By Al Paulson
Tom Bowers is one of the best known and best liked members of the Internet Class 3 community, and his www.subguns.com public forum on the Internet has become a backbone of the Class 3 community for the exchange of information and the sale of weapons and accessories. Tom was flabbergasted when I expressed interest in writing about his line of sound suppressors for the Ingram series of submachine guns in .45 ACP, 9x19mm, and .380 ACP. “These are cheap cans, Al,” Tom replied. “They don’t work as well as high dollar cans. I could have made them quieter, but then they would have cost more. I simply wanted to make an affordable, entry-level suppressor for folks who have recently bought a MAC, RPB or Cobray as their first machine gun. I wanted to find a compromise design that would give just enough suppression, maximum durability, and minimum price. I’m using simple technology that’s been around for years. There’s no rocket science here. Why would you want to write about my stuff when there are still high-end suppressors from the big manufacturers to write about that will be quieter?”
“The short answer,” I replied “is that I’ve received a lot of enthusiastic feedback from your customers who are very pleased with the performance, cosmetics, durability, and price of your suppressors. I’ve seen econo-cans that I would not want to shoot, much less own. The word I get is that yours are made extremely well at a very good price, and I have not received a single complaint, which is remarkable. You have created a phenomenon with your CAC suppressors, and I need to get up to speed on this phenomenon myself. Whether you realize it or not, you seem to have created a chapter in the history of silencer development in the United States.
“The long answer to explain my interest, Tom, begins back in the 1980s, when I established what I believe to be the first privately owned laboratory designed for the scientific measurement of sound suppressor performance. With a lot of help from scientists, suppressor industry leaders, and end-users from around the world, I put together the equipment and a testing regimen that could provide a scientific comparison of competing suppressor designs. The net result of subsequent research that has been conducted over the years is that end-users are no longer satisfied with subjective platitudes like ‘that silencer was real quiet’ or ‘it sounded like a Mercedes door closing’ or ‘the report was just a loud cough.’ Now, for better or worse, people want numbers. They want to know the suppressed sound signature and the net sound reduction produced by a silenced firearm.
“That’s good. In fact, that has been my goal from the very beginning: to provide objective scientific data akin to accuracy testing of firearms, what a scientist would term ‘hard data’ based upon repeatable experiments. Both manufacturers and end-users now have an objective methodology for comparing silencers. Today, manufacturers and even a number of military end-users around the world use the methodology I developed and popularized.
“But I may have created a monster. I’ve continually pointed out since the beginning of this quest that there are a lot of other factors in a silencer’s performance equation besides decibels. The amount of length and weight a suppressor adds to a firearm are critical factors for both tactical and sporting applications of silenced firearms. Diameter is crucial if one must use factory iron sights. Additional factors that may be critically important in the decision to purchase and deploy a given silencer design include: compatibility with a wide variety of ammunition, reliability of the parent weapon when a given silencer is attached, positive or negative effects on accuracy, durability, service life, maintenance requirements, purchase price, life cycle cost analysis, user-friendliness, and availability to a given category of end-user. For the private collector, pride of ownership is also a significant factor in the selection of a sound suppressor, and people tell me your CAC line of suppressors engenders that pride of ownership.”
The conversation went on for more than an hour, with Tom agreeing to loan me one of each caliber CAC suppressor for evaluation. The only potential fly in the proverbial ointment was that Craig Wheatley at Tactical Innovations Inc. was so impressed by the CAC 45 suppressor that he purchased the entire production run of CAC 45s for resale. So I arranged to borrow a specimen from a gracious Mr. Wheatley for this study.
The Bowers CAC .45 suppressor, like all CAC variants, is made from 1.75 inch aluminum tubing. This standardization, plus the fact that Bowers bought a third of a mile of tubing, was a major factor in keeping the retail price of standard CAC cans to $295. So was the fact that the aluminum frusto-conical baffles were mass produced in house on a Hardinge CNC turning center in such quantities that Bowers had two 55 gallon drums full baffles after his 9mm production run. Like its 9x19mm sibling, the CAC 45 is 11.25 inches long. It weighs 19.2 ounces. The suppressor can be disassembled for cleaning or maintenance, which is a warm fuzzy for many private collectors. The front end cap of the CAC 45 suppressor features extra spanner holes in a circular pattern similar to the one first conceived by Tim Bixler of SCRC, providing extra holes should the first pair become damaged over the years during disassembly. A spanner is not provided with the Bowers suppressor, however, in an effort to keep the price down. Normal cleaning can be accomplished by immersion in a suitable solvent such as mineral spirits or Varsol, so disassembly should not be required. It is also noteworthy that Bowers offers a lifetime warranty on the baffle stack.
Between the clearly robust, business-like construction, especially nice black anodized finish, and particularly handsome laser engraving, the Bowers CAC 45 sound suppressor exudes the gravitas of a serious working tool and the workmanship worthy of the demanding collector, at a bargain price.
So far so good. How does it perform? I examined the performance of the Bowers CAC 45 on an Ingram M10 submachine gun manufactured by RPB, using Black Hills 230 grain FMJ ammunition. Black Hills ammunition is noteworthy for its quality, accuracy and consistency, and it has become my reference standard in all available calibers for testing and evaluation. I also use Black Hills ammunition for my personal concealed carry handguns.
I compared the CAC 45’s performance to a Cobray M10 suppressor that was retrofitted in the late 1980s with a baffle kit from one of the major manufacturers. The kit replaced WerBell’s spiral diffusers and wipe with stamped baffles and spacers, and a reflective front end cap. This retrofitted M10 suppressor has an overall length of 11.5 inches and a weight of 27.2 ounces. The suppressor’s rear tube has a diameter of 2.22 inches, while the front tube has a diameter of 1.75 inches. The reflective front end cap has a bore of 0.57 inch, while the CAC 45 has a bore of 0.54 inch.
The retrofitted M10 eliminates the wipe with its need for periodic replacement, it provides better accuracy, and provides 1 dB better sound reduction. The only downside is that the sound signature seems harsher because there is a hard uncorking component to the sound, while the original WerBell design has a longer and softer sound that is actually more pleasing to the ear. Furthermore, the original WerBell’s softer sound signature seems less like a sound one might have to worry about.
I compared these two traditional suppressors for the Ingram M10 with the Bowers CAC 45, measuring the sound pressure levels (SPLs) in two locations: (1) 1.00 meter to the left of the muzzle or front of the sound suppressor, as appropriate, and (2) at the shooter’s left ear. Details on the testing regimen can be found in Chapter 5 of Volume 1, Silencer History and Performance. The mean (average) sound signatures appear in Table 1 and the net sound reductions appear in Table 2, confirming several suspicions I’ve kept to myself until this point in the discussion. The first is that .45 caliber submachine guns are hard to suppress. The second is that the CAC design seems really optimized for 9mm cartridges; I’d expect double the sound reduction out of the 9mm variant.
Looking Beyond the Decibels
What the numbers don’t show is the profound difference in subjective performance between the Bowers CAC 45 and the Cobray M10 retrofitted with baffles. The Cobray silencer produced a high-pitched, sharp uncorking sound. The Bowers CAC 45 produced a soft, low-pitch, relatively long depressurizing sigh that makes the CAC 45 much more comfortable to shoot than the sound pressure levels might suggest, since a significant portion of the sound energy seems to be below the frequency of peak hearing sensitivity in humans.
The sound pressure level at the shooter’s ear is 1 dB over the European Risk Limit for hearing loss from impulse sound and is equal to the pain threshold for impulse sound. The rule of thumb is that if a sound hurts, it is already above the safe limit. Yet shooting the CAC 45 did not hurt, presumably because the can shifts much of the sound energy to below the peak sensitivity of the human ear. Therefore, the amount of sound suppression is probably enough to safeguard the operator’s hearing, and it will certainly be safe for someone an armspan behind the shooter’s ear.
The Bowers CAC 45 also proved much better at recoil reduction during full-auto fire than the Cobray M10 retrofit, providing significantly better hit probability. The Bowers CAC also delivered much better accuracy at 25 yards with semiautomatic fire, producing an average of 2.70 inch groups, while the M10 retrofit delivered an average of 3.81 inch groups. That’s just part of the Bowers accuracy advantage. At 25 yards, the Bowers groups centered an average of 2.6 inches from the point of aim up and to the right to the 1 o’clock position, while the M10 retrofit groups centered an average of 4.3 inches to the 1 o’clock position. Thus, the Bowers CAC 45 provided a 29 percent advantage in terms of group size and a 40 percent advantage in terms of shot placement over the M10 retrofit, which is itself significantly more accurate than an M10 with fresh wipe. This adds up to about a 70 percent increase in accuracy or effective range when using the CAC 45 compared to the Cobray M10 with baffle retrofit kit. Since the point of shooting, whether one is a sport shooter or an armed professional, is hitting the target, the big news for me personally is how well the Bowers CAC 45 improves accuracy over the traditional competition.
So what’s the bottom line here? Tom Bowers had the goal of producing suppressors for submachine guns of Ingram heritage that provide just enough suppression, maximum durability, and minimum price. He succeeded admirably. The Bowers CAC 45 sound suppressor provides an especially nice black anodized finish and particularly handsome laser engraving that will provide the pride of ownership demanded by the serious collector. The CAC 45 also features the robust, business-like construction required of a working tool. The suppressor seems to generate enough frequency shift to not only create a pleasing sound signature, but also to just barely safeguard the operator from short-term and long-term hearing loss. The CAC 45 suppressor also delivers significantly better accuracy and effective range than Mitch WerBell’s M10 sound suppressor, whether or not the M10 is fitted with a baffle retrofit kit. Furthermore, the CAC 45 is a half-pound lighter than the upgraded M10.
Finally the bottom line to the bottom line ain’t bad either: this is a lot of silencer for $295 retail. Clearly, decibels aren’t always the whole story. That’s an important lesson. The late astronomer Carl Sagan would have called that a Big Truth. After this enlightening study, I’ve purchased a Bowers CAC 45 myself, and I plan to retire my M10 retrofit. That is the highest recommendation I can possibly make for the Bowers CAC 45.
To buy a Bowers CAC 45 suppressor, or a new or used MAC submachine gun, contact Craig Wheatley at Tactical Innovations Inc., Dept. SAR, 108 Holsum Way #D7, Glen Burnie, MD 21060; phone 410-760-3609; website www.tacticalinc.com/. For information on other Bowers suppressors, check out Tom Bowers’ website at www.subguns .com or go directly to his suppressor page at Bowers, P.O. Box 430, Cornelius, OR 97113; e-mail email@example.com; website www.subguns.com/products/cans. I’ll continue to report on the other suppressors in the Bowers line at the earliest opportunities. If your local retailer does not stock Black Hills ammunition, you can purchase it directly from Black Hills Ammunition, Inc., Dept. SAR, P.O. Box 3090, Rapid City, SD 57709-3090; phone 605-348-5150; fax 605-348-9827; website www.black-hills.com.
|This article first appeared in Small Arms Review V5N11 (August 2002)|