Just to have a visible container width

custom-class to masonry gallery: masonry41

Masonry Gallery with 4 columns

#top .container .av-masonry.masonry41.av-large-gap {
  width: calc(100% + 3px);
}

.masonry41.av-large-gap.av-flex-size .av-masonry-entry .av-inner-masonry {
  margin: 3px !important;
}

.masonry41 .av-masonry-entry:nth-of-type(5n) {
  width: 100% !important;
}

.masonry41 .av-masonry-entry:nth-of-type(5n) img {
  width: 100% !important;
  height: auto;
}

@media only screen and (min-width: 990px) {
  .masonry41 .av-masonry-entry:nth-of-type(5n) {
    width: calc(100% - 6px) !important;
  }
}

@media only screen and (max-width: 989px) {
  .masonry41 .av-masonry-entry:nth-of-type(5n) {
    width: calc(100% - 3px) !important;
  }
}

@media only screen and (max-width: 767px) {
  .masonry41 .av-masonry-entry:nth-of-type(5n) {
    width: 100% !important;
  }
}

You have to play a bit on the settings to fit to your needs

as i can see now in a Column it does not work as above where the masonry is directly in a color-section.

then the media query on min-width 990 : it is enough to have here  minus 3px !

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