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AR15 Design for SBR’s

AR15 design for SBR'S


The PTR VENT 3 is a highly advanced and relatively lightweight rifle silencer designed specifically for short-barreled rifles (SBR’s). It belongs to the VENT series of silencers, all of which feature hybrid designs. The VENT 3, along with its smaller counterpart, the VENT 2, incorporates elements of both conventional silencer geometry and high flow rate characteristics. This unique combination results in significant performance improvements when used with semiautomatic host weapons.

For a comprehensive overview of the three primary classes of rifle silencer designs, we recommend referring to the PEW Science Research Supplement 6.124.

Design Elements of the PTR VENT 3

Similar to the SilencerCo Velos LBP, the PTR VENT 3 is designed to minimize the accumulation of early-time internal blast impulse without concerning itself with external gas momentum accumulation. This approach allows for optimal weapon kinematics and improved sound field, even in close proximity to reflecting surfaces.

However, unlike the Velos LBP, the VENT series utilizes a distal venting system that forces gases through a porous material lattice structure before releasing them. This design feature significantly enhances performance by restricting late-time flow, resulting in a free field signature with gas momentum characteristics similar to a CAT ODB or CAT WB silencer on the same weapon system.

In contrast to the CAT silencers, the PTR VENT 3 achieves greater pressure amplitude suppression through increased turbulence and heat transfer. Although the CAT silencers may offer higher impulse attenuation, the PTR VENT 3 excels in reducing free field hazards in specific combustion regimes. Despite its larger size, the PTR VENT 3 delivers exceptional performance.

Please note that the PTR VENT 3, like other silencers in the VENT series, incorporates the PTR Purposely Induced Porosity (PIP) technology, along with staged flow geometry, to enhance early-time and gross flow rates. This technology also exhibits significant sound suppression capabilities with both subsonic and supersonic ammunition. Notable features of the PTR VENT 3’s high suppression performance on this platform include:

  1. Gross free field pressure amplitudes: The VENT 3 effectively suppresses pressure amplitudes, as shown in Figure 1a. The suppression is noticeable and rapidly decays in early time.
  2. Uniform gas momentum accumulation: Precursor flow, bullet shock, and primary jetting occur consistently and steadily from shot to shot, resulting in highly uniform gas momentum accumulation (Figure 2a).

Unprecedented Suppression Ratings

The PTR VENT 3’s longer path lengths and extended duration of gas flow contact with lattice structures, combined with stepped conventional baffle geometries, enable it to achieve exceptionally high suppression performance. In fact, in PEW Science testing, the PTR VENT 3 achieved a remarkable 42.6 Suppression Rating at the muzzle, an unprecedented accomplishment given its size. Additionally, it achieved a combined 29.0 Suppression Rating at the shooter’s ear, demonstrating a significant reduction in operator hazard on the MK18 weapon system. This combination of performance traits on the standard MK18 is unparalleled in PEW Science testing.

Furthermore, the PTR VENT 3 showcases its effectiveness across multiple combustion regimes, highlighting the significance of the PTR PIP technology as one of the most significant advancements in suppressed small arms.

Turbulence Generation and Heat Transfer

The duration of turbulence generation and heat transfer during annular venting plays a crucial role in maximizing muzzle blast suppression in high flow rate designs. Allowing the blast load gradient to maintain a minimum forward velocity without stagnation, or preventing secondary stagnation through staged venting, appears to yield the highest efficacy based on the Silencer Sound Standard research pedigree.

Among the high flow rate rifle silencer system designs evaluated, PIP, SURGE BYPASS, and Flow-Through technologies demonstrate the greatest performance potential. It is worth noting that only the first two technologies are hybrid designs. Blast load reflection factor phenomena suggest that hybrid designs offer the best chance of reducing hazards outside of the free field, particularly near reflecting surfaces. Ongoing research explores the load shapes and amplitudes of blast loads produced by suppressed small arms.

First-Round Pop Signature and Consistency

As typically observed, the first-round pop (FRP) signature of the PTR VENT 3 on the MK18 weapon system is noticeable to bystanders in the free field but not severe, according to PEW Science analysis. Following the FRP, both the measured signatures and the analyzed inner ear responses of bystanders exhibit remarkable consistency. The signature suppression consistency of the PTR VENT 3 is among the highest measured by PEW Science to date.

Bolt Closing Time and Back Pressure

In all semiautomatic AR15 weapon testing, a second pressure pulse originating from the ejection-port signature of the weapon coalesces with the muzzle signature early in time. At approximately 85 ms in Figure 1a, the mechanical noise of the bolt closing becomes apparent. However, this event is not observed in the pressure signature of Shot 6, as the bolt remains open after firing the final round from the magazine.

The closing time of the MK18 bolt is directly related to the flow restriction of a silencer for a specific weapon system. PEW Science has established a reliable correlation between bolt closing time variation from the unsuppressed state and silencer back pressure, as measured by the PEW Science Back Pressure Metric, Omega, and the alpha parameter. However, it is important to note that this indicator becomes unreliable in the presence of upper receiver fouling. Sound signatures are not influenced by fouling, as these kinematics occur in late time after gas venting to the atmosphere. Factors such as momentum transfer and weapon condition can significantly affect bolt closing time. Therefore, caution is advised when using published bolt closing times to determine silencer flow restriction or weapon system kinematics, as the weapon condition during each test is not publicly available. PEW Science recommends considering other signature features measured at the shooter’s ear to assist in quantifying weapon kinematics.

First-Round Sound Signatures and Ammunition Consistency

As mentioned earlier, first-round sound signatures often differ from subsequent shots due to changes in the atmosphere within the silencer. The FRP phenomenon cannot always be determined solely by examining peak sound pressure. This is one of the reasons why The Silencer Sound Standard employs multiple sound signature metrics. While ammunition consistency can influence the determination of FRP, close examination of measured pressure and impulse waveforms typically excludes ammunition as a significant factor, given the relative consistency of high-quality factory ammunition.


In conclusion, the PTR VENT 3 is a highly advanced and lightweight rifle silencer designed for SBR’s. Its hybrid design and utilization of the PTR Purposely Induced Porosity (PIP) technology contribute to its exceptional performance. With unprecedented Suppression Ratings and consistent signature suppression, the PTR VENT 3 represents a significant advancement in the state of practice for suppressed small arms. The combination of its high flow rate characteristics, effective turbulence generation, and heat transfer make it a top contender in the field of rifle silencer designs.

At, we aim to provide comprehensive information about the latest advancements in firearm technology. Stay tuned for more updates and detailed analyses of cutting-edge products like the PTR VENT 3.


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