Best Calibers for Hunting Pack Rat: Comparisons & Picks
Practical cartridge and shotgun picks for legal, ethical pack rat control in barns, brush, rock piles, and desert edges.
Pack rat hunting is usually less about sport and more about practical control when woodrats start damaging feed, wiring, sheds, cabins, outbuildings, or parked equipment. Because “pack rat” usually refers to native woodrats, not the common nonnative city rat, it pays to think in terms of precise, low-risk tools rather than raw power. The best pack rat hunting calibers are the ones that match your backdrop, your typical shot distance, your recoil tolerance, and the place you are shooting. Safe firearm handling matters even more around structures, and ethical shot placement still applies on small targets: take only clear shots with a solid backstop, use ammunition suited to the distance, and check local laws because seasons, discharge rules, minimum calibers, magazine limits, species status, and even non-toxic shot requirements can vary by area.
Where/When: Pack rats, or woodrats, occur across much of western North America and can show up from low desert and rocky slopes to chaparral, pinyon-juniper country, pine forest edges, cabins, garages, and other lightly used structures. Hunters and landowners commonly find sign around stick-and-cactus middens, brush piles, rock overhangs, tree bases, prickly pear patches, feed storage, pet food, and travel lanes between cover and food. They are typically most active from dusk through the night, so the best windows are often the last light period and the first few hours after dark where legal. In many areas, warm evenings and calm weather improve visibility and movement, while colder or stormy periods can push activity tighter to dens, vehicles, and sheltered structures. Timing varies by region and regulations, so always match your plan to local rules and conditions.
Caliber Comparisons
| Feature | .22 LR | .17 HMR | .22 WMR | .410 bore | 20 gauge |
|---|---|---|---|---|---|
| Recoil How much kick you can expect when firing. |
Very low | Very low | Low | Low | Moderate |
| Effective Range The distance at which the caliber remains accurate and lethal. |
25–60 yards | 40–125 yards | 40–100 yards | 10–25 yards | 10–30 yards |
| Bullet Weight Range The range of bullet weights typically available for the caliber. |
29–45 grain bullets | 17–20 grain bullets | 30–50 grain bullets | 1/2 oz shot or 1/4 oz slug | 7/8–1 oz shot or 5/8 oz slug |
| Versatility How well the caliber or gauge performs for other game species besides your primary target. |
High for pests and small game | Medium-high in open country | High for pests and tougher small game | Medium at very close range | Very high, but more gun than most rat work needs |
| Ammo Availability How easy it is to find ammunition for the caliber. |
Excellent | Good | Good | Good | Excellent |
.22 LR
.22 LR is the best all-around pack rat hunting caliber for most people because it solves the biggest real-world problem: making accurate shots at short range without excess recoil, noise, or cost.
PROS
- Cheap, common, and easy to practice with
- Very low recoil helps precise head or upper-chest shots
- Works well from barns to brush edges at modest distances
CONS
- Loses authority quickly as distance stretches
- Wind and small target movement matter more past about 50 yards
- Shot placement becomes unforgiving with poor bullet choice
Interesting Fact: .22 LR loads are offered in a wide spread of weights and velocities, which is why the cartridge can be tuned for quieter close work or faster varmint use.
Consider this Caliber If…
Choose .22 LR if your typical shots are inside 50 or 60 yards and you want a simple, affordable tool for repeated use around sheds, fence lines, feed areas, or rocky cover. It matters most when you need control over bullet placement and recoil more than raw reach. For pack rats, a 36- to 40-grain hollow point is a strong starting point, while standard-velocity or subsonic loads make sense where noise is a concern and distances stay short. A bolt action is often the easiest way to wring out accuracy, but a reliable semi-auto can also work well if local laws allow it.
.17 HMR
.17 HMR is the best pack rat hunting caliber for open-country shots where rats are hanging near rock piles, cactus edges, or brush islands and you want a flatter trajectory than .22 LR can give.
PROS
- Flat shooting for small targets at longer rimfire ranges
- Very mild recoil keeps the sight picture steady
- Excellent choice for deliberate shots in open terrain
CONS
- Usually costs more than .22 LR
- Not ideal where shots are extremely close and backstops are poor
- Can be more affected by wind than many shooters expect
Interesting Fact: CCI lists a 20-grain .17 HMR Gamepoint load at 2,375 fps and markets it specifically for small game.
Consider this Caliber If…
Pick .17 HMR when your main problem is range estimation and tiny targets rather than sheer number of rats. It matters in desert edges, sage, or broken rock country where a 70- to 100-yard shot is realistic and a flatter hold is useful. For choosing ammo, 17-grain loads are a common option for explosive varmint performance, while 20-grain soft points are often a better choice when you want a little more penetration and less splashy performance on quartering angles. Pair it with a low-power scope and keep shots away from metal structures, equipment, and other hard backdrops.
.22 WMR
.22 WMR fills the gap between .22 LR and centerfire varmints rounds, giving you more reach and impact for pack rats that stay just far enough out to make a standard rimfire feel marginal.
PROS
- Hits harder than .22 LR with useful extra range
- Still easy to shoot for most hunters
- Good choice when rats appear along brushy field margins or rock belts
CONS
- Ammo usually costs more than .22 LR
- Less common rifle selection than .22 LR
- Can be more cartridge than you want around very tight structures
Interesting Fact: CCI shows common .22 WMR varmint loads built around 40-grain bullets at about 1,875 fps, which helps explain the cartridge’s reputation for “more rimfire reach.”
Consider this Caliber If…
Go with .22 WMR if you like the simplicity of rimfire rifles but want a little more margin on larger woodrats, tougher angles, or shots that stretch toward 75 to 100 yards. It matters when you hunt brushy fencelines, stone walls, and edge habitat where rats pause briefly and you need a faster, firmer hit than .22 LR usually delivers. For selection, 40-grain jacketed hollow points are a practical starting point, and a compact bolt rifle with a clear 2-7x or 3-9x optic is an excellent fit. Just remember that the extra speed and penetration demand a better backdrop than close-in barn work.
.410 bore
.410 bore is the best close-range shotgun option for pack rats when movement is the problem and you need a forgiving pattern instead of a single tiny point of aim.
PROS
- Helpful on fast, darting rats at very short range
- Low recoil compared with larger shotguns
- Handy in light single-shots and compact field guns
CONS
- Patterns are thinner than many shooters assume
- Effective range is short
- Shotshell cost can surprise budget-minded hunters
Interesting Fact: Federal notes that .410 is identified by bore diameter rather than gauge, and its catalog includes common 1/2-ounce shot loads.
Consider this Caliber If…
Use .410 bore when rats break from cover at 10 to 20 yards and you are shooting in open space with a safe background, not inside buildings or toward machinery. It matters most in brush piles, weedy ditch edges, and outdoor cleanup situations where a rifle shot on a weaving target is harder than it sounds. For choosing loads, think in terms of small shot sizes for short-range pest work and pattern your gun first because .410 performance is highly choke- and load-dependent. Keep expectations realistic: this is a precision small shotgun, not a magic wand, and range discipline is critical.
20 gauge
20 gauge is the heavy-duty shotgun answer for pack rat hunting when you want denser patterns than .410 bore and you are working entirely outdoors in thicker cover where close opportunities come fast.
PROS
- Denser patterns and more margin than .410 bore
- Widely available loads and shotgun choices
- Useful when multiple rats flush from brush or junk piles
CONS
- More recoil and noise than most pack rat jobs require
- Overkill for routine precision shots around structures
- Demands careful attention to shot spread and safe zones
Interesting Fact: Federal’s 20-gauge catalog is broad enough to show why the chambering remains one of the most versatile shotgun options in the field.
Consider this Caliber If…
Choose 20 gauge if your pack rat problem looks more like outdoor brush-busting than careful single-target shooting. It matters on ranch edges, dump piles, creek bottoms, or thickets where rats jump and jink at close range and a fuller pattern is worth the extra recoil. For setup, stick with lighter field loads and smaller shot for rodents, and avoid the temptation to use this gauge around walls, roofs, vehicles, or confined work spaces. For most pack rat hunting calibers, the right answer is restraint; 20 gauge works best when the cover is thick, the backdrop is clean, and you genuinely need a shotgun’s wider pattern.
Final Picks for Pack Rat Hunting
For most readers, .22 LR is the smartest first choice because it balances precision, low recoil, cost, and practical range better than anything else here. Move to .17 HMR if your shots are longer and more open, or .22 WMR if you want extra punch while staying in the rimfire world. Choose .410 bore only for very close, outdoor moving shots, and reserve 20 gauge for thick-cover situations where pattern density matters more than finesse. Whatever you carry, treat pack rats like the small but significant native animals they are: verify that lethal control is legal where you hunt, identify the species correctly, keep every shot pointed into a safe backstop, and pass on angles that do not allow instant, ethical results.