SSS.6.216 - Rampart Range Suppression Carson 30 and the KAC SR-25 7.62x51mm 14.5-in Barrel Automatic AR-10 Rifle (Free Version)
/Rampart Range Suppression Carson 30 on the KAC 7.62x51mm SR-25 with 14.5-in Barrel
The Carson 30 is designed and distributed by Rampart Range Suppression. It is a 30 caliber centerfire rifle silencer, intended to suppress the 7.62x51mm cartridge with semiautomatic or fully automatic fire. The Carson 30 has a 1.71-inch diameter and is 6.59 inches long with no mount. The silencer may be attached to a variety of weapon systems depending on the user’s choice of mount; the tested third-party 3/4-24tpi direct-thread mount increased the system length to 7 inches. Other mounting options are possible due to the rear of the silencer body being HUB compatible (1.375-24 tpi threading). The core of the Carson 30 is a 3D printed titanium Otter Creek Labs Infinity derivative and the end cap is non-removable. The silencer weighs 9.8 ounces and the tested direct thread mount weighs 1.2 ounces, for a total system weight of 11 ounces, as tested. The Carson 30 can be obtained from Rampart Range Suppression.
Silencer Hazard Map:
The predicted personnel hazards generated by the tested weapon system in this report, in the free field, are shown in the adjacent Silencer Hazard Map. Click or tap the Map to enlarge. Please reference Silencer Hazard Map Brief 8.1.12 for further details. The PEW-SOFT HD Blast Hazard Prediction Tool and Hazard Mapper is presented in Report 8.1.1.
Rampart Range Suppression Carson 30 14.5-in SR-25 AR-10 Free Field Hazard Map Produced by PEW-SOFT HD Blast Hazard Prediction Tool using PEW Science Test Data
PEW Science is an independent private testing laboratory and also hosts the world’s only independent public suppressed small arms research cooperative. Testing, data analysis, and reporting is generated with funding provided by PEW Science members. Any test data that is generated with any portion of private funding contains this disclosure. The testing and analysis production for this Sound Signature Review was funded in part by PEW Science Project PEW-RAMP-138-25. Therefore, data pertaining to the Carson 30 in this Sound Signature Review is published with the express written permission of Rampart Range Suppression.
The testing and analysis presented in this Sound Signature Review are of the Carson 30 on the KAC SR-25 Automatic AR-10 rifle, chambered in 7.62x51mm NATO with a 14.5-inch barrel. Lake City M80 149gr ammunition was used in the tests. The standard PEW Science KAC SR-25 test host weapon system is described in Public Research Supplement 6.210.
Section 6.216.1 contains Rampart Range Suppression Carson 30 test results and analysis.
Section 6.216.2 contains overall gross Suppression Rating comparisons of the Rampart Range Suppression Carson 30, Dillon DRC308, and the unsuppressed KAC SR-25 automatic rifle.
Section 6.216.3 contains an article summary and PEW Science laboratory staff opinions.
Summary: When paired with the 14.5-in barrel KAC SR-25 and fired with Lake City M80 149gr ammunition, the Rampart Range Suppression Carson 30 achieved a composite Suppression Rating™ of 29.9 in PEW Science testing.
As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
Relative Suppression Rating Performance is Summarized in SSS.7 - PEW Science Rankings.
6.216.1 Rampart Range Suppression Carson 30 Sound Signature Test Results
A summary of the principal Silencer Sound Standard performance metrics of the Rampart Range Suppression Carson 30 direct-thread mounted is shown in Table 1. The data acquired 1.0 m (39.4 in) left of the muzzle is available for viewing to all. The data acquired 0.15 m (6 in) right of the shooter’s ear is only available to membership supporters of PEW Science and the Silencer Sound Standard. You can support public PEW Science testing, research, and development with a membership, here. State-of-the-art public firearm sound signature testing and research conducted by PEW Science is supported by readers like you.
Table 1. Rampart Range Suppression Carson 30 Sound Metric Summary
6.216.1.1 SOUND SIGNATURES AT THE MUZZLE
Real sound pressure histories from a 6-shot test acquired with PEW-SOFT™ are shown below. Six cartridges were loaded into the magazine, the fire control group positioned to single-shot, and the weapon was fired until the magazine was empty and the bolt locked back on the follower of the empty magazine. Only five shots are considered in the analysis. The signatures of Shot 6 are displayed in the data presentation but are not included in the analysis to maintain consistency with the overall PEW Science public dataset and bolt-closing signatures. The waveforms are not averaged, decimated, or filtered. The data acquisition rate used in all PEW Science laboratory sound signature testing is 1.0 MS/s (1 MHz). The peaks, shape, and time phasing (when the peaks occur in relation to absolute time and to each other) of these raw waveforms are the most accurate of any firearm silencer testing publicly available. PEW-SOFT data is acquired by PEW Science independent laboratory testing; the recognized industry leader in silencer sound research. For more information, please consult the Silencer Sound Standard.
The primary sound signature pressure histories for all 6 shots with the Rampart Range Suppression Carson 30 are shown in Figure 1a. The sound signatures of Shot 1 and Shot 2 are shown in Figure 1b, in early time. The real sound impulse (momentum transfer potential) histories from the same 6-shot test are shown in Figure 2a. In Figure 2b, a shorter timescale is shown comparing the impulse of Shot 1 to that of Shot 2 and Shot 3.
Fig 1a. Rampart Range Suppression Carson 30 7.62x51mm NATO 14.5-in SR-25 Automatic Rifle Muzzle Sound Pressure Signature
Fig 1b. Rampart Range Suppression Carson 30 7.62x51mm NATO 14.5-in SR-25 Automatic Rifle Sound Pressure Signature
Figure 2a. Rampart Range Suppression Carson 30 7.62x51mm NATO 14.5-in SR-25 Automatic Rifle Muzzle Sound Impulse Signature
Figure 2b. Rampart Range Suppression Carson 30 7.62x51mm NATO 14.5-in SR-25 Automatic Rifle Muzzle Sound Impulse Signature
The Rampart Range Suppression Carson 30 is a titanium battle rifle silencer that uses a modified Otter Creek Labs Infinity inner core, under license. Therefore, the Carson 30 is classified as a hybrid design, incorporating both high flow rate features and conventional geometries to control distal blast propagation while reducing adverse influence on weapon function. Like the Infinity 762 silencer, the Carson 30 is specifically classified as a staged hybrid in the PEW Science Silencer Sound Standard research taxonomy. For an overview of the three primary classes of rifle silencer designs, the reader is encouraged to review PEW Science Research Supplement 6.169. Another staged hybrid, the Dillon DRC308 (6.211), is included in the performance comparison in Section 6.216.1.2 of this report.
PEW Science Research Note 1: The Rampart Range Suppression Carson 30 differs from the Otter Creek Labs Infinity 762 in several ways:
The Carson 30 is constructed from 3D-printed titanium, whereas the Infinity 762 is 3D-printed Inconel.
The Carson 30 has a non-removable solid end cap assembly with different internal and external aperture geometries than those present in the Infinity’s removable solid end cap.
The proximal core sections of both silencers are similar; however, the distal geometry and termination of annular flow differs in the Carson 30.
The geometric changes in (2) and (3) result in elevated performance, for both operators and bystanders, when using the Carson 30 versus the Infinity 762 on the SR-25. The Carson 30 appears to be more optimized for 7.62 NATO combustion input while still maintaining relatively high early time flow rate.
PEW Science Research Note 2: Currently, the SR-25 (AR-10) research dataset is growing. The Carson 30’s Infinity-derived core is capable of significant efficiency in this combustion regime, and there are specific performance factors that bear examination observed in the above test data:
The Carson 30 produces relatively controlled free field blast overpressure amplitude, with a moderately extended blowdown duration (Fig. 1a).
Initial coupled jetting is consistent and primary jetting onset is gradual (Fig. 1b).
First-round-pop (FRP) from the system exhibits divergence after coupled jetting and during the initial primary jetting, and is relatively pronounced all the way through peak accumulation (Fig. 1b and Fig. 2).
Blast load impulse accumulation, post-FRP jetting, is significantly reduced in amplitude and consistent but loses some consistency later in the shot string (Fig. 2a).
When compared to the previously evaluated DRC308, the Carson 30 maintains early time flow rate with more late time control; its signature suppression is more robust which results in a greater degree of blast propagation control. The reader is encouraged to reference Silencer Hazard Map Briefs 8.1.8 and 8.1.13, respectively, for visual personnel risk comparisons.
PEW Science Research Note 3: With regard to behaviors the Carson 30 inherits from the Infinity, the FRP behavior is one. There is a postulated approximately 64% increase in FRP severity, to bystanders, when fielding the Carson 30 on the SR-25. This is somewhat a result of an inherent trait of the core design. The FRP to which the operator is subjected is characterized by less of a differential. The early time flow rate of the Carson 30 is relatively high; its gross flow rate, however, is lower than that from the Dillon DRC308 and that is one of the reasons why operator FRP differential is lower (operator risk is highly driven by ejection port blast; FRP is a muzzle blast driven phenomenon). This is discussed in further detail in Section 6.216.1.2 of this report. Nonetheless, the Carson 30 produces a less severe overall hazard field to both operators and bystanders than the Dillon silencer. In this case, its early time flow rate is high enough that when combined with its superior muzzle signature suppression, excess system backpressure is of less relative consequence.
PEW Science Research Note 4: Using the Suppression Rating Parametric Visualization Tool (Members Only) and limiting the maximum tested system length to 7 inches, filtering for .308 ammunition, 26 silencer configurations are shown to compare with the Rampart Range Suppression Carson 30. With a muzzle Suppression Rating of 29.0, the Carson 30 is among the top 3 performers in that metric, and the range of muzzle Suppression Ratings is 12 to 33.2, in that silencer length range on the 20-in bolt-action rifle test host. Preliminarily, it is postulated that the Carson 30 produces competitive signature suppression performance, for its size, in this combustion regime. It is extremely important to note that the blast overpressure input from a 20-in barrel 7.62 NATO system and 14.5-in barrel 7.62 NATO system are significantly different. Furthermore, it is also important to note that the Carson 30 is intended for automatic (reciprocating) rifle use; not bolt-action rifle use. Therefore, its flow rate and blast load input bias are optimized for the host weapon type in this test program, not for longer barrel locked breech weapons.
PEW Science Research Note 5: As in all semiautomatic rifle testing, a second pressure pulse originates from the ejection-port signature of the weapon and it occurs early enough in time such that its waves coalesce with that of the muzzle signature. However, in late time (at approximately 95 ms in Figure 1a) the mechanical noise of the bolt closing is observed. The pressure signature of Shot 6 does not display this event due to the bolt remaining open after the sixth and final round is fired from the magazine.
PEW Science Research Note 6: The closing time of automatic rifle bolts is often directly related to the flow restriction of a silencer for a given weapon system. PEW Science has determined bolt closing time variation from the unsuppressed state to be a reliable indicator of silencer back pressure, with strong correlation with the PEW Science Back Pressure Metric, Omega and the alpha parameter. However, PEW Science has also determined that the indicator is unreliable upon upper receiver fouling. Sound signatures are not influenced by this fouling, as these kinematics occur in late time, after gas venting to atmosphere. Momentum transfer, weapon condition (upper receiver fouling), and other factors, can significantly influence bolt closing time. PEW Science urges the reader to exercise extreme caution if using the published bolt closing time to make determinations regarding silencer flow restriction (back pressure) or weapon system kinematics. This type of calculation may provide erroneous results, as the weapon condition at the time of each test is not published data. The time-scale duration showing bolt closing time is only published by PEW Science such that the signature data pedigree may be verified.
The shape, timing, and magnitudes of the early-time pressure pulses and overall shape of the impulse waveforms measured at the muzzle, from shot-to-shot, are relatively consistent. The consistency of the waveform amplitudes highlight the silencer’s overall sound performance consistency at the muzzle after the FRP, as well as the relative consistency of the tested automatic rifle firearm configuration.
As typically indicated, first-round sound signatures always differ from subsequent shots, as the atmosphere within the silencer changes. The FRP phenomenon cannot always be shown by viewing only the peak sound pressure. This is one of the reasons why The Silencer Sound Standard requires examining multiple sound signature metrics. Ammunition consistency can play a role in the determination of FRP, however, the close examination of measured pressure and impulse waveforms typically excludes ammunition from the possible factors influencing true FRP, due to the relative consistency of most high quality factory ammunition.
PEW Science Research Note 7: Note that the muzzle Suppression Rating of the Carson 30 is 29.0 and the at-ear Suppression Rating is 21.1; the same zone on the Suppression Rating Dose Chart. In the tested configuration, the blast loads from the tested weapon system are significantly suppressed, but not suppressed enough for a human to forgo the use of hearing protection, for most use cases. Use of this silencer on the SR-25, when compared to firing the SR-25 unsuppressed, may significantly reduce the risk of blast overpressure injuries, such as traumatic brain injury (TBI), particularly near reflecting surfaces.
The signatures measured and analyzed at the shooter’s ear are presented in the full Member Version of this report.
Gross hazards and behaviors with the SR-25 weapon system are compared in the following section.
6.216.2 Suppression Rating Comparison (7.62x51mm from the 14.5-in SR-25)
Figure 5 presents a comparison of the PEW Science Suppression Ratings of the Rampart Range Suppression Carson 30 with that of the Dillon DRC308 and the unsuppressed KAC SR-25 weapon system. The standard PEW Science SR-25 test host weapon system is described in Public Research Supplement 6.210. As PEW Science research with the KAC SR-25 system continues, the dataset will be further populated.
Figure 5. Suppression Rating Comparisons of the Suppressed and Unsuppressed 14.5-in KAC SR-25, Using PEW-SOFT 5.56x45mm Supersonic Test Data and PEW Science Analysis
Figure 5 presents an overall summary of the postulated hazards to the operator and bystanders when fielding the Rampart Range Suppression Carson 30 and the Dillon DRC308 on the 14.5-in KAC SR-25 weapon system with a direct-thread mount. Data is also presented for the fielding case of the unsuppressed KAC SR-25. Hazards are expressed with the Suppression Rating; a holistic parameter that captures human inner ear damage risk potential from a measured impulsive complex overpressure signature during the entire time regime of weapon operation, including combustion, complete blowdown, and all mechanical operation, including the carrier group returning to battery, in the true free field. The parameter may be used with the dose chart at the beginning of this report. The PEW Science Suppression Rating is a damage risk criterion (DRC), a lower Suppression Rating indicates a higher personnel hazard in the free field - it is not a subjective quantity; it is an objective quantification of hearing damage risk potential. Due to its true free field test data origin and complete waveform analytical calculation basis, it is the only known universal suppressed weapon system signature comparison metric available.
As previously discussed in Research Note 3, with a muzzle Suppression Rating of 29.0, the 7-inch long Carson 30 is among the top 3 performers for its length suppressing 7.62 NATO in the Silencer Sound Standard, overall. The range of muzzle Suppression Ratings is currently 12 to 33.2 in that silencer length range on the 20-in bolt-action rifle test host. Preliminarily, it is postulated that the Carson 30 produces competitive signature suppression performance, for its size, in this combustion regime. Its higher muzzle suppression performance potential with its relatively high early time flow rate allow it to surpass the overall signature reduction performance of the Dillon DRC308 at both the operator and bystander locations.
It is also extremely important to note that the blast overpressure input from a 20-in barrel 7.62 NATO system and 14.5-in barrel 7.62 NATO system are significantly different. Furthermore, it is also important to note that the Carson 30 is intended for automatic (reciprocating) rifle use; not bolt-action rifle use. Therefore, its flow rate and blast load input bias are optimized for the host weapon type in this test program, not for longer barrel locked breech weapons. As it stands, the Carson 30 significantly reduces operator hazard when compared to the fielding of an unsuppressed 14.5-in barrel SR-25. Short barrel 7.62 NATO weapons are significantly hazardous to personnel. It is is important to note that blast overpressure may damage not only a human’s ears, but a human’s brain. Suppressed shooting is highly recommended.
PEW Science Research Note 12: Several silencers possessing hybrid design traits are expected to exhibit performance differentials on the standard 20-in .308 bolt-action and 14.5-in SR-25 test host weapon systems. PEW Science urges extreme caution when attempting to extrapolate the performance of a silencer on either of these weapon systems to the other without instrumented test data and engineering analysis. Performance differentials may be counterintuitive due to the complexities of hybrid systems’ response to varying blast load input pressure(s) and duration(s).
As detailed in this report, the Suppression Rating at the shooter’s ear may be significantly influenced by the ejection port signature from an automatic rifle; all other things equal. For details on performance increases that are possible when “tuning” an automatic weapon system for a silencer, please see Review 6.111. It is important to note that not all silencers will possess a significant increase in shooter’s ear Suppression Rating from weapon tuning. Signature at the operator’s head is a function of both muzzle and ejection port signatures from the AR weapon system. Specific weapon system parameters will dictate modification efficacy.
Small arm weapon system suppression performance is a spectrum. The PEW Science Suppression Rating and the Silencer Sound Standard help quantify this spectrum for end users and industry, objectively.
6.216.3 Review Summary: Rampart Range Suppression Carson 30 on the KAC 7.62x51mm SR-25 with 14.5-in Barrel
When paired with the 14.5-in barrel KAC SR-25 and fired with Lake City M80 149gr ammunition, the Rampart Range Suppression Carson 30 achieved a composite Suppression Rating™ of 29.9 in PEW Science testing.
As with all weapon systems, the user is encouraged to examine both muzzle and ear Suppression Ratings.
PEW Science Laboratory Staff Opinion:
The Rampart Range Suppression Carson 30 is a midsize titanium battle rifle silencer with competitive muzzle suppression for its size and a flow rate conducive to effective use on the semiautomatic rifles. The 3D printed titanium modified Infinity core of the Carson 30 is lighter weight than typical and is intended for field duty use; not heavy continuous strings of fully automatic fire. The 11 ounce system is optimized for semiautomatic AR-10 platforms and the rear is HUB mount system compatible.
The Carson 30 uses a modified Otter Creek Labs Infinity inner core, under license. Therefore, the Carson 30 is classified as a hybrid design, incorporating both high flow rate features and conventional geometries to control distal blast propagation while reducing adverse influence on weapon function. Like the Infinity 762 silencer, it is specifically classified as a staged hybrid in the PEW Science Silencer Sound Standard research taxonomy.
With a muzzle Suppression Rating of 29.0, the Carson 30 is among the top 3 performers in that metric for its 7-inch length if compared to evaluations on the 20-in bolt-action rifle test host. Therefore, it is preliminarily postulated that the Carson 30 produces competitive signature suppression performance for its size in this combustion regime. It is extremely important to note that the blast overpressure input from a 20-in barrel 7.62 NATO system and 14.5-in barrel 7.62 NATO system are significantly different. Furthermore, it is also important to note that the Carson 30 is intended for automatic (reciprocating) rifle use; not bolt-action rifle use. Therefore, its flow rate and blast load input bias are optimized for the host weapon type in this test program, not for longer barrel locked breech weapons.
Despite its titanium construction, it is likely that the durability of the Carson 30 is higher than many “hunting” or “bolt-action” silencers on 7.62 NATO weapons due to its internal geometry. The end user is encouraged to contact Rampart Range Suppression for further guidance.
The Carson 30 is HUB mount capable. The user may adapt the silencer to a variety of mounting systems of their preference. The tested system was used with a third-party direct-thread mount as the KAC SR-25 is threaded 3/4-24tpi (different from the common 5/8-24tpi of many 30 caliber systems).
Several silencers possessing hybrid design traits are expected to exhibit performance differentials on the standard 20-in .308 bolt-action and 14.5-in SR-25 test host weapon systems. PEW Science urges extreme caution when attempting to extrapolate the performance of a silencer on either of these weapon systems to the other without instrumented test data and engineering analysis. Performance differentials may be counterintuitive due to the complexities of hybrid systems’ response to varying blast load input pressure(s) and duration(s).
In this review, the Rampart Range Suppression Carson 30 performance metrics depend upon suppressing a supersonic centerfire rifle cartridge on a short barrel gas-operated 7.62 NATO rifle, which is an incredibly difficult task. PEW Science encourages the reader to remain vigilant with regard to all supersonic centerfire rifle suppression claims. The gas volume and combustion products created by the firing of the supersonic 7.62x51mm cartridge are significant; the measured pressure and impulse magnitudes, and their durations, illustrate this fact. Silencer performance on automatic (reciprocating) rifles depends on many factors. Weapon configuration may significantly influence total suppressed small arm system performance.
The hearing damage potential of supersonic centerfire rifle use is significant. PEW Science encourages the reader to consider the Suppression Rating when deciding on an appropriate silencer and host weapon combination for their desired use.
