versions of the models 33, G3 and MP5 (for more info: curtis@sandharms.com). While several other manufacturers also made the autosears, the S&H conversions were coveted due to the flawless cosmetics and functioning of the weapons. S&H was also known for its autosears for the FNC and, to a lesser extent, autosears for the Ruger 10/22. To this day, S&H is known as the premier gunsmithing facility for HK machine guns.

1986 also was the year S&H entered the suppressor market with MP5 muzzle suppressors, HK MP5SD integral suppressors and a variety of integral rimfire suppressors for Ruger .22LR weapons, the Ruger 77/44 and the Marlin .45 Camp Carbine. Curtis licensed his integral Ruger rimfire designs to John’s Guns.
Small Arms Review recently received S&H’s latest suppressed weapon, an integrally suppressed upper receiver chambered for the popular AAC .300 Blackout cartridge, an improved version of the SSK .300 Whisper originally designed by J.D. Jones.

Designed for a 9-inch barrel, the .300BLK’s popularity has risen dramatically due to the simple conversion of the AR-16/M16 weapons simply by changing the barrel with its associated gas block. Even the M249 belt-fed machine gun is set up for this cartridge. For many purposes, the .300BLK cartridge is ideal: .30 caliber bullet, short barrel, subsonic and supersonic loadings with bullet weights ranging from 110 grains to 220 grains. The loadings using bullets 150 grains or less are supersonic while those with the heavier bullets are generally subsonic.

The S&H Model 30 is a complete assembly consisting...

This article first appeared in Small Arms Review V22N9 (November 2018)
and was posted online on September 21, 2018


Comments have not been generated for this article.