Editing SA80 (section)

===1980s, 5.56×45mm, XL85, XL86===
Further development out of the initial so-called "Phase A" pre-production series led to the XL85 and XL86. While the XL85E1 and XL86E1 were ultimately adopted as the L85 and L86 respectively, a number of additional test models were produced. The XL85E2 and XL86E2 were designed to an alternate build standard with 12 components different from E1 variants, including parts of the gas system, bolt, and magazine catch. Three series of variants were created for "Environmental User Trials". XL85E3 and XL86E3 variants were developed with 24 modified parts, most notably a plastic safety plunger. The E4's had 21 modified parts, no modification to the pistol grip, and an [[aluminium]] safety plunger, unlike the E3 variants. Lastly, the E5 variants had 9 modified parts in addition to those from the E3/E4 variants.<ref name="Watters-Chronology"/>

SA80 development was complicated from the start. One complication was at least three project staffing changes at the Royal Small Arms Factory, which resulted in repetitive testing. One problem with the design of the gun itself was that the cases would be ejected at constantly varying angles as it heated up and the rate of fire changed, resulting in a large ejection port.<ref>{{cite web|url=http://www.historyofwar.org/articles/weapons_SA80.html|title=SA80 (Small Arms for the 1980s): The Sorry Saga of the British Bulldog's Bullpup|website=www.historyofwar.org|access-date=30 May 2017}}</ref> The conversion from 4.85mm to 5.56mm also caused a complication, as the rate of fire dropped but the pressure and time curve of the rounds were different. The 4.85mm round was based on the 5.56mm case in anticipation of the need to convert calibres. The barrel was changed easily, but the gas ports were much larger. Pressure problems had less of an effect on the LSW due to its longer barrel.{{sfn|Williams |2013}}