Barrel Cleaning, Not Such A Can Of Worms After All

Guest Blogger Russ Douglas cleans his 17HMR rifle’s barrel and shows us how he does it.

My two rimfire rifles have been sadly underused of late, thanks to a few health issues and the Nationwide Cv19 lockdown.  I’m looking to rectify this situation very shortly, partly by helping a friend explore his (first) new Permission.  He has a Scottish Airgun License but no FAC as yet, so with his new Permission sporting generous rabbit numbers I’ve offered to lend him a hand as he gets started.

Before I do there’s the small matter of barrel cleaning.  My rifles reside in a gun safe ‘protected’ by a sachet of Napier Super VP90 gun preservative, but that doesn’t actively clean the barrel.  I understand barrel cleaning can be a contentious issue, with strong opinions for and against various methods, so during my research I sought-out the opinions of some significantly more experienced shooter friends.  I should explain my greater experience is from Airguns (both FAC and non-FAC PCP air rifles), where I’m happy leaving barrels as-is and only cleaning when accuracy declines.  This was proven with my FAC AA S510XS reliably grouping in a single furry hole at 50m, despite never having been cleaned after devouring many tins of pellets.

Rimfire rifles on the other hand, expose your barrel not only to different metals, but also various propellant gases, many of which can be highly corrosive.  My current rimfire calibres are 22LR and 17HMR, which straightaway present different challenges.  When cleaning any barrel firing lead projectiles, you normally have to “re-lead” the barrel afterwards before returning to normal usage, to reinstate a certain amount of lead in the grooves and let accuracy settle-down.  This prevents downrange accuracy or Point-Of-Aim (POI) changing as the barrel re-leads and its properties change.  Friends explained when I first started using 22LR that due to the heavy wax coating on the bullets, barrels can be lined with both wax and lead.  An amount of which then must be re-established after any thorough clean.

Gun Cleaning Solvents

A choice of solvents to remove copper fouling.

17HMR is obviously a smaller calibre, the smallest possible in fact, so is especially sensitive to metal fouling and also travels at a significantly higher velocity.  This makes for greater chamber/barrel pressures and the gases lingering longer in the tighter bore.  Leaving the bolt open for a time in-between shots ‘can’ allow these gases to clear faster, resulting in slightly less residue being deposited (in addition to the barrel cooling faster during an extended session), but it’s no guarantee.  There’s no post-cleaning ‘re-leading’ process with Copper-based jacketed bullets, though there is a build-up to be removed, requiring specialist solvents.




There’s the pull-through or boresnake option, or the cleaning rod option.  Friends advised me against the former method with 17HMR, due to the solvents required to clean the bore of both metal and propellant residues.  These powerful chemicals must not be allowed to come into contact with the trigger mechanism, where they could strip-away essential lubricants or damage protective O-rings.  They can also damage wooden stock furniture, so must be used with care.

Rifle Cleaning Rod

Synthetic cleaning rod, threaded tip and rotating handle.

That leaves the cleaning rod method, whereby a brass or synthetic coated rod is fed through the barrel, with a choice of cleaning attachments on the threaded end.  Brass is the preferred metal for these as it’s softer than steel, so should cause minimal wear.  Synthetic coated rods are an even safer bet as softer than brass.  You must still be very cautious not to damage the crown of the barrel, as even tiny imperfections in this precisely-machined series of castellated surfaces can send a bullet off course.

Because of protecting both the barrel’s crown (from abrasion) and action (from solvents) an almost essential accessory here is the bore guide.  This is a hollow tube (often a synthetic moulding) that slides into the rifle receiver from the rear, in place of the bolt.  It roughly locks into position via a protrusion just like the bolt, then allows the cleaning rod to be inserted from the rear and propelled through the bore towards the muzzle.  As this happens you can apply any solvents as required, directly to either the cleaning patch or cleaning brush, ensuring they’re kept away from the trigger mechanism and wooden stock.

Bisley Rifle Cleaning Patches

Cleaning patches, here .22 cut-down to clean the smaller 17HMR bore.

The tip of the rod is male-threaded, to accept various accessories, commonly jags to hold solvent-impregnated cleaning patches to loosen impacted residues, or brushesCloth patches are available in individual small sheets, or on a roll that is then cut to suit depending upon the bore being cleaned.  Brushes can be stiff Phosphor-Bronze wire-bristled to remove stubborn debris, or softer (e.g. wool-based) brushes to clean away finer particles, then apply solvents or preservative oils.  To preserve the muzzle’s crown run each accessory through once from breech to muzzle, then unscrew it and gently withdraw the cleaning rod, before repeating as necessary with a fresh patch.  Do not change direction and reverse the direction of a Phosphor-bronze brush’s cleaning stroke, as this can bend the bristles causing it to jam in the tight bore.

Bisley Patches

Watch as patches get progressively cleaner.

Use each cleaning patch once, then once removed you can compare them and watch as they become progressively cleaner.  Finally run through a patch lightly oiled with gun oil or solvent, to leave a protective coating that will resist corrosion.  Another tip is to remove oily residue with a patch carrying a little solvent just before next use, if you’re after first shot MOA accuracy.  Care must also be taken to store these cleaning rods carefully, as being so slim they’re more prone to damage.  Another feature of cleaning rods is they must rotate freely around the handle, as the rod is pushed through the barrel.  This is especially important with the tight bore of 17HMR rifles.

Stability helps

Before starting you’ll need a stable surface to house your rifle, John Rothery kindly loaned me their excellent MTM Rifle Maintenance Vice for this purpose, as you’ll see from my associated video below.  This excellent accessory rests upon a flat surface, from where it can almost universally clamp most rifles, via a clever series of attachments.  This Gun Vice also includes a series of compartments for storing your cleaning accessories and consumables, so is very useful during many rifle maintenance operations, not just cleaning.

MTM Gun Vice

The Gun Vice keeps everything in its place.


Once again cleaning these can be contentious, with some brands I’ve seen being practically sealed, marked “Can contain harmful chemicals, do not open” (or similar).  This is in reference to lead build-up and also propellant residues.  Others are modular in design (e.g. the Swift Stumpy or DPT models) and relatively easy not only to open and clean but can also be reassembled with more or less sections, to increase or decrease both effectiveness and size, as required.  This can be especially useful if for example swapping a .22” moderator to use with a less powerful cartridge, where a smaller overall length can save vital inches in your gun bag.

Whatever route you choose, do your research to ensure you use not only the right solvents or cleaning products for the job at hand, but also protect yourself both any the hazards lurking within the moderator and the chemicals you’re using.  If any of these are especially harmful, they should be supplied with the relevant Material Safety Data Sheet (or MSDS).  This will tell you both how to handle the chemicals and how to avoid issues from possible skin contact and inhalation.

I hope this has been useful and that you enjoy your shooting.

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