WW1 Canvas Artillery Covers

So here's another story. I was driving down the street by the waterfront where all the big expensive homes are, and I noticed an old crate that looked interesting. I normally take whatever is in the crate because I do not like to dump contents out for someone else to pick up. The crate looks like an old ammunitions box, and in it were French newspapers from 1919 and these two items. They must be artillery covers from some of the big guns -- maybe howitzer. They have RAR which stands for Royal Artillery Regiment. The shorter one measures 98" and the longer one 118". The longer one seems to have a place where it billows out a bit near the end. I know very little about these and have not found an example of any. Does anyone know what type of guns these may have fit over? I also had my hardwood floors refinished -- but I digress...