Crosman Crosman Challenger 2021, Breech Opening?

I am looking at the Crosman Challenger 2021 but I have a concern that hopefully some of you can answer.

I have Very large hands, worked as a machinist my entire adult life, my concern is that opening to install the pellet looks pretty small..

Any 1st hand knowledge would be appreciated
If you buy it from airgun revisions, Rich Dudek can do for you what he did for me
design and machine breech to accept a single shot loader
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