Ishapore 2A/2A1

The Rifle 7.62mm 2A/2A1 (also known as the Ishapore 2A/2A1) is a 7.62mm NATO (7.62x51) calibre bolt-action rifle adopted as a reserve arm by the Indian military in 1963. The design of the rifle - initially the Rifle 7.62mm 2A - began at the Ishapore Rifle Factory of the Ordnance Factories Board in India, soon after the Sino-Indian War of 1962.
The Ishapore 2A/2A1 has the distinction of being the last bolt-action rifle designed to be used by a regular military force other than specialized sniper rifles. Due to fluctuating supplies of affordable .303 British ammunition, the Ishapore rifles are becoming increasingly popular with civilian shooters and collectors in Australia, United Kingdom and the United States

Design

Externally the Ishapore 2A/2A1 rifle was based upon (and is almost identical to) the .303 British calibre SMLE Mk III* rifle, with the exception of the distinctive “square” (10 or 12 round) magazine. The rifle was designed to allow the British Pattern 1907 (P'07) sword bayonet to be attached. There were other differences to the Ishapore 2A/2A1 rifles that include the use of improved steel (to handle the increased pressures of the 7.62mm NATO round), and a redesigned extractor to cope with the rimless round. Production of these rifles started in early 1960s and is believed to have been discontinued in 1975. The original (2A) design incorporated the Lee-Enfield rear sight which had metric graduations out to 2000 meters. The re-designated "Rifle 7.62mm 2A1" incorporated a more realistic 800 meter rear sight. The stock is recycled from the No. 1 Mk. III armory stock, with the addition of a cross screw forward of the magazine well. Some stocks were salvaged from existing surplus and show artificer repairs where rotted or damaged wood has been replaced, this is especially evident with the recoil draws that often fail over time due to the rifle being rack stored butt down / muzzle up that allows oils and grease to migrate downwards into this critical area
                     
The Ishapore 2A and 2A1 rifles are often incorrectly described as ".308 conversions". In fact, the 2A/2A1 rifles are not conversions of .303 calibre SMLE Mk III* rifles: they were designed and built right from the outset to fire 7.62mm NATO ammunition. Although the 7.62mm NATO and commercial .308 Winchester ammunition are physically interchangeable, these weapons were not designed for use with commercial .308 Winchester ammunition. One of the most noted misconceptions between the 7.62mm NATO and commercial .308 Winchester ammunition; "the .308 Winchester generates significantly higher pressures than 7.62mm NATO ammunition". This is due to incorrectly substituting the SAAMI (piezoelectric transducer) pressure measurement system with the (Copper Units of Pressure, "CUP") measurement system. The original specifications for 7.62mm NATO (M80 BALL) ammunition uses the CUP (Copper Units of Pressure) method. The commercial ammunition usually conforms to the SAAMI standards using the (piezoelectric transducer system) AND/OR the (Copper Units of Pressure, CUP) pressure measurement systems.
For example, 7.62mm NATO ammunition that has been subjected to 125°F to -65°F storage conditions can have an average pressure that shall not exceed 55,000 CUP (Copper Units of Pressure).Whereas commercial .308 Winchester ammunition can have a SAAMI/ANSI maximum average pressure of 62,000 PSI (piezoelectric method) OR a maximum average pressure of 52,000 CUP (copper units of pressure);both of these measurements from SAAMI are one and the same, they just represent different methods of measuring (such as inches and millimeters).
The real issue is the differences in the NATO vs. COMMERCIAL cartridge cases, typically the commercial cases are thinner than the NATO cases. Firing commercial cases in NATO chambers can possibly lead to problems, such as a ruptured case, because NATO chamber head space is longer.[4] Prior to firing ANY .308 Winchester ammunition through a 7.62mm NATO chambered rifle, it is strongly advised to check the headspace using a "field" gauge for commercial .308 Winchester ammunition. Doing so will ensure that it is truly safe to fire commercial ammunition in a NATO chamber. The simplest and safest solution is to use 7.62mm NATO ammunition exclusively.

Specifications
Weight 4.7 kg, unloaded
Length 44.5 in (1130 mm)
Cartridge 7.62mm NATO (7.62x51)
Action Bolt-action
Rate of fire 20-30 rounds/minute
Muzzle velocity 2600 ft/s
Effective range 800 m
Maximum range 2000 m
Feed system 10 or 12- round magazine, loaded with 5-round charger clips
Sights Sliding ramp rear sights, Fixed-post front sights