When it comes to shotguns, they are odd in that we can load a single round through the ejection port if we have managed to run the gun completely dry. Emergency loading, regardless of platform, is in my opinion an important skill to have. It falls into the category of tasks that are statistically a low probability, but have very high consequence if we cannot accomplish the task efficiently.
There a couple different approaches to accomplishing this with the shotgun. Assuming the use of a side saddle, one technique is to come over the top of the receiver, drop the shell into the ejection port, get back to shooting. This is generally assumed to be the most efficient method, but with the addition of red dots to shotguns or with some semi-auto shotguns, there can be complications.
The other variation is to approach the ejection port from underneath the receiver. This has the benefit of avoiding any optics on the gun, and positions the hand well for either running the action closed on a pump gun or activating the bolt release on semi-auto guns.
So the next questions that comes up is which is faster. All things being equal, faster is better in terms of emergency reloads.
But are all things really equal? I suppose this is up for debate. In my opinion, over the top is easier, if you run the shells in the side saddle with the brass up, as I do. However, it also means I have two distinct methods of loading, one for emergency loads and one for topping off the magazine tube. The argument for the coming under the receiver is that the technique is very similar to the technique used for topping off the magazine tube, creating continuity.
Let me know how you run your shotgun in the comments.
Priority: Performance 
With my Versa-Max (auto) the only way to do it is to come underneath or your had will get hit with the bolt handle when you hit the release. I don’t use a pump much but I think going over allows for better control and less contortion with my hand and arm.
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I agree. Going under the gun seems to work better on semiauto guns. At least on the few I have messed around with.
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The only time I can recall using a port load was swamp hunting deer. A buck following a doe came by my ground stand and I dropped both filling both tags but the 5 shots ran dry so I fished another slug from the butt cuff and dropped it into the 11-87. It wasnt needed at that point.In the years I carried a shotgun in the Army I can never recall using a port load.
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It’s easier to rotate the gun inward (for top loading). Imagine pouring out a bottle of water, most people turn it inward not outward.
But having a similar load for port and magazine feeding is valuable to me. In a shotgun class my instructor pointed out that on my semi-auto I didn’t need to run my support hand back out the foreend but could fire with my support hand right over the bolt release button. This produced a faster reload time and left my hand close to the side saddle to effect addition reloads as necessary.
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That is an interesting point to make with regard to a semiauto. I haven’t made the jump to running a semiauto yet, but I will keep that in mind when I do.
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Go to youtube and look up “Jasmine Jessie’s shotgun loading technique”. Yes, it is Cowboy Action Shooting. Yes it is for a pump shotgun. CAS only allows two rounds in the pump gun, and she gets through 6 with no side saddle.
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I am familiar with the video. For the context of her use, it certainly works. Somewhere there is a video of me doing something similar because the drill called for multiple port loads and particular shotgun I was using didn’t have a side saddle on it yet.
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Being a Southpaw, I have yet to find a way to manage either technique without unmounting the shotgun. I have to rely on my right hand to do all of the work and run the slide. I still experiment hoping to come up with a practical method. The best one I have so far is two shells between the fingers of my right hand and run it like a single shot rifle.
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