If the investigation into the loss of weapons during the battle has been going on for more than two months...?

You must inform the management that the official investigation must be completed within one month from the date of his appointment as a commander (chief). In some cases, this period can be extended by the commander (chief) who appointed the official investigation, or by the senior commander (chief), but not more than one month.

The total term of official investigation cannot exceed two months.

The period of official investigation does not include the time spent by the military serviceman, in relation to whom the investigation is being conducted, on leave, on medical treatment or the time of absence for other valid reasons.

Therefore, if the course of the investigation is more than 2 months and there are no grounds for its continuation, you can appeal such actions of the management by filing a corresponding complaint.