Contessa Picatinny Rail for Winchester 70 Long (20 MOA)

Introduction

Picatinny rail consists of slots with 5.23 mm spaces between one another, which means that it can be used across its entire length. It is simple to mount and interchangeable – if something is made for a Picatinny rail, it will fit regardless of the manufacturer or manufacturing date. It is affordable, resilient and reliable – this is why it so commonly used by professionals and military. Because of all its great qualities, Picatinny rail has been dominating the rail market in the recent years.

Picatinny is a big step forward from the Weaver standard. Weaver has a few predesignated slots while Picatinny has slots all over its surface, allowing the device to be mounted wherever the user finds it fitting. Weaver's slot is 3.8 mm wide, which is why ring mounts made for a Weaver rail will also fit on a Picatinny rail while ring mounts made specifically for a Picatinny rail will not fit on a Weaver rail. This is one of the main reasons why Picatinny is a far better mounting solution.

Contessa is an Italian company, famous for producing aesthetically appealing mounts with a nice finish. The tolerances of the produced pieces are very tight – there are no deviations, the mounts are very carefully machined. Contessa's Picatinny rails are made from steel and come with their unique screws which fit nicely into the rail. The screws have a huge contact surface and a bigger head than screws of other mount manufacturers, while the thread is the same. Contessa's Picatinny rails, made in Italy, are available in both 0 MOA and 20 MOA versions. Throughout the middle of the rail, there is a canal so that the rail can be used together with rifle's sights.

20 MOA Inclination

20 MOA inclination is only needed when the scope runs out of elevation. For example, when shooting at the range of 100 m, shooter gains 58.2 cm / 100 m of additional elevation range with a 20 MOA mount. This is approximately 5.8 Mrad of elevation. To make things even clearer – if the target was placed at 100 m, the scope with 20 MOA inclined rail would aim to the center of the target while the rifle’s barrel would aim 58 cm higher than the scope. This gives the shooter extra elevation needed for long range shooting. If you plan to shoot on distances longer than 600 meters, use of rail with 20 MOA is greatly recommended. There is no negative effect of the inclined Picatinny rail in the mounting setup if you only shoot on shorter distances. The same goes also the other way around, since if you don’t shoot on extreme distances then Picatinny rail with inclination is not needed.

About the rifle

In 1855, Horace Smith, Daniel B. Wesson and C.C. Palmer founded Volcanic Repeating Arms Company. Oliver F. Winchester, a clothing manufacturer, was one of the shareholders. He soon became the biggest shareholder, and with time the company changed the name to Winchester Repeating Arms Company. The first firearm that they made was Model 1866 – it reached high popularity. Some of its best-sellers are Model 1894 (more than three million pieces were made) and, of course, Model 70 – the Rifleman's Rifle. Winchester has also been a very successful ammunition manufacturer throughout its existence. These are their most famous cartridges: .30 WCF .44-40 WCF, .50 BMG, .270 Win., .308 Win., .243 Win., .22 WMR and .300 Win. Mag. Today, Winchester is owned by Olin Corporation.

First introduced in 1936, the Model 70, also known as the Rifleman's rifle because of its reputation among shooters, has an iconic place in the American culture. It is a bolt-action rifle. Models released before 1964 are nowadays referred to as “Classic“. These rifles had a claw-like extractor of the Mauser type (controlled-feed). Then, Winchester changed the extractor to push-feed but eventually decided to re-introduce the former one. Up to 1984, the same length of the receiver was used for every caliber, which was a disadvantage – the receiver and bolt were too long for some small calibers such as .223 Rem. The first Mod. 70 that had receiver adapted to small calibers was XTR Featherweight. Because Winchester Model 70 has been so popular throughout the years, many versions have been made. Winchester chambers their long-action models for .270 Win., .280 Rem., .30-06 Sprg., .300 Win. Mag., .338 Win. Mag., .375 H&H, .416 Rem., .458 Win. Mag. and 7mm Rem. Mag. For mounting purposes, there are two holes in the front part of the receiver and two holes in the rear part of the receiver.

Rifles Winchester Model 70 short, Model 70 long, Model 70 WSM and Model 70 WSSM have similar actions. The radiuses of the mounting surfaces are the same but there is a difference in B distance (see the picture below). This is why, for example, two-piece mounts made for Winchester Model 70 short will fit rifles Winchester Model 70 long, Model 70 WSM and Model 70 WSSM while one-piece mounts made for Winchester Model 70 short will not fit rifles Winchester Model 70 long, Model 70 WSM and Model 70 WSSM.

This mount is suitable for Winchester 70 LA (long-action).

A: 22 mm
B: 96.5 mm
C: 22 mm
BHU: 3.4 mm
Fi: 6-48
R1: R17
R2: R34

Mounting instructions

Remove all the stains (grease, oil etc.) from the rifle's receiver with a cleaning fluid (acetone). Once the surface is clean and dry, check whether the screws match the rail and the holes on the receiver. Make sure that the Picatinny rail is compatible with the rifle by inspecting the mounting holes on both. Before mounting the rail permanently, apply a minimal amount of thread-locking fluid 278 or 648 on screws and contact surfaces. Be careful not to get the fluid in or near the mounting holes. Carefully clean the remaining excess fluid around the rail with a cleaning fluid. Using a torque driver, screw the screws appropriately (up to 2.2 Nm) – do not overtighten.

Warranty

The product has a warranty period of 30 years.