I own a Henry Atkin sidelock ejector, No.2050, which I assume was made in the early part of the past century. The gun is in excellent condition and I use it regularly. It is, of course, a self-opener with a particularly strong opening mechanism. With increasing age and a couple of minor heart attacks, I now find the gun difficult to close, especially when I am in a hurry.
A shotgun should be easy to manipulate and if you have to struggle to operate the mechanism, this will have a detrimental effect on your shooting.
There are three potential solutions to your problem. First, take some advice from someone who is used to operating a gun similar to yours. They may well know a ‘nack’ which can be applied to make the gun easier to use.
Second, see if it is possible to modify the gun to make it easier to open and close.
You should seek advice from Atkin Grant & Lang Ltd, which is the most likely source of expertise for the Atkin mechanism.
The address is: Atkin Grant & Lang, Broomhill Leys, Windmill Road, St Albans, Hertfordshire AL3 8LP, Tel: 01582 842280.
Lastly, consider buying a new gun that fits you and which you can operate with ease.