Action bar lock on 1950 870

[AZCardinalsfan]

Hello, I'm sure some of you have dealt with this issue before. I inherited my grandfather's 870, which was made in November of 1950. I have not taken it out to shoot yet, but it's cleaned up pretty nicely and cycles shells properly. One issue I'd like to address is a weak action bar lock. That is my perception, anyway. It does not fail to function, it just takes pressing the lock almost flush with the receiver to engage. I compare it to my new Police Magnum, which engages with the action bar lock sticking a little further out. I'm not interested in doing any trigger assembly work myself, so I'm going to bring it to a gunsmith one of these days. What I would like to know is, will a new action bar lock and new action bar lock spring fix this problem? Possibly just the spring? Also, as long as I'm paying somebody to open it up, are there any springs or other parts I should replace? It's a 65 year old gun, so I'm happy to replace any high wear parts that need it. Thanks in advance for the help.

-Brandon

[Synchronizor]

One issue I'd like to address is a weak action bar lock. That is my perception, anyway. It does not fail to function, it just takes pressing the lock almost flush with the receiver to engage. I compare it to my new Police Magnum, which engages with the action bar lock sticking a little further out. I'm not interested in doing any trigger assembly work myself, so I'm going to bring it to a gunsmith one of these days. What I would like to know is, will a new action bar lock and new action bar lock spring fix this problem? Possibly just the spring?

Just how "flush" are we talking here? I have to press the action bar lock on my 870 down pretty far, but it's never been an issue for me. Can you post a picture showing how far down the "button" has to be to unlock the action? If it is excessive, it's possible your action bar lock is bent. If that's the case, you should probably have it replaced.

Also, what does the end of your left action bar look like? As you can see in the following image, the left action bar on my 870 has a chamfered end that allows the slide to start moving rearward even if the action bar lock is not fully depressed.

I know Remington has changed the design of the 870's action bars at least once since the gun was introduced, so maybe your older action bars don't have this feature.

Also, as long as I'm paying somebody to open it up, are there any springs or other parts I should replace? It's a 65 year old gun, so I'm happy to replace any high wear parts that need it.

Whether or not parts need replacing really depends on how much the gun was used; if it wasn't used heavily, odds are everything inside is just fine. But, if you don't mind paying for some inexpensive parts just to be safe, I'd suggest replacing the carrier dog follower spring, the sear spring, and the magazine spring. If your extractor or safety seem to move without much resistance, you could replace the springs there as well. If you're replacing the action bar lock, a new hammer spring wouldn't hurt either. Check the front of the barrel guide ring to make sure the spring-loaded magazine cap detent is still in place. I'd also take a look at the trigger plate pin detent springs, locking block, shell latches, action bar camming surfaces, barrel extension, carrier dog, ejector, ejector spring, extractor, sear, firing pin, and hammer to see if any of them show excessive wear, though odds are they'll be fine.

If you want to tinker a little more while you're at it, you could upgrade or remove the magazine spring retainer. If you're willing to spend the money, you could always update the action with flex-tab parts and/or install a magnum ejector & ejector spring to allow the gun to cycle 3" shells (with a 3"-chambered barrel, of course).

[AZCardinalsfan]

Great suggestions. I took some pictures. It looks like the action bar lock designs are different. Also in the pictures, I have tried to illustrate the degree of "flushness" of the action bar lock, with the newer one shown as well for comparison. It might not look like much, but it does amount to a (to me) distinctly different feel. "Positive engagement" is the term that comes to mind operating the new one. Now that I know there are different action bar lock designs, I believe I will change mine out to the newer style, assuming there is nothing about the older 870 that would prevent me from doing this. Your answers about which parts to upgrade for "peace of mind" is just what I was looking for. I have removed the retainer because it drives me nuts. I just put the crappy orange follower at the end to prevent spring on inside of magazine contact (maybe useless, but I don't see any real cons). I don't mind the spring coming out as much as I mind dealing with that old style retainer. I've thought about the flex tab conversion. Dies this just require a new carrier, or a whole trigger group? I hear this is a great idea for an 870 which might be relied upon in a self defense scenario. That's not exactly what I've got it for, but I certainly wouldn't mind the flexibility. I've aalso thought about converting it to a 3" receiver. I don't really need to fire 3" shells, but I do have a new 3" barrel on it, and it does drive me a little crazy having a barrel that says 2 3/4" or 3" knowing full well the 3" will not eject (that's right, isn't it?). Thanks again!

[AZCardinalsfan]

Also, no discernible difference in shape of left action bar lock. Both looked just like yours.

[AZCardinalsfan]

Also, looking at the pictures, "flush with the receiver" was an incorrect description. Flush with the trigger guard would have been more accurate.

[Synchronizor]

I've thought about the flex tab conversion. Dies this just require a new carrier, or a whole trigger group?

You should be fine just replacing the carrier (along with the bolt & slide assembly, of course), as long as you're comfortable working on your trigger plate assembly. Changing the carrier assembly really isn't difficult or complicated, but some folks just don't trust themselves to mess with the workings of their triggers.

I've aalso thought about converting it to a 3" receiver. I don't really need to fire 3" shells, but I do have a new 3" barrel on it, and it does drive me a little crazy having a barrel that says 2 3/4" or 3" knowing full well the 3" will not eject (that's right, isn't it?).

Yeah, the ejector parts and barrel are the only things that differentiate a magnum 870 from a non-magnum one, and the barrel is obviously the important part. If you want, go ahead and try shooting a 3" shell to see what happens. It'll feed just fine, and as long as you have a 3" or longer chamber, there'll be no safety concerns. Worst case, you'll just have to reach into the ejection port and pull the fired shell out by hand.

[AZCardinalsfan]

I've thought about the flex tab conversion. Dies this just require a new carrier, or a whole trigger group?

You should be fine just replacing the carrier (along with the bolt & slide assembly, of course), as long as you're comfortable working on your trigger plate assembly. Changing the carrier assembly really isn't difficult or complicated, but some folks just don't trust themselves to mess with the workings of their triggers.

Regarding the trigger assembly, I'm not categorically opposed to attempting the work, but I'm a novice. I hear many people advocating against home trigger assembly work. Remington says roughly the same thing. This is not to say it is not an entirely possible, perhaps even simple procedure. If you have a trigger group video that might illustrate how I would replace the parts we discussed, I'd be much obliged. I also don't have any firearm tools, other than an 870 pin remover and forearm wrench. To put it bluntly, I don't have nearly the mechanical experience or tool know how as I might need. I'm here to learn, though, and I don't believe the tools I'm missing for the job are terribly expensive.

[Synchronizor]

It is a smart rule of thumb to stay within your comfort zone when it comes to working on firearms - especially their triggers. However, apart from being attached to the trigger plate, the 870's carrier system is completely mechanically independent from the rest of the fire control components. In a pinch, you can completely remove the carrier system (except for the carrier pivot tube, which also serves as a bushing for the front trigger plate pin), and the 870 will still operate safely and reliably as a single-shot. This video of mine demonstrates this, and includes steps for removing and installing the carrier assembly:



As the video shows, this is not a complicated procedure, and as long as you can get the TPA out of the receiver, no additional tools are required. There are gunsmith tools intended to aid in removing & replacing the carrier pivot tube, but they're not necessary, and are actually pretty pointless if you're only working on one shotgun. See this thread for that discussion.

[AZCardinalsfan]

Very simple indeed! I will be buying a flexitab carrier after getting some parts for my new truck. Thanks for the video.

[Synchronizor]

Just in case you weren't aware, if you want to have the full flex-tab update, you'll also need to replace the slide assembly and breech bolt.