It may hit the moderator, but you should be alright. Alternatively, can you push it back with the magazine removed? Sometimes people double load pellets and one will end up clipping the moderator, with little effect except on accuracy for that shot.
If your barrel has an o-ring it might have a possibility of coming out. Perfectly fine for single shot and RAW guns that don't have barrel o-rings.
Believe it or not some pellets shot better backwards at 20-25 yards dropped birds deader than dead compared to shooting them normal and at 50 yards about an inch shooting out of an old Theoben Rapid 7/12 through its magazine.
When I try pellets my new guns don't like I try shooting them backwards and sometimes group better believe it or not.
I lessen the breech o-ring saying ELVIS HAS LEFT THE BUILDING risk by lubing with Lemon Pledge first. (Tom Holland style!)
Matter of fact I shoot my Mac1 Steroid Crosman 1322 long barrel carbine only shooting 22 caliber pellets backwards for dropping birds at up to 20 yards.