The 45-70 Government is one of the most rewarding cartridges you can handload – and one of the easiest to get dangerously wrong if you skip the most important first step. Unlike loading 223 Rem or 308 Win, where any safe load works in any rifle chambered for it, the 45-70 spans a pressure range so wide that a perfectly safe load in one gun could destroy another. This guide walks you through the entire process, from identifying your rifle’s pressure tier to reading your first fired cases at the range.
If you have loaded 38 Special, 357 Magnum, or any straight-wall cartridge before, you already have the mechanical skills. What you need now is the specific knowledge that makes 45-70 different. Let’s get into it.
Know Your Rifle Tier Before You Start
This is the step most online guides bury halfway through the article or skip entirely. Before you open a powder jug, before you even touch a piece of brass, you need to know which pressure tier your rifle falls into. The 45-70 is loaded to three distinct pressure levels depending on the action strength of the firearm, and mixing them up is not a minor mistake – it is a potentially catastrophic one. Ask yourself three questions in order:
- Is your rifle an original or reproduction Trapdoor Springfield (or similar weak-action antique)? If yes, you are in Tier 1 – Trapdoor loads only (around 18,000 PSI max).
- Is your rifle a Marlin 1895, Henry, or similar lever-action with a strong but not modern action? If yes, you are in Tier 2 – Lever-action loads (around 28,000-40,000 PSI max).
- Is your rifle a modern single-shot like a TC Encore, CVA Scout, or Ruger No. 1? If yes, you are in Tier 3 – Modern action loads (up to approximately 55,000 PSI max).
Write your tier on a sticky note and put it on your press. Every recipe, every powder charge, every bullet choice flows from this single decision. Reloading manuals from Hodgdon, Lyman, and others clearly mark which data applies to which platform. If a manual does not specify the tier, do not use that data. Your loading manual is your primary safety reference – always cross-check published data before charging a single case.
Three Proven Starter Loads by Platform
The table below gives you one conservative starting load for each tier. These are well below maximum and designed to get you safely on paper for your first range session. Always verify against your current edition reloading manual before loading.
| Tier | Bullet | Powder | Charge (Start) | Approx. Pressure |
|---|---|---|---|---|
| 1 – Trapdoor | 300gr cast lead FP | Trail Boss | 9.0gr | ~18,000 PSI |
| 2 – Lever-action | 405gr cast or jacketed FP | IMR 4064 | 46.0gr | ~28,000 PSI |
| 3 – Modern single-shot | 300gr jacketed HP | H4198 | 54.0gr | ~40,000 PSI |
These are starting loads, intentionally mild. The Trapdoor load with Trail Boss is soft-shooting and forgiving – perfect for learning the cartridge. The lever-action load with IMR 4064 behind a 405-grain bullet is the classic 45-70 combination and feeds reliably through tubular magazines. The modern single-shot load with H4198 takes advantage of the stronger action but still leaves significant headroom below maximum. Varget is another excellent powder option for Tier 2 loads if you already have it on your bench. Work up from these charges in small increments only after evaluating pressure signs.
Case Prep and Primer Seating Basics
Start by inspecting your brass. If you are using military surplus or once-fired commercial cases, look for cracks at the case mouth, deep scratches on the body, and signs of head separation – a bright ring near the base. Discard anything questionable. Trim cases to 2.100 inches, which gives you a comfortable margin below the 2.105-inch maximum. After trimming, chamfer the inside of the case mouth and deburr the outside. This small step prevents shaving lead or jacket material during bullet seating and ensures a clean, consistent crimp later.
For primers, use a standard Large Rifle Primer. At these starter charge levels, magnum primers are not needed and can actually cause erratic pressure behavior in the large 45-70 case. Seat each primer flush to slightly below flush with the case head. You should feel firm, even resistance as the primer bottoms in the pocket. If primers seat with no resistance at all, that brass has loose primer pockets and should be retired. If you are working with military brass, a primer pocket uniforming tool helps clean up the crimp ring and ensures consistent ignition – a simple upgrade that pays off in shot-to-shot consistency.
Quick Checklist – Case Prep
- Inspect brass for cracks, splits, and head separation signs
- Full-length resize and decap
- Trim to 2.100 inches
- Chamfer inside case mouth
- Deburr outside case mouth
- Uniform primer pockets (especially military brass)
- Seat Large Rifle Primers flush to slightly below flush
- Wipe cases clean before charging
Powder Charges and Bullet Seating Depth
The 45-70 case has a large internal volume, and that changes how you handle powder charging compared to smaller cartridges. On a single-stage press, use a powder measure that throws consistently with extruded (stick) powders like IMR 4064 or H4198. These powders can bridge in smaller measures, so a measure with a larger drum or drop tube helps. Weigh every charge on a scale for your first batch. Once you confirm your measure is throwing consistently within plus or minus 0.1 grains, you can trust it for subsequent rounds – but verify periodically.
Bullet seating depth affects both pressure and function. For lever-action rifles with tubular magazines, overall cartridge length (OAL) must be short enough to cycle through the action – typically around 2.550 inches for a 405-grain flat point, though you should verify with your specific rifle. Seat the bullet, then manually cycle it through the magazine and action before loading a full batch. For single-shot rifles, you have more flexibility with OAL, but stay within published data ranges. A firm roll crimp is mandatory for any 45-70 load destined for a lever-action tubular magazine. Bullets under recoil from other rounds firing can be driven deeper into the case (bullet setback), raising pressure dangerously. The roll crimp also prevents bullets from migrating forward under recoil, which could jam the action. Set your crimp die to turn the case mouth into the bullet’s crimp groove evenly. An under-crimped round will show a case mouth that barely contacts the groove. An over-crimped round will buckle the case below the mouth. Neither is acceptable. Adjust in small increments until you get a firm, even roll with no buckling.
Common Mistakes New 45-70 Loaders Make
Even experienced handloaders stumble on these when they first approach the 45-70. Every one of these mistakes is avoidable with a little attention.
- Ignoring the platform tier. Loading Tier 3 data into a Trapdoor rifle is the single most dangerous mistake in 45-70 reloading. It is not a matter of “a little extra recoil” – it can cause a catastrophic failure.
- Skipping the roll crimp on lever-action loads. Bullet setback in a tube magazine raises pressure unpredictably. Bullet migration forward can lock up the action at the worst possible time.
- Using magnum primers at starter loads. Standard Large Rifle Primers provide plenty of ignition for these charge levels. Magnum primers can spike pressure and introduce inconsistency.
- Not trimming brass to a consistent length. Inconsistent case length means inconsistent crimps, which means inconsistent pressure. Trim every case in the batch to the same length.
- Trusting internet load data without manual verification. Forum posts and social media loads are not peer-reviewed. Always cross-reference with at least one published manual from a powder or bullet manufacturer.
- Loading maximum charges on the first session. Start low, shoot groups, read brass, and work up. The 45-70 has plenty of performance available without pushing limits on day one.
- Failing to read pressure signs on fired brass. Flattened primers, sticky bolt lift or extraction, shiny marks on the case head, or a primer pocket that suddenly feels loose – these are your early warning system. Learn what normal looks like for your specific rifle and tier.
Quick Takeaways
- Identify your rifle tier first – this is not optional, it is the foundation of safe 45-70 loading
- Use published starting loads and work up slowly in 0.5-grain increments
- Standard Large Rifle Primers are correct for starter loads – skip the magnum primers
- Roll crimp every round loaded for a lever-action tubular magazine
- Trim all brass to 2.100 inches for consistent crimps and reliable feeding
- Read your fired brass after every range session, especially when working up charges
- Cross-check every load against at least one current reloading manual
FAQ – Loading Your First 45-70 Round
Can I use the same load in my Marlin that my friend uses in his Ruger No. 1?
No. If your friend is loading Tier 3 data for his Ruger No. 1, those loads may exceed safe pressure limits for your Marlin lever-action. Always load to your rifle’s tier. You can safely shoot Tier 1 loads in any 45-70 rifle, but you cannot shoot Tier 3 loads in a Tier 1 or Tier 2 gun.
Do I need to use cast lead bullets, or can I use jacketed?
Either works. Cast lead bullets are traditional, affordable, and perfectly effective for the 45-70. Jacketed bullets are also widely available and tend to be easier for beginners to seat consistently. For lever-action rifles, use flat-point or flat-nose bullets only – pointed bullets in a tubular magazine can set off the primer of the round ahead under recoil.
How do I know if my load is showing too much pressure?
Look at your fired cases. Flattened primers (where the firing pin indent is surrounded by a flat, squared-off primer) are an early sign. Sticky extraction – where the lever or bolt requires noticeably more force to open – is a stronger warning. Cratered primers (brass flowing into the firing pin hole) or a primer pocket that feels loose when you try to reprime the case means you are over pressure. Stop shooting that load immediately and reduce the charge.
Is Trail Boss only for Trapdoor loads?
Trail Boss is popular for Trapdoor-level loads because it is a bulky powder that fills the large 45-70 case at low charge weights, making it nearly impossible to double-charge. However, it can also be used for reduced-recoil loads in lever-action and modern rifles. It is not a good choice for full-power loads in any tier.
How many times can I reload 45-70 brass?
With moderate loads and proper case inspection, quality 45-70 brass can last 10 or more reloading cycles. Brass life shortens as pressure increases. Inspect for cracks and loose primer pockets every time you reload. When a primer seats with no resistance, retire that case.
Do I need a progressive press for 45-70?
Not at all. A single-stage press is ideal for learning and produces excellent results. The 45-70 is not a high-volume cartridge for most shooters. If you already have a progressive press, it works fine – just pay extra attention to powder charge consistency with the stick powders commonly used in this cartridge.
