‘Idiocy’ may be a strong word, but clickbait gonna clickbait. Let’s move on.
I was first introduced to the idea of a pinned & welded AR barrel in about 2011. NFA laws being what they are, a rifle has to have a barrel of 16″+ to not be considered a Short Barreled Rifle (aka, SBR). That rule is oppressive and arbitrary and dumb, but we can work around it.
The US Army uses 14.5″ barrels on their M4 carbines. They can do this, because they are working for the government. It’s the classic “Laws for thee, but not for me”, but that’s irrelevant to this particular post. Why 14.5″? Why not 14 even? Or 15? A quick google search indicates that 14.5″ (with carbine length gas tube) was the shortest length to which they could still attach their bayonets. I have no idea if that is really the case or not, but it’s also irrelevant to this discussion.
The problem occurs when civilians want to be like the military and use what the cool guys use, or returning vets want to continue using what they were issued. The US military issues SBRs as the standard service rifle (technically they’re machineguns, but whatever). Us normal folk can’t run 14.5″ barrels on our rifles unless they are registered as SBRs. That means that we have to fill out registration forms, pay $200 to the government, wait for months, and then what do you have? A rifle that you cannot take across state lines without express, written permission from the ATF. Totally worth it, right?
So, what’s a gun bro to do? A lot of people noticed that the military’s standard issue muzzle device, the A2 flash hider, is a little over 1.5″ long. If they permanently attached an A2 flash hider to their barrel, they’d be legal and they’d achieve the look they want. It looks like what the boys ‘over there’ use, it saves some weight & length, and it doesn’t have the ridiculous legal baggage that comes along with an SBR. It’s a win-win. Well, only if you never want to modify the rifle at any point in the future. ‘Permanently attached’ muzzle devices can be removed, but you run a very real risk of severely damaging the barrel, and that’s when you’re paying a gunsmith to do it. To understand that aspect of it, we need to understand what ‘permanently attached’ means.
First, let’s go over how to ‘permanently’ attach a muzzle device. This is usually done by drilling a small hole in the muzzle device (if it doesn’t come with one already), driving a pin into the hole so that the device cannot come off the threads, and welding that pin in place. When you see someone mention a “pinned and welded” barrel, that is what has been done. To remove a pinned & welded muzzle device, it means locating the welded-in pin, drilling/milling out, but not into the barrel threads, and then removing the device. I’m not a fan of this method. Here’s a good write-up of the process by people who actually know what they’re doing.
Another way of attaching a muzzle device is to use 1100°F degree silver solder to attach it, but that’s very uncommon (ATF NFA handbook, page 5). I’ve only heard one person mention it, and he was a gunsmith. To remove the device, you would re-heat the muzzle end of the barrel and unscrew the device once the solder melts. I like this way a lot more than removing a welded pin. Based on the material properties of 4150 Chrome-moly steel and 416 stainless, 1100°F is far enough below the point where you start screwing up the hardening of your barrel, as long as you don’t go much above 1200°F. If you reach 1500°F, you’re going to lose the heat treat of your barrel. Be very careful, and pay a professional to do it when appropriate. I don’t care how cool your M4gery looks with a 14.5″ barrel, you’ll look real stupid when your barrel explodes.
Now that that’s out of the way, why should you care about modifying your rifle? Can’t you just run what the Army runs and be fine? Well, what if you don’t want to run an A2 flash hider? Want to try out a muzzle brake for competition this year? Want to screw on a silencer? Too bad. Between the different handguards different brakes, comps, & flash hiders, the recent rise of QD suppressor mounts, and even the SB Tactical Arm Brace, having a pinned & welded barrel is not optimal. Take free float rails for example. If you (like me) didn’t get MLok on all your rifles, you’re probably wishing you did. If your flash hider is pinned & welded, you have to pay someone to get that handguard switched out, and if you don’t replace the barrel entire barrel, you’re either paying that guy to re-weld that flash hider back in place or filing SBR paperwork.
Pinned & welded a QD suppressor mount to your barrel? That’s not a terrible option. Most people (in the US) who buy a can do so for life. They’ll keep that silencer basically forever. The problem comes when you want to try a different can on that rifle. Unless you buy a new can that’s backwards-compatible, you’re looking at a headache. And if you do, how long will that company keep supporting that QD system? In the future you may just want to buy a new upper entirely and not deal with the hassle, which leads to my next point…
Some people (as have mentioned in the comments below) pin & weld their uppers with the thought process of just buying/building a new upper when they don’t like this one anymore. If you have that kind of cash flow, go for it. I’m nowhere near that kind of financial position, so that’s a complete non-starter for me. I assume that most people reading this are in a similar position.
The muzzle device basically has to come off any time you want to change anything about your upper (besides swapping the entire barrel and gas system together). It’s like the very last thing you put on the gun, and permanently attaching it means that everything else behind it is just as permanently attached. One of the most appealing aspects of an AR is the ability to change it to your liking, permanently attaching your muzzle device completely nullifies that whole aspect. It’s like building Legos with glue.
There are some options for 16″ barrels with muzzle devices machined into the end of them, negating the costs of attaching a device to a barrel and allowing much more rifle/rail/gas block customization in the future. The issue with this concept is that the muzzle device you choose at purchase is literally the only one you can ever have on this barrel, as it is literally part of the barrel. That means swapping to a flash hider instead of a compensator (or vice-versa) requires a whole new barrel. Silencers are completely out of the question. I would not recommend this route to someone unless they really know what they’re getting into, or already have other uppers in their inventory.
Permanently Attached Suppressor
Stop it. Just, stop.
There really isn’t a lot of reason to pin & weld devices on your AR in today’s market. It might have been a good idea back in the day, when there as much less modularity in the AR platform. If you were one of those guys who really wrings every bit of performance out of a rifle, a 14.5″ might be enough length and weight savings to justify NFA paperwork, tax, and wait times, and interstate headaches. But that was back then, not today. With the current availability and legality of SB arm braces and the huge amount of options for customizability you’d lose out on, I just don’t see the value.
There is always the reason of “I just want to”, which is always valid. If you are willing to make the demonstrable sacrifices for the seemingly marginal gains, be my guest. If you are in a place financially where you can just buy whatever you feel like, more power to you. Who knows, you might find that I’m completely wrong and a permanently attached muzzle device is great.
Keep your options open, and I’ll see you on Friday. -S_S