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Clearing Up Gas Guns

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Burning powder, hot particles and noxious gases have been jetting into shooters’ faces since the first brave souls thrust red-hot wires or matches toward the touchholes of thick-walled, cast-metal tubes packed with powder and projectiles. By the beginning of the 20th century, locked-breech lever, bolt- and single-shot rifles using metallic cartridges and “smokeless” propellants had eliminated most of these face-level, blackpowder irritants. Whether solid-receiver or open-topped, even the early and mid-20th century semi-automatic actions were not terribly hard on the nose or eyes. But, thanks to rifledom’s boundless quest to increase capabilities while reducing weights and costs, we’ve managed to gas things up mightily in the decades since.

Short barrels and gas systems, the increasing use of sound suppressors, over-porting of barrels and low-budget ammo all conspire to foul the air we see through and breathe in when shooting modern semi-auto rifles. The experience can be severe enough to turn off young, new and seasoned shooters alike, especially in hot, still air. If you’re tired of burning eyes, fume-filled nostrils and powder-flecked cheeks, there are ways to reduce the amount of junk that your rifle ejects at head level.

An Eye for Design
Later 20th century semi-autos, such as the AK, FAL, AR and H&K, as well as their related spin-offs, have gaps and seams that channelize gas from combustion chambers and bleed-off ports to the immediate area around shooters’ faces. Traditional ARs are particularly fumy due to the additional gaps created by rear-mounted, nose-level charging handles. The common AR solution is to use a charging handle that has some form of gas shield. While this helps, the offending fumes are merely redirected to the receivers’ other openings, just as with other gap-laden semi-autos.

As a lefty, I can verify that having an ejection port on the same side as one’s face can make for a miserable shooting session. Fortunately, there are options for configurable left and right-side ejection, such as the Beretta ARX 100, the Faxon ARAK-21 and many modern bullpup designs. While most other semi-auto rifles have little flexibility here, ARs are an exception—sort of. Small-frame, left-side ejection upper receivers and bolt-carrier groups are fairly easy to find, while large-frame options come and go. But, lacking the deep pockets needed to replace or completely rebuild a favorite rifle, most of us are stuck with what we have and differing degrees of unsightly powder freckles.

Pump Down the Volume
Turning down a gas-operated rifle’s flow to the minimal level needed for reliable operation helps reduce the excess gas that ends up outside the receiver. The increased use of adjustable gas systems in both op-rod and direct-impingement centerfire rifles makes this capability fairly common on factory guns today. Fixed-gas ARs can be retrofitted with adjustable gas blocks by gunsmiths and DIYers without much difficulty. If you have an FAL-pattern rifle, you likely already have a highly adjustable gas block. Mini-14 and M1A shooters have the advantage of open-topped receivers that allow greater venting, but when suppressed, both rifles can still benefit from aftermarket adjustable gas blocks or plugs. AK shooters also have retrofit options for gas adjustability. When considering such products, avoid options that vent excess gas into the receiver. Some AK-pattern adjustable-gas pistons and AR adjustable bolt carriers do just that, which doesn’t solve the main issue plaguing our noses and eyes. Blowback-operating systems, such as those used in pistol-caliber carbines, lack such adjustability, but there are still other ways to help clear the air.

Feeding Time
Sometimes a simple change of ammo can do the trick. While steel-case, foreign loads are the most cost-effective target and hunting fodder, they’re notoriously smoky as well. The same goes for some of the brass-case, foreign surplus ammunition in circulation. Using higher quality (and cost), brass-case commercial ammo can help. I find that lighter factory loads, such as those used in varmint ammo, are usually less gassy. Handloaders have ultimate control here and when not pushing for record-breaking velocities, stepping down charge weights or changing powders can also reduce receiver gasses.

Can It
I’m sure there’s a graphable relationship between different suppressor lengths/bore sizes/baffle styles and the amount of pressure they push back into our operating systems and faces. I’m equally sure that I’m not the guy to graph it. Instead, I’ll share the simple observation that the less resistance encountered by gasses leaving a muzzle, the less of anything I get back in my face. I prefer to use .30-caliber suppressors on .22-caliber, 6 mm and 6.5 mm rifles as well as .45-caliber suppressors on 9 mm rifles for this specific reason. I’m also a cheapskate, so needing fewer suppressors may factor in somewhere, too. There’s some loss in sound reduction when using an over-bored can, but it’s not enough to matter to me. Low-back-pressure suppressor designs are another option to effectively reduce the volume of gasses coming back into a rifle’s action.

Slick Tips
There’s one other source of airborne irritants that’s worth examining: lubrication. As metal components heat up through repetitive firing, oil (or grease) elements begin to burn off. The rate of burn and volume of fumes given off varies by lubricant type, so trying different products may yield a less smoky lube for your rifle. I’ve found that synthetic and conventional gun oils tend to last longer and smoke less than veggie-based options, but I haven’t tested everything out there. Since most gas guns work well—or better—when they aren’t completely slathered in oil, it’s also worth limiting lubricant applications to only those bearing surfaces specified by your rifle’s manufacturer.

Nowadays, it should go without saying that ballistic eye protection is a must for any planned shooting pursuit. This point is driven home each time I shoot a suppressor-equipped semi-auto, which is a weekly event. When my combined efforts to reduce the face-level gas from a particular rifle fail, a pair of ballistic protective swim goggles to seal off my eyes and foam earplugs in my nostrils seem to do the trick. Just remember to breathe through the corner of your mouth with this approach. That will keep the powder flecks out of your teeth and you won’t pass out behind a loaded rifle, which is frowned upon by most RSOs.



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