Bore Obstructions

As we know, the bore of your gun is the interior of the barrel which extends beyond the chamber. If any object or material within the bore slows or blocks the bullet from its normal progress, then there is the potential of the interior pressure being raised to a dangerous level. Obstructions could include anything from mud, ice or twigs to cleaning patches, squib loads and bullet jacket fragments.

There are numerous factors that affect exactly what the result may be when it comes to bore obstructions. You would have to consider the gun and the type and strength of the action, the thickness of the barrel walls, the pressure of the cartridge being fired and the size and location of the obstruction itself. A fouled bore may simply result in a relatively minor issue like reduced bullet speed or decreased accuracy. In the worst cases, it can create a much more serious incident including a bulging or burst barrel, gas and shrapnel rapidly blowing back and to the sides, or the gun completely coming apart in your hands. This latter situation is obviously horrific and there are reports every year of critical injuries and fatalities being caused by catastrophic gun failures.

 As far as location goes, it all depends on how far down the barrel the obstruction is situated. Anything in or just forward of the chamber will have a direct effect on chamber pressure, and depending on some of the factors mentioned above, these ones can cause the most personal damage due to the proximity to the shooter’s hands and face. Any blockages further down the pipe are more likely to damage the barrel, but also have the potential for serious injury.

Prevention

With good inspection and cleaning practices, you can help to avoid cases of bore obstructions from happening. While you can’t always account for every potential issue when using combustible materials, you can certainly minimize the chances of something nasty from happening. It should also go without saying that your gun would have to be safely unloaded before attempting any form of inspection.

A diligent cleaning routine can be a good way to stay on top of what’s happening with your guns. It’s a great method of regularly checking to see if everything is in good working order. After cleaning the bore, be sure to visually inspect it from the breech end to ensure that no cleaning patches or other materials remain. This is more easily done on some gun types than others. You may have to remove the bolt or barrel to do this, or simply run a cleaning rod through. There are also bore lights, scopes and snakes available that can help with the process.

A lot of shooters are in the habit of checking the bore every time before they use their guns. This could just be a visual, but could also include the use of a cleaning rod. It’s just a thing that they do and it’s not a bad idea. Why take the chance? It doesn’t take a lot of time and it promotes safety and peace-of-mind.

Hunters are typically at more risk of ‘stuff’ getting into their barrels. Trekking through trees, snow and mud in potentially inclement weather can be a good way for foreign matter to find its way in through the muzzle. If you’re pretty certain that you may have picked up a blockage, don’t be lazy about it. Immediately check the bore, even if that means a field strip. It’s not worth the risk. Keeping a bore light and a brush/rod in your gear is good for these situations. A common way to prevent this from happening is to cover the end of the barrel with electrical tape, a small balloon, the fingers of a neoprene glove or something similar. It doesn’t affect your ballistics at all (as a hole gets blown out before the bullet even gets there) and it’s an effective and inexpensive way to keep things clear.