The Heym SR 30 is a straight-pull rifle produced in

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

Heym Heym is a surname. Notable people with the surname include: * Georg Heym (1887–1912), German author * Stefan Heym (1913–2001), German author See also * Heym (gun manufacturer) * Chayyim, the basis for this name * Haim (disambiguation) * Hei ...

. The rifle is also available in a left hand version.

Locking mechanism

The mechanism uses 6 ball bearings symmetrically positioned around the circumference of the bolt head as locking elements. When the bolt handle is pushed forward, it forces a central plunger down the interior of the bolt body, forcing the diameter ball bearings out to lock into a negative recess in the receiver. There are not six matching negative shaped (concave) recesses in the receiver. That would be very hard to practically produce at the required precision level. Instead there is a simple continuous groove machined for the six ball bearings to lock into. The continuous semi-round groove in conjuncion with the barrel positions the bolt to the front and back and regulates a practically achievable headspace during production. The lockup strengthens with increased chamber pressure. The plunger retracts when the bolt handle is pulled back, allowing the locking bearings to retract into the bolt body so the bolt can open. The bolt can be classified as a semi-rigid type, since the locking elements are movably mounted on the bolt.

Primary extraction In breechloading firearms, primary extraction is the initial phase (the first few millimeters) of the extraction of a spent casing from the firearm chamber. After the primary extraction comes the secondary extraction where the bolt is moved furt ...

is performed by retracting the bolt handle, which uses leverage from the opposite side of the bolt to swing the handle to the open position, giving a

mechanical advantage Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. The device trades off input forces against movement to obtain a desired amplification in the output force. The model for ...

. The bolt handle can be placed in three positions: (1) Open, (2) Locked and uncocked, and (3) Locked and cocked. By pressing the bolt handle fully forward to position 3 the user can manually cock the action just before firing. When the user chooses not to fire manually pulling the bolt handle backward to position 2 uncocks the action again for safe carry. The locking mechanism was designed by Peter Fortner junior. A preceding example of a semi-rigid bolt lock using ball bearings as locking elements is the

Anschütz 1827 Fortner Anschütz 1827 Fortner is a straight pull rifles, straight-pull action biathlon rifle designed by Peter Fortner junior and produced in cooperation with J. G. Anschütz. The rifle has been dominant in the sport of biathlon since the late 1980s, ...

rifle, also designed by Peter Fortner junior. Peter Fortner junior patented the in the Anschütz 1827 Fortner used locking mechanism in 1984. Unlike the Heym SR 30 six ball bearings the seven ball bearings in the

.22 LR The .22 Long Rifle or simply .22 LR or 22 (metric designation: 5.6×15mmR) is a long-established variety of .22 caliber rimfire ammunition originating from the United States. It is used in a wide range of rifles, pistols, revolvers, smooth ...

(5.6×15mmR) chambered Anschütz 1827 Fortner are located at the back of the bolt. As the commercial introduction of the Heym SR 30 occurred within 20 years after 1984, Peter Fortner junior's patent at the time had not expired. Heym states they successfully had the SR 30 locking mechanism tested by the C.I.P. accredited Suhl proofhouse loaded up to a P_max piezo pressure of . Websites report on a Heym SR 30 rifle chambered in

.30-06 Springfield The .30-06 Springfield cartridge (pronounced "thirty- aught-six" ), 7.62×63mm in metric notation, and called the .30 Gov't '06 by Winchester, was introduced to the United States Army in 1906 and later standardized; it remained in military use ...

subjected to by

QuickLOAD QuickLOAD is an internal ballistics predictor computer program for firearms. For computations apart from other parameters, * the cartridge * the projectile (bullet) * the gun barrel length * the cartridge overall length * the propellant type and ...

calculated/predicted peak chamber pressure tests of (a 241% overload) and (a 258% overload) by firing intentionally incorrectly loaded .30-06 Springfield cartridges. These pressure levels generate over double the maximum allowed

bolt thrust Bolt thrust or breech pressure is a term used in internal ballistics and firearms (whether small arms or artillery) that describes the amount of rearward force exerted by the propellant gases on the bolt or breech of a firearm action or breech wh ...

and the 258% overload comes near the bolt thrust exhibited by a .50 BMG (12.7×99mm NATO) cartridge. After examening the remotely fired rifle the SR 30 extractor turned out to be damaged as high pressure gases out of ruptured cartridge cases were relieved out of the action, and the bolt was deformed rendering the rifle unusable. The bolt was however retained in the rifle during these tests avoiding a catastrophic failure of parts unintentionally moving backwards towards the user type.

Similar Designs

The Savage Impulse straight-pull rifle introduced in early 2021 features a similar locking mechanism as the SR 30. Besides differences in the applied control mechanisms a major technical difference between the locking mechanisms of the Heym SR 30 and Savage Impulse rifles is that the 6 'hexlock' hardened steel locking bearings of the Savage Impulse bolt head, lock into a machined half-round recess of a steel barrel extension, allowing the use of a receiver made of mechanically less robust but lighter 7075-T6 billet aluminum with an integral 20-MOA

picatinny rail The Picatinny rail ( or ), or Pic rail for short, also known as a MIL-STD-1913 rail, 1913 rail or STANAG 2324 rail (cancelled), is a military standard rail interface system that provides a mounting platform for firearm accessories. It was o ...

and the possibility for the user to switch bolts and barrels to use different chamberings when such parts become available. At the introduction three hunting orientated Savage Impulse model variants were available. Their listed weights vary between {{convert, 8.4, -, 9.1, lbs, abbr=on, lk=on. In 2022 a dedicated long range or precision model using an adjustable aluminum chassis stock and detachable box magazine became available that is offered in chamberings up to the high bolt thrust

.338 Lapua Magnum The .338 Lapua Magnum (8.6×70 mm or 8.58×70 mm) is a rimless, bottlenecked, centerfire rifle cartridge. It was developed during the 1980s as a high-powered, long-range cartridge for military snipers. It was used in the War in Afghanistan and ...

Trigger

The rifle is offered with two trigger options, either a shotgun style trigger set at 1600 grams or a set trigger set to 1100 grams. To activate the lighter release, the set trigger must be pushed forward.

Cartridges

The rifle is available in the two main configurations SR 30 N (normal cartridges) and SR 30 G (larger cartridges). ;Normal action :The Heym SR 30 N is available chambered for

.22-250 The .22-250 Remington is a very high-velocity, short action, .22 caliber rifle cartridge primarily used for varmint hunting and small game hunting. It is capable of reaching over 4000 feet per second. It does find occasional use by women and yo ...

.243 Win The .243 Winchester (6×52mm) is a popular sporting rifle cartridge. Developed as a versatile short action cartridge to hunt both medium game and small game alike, it "took whitetail hunting by storm"Ron Spomer.Whitetail Deer Cartridge Shoot-Out ...

.25-06 Considered by many as the most balanced of the "quarter bores" for hunting medium-sized game, the .25-06 Remington remained in obscurity as a wildcat cartridge for nearly half a century before being standardized by Remington in 1969. Its design ...

6.5mm Creedmoor The 6.5mm Creedmoor (6.5×48 mm), designated 6.5 Creedmoor by SAAMI, 6.5 Creedmoor by the C.I.P. or 6.5 CM or 6.5 CRDMR for short, is a centerfire rifle cartridge introduced by Hornady in 2007. It was developed by Hornady senior ballistics ...

, 6.5×55mm, 6.5×64mm, .270 Win,

7×57mm 7 (seven) is the natural number following 6 and preceding 8. It is the only prime number preceding a cube. As an early prime number in the series of positive integers, the number seven has greatly symbolic associations in religion, mythology, ...

7×64mm The 7×64mm (also unofficially known as the 7×64mm Brenneke, though its designer's name was never officially added as a part of the cartridge name) is a rimless bottlenecked centerfire cartridge developed for hunting. As is customary in Europe ...

.308 Win The .308 Winchester is a smokeless powder rimless bottlenecked rifle cartridge widely used for hunting, target shooting, police, military, and personal protection applications globally. It is similar but not identical to the 7.62×51mm NATO ...

, .30-06, 30-06

Ackley Improved Parker Otto Ackley (May 25, 1903, Granville, New York – August 23, 1989) was an American gunsmith, barrel maker, author, columnist, and wildcat cartridge developer. The Ackley Improved family of wildcat cartridges are designed to be easily made ...

, 8×57 JS, 8×64mm S, 8.5×63mm and 9.3×62mm.Heym SR30 Straight Pull Rifle - Revivaler
/ref> ;Magnum action :The Heym SR 30 G (Groß meaning large) is available chambered for 6.5×68mm,

.270 WSM The 270 Winchester Short Magnum or 270 WSM is a short, unbelted, magnum cartridge created by necking down the .300 Winchester Short Magnum and fitting it with a .277 caliber bullet. The correct name for the cartridge, as listed by the Sporting A ...

.300 WSM 300 Winchester Short Magnum (also known as 300 WSM) is a .30 caliber rebated rim bottlenecked centerfire short magnum cartridge that was introduced in 2001 by Winchester. Specifications The overall cartridge length is 72.6 mm. The cart ...

, 7mm Rem Mag,

.300 Win Mag The .300 Winchester Magnum (also known as .300 Win Mag or .300 WM) (7.62×67mmB, 7.62x66BR) is a belted, bottlenecked magnum rifle cartridge that was introduced by the Winchester Repeating Arms Company in 1963. The .300 Winchester Magnum is a m ...

8×68mm S The 8×68mm S rebated rim bottlenecked centerfire rifle cartridge was developed in the 1930s by August Schüler of the ''August Schüler Waffenfabrik, Suhl, Germany'' as a magnum hunting cartridge that would just fit and function in standard-size ...

, .338 Win Mag and

.375 Ruger The .375 Ruger (9.5×65.5mm) is a rimless, standard-length rifle cartridge designed for the hunting of large, dangerous game. It is designed to provide an increase in performance over the .375 H&H cartridge, yet to be chambered in a standard-len ...

. ;Mini action :The rifle is also available in a smaller Mini Calibre action length for the chamberings .222 Rem and .223 Rem, but this action length is only available in a right handed version.

Barrels

The rifle comes with a hammer forged barrel made in-house at Heym. The SR 30 uses traditional

action threads In firearms, barrel threads refer to the screw threads used to attach a barrel. Action threads, also called receiver threads, are situated at the chamber end of the barrel, and can be used for attaching the barrel to the receiver. The receive ...

for fixing the barrel to the receiver. Barrel change must be performed by a competent gunsmith, and consists of setting the headspace as well as fitting the recoil lug between the barrel and stock.

Precision

The Heym High Performance Precision rifle variant is guaranteed by the factory to deliver a five shot group of 20 mm at 100 meters (0.2

mrad The Barrett MRAD (Multi-role Adaptive Design) is a bolt-action sniper rifle designed by Barrett to meet the requirements of the SOCOM PSR. The MRAD is based on the Barrett 98B and includes a number of modifications and improvements. The Barret ...

).HEYM High-Performance Precision Rifle (HPPR)
/ref> This is equivalent to 0.72 inches at 100 yd, or just below 0.69

moa Moa are extinct giant flightless birds native to New Zealand. The term has also come to be used for chicken in many Polynesian cultures and is found in the names of many chicken recipes, such as Kale moa and Moa Samoa. Moa or MOA may also refe ...

References

External links

Heym SR 30 Repetierbüchse

Heym SR30: Straight Pull Ball-Bearing Lock? – Forgotten Weapons
Rifles of Germany Straight-pull rifles