Published: 2026 | Last updated: April 2026
IMR 4955 Enduron fills a specific and well-defined gap in the slow-burn-rate rifle powder market. It sits between IMR 4451 Enduron and IMR 7977 Enduron in the Enduron lineup – slower than the medium-slow powders that anchor 6.5 Creedmoor and 308 Winchester applications, and faster than the ultra-slow powders reserved for the largest overbore magnums. In North American hunting and long-range shooting, that position covers some of the most important cartridges in use: 300 Winchester Magnum, 270 Winchester with heavy bullets, 30-06 Springfield with 180-220 grain projectiles, and 7mm Remington Magnum.
What separates IMR 4955 Enduron from older powders at the same burn rate position is the Enduron technology package: a proprietary coating and grain structure that regulates burn rate as temperature changes, keeping muzzle velocity within a predictable window across the full range of field conditions a hunting rifle encounters. That stability is not marketing language – it is a measurable, field-verified property that shows up as consistent point-of-impact from the summer scouting season through late-November mountain conditions where temperatures can swing 70°F between a warm afternoon and a freezing dawn.
The second Enduron feature is the integrated decoppering agent embedded in the propellant chemistry itself. Unlike a surface coating that wears off, the decoppering chemistry is present throughout the powder grain and continues to work throughout the burn cycle, creating combustion byproducts that prevent copper jacket material from bonding to bore steel. For a precision hunting rifle that may go weeks between cleanings in the field, this is a practical benefit that shows up in real-world maintenance rather than just on a specification sheet.
This guide covers the full technical profile, Enduron chemistry explained practically, burn rate positioning, cartridge applications, component pairings, and where IMR 4955 Enduron earns its place – and where other options are more appropriate.
Powder Description and Technical Profile
IMR 4955 Enduron is a single-base, short-cut extruded powder. Both design elements matter in practice.
The single-base formulation – nitrocellulose without nitroglycerin – produces a cooler flame temperature than double-base alternatives like Alliant Reloder 22 or Alliant Reloder 25 at the same burn rate position. In the magnum cartridge context where charge weights run 70-85 grains per load and barrel erosion is an ongoing concern, the cooler burn translates to meaningfully extended barrel life compared to high-energy double-base powders at the same pressure level. For a 300 Winchester Magnum barrel that costs $400-600 to rebarrel, those additional hundreds of rounds of accurate barrel life are tangible value.
The short-cut extruded geometry is the characteristic that distinguishes all Enduron powders from traditional long-stick extruded propellants. Longer sticks bridge in drop tubes, shear at the measure drum edge, and pack inconsistently depending on how quickly the measure handle is cycled. Short-cut grains pack into a measure drum more uniformly, shear less often, and flow through drop tubes without bridging. The practical result is charge-to-charge consistency of ±0.1 grains on a quality volumetric measure – an improvement over long-stick extruded powders that gets the performance of a ball powder’s metering convenience into a single-base extruded propellant.
Bulk density is 0.935-0.945 g/cc – notably high for an extruded powder. That density is part of why IMR 4955 Enduron fills the 300 Winchester Magnum case so efficiently. At working charge weights, the case is typically 95-98% full – a case fill percentage that produces consistent powder column ignition, predictable start pressure, and the tight standard deviations that hunters developing long-range loads spend considerable time chasing.
The graphite and Enduron decoppering agent coating serves two functions: graphite controls static buildup and improves flow through the measure and drop tube; the decoppering agent is the chemically active component that prevents copper fouling accumulation. In extended shooting sessions – whether that is 50 rounds of load development at the bench or the occasional cold-weather group from a hunting rifle – the decoppering chemistry keeps fouling levels low enough that a light patch job maintains accuracy where other powders would require full cleaning before the barrel shoots back to its normal standard.
Strengths:
- World-class temperature stability – measured velocity variance below 0.5 fps per degree Fahrenheit, keeping point-of-impact consistent across the full range of hunting conditions
- Short-cut geometry meters at ±0.1 grains on a quality volumetric measure – performance that approaches ball powder consistency in an extruded single-base propellant
- Integrated decoppering agent embedded in the propellant reduces copper fouling accumulation, extending accuracy intervals between full barrel cleanings
- High bulk density (0.935-0.945 g/cc) fills medium-to-large magnum cases efficiently, producing the 95-98% case fill that supports consistent ignition and low standard deviations
- Single-base chemistry burns cooler than double-base alternatives at the same burn rate, reducing long-term throat erosion in magnum barrels
- Broad cartridge compatibility – covers the most popular big-game hunting and long-range cartridges in the medium-magnum burn rate range without needing separate powders for each
Limitations:
- Extruded geometry still occupies more volume than an equivalent charge of a spherical powder – relevant only in very tight case-fill situations where a ball powder would allow an additional grain of charge
- Magnum primers recommended for the upper charge ranges in large-capacity cases and in cold-weather conditions – not a hard limitation but a component cost consideration
- Temperature stability advantage is less relevant for indoor range work or competition at controlled-temperature venues, where a double-base powder’s velocity ceiling becomes the more relevant variable
- Availability can tighten during market shortages because Enduron powders command dedicated demand from the precision hunting community – maintain a working inventory reserve
Technical Characteristics
| Property | Specification |
|---|---|
| Manufacturer | IMR Powder Company (Hodgdon) |
| Technology | Enduron |
| Type | Short-Cut Extruded |
| Base | Single-Base (Nitrocellulose) |
| Bulk Density (g/cc) | 0.935 – 0.945 |
| Coating | Graphite + Enduron Decoppering Agent |
| Burn Rate Category | Medium-Slow to Slow Rifle |
| Primary Application | Big-Game Hunting and Long-Range Precision |
The Enduron Technology – What It Actually Means
The Enduron line includes IMR 4166 Enduron, IMR 4451 Enduron, IMR 4955 Enduron, IMR 7828 SSC, and IMR 7977 Enduron. Each carries the same core technology applied to a different burn rate position. Understanding what Enduron does – and what it does not do – helps calibrate expectations honestly.
Temperature stability is the headline claim. Most double-base powders show velocity variation of 1.5-2.5 fps per degree Fahrenheit. A load developed in 75°F summer conditions that chronographs 2,950 fps might clock 2,800 fps on a 15°F January morning – a 150 fps swing that, at 500 yards, produces roughly 3-4 inches of additional drop. IMR 4955 Enduron’s measured variance typically runs 0.3-0.5 fps per degree Fahrenheit. That same 60°F temperature drop produces a velocity change of 18-30 fps – drop variation at 500 yards drops to under an inch. For hunters who zero their rifles in autumn and expect that zero to hold through late-season hunts in cold mountain conditions, this is a real-world difference that shows up in field results.
The decoppering agent is the less-discussed Enduron feature and arguably the more practical one for hunters. Copper jacket fouling in a barrel is a progressive problem – it accumulates shot-by-shot, builds pressure points in the bore that cause accuracy degradation, and requires aggressive chemical solvents or extended patch-and-wait sessions to fully remove. A barrel loaded with IMR 4955 Enduron accumulates copper fouling far more slowly because the combustion chemistry actively prevents copper from bonding to bore steel rather than simply burning cooler. For a hunting rifle that sees field use over days or weeks without access to a cleaning bench, this is not trivial.
What Enduron does not do is eliminate all temperature sensitivity, prevent all copper fouling, or match the peak velocity ceiling of high-energy double-base powders. The stability advantage is real but finite. The decoppering benefit extends cleaning intervals rather than eliminating the need for cleaning. And at comparable pressure levels, a double-base powder like Alliant Reloder 22 or Alliant Reloder 23 will produce 40-80 fps more velocity in the same cartridge. These are known, accepted trade-offs for choosing the Enduron system.
Temperature Stability Comparison
| Powder | Stability | Approx. Velocity Variance | Type |
|---|---|---|---|
| IMR 4955 Enduron | World-Class Stable | 0.3 – 0.5 fps / °F | Single-Base Extruded |
| Hodgdon H4831 | Extreme Stable | 0.2 – 0.4 fps / °F | Single-Base Extruded |
| Alliant Reloder 23 | Stable | 0.4 – 0.7 fps / °F | Double-Base Extruded |
| Alliant Reloder 22 | Moderate | 0.8 – 1.2 fps / °F | Double-Base Extruded |
| IMR 4831 | Sensitive | 1.8 – 2.4 fps / °F | Single-Base Extruded |
The comparison with Hodgdon H4831 is worth noting. H4831 belongs to the Hodgdon Extreme series and carries its own excellent temperature stability credentials. The two powders are genuinely close in this metric – IMR 4955 Enduron’s advantage over H4831 is primarily the decoppering chemistry and the short-cut metering improvement, not a dramatic gap in thermal stability. Both are among the best-behaved powders in this burn rate range across temperature extremes.
Burn Rate Comparison and Competing Powders
| Powder | Burn Rate | Density (g/cc) | Key Character |
|---|---|---|---|
| IMR 4451 Enduron | Faster | 0.920 | Enduron – 6.5 Creedmoor, 308 Win |
| Hodgdon H4831 | Slightly Faster | 0.860 | Extreme stable, classic magnum range |
| Hodgdon H4831SC | Slightly Faster | 0.875 | H4831 with better metering |
| IMR 4955 Enduron | Reference | 0.940 | Enduron – 300 Win Mag, 270 Win heavy |
| IMR 4831 | Similar | 0.870 | Traditional – broad data library |
| Alliant Reloder 22 | Slightly Slower | 0.860 | Double-base – higher velocity |
| Alliant Reloder 23 | Slightly Slower | 0.890 | Double-base temp-stable hybrid |
| IMR 7977 Enduron | Slower | 0.910 | Enduron – 7mm Rem Mag, 300 PRC |
| Hodgdon H1000 | Slower | 0.880 | Extreme stable, large magnum staple |
| Ramshot Hunter | Slightly Slower | 0.970 | Ball powder, excellent metering |
vs. Hodgdon H4831SC: H4831SC is the short-cut version of H4831 and the most direct non-Enduron comparison. Both powders are single-base, temperature-stable extruded powders in the same burn rate range, and both are appropriate for 300 Winchester Magnum and 270 Winchester with heavy bullets. IMR 4955 Enduron has a density advantage (0.940 vs 0.875 g/cc) that gives it better case fill in large-capacity magnum cases, and the decoppering chemistry is unique to Enduron. H4831SC has the deeper North American data library and Hodgdon Extreme series stability credentials. Neither is categorically superior – the choice comes down to whether the Enduron decoppering benefit justifies the premium.
vs. Alliant Reloder 22: Reloder 22 is double-base and burns with higher energy per gram, producing 40-70 fps more velocity in 300 Winchester Magnum and 7mm Remington Magnum at comparable pressures. That velocity advantage is real and documented. The trade-offs are greater temperature sensitivity (roughly 0.8-1.2 fps/°F) and faster throat erosion from the higher flame temperature. For a hunter who reloads one or two batches of hunting ammunition per year and shoots a single rifle over a long-term hunting program, IMR 4955 Enduron is the more conservative and consistent choice. For a competition shooter who replaces barrels on a schedule and wants maximum velocity, Reloder 22 has the edge.
vs. Alliant Reloder 23: Reloder 23 closes the temperature stability gap between double-base and single-base powders considerably – it is a temperature-stabilized double-base powder that produces less velocity variation across seasons than conventional double-base alternatives while still providing a velocity advantage over single-base powders. For the hunter who wants maximum velocity with acceptable seasonal stability, Reloder 23 occupies an interesting middle position. IMR 4955 Enduron remains the better choice where long-term barrel life and the decoppering benefit are priorities.
vs. Ramshot Hunter: Ramshot Hunter is a double-base spherical powder at a comparable burn rate with the highest density in the class (0.970 g/cc). Its ball powder metering advantage is real and significant for progressive press loading at volume. The decoppering benefit and single-base barrel life advantage of IMR 4955 Enduron do not apply. For a hunter who loads 270 Winchester or 300 Winchester Magnum at moderate volume on a progressive press where metering speed matters, Ramshot Hunter deserves consideration. For single-stage precision loading where every charge is weighed, IMR 4955 Enduron’s short-cut geometry already narrows the metering gap substantially.
Recommended Cartridges and Applications
IMR 4955 Enduron is positioned for medium-to-large capacity cartridges loaded with standard to heavy-for-caliber bullets – the cartridges that define western big-game hunting and extreme long-range shooting in North America.
| Cartridge | Bullet Weight Range | Application |
|---|---|---|
| 300 Winchester Magnum | 180-220 gr | Elk, moose, long-range precision |
| 270 Winchester | 140-160 gr | Heavy bullet deer and elk |
| 30-06 Springfield | 180-220 gr | Heavy bullet hunting and precision |
| 7mm Remington Magnum | 154-175 gr | Mountain hunting, long-range |
| 25-06 Remington | 117-120 gr | Long-range deer and varmint |
| 270 WSM | 140-160 gr | Short magnum heavy bullet |
| 300 WSM | 180-200 gr | Heavy bullet short-action magnum |
| 6.5 PRC | 143-156 gr | Precision hunting long range |
The 300 Winchester Magnum application is the showcase cartridge for IMR 4955 Enduron. The case capacity and pressure ceiling of the 300 Win Mag with 180-210 grain bullets sit precisely in the burn rate window where this powder operates most efficiently. At working charge weights, case fill runs 95-98% – the sweet spot that produces consistent ignition, low standard deviations, and the tight extreme spreads that translate to predictable trajectories at 600-1,000 yards. For late-season elk hunts where a temperature swing from 60°F at midday to 10°F at dawn is entirely normal, the Enduron stability keeps the point-of-impact constant without requiring separate load development for cold conditions.
For 270 Winchester reloaders who push past the standard 130-140 grain bullet weights into the 150-160 grain heavy-for-caliber range, IMR 4955 Enduron is worth evaluating. The burn rate is slightly slow for standard 130-grain 270 Winchester loads where H4831 or H4831SC are better matched. With 150-160 grain bullets, the effective powder space decreases and 4955’s burn rate becomes appropriate.
For 30-06 Springfield with 200-220 grain bullets – a genuine niche application for long-range hunting and deep-penetration dangerous game loads – IMR 4955 Enduron fills a role that medium-fast powders like Hodgdon Varget cannot handle. Very heavy 30-caliber bullets in the 30-06 case need a slow powder to reach working pressure without spiking too fast. This is the application where the powder’s density advantage (0.940 g/cc) pays off most clearly – the case fills well at appropriate charge weights without reaching dangerously compressed territory.
Bullets
IMR 4955 Enduron delivers best results with premium hunting bullets and high-BC match projectiles in the 150-220 grain range across its primary calibers. The sustained, progressive pressure curve benefits bullets with substantial bearing surface – longer, heavier projectiles that need a sustained push rather than a fast-spiking pressure spike.
| Brand | Model | Weight | Cartridge | Application |
|---|---|---|---|---|
| Hornady | ELD-X | 178-212 gr | 300 Win Mag / 30-06 | Long-Range Hunting |
| Hornady | ELD-M | 195 gr | 300 Win Mag | Long-Range Match |
| Hornady | InterBond | 150-180 gr | 270 Win / 300 Win Mag | Bonded Hunting |
| Nosler | AccuBond | 150-210 gr | 270 Win / 300 Win Mag / 30-06 | Bonded Long-Range |
| Nosler | Partition | 150-200 gr | 270 Win / 300 Win Mag / 30-06 | Classic Big Game |
| Berger | Hybrid Target | 168-215 gr | 300 Win Mag / 7mm Rem Mag | ELR Competition |
| Berger | Elite Hunter | 168-195 gr | 300 Win Mag / 30-06 | Precision Hunting |
| Berger | LRHT | 180-210 gr | 300 Win Mag | Extreme Long Range |
| Sierra | MatchKing | 175-220 gr | 300 Win Mag / 30-06 | Competition |
| Sierra | GameKing | 150-180 gr | 270 Win / 300 Win Mag | Hunting |
| Sierra | Tipped MatchKing | 175-200 gr | 300 Win Mag | Long-Range Match |
| Barnes | LRX | 145-180 gr | 270 Win / 300 Win Mag | Lead-Free Long Range |
| Barnes | TTSX | 150-180 gr | 300 Win Mag / 30-06 | Lead-Free Hunting |
| Federal | Trophy Bonded | 165-200 gr | 300 Win Mag / 30-06 | Premium Hunting |
One load development note worth stating explicitly: IMR 4955 Enduron typically achieves its best standard deviation numbers at 95-98% case fill. If your velocity spreads are wider than expected during early load development, try a slightly heavier bullet before adjusting the charge weight down – the increased bullet bearing surface raises start pressure, which helps stabilize the powder’s progressive burn and tighten the velocity spread. This is counterintuitive for reloaders accustomed to working down from maximum charge, but it reflects how high-density powders in large cases behave at the lower end of the pressure curve.
Primers
IMR 4955 Enduron in standard-capacity cartridges like 270 Winchester and 30-06 Springfield works reliably with standard large rifle primers at normal temperatures. For 300 Winchester Magnum, 7mm Remington Magnum, and the WSM cartridges – particularly with maximum charges or in cold-weather conditions below 20°F – a magnum large rifle primer is recommended to ensure complete ignition of the dense powder column.
| Primer | Type | Application |
|---|---|---|
| Federal GM210M | Large Rifle Match | Competition loads, minimum SD |
| CCI BR-2 | Large Rifle Benchrest | Absolute lowest extreme spread |
| CCI 200 | Large Rifle Standard | 270 Win and 30-06 general development |
| Federal 210 | Large Rifle Standard | Reliable general-purpose option |
| Winchester WLR | Large Rifle Standard | Hunting loads, general use |
| Remington 9-1/2 | Large Rifle Standard | Standard precision development |
| CCI 250 | Large Rifle Magnum | 300 Win Mag, cold-weather loads |
| Winchester WLRM | Large Rifle Magnum | Dense magnum charges |
| Federal 215 | Large Rifle Magnum | Maximum ignition in large cases |
| Remington 9-1/2M | Large Rifle Magnum | Magnum hunting loads |
| Fiocchi Large Rifle Magnum | Large Rifle Magnum | Consistent alternative |
| RWS 5337 | Large Rifle Magnum | Premium European option |
For 300 Winchester Magnum competition loading where standard deviation is the primary metric, the Federal GM210M and CCI BR-2 are the most commonly paired primers with Enduron powders in large-capacity cases. The tight brisance tolerances of benchrest-grade primers complement the consistency that the Enduron temperature stabilization delivers.
As always, when changing primer type from published data – particularly stepping up from standard to magnum – reduce the starting charge by at least 5% and work back up independently. Magnum primers deliver more energy into the powder column and can push an otherwise-safe load into elevated pressure territory.
Metering and Equipment Compatibility
The short-cut geometry of IMR 4955 Enduron delivers the primary practical benefit at the loading bench: consistent metering without the bridging and grain-shearing problems that make traditional long-stick extruded powders frustrating to work with at volume. On a quality volumetric measure, ±0.1 grain charge-to-charge variance is achievable and typical.
Measures that handle IMR 4955 Enduron particularly well include the Redding Match Grade 3BR, Forster Bench Rest Powder Measure, and the Hornady Lock-N-Load Bench Rest Powder Measure. All three meters accommodate the short-cut grain geometry effectively and deliver consistent throws at the large charge weights typical of 300 Winchester Magnum and 7mm Remington Magnum loading.
For maximum charge precision in competition-grade ammunition, auto-dispensers outperform volumetric measures by weighing each charge rather than relying on volumetric consistency. The RCBS MatchMaster Digital Powder Scale and Dispenser, RCBS ChargeMaster Supreme, and Hornady Auto-Charge Pro all handle IMR 4955 Enduron reliably. The short-cut grain geometry flows through trickler mechanisms without bridging, reducing per-charge dispense time compared to long-stick powders.
For single-stage precision reloading on a Forster Co-Ax, Redding Big Boss II, or RCBS Rock Chucker Supreme, the manual throw-and-trickle approach using a Frankford Arsenal Powder Trickler with a Hornady Precision Lab Digital Powder Scale or Lyman Gen 6 Compact gives charge-to-charge precision of 0.02 grains – the level appropriate for precision hunting and long-range competition loads where the Enduron stability advantage is most relevant.
Reloading Safety Notes
Large magnum charges with slow powders require disciplined pressure management. Pressure in cartridges like 300 Winchester Magnum can rise steeply in the final few tenths of a grain near maximum. The high bulk density of IMR 4955 Enduron (0.940 g/cc) means that approaching 100% case fill happens relatively quickly as charge weight increases – which is an asset for velocity and consistency, but requires attention as you approach maximum load data.
All charge weights must come from current published IMR/Hodgdon load data for IMR 4955 Enduron specifically. IMR and Hodgdon publish free load data online. Do not substitute H4831, H4831SC, IMR 4831, or Reloder 22 charge weights for 4955 Enduron without verification. Burn rate proximity does not guarantee identical charge weight safety margins, and the density difference between powders affects how quickly case fill approaches maximum.
Start 10% below the listed maximum and work up in 0.3-grain increments. At each step, watch for pressure signs: flattened or cratered primers, stiff bolt lift, ejector marks on case heads, case body swelling ahead of the web. In magnum cartridges, stiff bolt lift is often the earliest reliable pressure indicator – do not dismiss it.
For a systematic approach to pressure sign identification and safe load development protocol, see the guide to overpressure in reloading.
For context on why single-base chemistry matters for long-term barrel maintenance in magnum applications, see the single-base vs. double-base powder overview.
FAQ
How does IMR 4955 Enduron compare to H4831SC in 300 Winchester Magnum?
Both are single-base extruded powders with excellent temperature stability and documented 300 Win Mag performance. IMR 4955 Enduron has a higher bulk density (0.940 vs 0.875 g/cc), which provides better case fill in the 300 Win Mag case, and carries the Enduron decoppering chemistry that H4831SC does not. H4831SC has a deeper North American data library and is part of the Hodgdon Extreme series. Both are legitimate choices – develop each from its own published data.
Do I need a magnum primer for all IMR 4955 Enduron loads?
Not necessarily. In standard-capacity cartridges like 270 Winchester and 30-06 Springfield at normal temperatures, a standard large rifle primer like the CCI 200 or Federal 210 works reliably. In large-capacity magnum cases like 300 Winchester Magnum and 7mm Remington Magnum, particularly at or near maximum charges or in cold weather below 20°F, a magnum primer like the CCI 250 or Federal 215 ensures complete ignition.
What makes the Enduron decoppering agent different from using a bore cleaner afterward?
The Enduron decoppering agent works during combustion by creating chemical byproducts that prevent copper jacket material from bonding to bore steel in the first place. A bore cleaner removes copper that has already bonded. The Enduron approach means less copper bonds to the bore per shot, which extends the accuracy life between cleanings rather than simply making cleaning easier after the fact.
Can IMR 4955 Enduron be used in 6.5 PRC?
Yes, with appropriate bullet weights in the 143-156 grain range. The 6.5 PRC has more case capacity than 6.5 Creedmoor and benefits from a slower powder than the H4350-class propellants that anchor Creedmoor loading. IMR 4955 Enduron falls in a useful range for the PRC with heavy 6.5mm bullets. Verify against IMR/Hodgdon published data for this specific application.
Is IMR 4955 Enduron suitable for 270 Winchester with standard 130-grain bullets?
The burn rate is slightly slow for 270 Winchester with standard 130-grain bullets, where H4831 or H4831SC are better matched. IMR 4955 Enduron becomes more appropriate in 270 Winchester with 140-160 grain heavy-for-caliber bullets where the reduced effective powder space shifts the optimal burn rate toward slower. Verify against published data for the specific bullet weight you are loading.
Conclusion
IMR 4955 Enduron earns its place in the precision hunting powder lineup by addressing the two most common complaints western big-game hunters have about traditional magnum powders: velocity shifting with temperature, and copper fouling accumulating between hunting sessions. The Enduron chemistry solves both problems in a single-base extruded package that meters better than any long-stick extruded powder has a right to, and produces the case fill and pressure behavior that 300 Winchester Magnum and 7mm Remington Magnum loads need to shoot consistently at extended range.
It is not the maximum-velocity option in its burn rate class – double-base powders like Reloder 22 and Reloder 25 hold that ground, at the cost of seasonal consistency and barrel life. For hunters whose rifle doubles as a precision instrument across varying field conditions and must perform reliably from first light on a cold morning to midday heat, the trade is worth making.
Choose IMR 4955 Enduron if you load 300 Winchester Magnum, 270 Winchester with heavy bullets, or 7mm Remington Magnum for hunting in variable temperature conditions and want the Enduron stability and decoppering benefit. Choose Hodgdon H4831SC if North American availability and the deepest data library in this burn rate range are the priority. Choose Alliant Reloder 22 if peak velocity is the goal and you accept the seasonal variation and erosion trade-off. Choose Alliant Reloder 23 if you want double-base energy density with improved temperature stability over conventional double-base options.
Editorial note: Originally published 2026, revised April 2026. The revision expanded the powder description with detailed Enduron chemistry context, added a dedicated section on what Enduron does and does not deliver, rewrote the comparison section with specific guidance for each competitor, added the 95-98% case fill load development note, extended the bullet table with application guidance, added the primers table with full internal links, and added a reloading safety section with magnum-specific pressure guidance.
