Magpul PMAG +5 Magazine Extension: Complete Buyer's Guide for 3-Gun & Competition Rifle
If you're running a Magpul PMAG in competition or at the range, you've probably done the maths: five extra rounds per magazine means fewer reloads per stage, fewer transitions under pressure, and more time focused on targets instead of fumbling for a fresh mag. That's exactly what the Boss Components PMAG +5 Magazine Extension delivers — available in both .223/5.56 NATO and .308/7.62 NATO variants.
This guide covers everything you need to know before buying: full specs, real competitor pricing, compatibility, division compliance, installation, and what else to pair with your extension. If you're here to decide whether it's worth it — short answer: yes. Here's the long answer.
What Does a PMAG Magazine Extension Actually Do?
A magazine extension (also called an extended base pad) replaces the factory floor plate on your Magpul PMAG, adding physical length to the magazine body and increasing round capacity. The Boss Components extensions add exactly 5 rounds — turning a standard 30-round .223 PMAG into a 35-rounder, or a 20-round .308 PMAG into a 25-rounder.
Beyond capacity, the added weight at the base of the magazine serves a practical purpose: it helps empty magazines drop free from the magwell faster and more reliably during reloads. In 3-Gun and multi-gun competition, where rifle stages often demand 30+ rounds, that combination of extra capacity and faster mag changes is a genuine competitive advantage.
Boss Components .223 PMAG +5 Extension — Full Specs
The .223 PMAG +5 Extension is designed for Magpul PMAG Gen M2 and Gen M3 magazines in .223 Remington / 5.56 NATO.
| Specification | Detail |
|---|---|
| Capacity Increase | +5 rounds (30 → 35) |
| Calibre | .223 Remington / 5.56 NATO |
| Material | High-impact polymer |
| Weight | 65 g |
| Compatibility | Magpul PMAG Gen M2 & Gen M3 |
| Colours | Black, Blue, Red, Gold Plated |
| Price (Single) | $59.99 AUD |
| Price (3-Pack) | $149.99 AUD ($50.00/unit) |
The .223 variant uses a durable high-impact polymer construction, keeping weight minimal while maintaining structural integrity through hundreds of magazine drops and thousands of rounds. It works with the factory PMAG spring — no aftermarket springs needed.
Boss Components .308 PMAG +5 Extension — Full Specs
The .308 PMAG +5 Extension steps up to CNC-machined aluminium construction, designed for the heavier demands of .308 Winchester / 7.62 NATO.
| Specification | Detail |
|---|---|
| Capacity Increase | +5 rounds (20 → 25) |
| Calibre | .308 Winchester / 7.62 NATO |
| Material | CNC-machined aluminium, anodised finish |
| Weight | 109 g |
| Compatibility | Magpul PMAG Gen III (.308) only |
| Retention | Grub screw with Allen key (included) |
| Features | Knurled base, side serrations |
| Colours | Black, Blue, Red, Gold Plated |
| Price (Single) | $64.99 AUD |
| Price (3-Pack) | $164.99 AUD ($55.00/unit) |
Key difference from the .223 variant: the .308 extension uses CNC aluminium with an anodised finish for extra durability under the heavier recoil of .308 cartridges. The knurled base and side serrations provide positive grip for magazine changes with wet or gloved hands — a real advantage during winter matches or long training days. The grub screw retention system keeps the extension locked to the magazine body; apply a drop of medium-strength threadlocker (blue Loctite 243) for permanent installation under sustained recoil.
Competitor Comparison: How Boss Components Stacks Up
Here's how the Boss Components PMAG extensions compare against other options available to Australian shooters. All prices in AUD.
| Brand | Price (AUD) | Material | Colours | Ships from AU? |
|---|---|---|---|---|
| Boss Components (.223) | $59.99 | High-impact polymer | 4 | Yes |
| Boss Components (.308) | $64.99 | CNC aluminium | 4 | Yes |
| Digger Tactical | $39–$49 | Carbon fibre polymer | 1 (Black) | Yes |
| Taran Tactical (TTI) | ~$68–$75* | CNC aluminium | 11 | No (import) |
| 365+ Tactical | ~$55–$65* | Aluminium | 1 (Black) | No (import) |
*Estimated AUD including shipping. TTI and 365+ prices based on USD conversion plus typical international freight. Final cost varies with exchange rates and customs.
The takeaway: Digger Tactical offers the lowest entry price in a single colour. TTI is the premium brand with the widest colour range but requires importing from the US, adding cost and wait times. Boss Components sits in the sweet spot — competitive pricing, four colour options, CNC aluminium construction on the .308 variant, and ships from Australia with no import delays or surprise customs charges. The 3-pack pricing ($50–$55 per unit) brings the per-unit cost below most competitors.
Compatibility: Which PMAGs Work?
Getting the right fit matters. Here's the breakdown:
.223/5.56 Extension: Fits both Magpul PMAG Gen M2 and Gen M3 magazines. This covers the vast majority of PMAGs in circulation. If your PMAG has a dust cover and is chambered in .223/5.56, it almost certainly fits.
.308/7.62 Extension: Fits Magpul PMAG Gen III (Series III) only. Does not fit Gen II .308 PMAGs or non-Magpul .308 magazines. The Gen III uses a different base plate geometry, so check your magazine generation before ordering.
How to identify your PMAG generation: Look at the base plate and the side of the magazine body. Gen M3 PMAGs have "M3" moulded into the body, a dot matrix identification panel, and a slimmer profile than Gen M2. Gen III .308 PMAGs are marked "GEN M3" on the body.
Competition Division Compliance
Magazine extensions are legal in most competition formats, but the rules vary. Here's what you need to know for Australian shooters:
3-Gun / Multi-Gun: Extended magazine base pads are legal in virtually all 3-Gun divisions, including Tactical and Open. Most 3-Gun matches in Australia don't impose rifle magazine capacity limits beyond what your state permits. This is the primary competition use case for these extensions.
IPSC Rifle: In Australia, IPSC rifle divisions are currently restricted to manual action categories — Manual Action Open (MAO), Manual Action Standard (MAS), and Manual Action Lever Release (MALR). Semi-automatic rifle divisions (SAO, SAS) are not available in Australia. For manual action divisions, extended base pads are generally legal, but always check your specific match rules and state regulations.
State Regulations: Magazine capacity laws vary by Australian state and territory. Some states restrict magazine capacity regardless of competition use. Always verify your state's regulations and your club's rules before competing with extended magazines. When in doubt, contact your state shooting body or match director.
For a broader overview of division equipment rules, see our IPSC Divisions Equipment Guide.
Installation: Under 5 Minutes Per Magazine
Both the .223 and .308 extensions are designed as drop-in replacements for the factory base plate. No permanent modifications, no aftermarket springs, no special tools required.
Step 1: Ensure the magazine is unloaded and the firearm is clear. Safety first — always.
Step 2: Remove the factory floor plate. On Gen M3 PMAGs, press the retention tab at the base and slide the floor plate off. On Gen M2, depress the base plate lock and slide forward.
Step 3 (.223): Slide the Boss Components extension into place using the same retention method as the factory plate. It clicks in and you're done.
Step 3 (.308): Slide the extension onto the magazine body and secure with the included grub screw using the provided Allen key. Apply a drop of blue Loctite 243 to the grub screw threads for permanent retention under heavy recoil.
Step 4: Load the magazine fully (35 rounds for .223, 25 rounds for .308) and function-test. Ensure rounds feed reliably and the magazine seats properly in your rifle's magwell.
Pro tip: If you're kitting out multiple magazines for match day, the 3-pack is the way to go — better per-unit pricing and you'll want at least three extended mags for a typical rifle stage.
What Else Should You Buy With It?
If you're upgrading your rifle magazines, you're probably optimising your entire rifle setup. Here are the most common companion products:
For .223 shooters: The .223 Muzzle Brake (1/2x28 TPI) reduces felt recoil by 40–60%, keeping you on target for faster follow-up shots between magazine changes. Pair it with a Competition Scope Throw Lever for rapid magnification adjustments on transition-heavy stages.
For .308 shooters: The .308 Muzzle Brake (5/8x24 TPI) is essential for managing the substantially heavier recoil of .308 platforms. If your muzzle is threaded in a different pitch, the Muzzle Brake Thread Adapter converts between 1/2x28 and 5/8x24.
Range essentials: A Brass Catcher Bag keeps your fired cases together for reloading, and Chamber Safety Flags (4-pack) are required at most Australian ranges.
Frequently Asked Questions
Will the .308 extension fit a Gen II Magpul PMAG?
No. The .308 extension is engineered exclusively for Gen III (Series III) Magpul PMAG .308 magazines. Gen II uses a different base plate geometry and the extension will not lock in place. Check for "GEN M3" markings on your magazine body before ordering.
Do I need to buy a longer spring?
No. Both the .223 and .308 extensions work with the factory Magpul spring. The standard spring provides sufficient tension to reliably feed the additional 5 rounds without modification.
Is threadlocker really necessary on the .308 extension?
Recommended but not strictly required. The grub screw holds firm under normal use. However, the sustained heavy recoil of .308 can gradually loosen the screw over hundreds of rounds. A single drop of medium-strength threadlocker (blue Loctite 243) during installation prevents this — it's a one-minute step that saves potential problems down the track.
What's the advantage of the 3-pack over buying singles?
Price. The .223 3-pack works out to $50.00 per unit (saving $9.99 each vs. singles). The .308 3-pack is $55.00 per unit (saving $9.99 each). For a typical 3-Gun rifle stage requiring 3–4 magazines, the 3-pack covers your full match loadout at a better price point.
Can I use these extensions for hunting or recreational shooting?
Absolutely. While designed with competition in mind, these extensions work for any application where extra magazine capacity is useful — including range days, training courses, and recreational shooting. Just ensure your state permits the total magazine capacity for your intended use.
How durable are the polymer .223 extensions compared to the aluminium .308?
Both are built for sustained competition use including repeated magazine drops onto hard surfaces. The .223 polymer construction is lighter (65g vs 109g) and absorbs impact well. The .308 CNC aluminium is more rigid with a premium anodised finish that resists scratches and corrosion. For the heavier .308 platform, the added weight of aluminium also aids free-drop reliability during fast reloads.
