Barrel Material

From NerferWiki

The primary difference between a modified blaster and an unmodded, or stock, blaster is the barrel. In order to be useful at an NIC-organized war, a blaster must be able to shoot Stefan darts and thus must have it's barrel replaced with one of the materials listed below (or some other undocumented material which is capable of accelerating a homemade nerf dart).

Descriptions

Brass: Brass tubing was once the most common barrel material used for firing micros, but has declined in popularity with the introduction of the lighter, less expensive PETG, which is discussed below. You can find brass at any hobby shop, especially those that carry model kits. The most commonly used size is 9/16" which usually fits a standard mini-stefan (micro) quite well. Other brass sizes are 17/32" which fits mini-stefans made of slightly narrower foam, and stock darts. Also 19/32" and 1/2" brass can be used in breaches, since a brass tube of one size will slide easily and fit snugly in a tube of the next largest size. Note: don't confuse Brass with copper, brass has a more golden color while copper looks darker, like a copper penny. While some people have been known to use copper for barrels, brass is more widely used because of the standard sizes that accommodate mini-stefans much more consistently.
Picture: Brass Tubing

CPVC: Carbonated Polyvinyl Chloride. A type of pipe that can be found at local hardware stores in the plumbing section. It will usually found near PVC, but has a slightly beige/off-white color when compared to PVC. The 1/2" size is the size used for micros. CPVC typically has greater barrel friction, and is typically narrower in diameter than most other materials. CPVC is also much thicker than PETG and brass.

CPVC is manufactured to strict specifications for it's outside diameter (od) in order to fit into slip fittings, but it is only required to have a minimum thickness that can withstand certain pressures. Because of this, the inside diameter is rarely consistent from one brand to another. You may notice that darts will fit more snugly into one length of CPVC than another for this reason. Individual tests to determine which size and type of CPVC pipe you need should be conducted with samples of the foam you use to make darts.
Also sold in Schedule 80 like PVC. 6803K52 Is part#. Picture: CPVC Piping

PETG: Polyethylene Terephthalate Glycol (Polyester). A type of rigid plastic tubing that can be ordered on the internet and at some hardware stores. The sizes required for proper barrels need to be specially ordered in bulk, and there is usually a nerfer or two that have ordered a large quantity and are reselling it to other nerfers at nerf wars. At this time, the only supplier is [OMC]. It comes in various sizes and can be used to shoot different darts, depending on the diameter of the barrel. PETG is the lightest, thinnest, cheapest barrel material available and it is also clear, all of which makes it the preferred barrel material of the NIC.

PVC: Polyvinyl Chloride. A type of pipe that can be found at local hardware stores in the plumbing section. The Schedule 40 1/2" size is typically used to shoot 5/8" Stefans or megas, and Nerf brand Micro darts (the suction cup tip usually fits snugly inside the PVC). There is a less common Schedule 80 1/2" size of PVC which has thicker walls and can shoot micros. Schedule 40 PVC is also frequently used as a housing for smaller barrel materials because modified guns are frequently equipped with 1/2" PVC couplers, which allow barrels to be removed for easier loading. In these cases the Brass or PETG is wrapped in tape and then glued into the PVC.

PVC is manufactured to strict specifications for it's outside diameter (od) in order to fit into slip fittings, but it is only required to have a minimum thickness that can withstand certain pressures. Because of this, the inside diameter is rarely consistent from one brand to another. You may notice that darts will fit more snugly into one length of PVC than another for this reason. Individual tests to determine which size and type of PVC pipe you need should be conducted with samples of the foam you use to make darts.
Picture: PVC Piping

More info on Dimensions and Specifacations of PVC Pipe.

PEX Polyethylene tubing sometimes found in hardware stores that do a lot of sales to plant nurseries. Not popular due to its rarity. Can only be used for short barrels because it is extremely flexible. 1/2" PEX is slightly more snug than 17/32" brass and fits perfectly in 1/2" PVC.

Aluminum CaptainSlug has been exploring Aluminum as a barrel material ever since it became available in a usable size through McMaster-Carr. The part number is 1658T49 and has an ID of .527 inches and an OD of .625 (5/8) inches. The inside surface is extremely smooth and offers very little friction. So far it has worked best with air guns for this reason. Will not tarnish like brass and is more receptive to adhesives and can be welded with the right equipment.

Picture: Aluminum barrel

Relative Sizes

As noted in the descriptions above, some of these materials are manufactured to stricter specifications than others. Inner Diameters of PVC and CPVC fluctuate wildly, and PETG is prone to warping and sensitive to temperature. All of these materials were marked by the same person using the same instrument unless otherwise noted.

Material	Nominal Size	Actual Size
Brass	1/2"	.472"
Brass	17/32"	.5033"
Brass	9/16"	.5345"
Brass	19/32"	.566"
PVC	SCHED 40 1/2"	.608"
PVC	SCHED 80 1/2"	.527"
CPVC	SCHED 80 1/2"	.526"
Aluminum ( MMC Part# 9245K25)	5/8"	.527"
OMC's PETG	Medium	.548 "
OMC's PETG	Thick	.528"