Grizzly Cartridge Co. Big Bore Hunting, .45-70 Gov’t +P, JHP, 300 Grain
Ammo Reports Team
| Feature | Detail |
|---|---|
| Primary Use | Big game hunting, dangerous game, lever-action field use |
| Bullet Type | Jacketed Hollow Point (JHP) |
| Bullet Weight | 300 grain |
| Case Material | Brass (standard for Grizzly Cartridge Co.; unconfirmed from product listing) |
| Primer Type | Not published |
| Packaging | 20 rounds per box |
| Typical Price | $69.34/box · $3.47/round |
| Closest Competitors | Buffalo Bore Heavy .45-70 Gov’t +P JHP 300 gr · Hornady LEVERevolution .45-70 Gov’t FTX 325 gr · Federal Premium .45-70 Gov’t Trophy Bonded Bear Claw 300 gr |
Official Specs
| Spec | Value | Source |
|---|---|---|
| Muzzle Velocity (fps) | — | Not published |
| Muzzle Energy (ft-lbs) | — | Not published |
| Bullet Weight | 300 gr | Manufacturer label |
| Bullet Type | Jacketed Hollow Point (JHP) | Manufacturer label |
| BC G1 | — | Not published |
| BC G7 | — | Not published |
| Manufacturer SKU | — | Not published |
| UPC | — | Not published |
| Reloadable | Yes (brass case assumed) | Industry standard for this manufacturer |
Note — Missing Velocity and Energy: Grizzly Cartridge Co. does not publish muzzle velocity or muzzle energy data through the available product listing or manufacturer documentation accessible at time of writing. The ballistics table below uses a physics-based estimate derived from comparable +P factory loads in this bullet weight class from the same caliber. All estimated values are clearly marked.
Note — Case and Primer: Brass case construction and boxer primer are standard across Grizzly Cartridge Co.’s product line, but these details are not confirmed in the specific product listing provided. Treat as probable, not verified.
Ballistics Table
Calculated estimate. Real-world results vary by barrel length, temperature, altitude, and lot. Community submissions will provide measured muzzle velocity for comparison.
Assumptions: 1,880 fps estimated muzzle velocity (consistent with comparable 300 gr +P .45-70 factory loads from similar manufacturers), G1 BC ≈ 0.185 (typical for flat-base JHP at this weight class), sight height 1.5″ above bore, zero at 100 yards, standard atmosphere (59°F, sea level).
| Yards | ~Velocity (fps) | ~Energy (ft-lbs) | ~Trajectory (in) |
|---|---|---|---|
| 0 | ~1,880 | ~2,355 | −1.5 |
| 50 | ~1,744 | ~2,026 | +1.2 |
| 100 | ~1,615 | ~1,737 | 0.0 ← zero |
| 150 | ~1,494 | ~1,486 | −5.1 |
| 200 | ~1,382 | ~1,271 | −15.0 |
| 250 | ~1,281 | ~1,092 | −31.4 |
| 300 | ~1,193 | ~948 | −55.8 |
Key takeaway: At 100 yards, this load retains an estimated 1,737 ft-lbs of energy — more than sufficient for ethical harvest of large North American game including elk and black bear when shots are kept within practical lever-action distances. The trajectory drops sharply beyond 150 yards, which is entirely expected for a heavy, large-bore projectile at these velocities. Hunters should treat this as a 0–150 yard hunting load in most field conditions. The +P pressure rating gives this load an edge in muzzle authority over standard .45-70 Gov’t offerings, but it also demands verification that the host firearm — typically a Marlin 1895 or Browning 1886 reproduction — is rated for +P use before firing.
The +P Designation and What It Means for .45-70 Gov’t
The .45-70 Government cartridge has one of the widest pressure-tier spreads of any commercially loaded centerfire rifle round. SAAMI maximum average pressure for standard .45-70 Gov’t is 28,000 CUP. However, the +P designation used by Grizzly Cartridge Co. and a handful of other specialty manufacturers indicates loads pushed well above that standard ceiling — sometimes to 40,000 CUP or beyond — intended exclusively for modern, strong-action firearms such as the Marlin 1895 series, Ruger No. 1, and select bolt-action platforms.
This is not a trivial distinction. Antique Springfield Trapdoor rifles, reproduction single-shot actions rated to original black powder pressures, and early lever-action designs are not safe for use with +P .45-70 ammunition. Grizzly Cartridge Co. explicitly targets this load at hunters using contemporary, reinforced actions. Buyers must confirm their firearm’s pressure rating before chambering any +P round. This is a fundamental safety requirement, not a precaution to be dismissed.
Best Uses
Good fit:
- Black bear and feral hog hunting at woods distances (inside 150 yards)
- Elk and large deer hunting in dense cover where shots rarely exceed 100 yards
- Lever-action rifle users carrying Marlin 1895 or equivalent modern strong-action platforms rated for +P
- Hunters who prefer a controlled-expansion JHP over a bonded or monolithic bullet for maximum energy transfer on medium-to-large game
- Field carry where a heavy, hard-hitting round is prioritized over flat trajectory
Not the right tool for:
- Antique or reproduction single-shot rifles rated to original black powder or trapdoor pressures — +P is unsafe in these actions
- Long-range hunting scenarios beyond 150–200 yards where trajectory becomes a significant factor
- Dangerous game situations where deep, straight-line penetration through heavy bone is the primary requirement — a bonded or solid bullet may be more appropriate
- Budget-sensitive buyers who shoot high volumes for practice, given the $3.47/round cost
- Handgun or pistol-caliber carbine use — this is a rifle cartridge
Reliability Notes
No structured submissions yet.
Based on manufacturer claims and open-source product information: Grizzly Cartridge Co. is a small-batch, specialty ammunition producer with a reputation in the lever-action and big-bore community for producing high-pressure, hunting-specific loads not commonly offered by major manufacturers. The company’s Big Bore Hunting line is positioned as a field-ready product with consistent case quality typical of brass-cased, boxer-primed construction. No documented feeding, ignition, or extraction issues specific to this load appear in publicly available sources at time of writing. All reliability assessments here reflect manufacturer claims and open-source community references, not structured test data.
Competitors
| Load | Weight | Bullet | BC G1 | Adv. Velocity | Price/box | Notes |
|---|---|---|---|---|---|---|
| Buffalo Bore Heavy .45-70 +P JHP | 300 gr | JHP | ~0.185 | ~1,925 fps | ~$65–$75 | Direct +P competitor; same bullet class; widely available |
| Hornady LEVERevolution .45-70 Gov’t | 325 gr | FTX (polymer tip) | ~0.230 | ~2,050 fps (24″ bbl) | ~$45–$55 | Higher BC, better trajectory; standard pressure; budget-friendlier |
| Federal Premium .45-70 Gov’t Trophy Bonded Bear Claw | 300 gr | TBBC (bonded) | ~0.185 | ~1,850 fps | ~$70–$85 | Bonded construction; premium penetration; better for dangerous game |
| Underwood Ammo .45-70 +P+ Xtreme Hunter | 300 gr | Lehigh Xtreme Penetrator | ~0.210 | ~2,000 fps | ~$70–$80 | Monolithic solid; extreme penetration; lead-free; +P+ rated |
| Winchester Super-X .45-70 Gov’t | 300 gr | JHP | ~0.180 | ~1,880 fps | ~$40–$50 | Standard pressure; budget alternative; widely available; not +P |
| Garrett Cartridges .45-70 +P Hammerhead | 420 gr | Hard cast flat nose | ~0.240 | ~1,550 fps | ~$80–$95 | Heavier; deeper penetration; premium dangerous game option |
Price Reality
- Typical retail range: $65–$75 per 20-round box; case pricing not widely published for this specialty load
- Per-round cost: approximately $3.47/round at the listed price of $69.34
- Compared to Hornady LEVERevolution (~$45–$55/box): Grizzly runs approximately $15–$20 more per box, reflecting the +P specialty positioning and smaller production volume
- Compared to Buffalo Bore +P JHP (~$65–$75/box): pricing is directly competitive; buyers should compare current availability and velocity data between the two
- Compared to Winchester Super-X (~$40–$50/box): standard-pressure alternative costs roughly $20 less per box, making it the clear budget option if +P is not required
- Fair price benchmark: At $3.47/round, this load sits within the expected range for small-batch, specialty +P hunting ammunition. Prices above $80/box for this specific load should prompt a comparison check against current Buffalo Bore and Federal Premium listings
Prices change. Check the Where to Buy block for current listings.
Where to Buy
Grizzly Cartridge Co. Big Bore Hunting, .45-70 Gov't +P, JHP, 300 Grain, 20 Rounds
Affiliate links. These do not influence ratings, data, or any editorial content on this page.
FAQ
Is this load safe to fire in any .45-70 Gov’t rifle?
No — and this is the most important question a buyer can ask before purchasing. The +P designation means this ammunition operates at pressures above the SAAMI standard for .45-70 Gov’t. It is not safe for use in antique Springfield Trapdoor actions, original-specification single-shot rifles, or any lever-action not explicitly rated for elevated pressure. Safe platforms include the Marlin 1895 (post-1972 production), Ruger No. 1, and modern bolt-action rifles chambered in .45-70. Always consult your firearm’s manual or the manufacturer directly before firing +P ammunition.
How does the JHP bullet perform on big game compared to a bonded or monolithic design?
A jacketed hollow point at .45-70 velocities typically expands reliably on medium-to-large soft-tissue targets, delivering high energy transfer and a wide wound channel. However, JHP bullets can deform or fragment when encountering heavy bone at close range, which may limit straight-line penetration compared to a bonded bullet like the Federal Trophy Bonded Bear Claw or a monolithic design like the Lehigh Xtreme Penetrator. For most deer, black bear, and hog hunting where shots are taken at moderate range without encountering heavy shoulder bone head-on, the 300 gr JHP is a capable choice. For dangerous game or situations requiring maximum penetration through thick hide and bone, a bonded or solid projectile is generally preferred.
What is the practical maximum hunting range for this load?
Based on estimated ballistics for a 300 grain +P JHP at approximately 1,880 fps, the trajectory drops roughly five inches below line of sight by 150 yards and over fifteen inches by 200 yards. Most experienced .45-70 hunters treat 150 yards as the ethical maximum for field shooting without a confirmed zero and precise holdover knowledge. The lever-action platform this cartridge is designed for further reinforces a practical hunting distance of 100–150 yards in most cover conditions. This is not a limitation of the load specifically — it is inherent to the physics of large-bore, heavy-bullet cartridges at these velocities.
How does this load compare directly to Buffalo Bore’s 300 grain +P JHP?
Both loads occupy the same performance tier: 300 grain JHP at +P pressure in .45-70 Gov’t. Buffalo Bore publishes velocity data for their comparable load (approximately 1,925 fps from a 22″ barrel), which gives buyers a reference point that Grizzly does not currently provide in available product documentation. Pricing is comparable between the two. The choice often comes down to availability and whether the buyer values published velocity data — Buffalo Bore provides it, while Grizzly’s listing does not. Neither load is clearly superior without independent velocity testing under matched conditions.
Can this ammunition be used in a .45-70 lever-action for bear defense in addition to hunting?
The 300 grain JHP at +P pressure is a credible bear defense option when carried in a strong-action lever-action rifle such as the Marlin 1895. The combination of bullet diameter, weight, and elevated velocity produces substantial energy and a large wound channel. That said, many bear defense specialists prefer hard cast flat-nose or bonded bullets over hollow points for maximum straight-line penetration through heavy muscle and bone — a hollow point may expand prematurely on surface tissue before reaching vital organs in a large bear. For dual-purpose hunting and defense use, this load is a reasonable compromise, but dedicated dangerous game loads with deeper penetration designs may offer a meaningful edge in a worst-case encounter.
