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Ultimate Guide to Inner Barrels [Airsoft Essentials]


Inner Barrel

What is it?

The outer barrel that is visible acts as a cover for a smaller hidden inner barrel inside. The inner barrel itself is connected to the hop-up mechanism which feeds each BB from the magazine. The BB then passes through the inner barrel as it gets shot out; consequently the inner barrel plays a part in its accuracy and range. It’s really as simple as that.

However, what you need to be aware of is that there are two types of airsoft inner barrels – one is made for AEGs, and the other for Snipers and PᎥstols. So whenever purchasing a new barrel or hop-up bucking/nub, make sure they’re compatible with each other. 

In this guide to airsoft inner barrels, we will cover the dos and don’ts and a spectrum of options available to you in the market. Especially the multitude of companies that produce inner barrels for Airsoft; therefore we we’ll kick this article off with our top 6 picks for best inner barrel brands!

Recommended brands and shops

There are a number of companies which produce high quality inner barrels, here’s our top 6 picks that will never disappoint in order from most expensive to the most budget friendly!

  • EDGi
  • PDI
  • Prometheus
  • ORGA  (Wide-Bore)
  • Maple Leaf
  • Mad Bull

Also when looking for highest quality inner barrels, you might often find that they’re out of stock. Do not despair, we’ve also compiled a list of shops with barrels they often have in stock for your convenience; definitely give these a try when looking for your purchase:


Is it all that really important?

Yes, however, the longest doesn’t always mean the best… For example, the barrel in one of the most popular entry airsoft replicas – G&G Combat Raider is 363mm long which is an optimal length for an AEG rᎥfle in UK based on the 350 FPS limits. Anything above 300mm will not have significant difference in range and accuracy. However, as the BB passes through barrels between 280 – 300mm, they’re just long enough to provide good stability and consistency during the entirety of the BB’s flight.

Longer barrels are only important in replicas with higher power outputs thus longer range, such as Snipers or DMRs. However, even then, the most important accuracy and range tool is the hop up itself!

The picture besides shows an inner barrel along with a hop up unit which is essential in every Airsoft replica.

There are a few simple upgrades that can significantly improve your replica’s performance such as; changing the hop-up rubbers, nub and bucking.

Recommended lengths

AEGs (Fully Automatic – 350 FPS Limit)

  • 280mm – 363mm

Some AEGs variants will naturally have longer inner barrels such as the AK-47; we recommend sticking to the stock length in those instances.

DMRs (Semi Automatic – 400 FPS Limit)

  • 430mm – 455mm

Snipers (Bolt Action – 500 FPS Limit)

  • 430mm – 550mm

In general, it will take quite a bit of trial and error to find the perfect inner barrel for your replica, purely because this is only a small part of the bigger picture. There are other aspects that come into play, such as the inner barrel – cylinder ratio, correct airseal and so on. The above are just helpful guidelines which you can fall back on in case your replica isn’t performing well.


Is width more important than the length?

Airsofters often upgrade to a 6.03mm inner barrel, although, there are even tighter versions which go down to 6.00mm. Tighter equals better, right? Not always. On the contrary, other players upgrade to wide bore barrels which produce a larger air cushion around a BB in order to improve accuracy, however they reduce FPS significantly. 

However, one thing that is common between all players is that quality is far more important than diameter or length put together. The finish quality of the inner barrel is incredibly important in order to produce consistent results with each shot. For example, tight bore barrels might potentially cause jamming if they’re not made in precise manner.

In general, Airsoft inner barrels are made of aluminium, brass and stainless steel, although some companies also provide teflon coating which is more durable and resistant to damage; such as scratches, which can subsequently affect accuracy.

Recommended diameters

Recommended Diameters

Tight Bore

High quality 6.01mm to 6.03mm inner barrels are your best options in most scenarios. When using such low diameters, especially if you experiment with anything below, make sure to clean your barrel regularly!

Wide Bore

On the other hand, if you’re interested in the performance of the wide bore, we simply recommend the Orga Magnus 6.23mm. However, due to the larger diameter, installing this product will result in a drop of around 26-33 FPS compared to most stock barrels. We recommend installing a higher power main spring to compensate for the difference.

When using high quality inner barrels, make sure to also use high quality BBs! 

The quality and weight of a BB can significantly increase replica’s range and accuracy. Diameters can slightly vary depending on the BB’s quality. Lower variation ensures more consistent accuracy and velocity of a BB. Best quality BB’s vary by +/- 0.01mm whereas lower quality can vary up to +/- 0.05mm.

Read More: Did you know that polished BBs produce better results? Do you know how to identify quality BBs and what makes them better? If not, click here to get the best bang for your buck!

Read More: A detailed breakdown of how different BBs affect range and accuracy including recommended weights and brands.

Cleaning and Maintenance

Why, how and when?

Cleaning your inner barrel is important to simply ensure that the BB flying out the barrel doesn’t get obstructed by any dirt within which might skew it’s accuracy and potentially cause damage if the barrel gets jammed. 

If you are a regular player, I suggest cleaning your inner barrel at the end of each month; however, if you’re super serious about peak performance of your replica – do it after each game. 

To clean your inner barrel, you will need these: 

  • Cleaning Rod – should come packaged with your replica
  • Cleaning Cloth – microfiber glasses cloth or piece of old t-shirt 
  • Cleaning Liquid – water or rubbing alcohol

Important – Before you start, make sure to set your hop-up to 0 or remove the inner barrel from the hop-up unit if you’re running a modified hop, such as Flat Hop; this ensures that the rod doesn’t touch the hop up rubber and damage it by any chance.

Once that’s done, simply insert the rod in the barrel and gently go up and down until you feel there is no more gunk. Use common sense and don’t push too far in when you feel resistance. You can simply use another clean cloth at the end to test whether there’s any dirt left; if not, then you’ve finished!

Do not use oils, waxes or grease to clean your inner barrel as they will stick to the BB as it passes through and affect its accuracy!

Extra Tip

Barrel Spacers

It is very important to ensure that the inner barrel sits tightly inside the outer barrel because movement and automatic fire can make it slightly vibrate and bounce around which leads to poor and inconsistent accuracy.

So how do I stabilise the inner barrel?

Barrel Spacers

Fortunately, quite simply! You can purchase barrel spacers, such as these at FireSupport.co.uk. Barrel spacers come designed specifically to fit a certain model of Airsoft replica which means they’re a perfect fit for that particular platform! 

DIY Barrel Spacers

Otherwise you can go “DIY” and simply wrap the inner barrel with Gaffer tape in a few spots until it just about fits in the outer barrel; make sure you can still freely move it in and out.

This article is part of our AEG Wiki, click here to check out the rest of informative series.

Final Words

We hope this article has been helpful and helped you narrow down your options for upgrades! Please feel free to leave a comment, start a thread in our forum or simply check out the rest of the AEG Wiki!

Peace out Rancher!

Written by Wojtek Lawer

Edited by Kamil Turecki

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