Editing Challenger 2 (section)

=== CLIP ===
The Challenger Lethality Improvement Programme (CLIP) was a programme to replace the current L30A1 rifled gun with the smoothbore [[Rheinmetall 120 mm gun]] currently used in the [[Leopard 2]] and [[M1 Abrams]]. The use of a smoothbore weapon would have allowed Challenger 2 to use NATO standard ammunition, including tungsten-based [[kinetic energy penetrator]]s which do not have the same political and environmental objections as [[depleted uranium]] rounds. The production lines for rifled 120{{spaces}}mm ammunition in the UK have been closed for some years so existing stocks of ammunition for the L30A1 are finite.<ref name=forecastinternational>{{cite web |url=http://www.forecastinternational.com/archive/or/vo0190.doc |title=ForecastInternational |format=doc |access-date=8 August 2009}} {{dead link|date=July 2013|fix-attempted=yes}}</ref>

[[File:The 120mm smooth bore tank gun, looking down the barrel. MOD 45146593.jpg|thumb|Challenger 2 fitted with 120&nbsp;mm smoothbore gun for trials]]
A single Challenger 2 was fitted with the L55 and underwent trials in January 2006.<ref>{{cite web |title=100 Years of Firing At Lulworth Training Area |type=Blog |url=https://insidedio.blog.gov.uk/2016/07/25/100-years-of-firing-at-lulworth-training-area/ |access-date=28 March 2021 |website=[[Defence Infrastructure Organisation]] |date=25 July 2016}}</ref> The smoothbore gun was the same length as the L30A1 and was fitted with the rifled gun's cradle, thermal sleeve, bore evacuator and muzzle reference system. Early trials apparently revealed that the German tungsten DM53 round was more effective than the depleted uranium CHARM 3.<ref name="Fprado"/> The ammunition storage and handling arrangements had to be changed to cater for the single-piece smoothbore rounds, instead of the separate-loading rifled rounds. Other improvements were also considered, including a regenerative [[CBRN defense|NBC]] protection system.<ref>{{cite web |first=Christopher F |last=Foss |url=http://www.janes.com/defence/news/jdw/jdw060329_2_n.shtml |title=UK fields regenerative NBC system |work=Jane's Defence News |archive-url=https://web.archive.org/web/20080527151434/http://www.janes.com/defence/news/jdw/jdw060329_2_n.shtml |archive-date=27 May 2008}}</ref>