The FTSE 250-listed firm, which makes surveillance systems, detectors and flares for military aircraft, said underlying pre-tax loss more than tripled to £4m in the first half. Chemring added full-year results would be "slightly below expectations".
It's struggled for several years as Western government cut their military budgets following the withdrawal of troops from Iraq and Afghanistan.
This was partly due to another delay to its £100m contract to make 40mm grenade cartridges for an unidentified customer in the Middle East. It had previously said the contract was on track after delays last year led to an £80m rights issue.
The further delay sent the company's share price crashing as much as 21.9 per cent to 109.1p per share this morning, before settling around 114.5p later in the day. They've fallen nearly 40 per cent over the past 12 months.
Michael Flowers, Chemring group chief executive, said: "We continue to expect our full year 2016 result to be heavily weighted to the second half, due to substantially higher 40mm contract revenues and greater consistency in production."
"While it is encouraging that approximately 90 per cent of expected second half revenue is in the order book, the board's current assessment is that the full year 2016 out-turn is likely to be slightly below market expectations," he added.