ASTM Paintball Subcommittee Conference at Reno, May 19, 2005.
Presenter: Stephen Ho, M.D.

Our first topic: Adequacy of Safety of Barrel Blocking Device.

In the opinion of many paintball, engineering, and medical experts, the current ASTM performance requirements for barrel blocking devices need to be updated. This is due to advancements in the technology of modern paintball equipment which has led to a sharp increase in the number of paintball injuries. We worry that certain performance requirements for barrel blocking devices may have become inadequate. Therefore it is necessary to employ more effective testing methods to determine the safety adequacy and protective functions of barrel blocking devices.


The current ASTM barrel blocking standard states that a barrel blocking device satisfies the performance requirements if the device remains in place after two shots are fired from the paintball gun allowing a three second pause between shots.

This may be adequate for some pump guns and semi-automatic paintball guns, but can be inadequate for certain modern electronic paintball guns or mechanical paintball guns equipped with advanced reactive triggers that can deliver many shots per second.

Consequently additional tests are necessary to separate the good barrel blocking devices from the sub-standard devices and keep the dangerous ones from getting into the hands of consumers and causing irreparable damages.


In this presentation the paintball guns have been chronographed at a higher velocity of 330 fps for testing of barrel blocking devices.

At the present time the most commonly used barrel blocking device is the barrel condom or bag that is placed over the muzzle of the paintball gun and is attached by stretching an elastic cord over the rear of the paintball gun.

The durability of this device depends on the workmanship and material used in its manufacture. Some bags are poorly stitched and can be easily torn by the impact of discharged paintballs. Most barrel bags are not equipped with a reliable security feature that can secure the device tightly to the muzzle and can be disengaged after two or more shots have been fired as seen this demonstration. Some bags can perform better than others, however, the performance of barrel bags can and do vary greatly because it is difficult if not impossible to set standards as to how a barrel bag should be stitched or what fabric should be used to make them from.


The second barrel-blocking device that is commonly used is the barrel-blocking plug which is inserted into the muzzle of a paintball gun to block accidentally discharged paintballs. For the most part the material used to make these plugs is durable but the security of barrel plugs is inconsistent. The reason for this inconsistency is that in order for a barrel plug to fit tightly and to be secured inside of the muzzle, the diameter of the plug and the inside diameter of the barrel must match very closely.

A perfect barrel plug-muzzle match renders the barrel-blocking plug to be good safety device, but a mis-match causes the same device to be unsafe to use. Barrels for paintball guns are manufactured in different sizes because paintballs are made in different sizes. Therefore it is inconvenient and impractical to employ a variety of barrel plugs that will properly match barrels of varying inside diameters.

In this presentation we are proposing two additional tests that will effectively help to identify the adequacy of the safety of barrel blocking devices.

The first proposed test is the “Pull Test” which is an excellent test to assess the
security and adequacy of the barrel-blocking device.

The method of testing is to apply the strength of an adult arm pull on the barrel-blocking device after the device has been inserted in or over the muzzle of the paintball gun.

The barrel-blocking device fails the test if the device can be easily pulled off of the muzzle. Obviously, if the barrel-blocking device can be easily pulled off by such an arm pull, it could just as well be disengaged by the impact of a paintball or paintballs when the paintball gun is discharged. This test can be readily performed without actually firing the paintball gun.

The second test is the “Impact test” which is used to test the durability and the retention of the barrel-blocking device. The testing includes increasing the number of two shots as stated in the present ASTM standard to a minimum of ten shots fired from the paintball gun into the barrel-blocking device. The increase in the number of shots is necessary in order to adequately test barrel-blocking devices and to effectively exclude sub-standard barrel blocking devices.

The barrel-blocking device fails the impact test if it is disengaged from the muzzle of the paintball gun before ten shots have been fired or is damaged during the test in such a manner as to render it dangerous and unsuitable for use as an effective barrel blocking device.



In this demonstration the pull test will be applied to a barrel condom and it fails the proposed test. Now we will subject the barrel condom to the proposed impact test and after only three shots it is disengaged and fails the test.

In this demonstration, the pull test will be applied to a barrel plug. It fails the pull test. This test is simple to perform and when employed, it quickly identifies an unsafe barrel blocking device that might otherwise escape detection and get into the hands of a consumer and expose them to the risk of serious accidental injuries.

Next, we will subject a barrel plug to the proposed impact test. In our demonstration, this barrel plug passes the proposed impact test due to a perfect match in the external diameter of the plug and the inside diameter of the barrel.
Now we will insert the same plug into a different barrel. The inside diameter of this barrel is just slightly larger than that of the first barrel, and now it fails the impact test after the first shot is fired.

At this time we will briefly discuss two excellent alternative barrel-blocking devices that are designed differently from a standard barrel plug or bag and generally speaking they perform better as well.

The first example has a twist-off barrel blocking device for securing the device very tightly to the muzzle of the paintball gun. It satisfies the pull test and the impact test. We do not have an example of the second device. It is composed of a metallic closed end muzzle and the opposite end is threaded into the muzzle of the paintball gun which makes it very durable and secure.

At this time we would like to take a moment to thank those caring manufacturers and organizations for their great contributions to the safety of the paintball industry.


Our next topic: The Importance of Adding a Safety Feature to the Hopper of a paintball gun that does not presently have a safety mechanism.

At the present time there is no ASTM hopper safety standard for regulating the use of a hopper that would contribute to the safety of paintball guns and would prevent many paintball accidents.

A hopper is one of the most important pieces of paintball equipment because it holds and supplies paintballs or the ammunition to the paintball gun. Serious paintball injuries have occurred due to the premature loading of paintball guns. These accidents can be prevented and the safety of the paintball sport can be radically improved by just adding a simple and cost effective safety feature to the paintball hopper.

In this illustration we are loading a hopper that is attached to a paintball gun. This hopper has no safety device installed on it and as you can see, when the paintballs fall into the hopper, they drop directly into the firing mechanism of the paintball gun which prematurely loads it. This obviously presents a very dangerous situation that can be easily corrected by equipping the hopper with a very simple safety feature that when set in the “Safe” or “Locked” position will effectively block paintballs from entering the feed of the hopper and will prevent paintballs from reaching the firing mechanism.

Remember, when your load a paintball in the firing mechanism, you are armed, dangerous.

Next we will illustrate the safest method of loading paintballs into a hopper. You preload the paintballs into a hopper that is not attached to a paintball gun. Then you attach the loaded hopper to the paintball gun only when you are ready for a game or for target practice.

Remember, the practice of loading an unattached hopper is extremely important. This will effectively prevent you or people near you from getting hurt when you are not in a supervised game or target practice.

The demonstrations that we have shown you vividly illustrate the importance of using an effective safety feature on a paintball gun hopper that will dramatically reduce injuries and increase the safety of the paintball sport.

Paintball safety awareness is on the rise due to many tragic paintball accidents. The good news is that more effective paintball safety devices are on the way that will make this exciting sport much safer for both participant and bystanders.

This concludes our presentation. We thank you very much for your time and interest in this important safety issue.