In this article, we’re going to cover a few things that are not directly related but which do have to do with MP5 barrels. These are 922r parts and barrel shoot-out.
So let’s peel back the layers here.
Barrel Shoot Out: Case Pressure and Considerations
Barrel shootout is a condition that occurs when a barrel’s rifling degrades, naturally, over time.
What happens is, each time you pull the trigger and send a bullet through the bore, it literally wears away some of the rifling.
For many common cartridges, it takes hundreds to thousands (to tens of thousands) of rounds before you will ever even notice a difference.
When you do notice a difference, however, accuracy will start to suffer. As the rifling wears down, shooting through a “shot out” barrel will produce groups that are wider open at greater ranges.
So you need to know what to look for. For most handguns, barrel shootout isn’t a problem because it is tied mostly to cartridge case pressure and bullet speed.
Cartridges that are associated with barrel wear are those that shoot fast and have very high case pressures. Consider the .220 Swift, which can produce case pressures in excess of 60,000 PSI and muzzle velocities in the neighborhood of 4,000 FPS, or the .22-250 Remington, which can produce case pressures of 65,000 PSI and muzzle velocities above 3,600 FPS.
These extremely-high pressure, high-speed cartridges wear out barrels faster than others. Some shooters report that groups start to turn into patterns after as few as 2,000 rounds.
With the 9mm, with which the ZF-5 and MP5 are chambered, barrel shootout is less of a problem.
The 9mm is a slower, lighter cartridge. Case pressures are usually around 35,000 PSI, with muzzle velocities way lower, in the area of 1,000 FPS.
Most shooters report that they can go through 100,000 or more rounds of 9mm before they start to see any issues with grouping, and even then, it’s only at extended ranges. Up close, you’d never even notice.
So if you have a fresh ZF-5 that you got from us and haven’t put more than 100,000 rounds through it (and kept the barrel clean) you’re almost definitely not dealing with shootout.
But, there is a caveat here.
For Buyers with Used Guns
If you own an HK MP5 that was previously owned or was in service somewhere in the line of official duty, the likelihood is that it has had many thousands of rounds put through it.
It’s also possible, although not necessarily likely, that it wasn’t cared for as meticulously as it would have been if it was someone’s personal property.
You should also consider the age of the MP5. the older it is, the more likely it’s been used extensively and had a ton of rounds sent downrange through it.
If you do own one of these used, post-duty MP5 platforms, you’re more likely to need an MP5 barrel replacement than others.
The next time you take your MP5 down for cleaning, shine a bore light through it and check out the rifling. Take a look at the crowning, too.
If either seems compromised, you may need to replace the barrel.
Well, you won’t need to replace it, because a shot-out barrel will still shoot fine at close ranges.
But if you shoot at greater distances or compete, it might be worth it.
If you have any questions (sometimes you can’t tell if a barrel is shot out just by looking) take it to a gunsmith.
What Our MP5 Barrel Offers: Specifications and Compatibility
For those of you that do determine that a barrel replacement is necessary, there’s a lot to love about the Zenith Firearms MP5 barrel replacement.
Our MP5 barrels are made from mil-spec, cold hammer forged 4150 CMV steel that is extremely hard and durable.
They’re treated with an FNC finish that leaves an even harder, corrosion-resistant surface on the face of the barrel.
The barrel is also threaded (½ x 28 RH) and features a 3-lug configuration that is compatible with MP5 3-lug flash hiders and other muzzle devices.
A great thing about these MP5 barrels is that they are not only compatible with the ZF-5, but also with the MP5, SP5, and other full-size 9mm roller-delayed blowback firearms.
Also important is the fact that they are made in the United States, which makes them 922r compliant – a big bonus for those that have actual HK MP5 subguns.
On 922r Parts and Compliance
For owners of HK MP5 platforms and those whose platforms contain foreign-made parts, it is very important to keep 922r compliance in mind.
In a nutshell, Section 922(r) of Title 18 USC makes it illegal to assemble a firearm platform (semiautomatic rifles or shotgun) that contains more than 10 imported parts.
Since the HK MP5 is foreign-made, this raises a bit of an issue. An even bigger problem is the fact that some “parts” actually constitute more than one.
For instance, a foreign made magazine is considered three, since it contains a magazine body, follower, and floor plate. (Our MP5 magazine is American-made so it doesn’t count).
Since our MP5 barrel is made in the United States, it is 922(r) compliant.
There are a few other considerations to make here. For more information, please see our previous post on “922r Parts and Compliance: A Few Things You Should Know.”
If you have additional questions about 922r parts, consult a firearms lawyer in your area to be sure you are in compliance with all applicable codes and regulations.
Questions? Contact Us
If you have any quetsions about our MP5 barrels or other American-made parts, feel free to get in touch with us.
It’s probably not shoot-out, but if it is, we might be able to get you to the bottom of it, and we also carry 922r compliant parts.
Contact us at 434-202-7790 or email us at Info@ZenithFirearms.com.