6 Solvent Trap Cups and How They Are Different
Straight Cone (60- or 50-degree angle)
The straight cone is most effective in centerfire rifles shooting high-velocity supersonic ammunition, with speeds approaching 2,500 to 3,000 feet per second. These are used most often for calibers like 5.56 NATO, .308 Winchester, .300 Win Mag, and similar supersonic .22 and .30-caliber cartridges. Straight cones are most often sold in 50- and 60-degree variants. A general consensus among experienced suppressor builder says 60-degree cones work best for higher velocities, while 50-degree cones work better for intermediate velocities above 1,125 feet per second but below 2,500 feet per second.
Radial cones are effective “hybrids” most often used for both centerfire rifle rounds and subsonic pistol or carbine rounds. Many commercial suppressor manufacturers use baffles with a similar radial or curved design. These are most often used on guns that can fire both supersonic and subsonic ammo, and are favored for 300 Blackout and 9mm Parabellum cartridges.
Stepped cones are often called “Aztec” cones for their unique stepped shape. These cones have been reported to produce lower pitches and overall tones when used to suppress either subsonic or slower supersonic cartridges. The builders’ theory is that the cone’s stepped design works to induce greater turbulence to the gas flow. Other feedback says high-velocity cartridges do not benefit so much from this design, while slower cartridges can see a small increase in performance. Stepped cones are often similar in their overall length and angle as straight cones, providing a 50- to 60-degree slope.
K-cups or K-baffles represent an older design. They stack directly atop each other and provide excellent performance for handguns, pistol cartridges, and exclusively subsonic rounds. If you’re building a setup meant for a 9mm handgun, .22 LR, or 300 Blackout shooting only subsonic loads, the K-cup stack is a top choice. These internals can also be the most difficult to machine since they require additional machining beyond simply drilling pass-through holes and basic clips, so they may not be favored for first-time builders or those without a milling machine or lathe.
Freeze Plug-style Cups
These “freeze plug”-type cups are the most affordable, arguably the simplest, they’re highly stackable, and they’re versatile. They’re the “OGs” of the form 1 suppressor world and were used long before manufacturers began producing newer styles like the options listed above. They can generally be drilled for any caliber up to .308 Winchester and provide mild to good performance for a wide variety of supersonic and subsonic loads. Their performance will be poorer compared to a by-design conical or radial setup. Before different options became available commercially, the freeze plug was the top choice for most Form 1 suppressor builders.
You can find many of the cones listed above with a skirt, or pre-fabricated spacer machined directly into the cone itself. This eliminates the need to buy your own spacers or cut them from raw tubing. There are various other types of internals made for form 1 builds, though the options listed above are the most popular and comprise a majority of configurations for most calibers, including both centerfire and rimfire rifles and pistols.