If you own an AR-15 rifle, you can enhance its versatility with caliber conversion kits. These kits let you change the barrel, bolt, and magazine, enabling the use of different ammunition.
In this article, we will reviews top AR build caliber conversion kits, benefits, and selection criteria.
Understanding AR Build Caliber Conversion Kits?
AR build caliber conversion kits allow you to change the caliber of your AR-15 rifle by replacing components like the barrel, bolt carrier group (BCG), and magazine.
Some kits may include additional parts like the upper receiver, gas system, or muzzle device.
Caliber conversions are useful for adapting the rifle to various shooting purposes, such as using smaller calibers like .22 LR for plinking or hunting small game, or larger calibers like .300 Blackout for home defense or hunting big game with suppressed shooting capabilities.
There are many advantages of using caliber conversion kits for your AR-15, such as:
- Saving money: Instead of buying a new rifle for each caliber, you can use one base rifle and swap out the parts as needed.
- Saving space: You don’t need to store multiple rifles in your safe or closet, just one rifle and some extra parts.
- Saving time: You don’t need to go through the hassle of registering, transferring, or waiting for a new rifle, just order the parts online and install them yourself.
- Having fun: You can experiment with different calibers and see how they perform on your AR-15 platform.
However, there are also some drawbacks to using caliber conversion kits for your AR-15, such as:
- Losing accuracy: Some calibers may not be compatible with the twist rate or chamber of your original barrel, resulting in reduced accuracy or reliability.
- Losing functionality: Some calibers may require a different gas system or buffer weight to function properly, which may affect the cycling or recoil of your rifle.
- Losing warranty: Some manufacturers may not honor the warranty of your rifle if you modify it with aftermarket parts.
Therefore, before you decide to convert your AR-15 to a different caliber, you should do some research and compare the pros and cons of each option.
Popular AR Build Caliber Conversion Kits
There are many types of caliber conversion kits available for the AR-15 platform, but we will focus on some of the most popular and practical ones for 2023. Here are our top picks:
.22 LR Conversion Kits
One of the easiest and cheapest ways to convert your AR-15 is to use a .22 LR conversion kit.
This kit allows you to shoot .22 LR rimfire cartridges from your standard 5.56 NATO or .223 Rem barrel.
All you need to do is replace the BCG with a .22 LR bolt and use a .22 LR magazine.
Some of the benefits of using a .22 LR conversion kit are:
- Low cost: .22 LR ammo is much cheaper than 5.56 NATO or .223 Rem ammo, so you can shoot more for less money.
- Low recoil: .22 LR ammo has very little recoil, so you can shoot more comfortably and accurately.
- Low noise: .22 LR ammo is much quieter than 5.56 NATO or .223 Rem ammo, so you can shoot without disturbing your neighbors or damaging your hearing.
Some of the drawbacks of using a .22 LR conversion kit are:
- Low power: .22 LR ammo is not very effective for self-defense or hunting large game, so you should not rely on it for those purposes.
- Low reliability: .22 LR ammo is prone to misfires, jams, or failures to feed or eject, so you should clean and maintain your rifle regularly.
- Low compatibility: Some .22 LR magazines may not fit or feed well in your lower receiver, so you should test them before using them.
One of the best .22 LR conversion kits on the market is the CMMG – AR-15/M16 22LR Bravo Conversion Kit. This kit comes with a stainless steel bolt group and three 25-round magazines.
It is easy to install and works with most AR-15 barrels and triggers. It is also very accurate and reliable, as long as you use high-quality ammo.
Another good option is the CMMG – AR-15 Echo Conversion Kit 22LR. This kit is similar to the Bravo kit, but it comes with a nitride-finished bolt group and one 25-round magazine.
It is also compatible with most AR-15 barrels and triggers, and it offers good accuracy and reliability.
9mm Conversion Kits
Another popular way to convert your AR-15 is to use a 9mm conversion kit. This kit allows you to shoot 9mm pistol cartridges from your AR-15 rifle.
However, unlike the .22 LR conversion kit, you need to replace the barrel, the BCG, and the magazine. Some kits may also include a new upper receiver, a gas system, or a muzzle device.
Some of the benefits of using a 9mm conversion kit are:
- High availability: 9mm ammo is one of the most common and widely available pistol calibers in the world, so you can find it easily and cheaply.
- High versatility: 9mm ammo is suitable for a variety of shooting applications, such as plinking, training, competition, home defense, or concealed carry.
- High compatibility: 9mm magazines are compatible with many popular pistol models, such as Glock, Sig Sauer, Beretta, or Smith & Wesson.
Some of the drawbacks of using a 9mm conversion kit are:
- High recoil: 9mm ammo has more recoil than .22 LR ammo, so you may need to adjust your grip and stance accordingly.
- High noise: 9mm ammo is louder than .22 LR ammo, so you may need to use ear protection or a suppressor when shooting.
- High complexity: 9mm conversion kits are more complicated and expensive than .22 LR conversion kits, so you may need to do more research and installation work.
The PSA 9mm Upper is a top 9mm conversion kit for AR-15s. It has a complete upper assembly with a 16″ barrel, BCG, charging handle, and flash hider. It comes with a lower parts kit and uses Glock-style mags.
The Macon Armory AR-45 Conversion Kit is another good option. It shoots .45 ACP and has an 8″ barrel, BCG, charging handle, and muzzle brake. It also includes a lower parts kit and uses Glock-style mags
.300 Blackout Conversion Kits
Another way to convert your AR-15 is to use a .300 Blackout conversion kit. This kit allows you to shoot .300 Blackout rifle cartridges from your AR-15 rifle.
However, unlike the previous two kits, you only need to replace the barrel of your AR-15. The BCG and the magazine can remain the same as your original 5.56 NATO or .223 Rem setup.
Some of the benefits of using a .300 Blackout conversion kit are:
- High performance: .300 Blackout ammo offers better ballistics than 5.56 NATO or .223 Rem ammo, especially at shorter ranges or with suppressed shooting.
- High compatibility: .300 Blackout ammo uses the same case as 5.56 NATO or .223 Rem ammo, so you can use the same BCG and magazine for both calibers.
- High flexibility: .300 Blackout ammo comes in both supersonic and subsonic loads, so you can choose between more power or more stealth depending on your needs.
Some of the drawbacks of using a .300 Blackout conversion kit are:
- High cost: .300 Blackout ammo is more expensive than 5.56 NATO or .223 Rem ammo, so you may need to spend more money on ammunition.
- High risk: .300 Blackout ammo can fit in a 5.56 NATO or .223 Rem chamber, but if you fire it by mistake, it can cause catastrophic damage to your rifle and yourself.
- High confusion: .300 Blackout ammo looks very similar to 5.56 NATO or .223 Rem ammo, so you may need to label or separate your magazines and ammo boxes carefully.
The Brownells AR-15/M16 300 BLK Barrels are among the top .300 Blackout conversion kits available. They feature high-quality stainless steel or chrome moly steel barrels with a 1:7 or 1:8 twist rate, along with carbine or pistol gas systems.
The kit includes a low-profile gas block and gas tube. Installation is straightforward, and it is compatible with standard AR-15 upper receivers
7.62x39mm Conversion Kits
Another way to convert your AR-15 is to use a 7.62x39mm conversion kit. This kit allows you to shoot 7.62x39mm rifle cartridges from your AR-15 rifle. However, unlike the .300 Blackout conversion kit, you need to replace the barrel, the BCG, and the magazine of your AR-15. Some kits may also include a new upper receiver, a gas system, or a muzzle device.
Some of the benefits of using a 7.62x39mm conversion kit are:
- High availability: 7.62x39mm ammo is one of the most common and widely available rifle calibers in the world, so you can find it easily and cheaply.
- High power:62x39mm ammo offers more energy and penetration than 5.56 NATO or .223 Rem ammo, especially at shorter ranges or with barrier penetration.
- High diversity:62x39mm ammo comes in various types and brands, such as steel-cased, brass-cased, hollow-point, soft-point, or armor-piercing.
Some of the drawbacks of using a 7.62x39mm conversion kit are:
- High recoil: 7.62x39mm ammo has more recoil than 5.56 NATO or .223 Rem ammo, so you may need to adjust your grip and stance accordingly.
- High noise: 7.62x39mm ammo is louder than 5.56 NATO or .223 Rem ammo, so you may need to use ear protection or a suppressor when shooting.
- High complexity: 7.62x39mm conversion kits are more complicated and expensive than .300 Blackout conversion kits, so you may need to do more research and installation work.
The Brownells AR-15/M16 300 BLK Barrels are among the top .300 Blackout conversion kits available. They feature high-quality stainless steel or chrome moly steel barrels with a 1:7 or 1:8 twist rate, along with carbine or pistol gas systems.
The kit includes a low-profile gas block and gas tube. Installation is straightforward, and it is compatible with standard AR-15 upper receivers
.224 Valkyrie Conversion Kits
Another way to convert your AR-15 is to use a .224 Valkyrie conversion kit. This kit allows you to shoot .224 Valkyrie rifle cartridges from your AR-15 rifle.
However, unlike the previous kits, you need to replace the barrel and the magazine of your AR-15. The BCG can remain the same as your original 5.56 NATO or .223 Rem setup.
Some of the benefits of using a .224 Valkyrie conversion kit are:
- High accuracy: .224 Valkyrie ammo offers better accuracy than 5.56 NATO or .223 Rem ammo, especially at longer ranges or with wind drift.
- High performance: .224 Valkyrie ammo offers better ballistics than 5.56 NATO or .223 Rem ammo, especially at supersonic speeds or with terminal effects.
- High compatibility: .224 Valkyrie ammo uses the same case as 6.8 SPC ammo, so you can use the same BCG for both calibers.
Some of the drawbacks of using a .224 Valkyrie conversion kit are:
- High cost: .224 Valkyrie ammo is more expensive than 5.56 NATO or .223 Rem ammo, so you may need to spend more money on ammunition.
- High risk: .224 Valkyrie ammo can fit in a 5.56 NATO or .223 Rem chamber, but if you fire it by mistake, it can cause catastrophic damage to your rifle and yourself.
- High confusion: .224 Valkyrie ammo looks very similar to 5.56 NATO or .223 Rem ammo, so you may need to label or separate your magazines and ammo boxes carefully.
Two top .224 Valkyrie conversion kits on the market are the Brownells AR-15/M16 224 Valkyrie Barrels and the Faxon Firearms AR-15 Gunner Barrels 224 Valkyrie.
The Brownells kit features a stainless steel barrel with a 1:7 twist rate and a rifle gas system, while the Faxon Firearms kit offers a lightweight nitride-coated steel barrel with a 1:6.5 twist rate and a rifle gas system.
Both kits include a low-profile gas block and gas tube, are easy to install, and are compatible with standard AR-15 upper receivers.
.17 HMR Conversion Kits
Another way to convert your AR-15 is to use a .17 HMR conversion kit. This kit allows you to shoot .17 HMR rimfire cartridges from your AR-15 rifle.
However, unlike the .22 LR conversion kit, you need to replace the barrel, the BCG, and the magazine of your AR-15. Some kits may also include a new upper receiver, a gas system, or a muzzle device.
Some of the benefits of using a .17 HMR conversion kit are:
- High velocity: .17 HMR ammo offers higher velocity than .22 LR ammo, especially at longer ranges or with flat trajectories.
- High accuracy: .17 HMR ammo offers better accuracy than .22 LR ammo, especially at longer ranges or with wind drift.
- High performance: .17 HMR ammo offers better ballistics than .22 LR ammo, especially at supersonic speeds or with terminal effects.
Some of the drawbacks of using a .17 HMR conversion kit are:
- High cost: .17 HMR ammo is more expensive than .22 LR ammo, so you may need to spend more money on ammunition.
- High noise: .17 HMR ammo is louder than .22 LR ammo, so you may need to use ear protection or a suppressor when shooting.
- High complexity: .17 HMR conversion kits are more complicated and expensive than .22 LR conversion kits, so you may need to do more research and installation work.
Two top .17 HMR conversion kits on the market are the Franklin Armory BFSIII AR-C1 Trigger – Binary Firing System and the Alexander Arms AR-15/M16 17 HMR Complete Upper Receiver.
The Franklin Armory kit includes a complete upper receiver assembly with a 16-inch barrel, BCG, charging handle, and flash hider. It also features a binary trigger system for firing one round on pull and one round on release.
It requires proprietary magazines and is compatible with any standard AR-15 lower receiver.
The Alexander Arms kit is similar but comes with a standard single-stage trigger system and an 18-inch barrel. It also requires proprietary magazines and is compatible with any standard AR-15 lower receiver.
Tips for Using Caliber Conversion Kits
Consider the following tips for effectively using caliber conversion kits:
- Familiarize yourself with the specific ammunition requirements and any unique considerations associated with the converted caliber.
- Ensure proper cleaning and maintenance practices specific to the new caliber.
- If using different magazines for each caliber, properly label and store them to avoid confusion during range sessions or critical situations.
- Keep track of the number of rounds fired in each caliber to monitor maintenance intervals and address potential issues promptly.
AR build caliber conversion kits offer AR-15 rifle owners the ability to change the caliber of their firearm by replacing components such as the barrel, bolt carrier group, and magazine.
These kits provide advantages such as cost savings, space efficiency, time savings, and the opportunity to explore different calibers. However, drawbacks include the potential loss of accuracy, functionality, and warranty.
Popular conversion kits 2023 include .22 LR, 9mm, .300 Blackout, 7.62x39mm, .224 Valkyrie, and .17 HMR options, each with benefits and considerations.
Read More
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- Top 10 Pocket Pistols With Single-Action Trigger: Best Ever
- 9mm Pistols With Double-Action Triggers: Best For You!
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