Cross sectional drawing of gun barrels
<div class="legend" style="direction:ltr;line-height:23px;"><div class="legend-content" style="display:inline-block;vertical-align:top;box-sizing:border-box;width:34px;height:23px;overflow:hidden;font-size:15px;border:1px solid #000;background:#9292B9;color:#202122;text-align:center;"> </div> smoothbore</div>
<div class="legend" style="direction:ltr;line-height:23px;"><div class="legend-content" style="display:inline-block;vertical-align:top;box-sizing:border-box;width:34px;height:23px;overflow:hidden;font-size:15px;border:1px solid #000;background:#65B965;color:#202122;text-align:center;"> </div> rifled</div>
<div class="legend" style="direction:ltr;line-height:23px;"><div class="legend-content" style="display:inline-block;vertical-align:top;box-sizing:border-box;width:34px;height:23px;overflow:hidden;font-size:15px;background:#FFF;color:#202122;text-align:center;">A</div> land diameter</div>
<div class="legend" style="direction:ltr;line-height:23px;"><div class="legend-content" style="display:inline-block;vertical-align:top;box-sizing:border-box;width:34px;height:23px;overflow:hidden;font-size:15px;background:#FFF;color:#202122;text-align:center;">B</div> groove diameter</div>
<div class="legend" style="direction:ltr;line-height:23px;"><div class="legend-content" style="display:inline-block;vertical-align:top;box-sizing:border-box;width:34px;height:23px;overflow:hidden;font-size:15px;border:1px solid #000;background:#B98888;color:#202122;text-align:center;"> </div> polygonal</div>
<a href="//commons.wikimedia.org/wiki/User:Thuringius" title="User:Thuringius">Thuringius</a>
<span class="int-own-work" lang="en">Own work</span>