AR-10 Magazines
Magpul PMAG LR/SR GEN M3 • SR-25 Pattern • 7.62×51 NATO / .308 Winchester • 20 – 50 Round
Keep Shooting carries the Magpul PMAG LR/SR GEN M3 family for 7.62×51 NATO / .308 Winchester AR-10 pattern rifles — Eugene Stoner's 1956 ArmaLite design that preceded the AR-15 and returned to widespread civilian use through the Knight's Armament SR-25, DPMS LR-308, and Armalite AR-10A platforms. The PMAG 20 LR/SR GEN M3 is the flagship 20-round SR-25 pattern magazine; the 25-round windowed GEN M3 adds visual round count; and the D-50 drum delivers 50 rounds of 7.62×51 for range-day and defensive applications. All four SKUs are SR-25 pattern — compatible with SR-25, M110, KAC LMT, and licensed SR-25-pattern rifles.
About AR-10 Magazines at Keep Shooting
Keep Shooting carries four Magpul PMAG AR-10 magazines covering the SR-25 pattern 7.62×51 NATO / .308 Winchester battle-rifle platform. The PMAG 20 LR/SR GEN M3 ($23.07) is the flagship 20-round magazine — standard capacity for SR-25, M110, and licensed AR-10-pattern DMR and battle-rifle platforms. The PMAG 25 LR/SR GEN M3 Window ($25.09) adds 5 rounds of capacity plus a translucent window for visual round count. The PMAG D-50 7.62×51 Drum ($157.53) delivers 50 rounds of 7.62 NATO from a drum magazine architecturally similar to Magpul's better-known D-60 for AR-15 / 5.56 NATO. (A 25-round standard PMAG for SR-25 is currently out of stock.) All four are SR-25 pattern magazines — if your AR-10 uses the DPMS LR-308 or SR-25 feed-lip geometry, these magazines will fit your rifle.
The AR-10 is Eugene Stoner's 1956 ArmaLite design — the 7.62×51 NATO battle rifle that actually preceded the AR-15 and introduced the direct-impingement gas system, aluminum receiver, and straight-line stock geometry that would define the Stoner family for the next 70 years. ArmaLite manufactured the rifle in limited numbers between 1956 and 1960 but lost the 1957 US Army rifle trials to the Springfield M14, after which Stoner's design was scaled down to 5.56mm as the AR-15 / M16. The AR-10 remained a niche rifle until the 1990s, when Knight's Armament Company resurrected the platform as the SR-25 for US Special Operations Command precision-rifle contracts, and DPMS Panther Arms launched the LR-308 commercial line. Since the mid-2000s the AR-10 platform has become the dominant American semi-auto 7.62 NATO architecture, powering the US Army's M110 SASS, the Marine Corps' M110A1 CSASS, the Navy's Mk 11 Mod 0, and commercial hunting and precision-rifle rifles from 15+ manufacturers.
AR-10 magazine pattern compatibility is the critical purchasing decision in this category and the source of the most customer confusion. Unlike the AR-15 world — where the STANAG 4179 specification standardized magazine dimensions across manufacturers in the 1980s — the AR-10 world has two dominant and mutually incompatible magazine patterns: the SR-25 / KAC / Knight's Armament pattern (also used by DPMS GII, Rock River Arms LAR-8, LMT MWS, Armalite AR-10A, SIG 716i, and many modern AR-10-pattern rifles) and the legacy DPMS LR-308 pattern (used by the classic DPMS LR-308, Panther Arms first-generation, Bushmaster ACR, and older AR-10 clones). Magpul's PMAG LR/SR GEN M3 family is SR-25 pattern, matching the modern commercial and military standard. Before ordering any of these magazines, verify your rifle's magazine pattern — your rifle's manual or manufacturer specification will identify whether it's SR-25 or DPMS pattern.
The Magpul PMAG 20 LR/SR GEN M3 is the flagship product in this category and the magazine that effectively set the modern commercial AR-10 magazine standard. Introduced in the early 2010s and refined across three Magpul "GEN" revisions, the GEN M3 revision improved magazine-well fit tolerance across the full range of commercial SR-25-pattern rifles. The 20-round capacity is the traditional battle-rifle standard — the capacity used by the US military across the M14 / M1A (7.62 NATO), FN SCAR-17 (see our SCAR-17 Magazines category for comparison), and M110 SASS / M110A1 CSASS. The polymer body is Magpul's standard high-impact polymer, matched to anti-tilt follower and stainless-steel spring construction.
The Magpul PMAG 25 LR/SR GEN M3 Window is the intermediate-capacity option — 5 rounds over the standard 20 plus Magpul's translucent window strip on each side of the body for visual round count without disassembling the magazine. The window feature originated in the AR-15 PMAG GEN M3 window variants (see our AR-15 Magazines category for window-variant AR-15 options) and migrated to the AR-10 line in the GEN M3 generation. The 25-round capacity is particularly popular among competitive shooters where the extra five rounds reduce magazine-change frequency during stages, and among DMR / precision- rifle shooters who want modest capacity upgrade without going to full drum-magazine territory.
The Magpul PMAG D-50 7.62×51 Drum is the highest-capacity 7.62 NATO magazine in commercial production, delivering 50 rounds from a single drum. The D-50 shares its design heritage with Magpul's better-known D-60 drum for AR-15 / 5.56 NATO but is scaled up for the larger 7.62 NATO cartridge. 50 rounds of 7.62 is a significant capacity — more than twice the standard battle-rifle 20-round magazine — and the drum fills a specific niche: suppressive fire applications in .308, defensive preparations where magazine-change frequency is a critical reliability concern, and range-day applications where reloading less is the primary goal. At $157.53 the D-50 is a premium purchase relative to standard 20 or 25-round magazines, but the capacity-per-reload ratio makes it worthwhile for the right user. Weight and length considerations are meaningful — a loaded D-50 drum adds roughly 5 pounds to rifle weight and sits considerably below the magazine well, which affects prone-position shooting and long-range rest-based positions.
Magpul PMAG construction across the entire LR/SR GEN M3 family uses the same core material standards: high-impact polymer body (Magpul's proprietary polymer blend), stainless-steel spring, anti-tilt follower (the self-leveling follower that prevents the nose-down follower position that causes feeding failures), and paint-pen round indicator windows (on the non-windowed 20-round variant — small witness holes allowing round-count verification). The GEN M3 iteration specifically addresses magazine-well fit across the full range of SR-25-pattern commercial rifles; earlier GEN M1 and GEN M2 variants had known fit issues with certain specific rifle manufacturers, which GEN M3 resolves.
Comparison to alternative 7.62 NATO semi-auto rifle magazine platforms provides useful context for AR-10 shooters. The M14 Magazines category covers the Springfield Armory M14 / M1A (Eugene Stoner's 1957 competitor for the same US Army contract the AR-10 lost) — an internal-magazine rotating-bolt design that takes a fundamentally different 20-round 7.62 magazine with a steel body and different feed-lip geometry. The FN SCAR-17 Magazines category covers FN's 2000s-era 7.62 NATO battle rifle (adopted by US Special Operations Command as the Mk 17) which uses a proprietary non-STANAG polymer magazine. AR-10, M14, and SCAR-17 magazines are all completely mutually incompatible — three separate 7.62 NATO magazine ecosystems. For 5.56 NATO compatibility comparison, see the AR-15 Magazines category where Magpul's 5.56 PMAG GEN M2 and GEN M3 lines dominate the commercial AR-15 magazine market.
Magpul itself — founded in Boulder, Colorado in 1999 and relocated to Austin, Texas in 2014 after Colorado's high-capacity-magazine legislation — is one of the most commercially significant American firearm accessory manufacturers of the last 25 years. The PMAG product line is Magpul's flagship category, with aggregate production across all variants in the tens of millions of units. The LR/SR GEN M3 variants represent Magpul's 7.62 NATO product line — a smaller subset of the overall PMAG production but effectively the commercial standard for SR-25-pattern rifles.
For loading and unloading AR-10 magazines efficiently, the standard Maglula AR-15 LULA does NOT work — the 7.62 NATO cartridge and SR-25 magazine feed-lip geometry are both dimensionally different from STANAG AR-15 magazines. Maglula produces a dedicated 7.62 NATO LULA for AR-10 / SR-25 / LR-308 magazines, though Keep Shooting does not currently stock it — see the Maglula brand page for the AR-15 and other rifle LULA variants we do stock. Manual thumb-loading of 20-round and 25-round AR-10 magazines is entirely practical for the casual range shooter; competition and training shooters running high round counts will want a dedicated 7.62 NATO loader tool.
Keep Shooting ships all AR-10 magazines from our Pennsylvania warehouse with free shipping on orders over $49.95 and hassle-free returns. High-capacity magazine restrictions apply in California, Colorado, Connecticut, Hawaii, Illinois, Maryland, Massachusetts, New Jersey, New York, Oregon, Vermont, Washington, and the District of Columbia — the 20 and 25-round PMAG and especially the 50-round D-50 drum fall under magazine-capacity limits in those jurisdictions. We automatically filter shipping to compliance- restricted states. Whether you're a SR-25-pattern rifle owner needing factory-reliable 20-round battle-rifle magazines, a competitive shooter looking for 25-round capacity with visual round-count indication, or a suppressive-fire enthusiast wanting a 50-round drum, every AR-10 magazine in our catalog is authentic Magpul production and matches the SR-25 commercial standard.
Frequently Asked Questions — AR-10 Mags
Keep Shooting carries a wide selection of AR-10 Mags products from trusted brands. Browse our catalog to see the full range, and use the filters on the left to narrow by brand, price, or product type.
Yes! All orders over $49.95 qualify for free shipping, including AR-10 Mags products. Orders typically ship within 1–2 business days.
Keep Shooting offers hassle-free returns on AR-10 Mags products. If you're not completely satisfied, contact our customer service team for a return authorization. All products must be in original, unused condition.
If you need help choosing the right AR-10 Mags product, our team is available to assist. Check individual product descriptions for detailed specifications, or contact us directly and we'll help you find the best fit for your needs.