Rem 550 H

[TonyWells]

Rem 550-I

First, thank to the Admin(s) and Mods for all the work they put in on this site, and thank to the owner, and those who helped establish it and those who keep building it.

Second, I beg pardon for asking a question that has been addressed. I have done what I think is a thorough search, and while I have read (and learned) a great deal about the 550 family of .22 rifles, I cannot seem to locate the solution to my problem.

I have a Model 550-I. It does have the loose fitting recoil chamber, but I have no issues with any of that. Nor do I have the typical problem of the cross-threaded sear housing. I do however, wonder about some things I see with the rifle's internal parts that I question. But one thing at a time. I am not the first person to service this firearm, so some of this is guesswork, and part knowledge gained from studying drawings as I can find them.

My problem/question is related to the firing pin and the mechanism used to lock it back when the bolt is cycled. When manually cycled, as in first charging, the firing pin stays in it's rearward position, held in place by ??. When discharged, the bolt seems to travel the full length, although it's fast, so I cannot be sure for 100% of the shots, but on some of the shots....

Sometimes the second, sometimes the 10th, sometimes the 5th, etc., random shots a jam occurs and although the bolt retracts far enough to attempt to grab the next round from the magazine, and sometimes even complete an ejection, the firing pin is still proud of the bolt face, then obviously preventing the round from "sliding" up the bolt face and lining up for a smooth chambering and return to battery.

It seems to me that whatever should be "latching" for lack of a better word the firing pin in a retracted position is failing to be consistent. In addition to being quite a hassle to remove the now mangled round, it strikes me(pardon the pun) that if the mechanism designed to hold the spring loaded firing pin may not have a secure "grip", leading me to believe the rifle could arbitrarily fire after a successful load, as long as it was able to return fully to battery with a live round chambered. Sounds dangerous, and I will not allow anyone else to handle this gun until this is resolved.

Anyone have any suggestions? It is clean and lightly oiled. I did try operating it completely dry, just to see if made any difference. It did not. I'm open. The one thing I am suspicious of is the sear spring and housing. Apparently some previous mechanic employed the "grind off the unneeded part" of the sear housing. The sear spring was distorted, as in banana shaped to a degree. I straightened the best I could, but I really have no idea if there was unseen damage done by this previous mechanic in his attempts to reassemble the sear housing, etc.

This is a pretty nice example of this model, and does shoot accurately when it does shoot. I really would like to iron out all the problems it has.


Oh, one last question, not quite on the specific subject. The rear plug that retains the recoil spring and firing pin spring. Nice straight knurl on this one, no pliers....what is the purpose of the serrations(?) that engage when it is tightened?

Thanks for all your helps....I am confident from reading over this Forum that I will get the answers I seek.

Tony

 

[tark]

Welcome to the Monkey House, Tony.

I am a bit confused as to the model number of your rifle. The Remington 550 series consisted of two models, the earlier 550 and the later 550-1. I can find no references of a "550-H" Both 550s had the floating chamber, which I assume you are referring to as the loose fitting recoil chamber, so you you DO have a 550 something!

The firing pin in the bolt is held in the retracted position by the sear. pulling the trigger releases it. If I understand you correctly, the bolt doesn't always travel far enough rearward to eject the spent case, but it does travel far enough to release the next round from the magazine, and the result is a jammed gun and a dented round. When you say "proud of the bolt face" do you mean that the firing pin is sticking out of the front of the bolt face so far that a round cannot chamber? If that is the case you may have a broken firing pin! Pull the bolt apart and look. The firing pin is long and skinny but it is a single piece. If it sticks out the front of the bolt face it is broken.

There are all kinds of other things that could cause your problems...so... , if possible, a couple of pics would be enormously helpful. If you can pull the gun apart and send a picture of the parts you suspect were buggered up by a previous owner. This may reveal something.

Second, and most importantly, take the gun out and shoot it until it jams up in the manner you describe. When it does, don't touch anything and grab a few pictures of the jammed gun, showing the relationship of all the parts and the jammed ammo. Try and get really close-up pictures. These could help in diagnosing the problem.

Does the gun ever go off when it isn't supposed to? Like when you are chambering the first round? Does it ever fail to fire, when you chamber a round and get nothing when you pull the trigger, not even a click? These would indicate sear problems, or an extremely dirty rifle. But you have mentioned that is is clean...

Hopefully you can send pics. That will be a good starting point.

 

[Vern Humphrey]

The rifle in question is the 550 A. I had one many years ago.

This rifle uses a rocking sear. There are actually two sears -- triangular pieces sticking up on either end of the sear bar. When the bolt comes back after firing, the bent (the part on the firing pin that engages the sear) winds up behind the rear sear, and is caught. When you release the trigger, the rear sear is pulled down under spring pressure and the forward sear moves up, catching the bent and preventing the rifle from firing automatically.

So the firing pin should remain in the forward or "fired" position until the bolt has reached the end of it's rearward travel and started forward. The "Unneeded part" which you mention is apparently the rear sear.

Your firing pin, according to your post, is not being held back at the end of the bolt's recoil. This could be due to three things:

1. A dirty rifle. Clean it thoroughly, including the floating chamber. Make sure the chamber is "loose" in its recess.

2. A damaged rear sear -- replacement is indicated.

3. A worn bent -- replace the firing pin.

The purpose of the serrations on the plug is to prevent it from unscrewing under the vibration of firing. You should hear a "krraaach" when you tighter the plug, which is the serrations engaging.

 

[TonyWells]

Thanks for the replies.

I'll get some pics as soon as possible. I think I need a min number of posts before I can upload locally, so I may use photobucket and simply link to them if I can do that.

"unneeded" well....the sear housing (fancy screw) has a groove cut in what might be called in some generic cases a "dog point" This groove engages with a tang from another part that I do not know the name of. I have read that it can be a little difficult to reassemble because of the design, so some people have run the sear spring housing all the way in without the rest of the internal parts installed, marked the head on the side away from the engaging side and then removed material from the housing to allow it to drop into position before the threads start, and end up with the threads tight and the unground side of the screw still engaging the other part. I need to locate a good drawing so I can at least get the names right.

I have had the firing pin out, and it is not broken. Worn a bit perhaps, but not broken. The rifle was malfunctioning prior to disassembly.

I'll be back.

thanks for the answer on the serrations. I hoped it was not some adjustment. It didn't strike me as a very good method if so.

 

[Vern Humphrey]

The dog-tooth looking parts are the sears. The part on the firing pin that engages the sears is the bent. Wear on sears and bents can cause the problem you discuss.

 

[TonyWells]

Pics coming. Please bear with me. I am recuperating from a broken femur and just now can get around (more or less) with a cane. My shop is about 200 feet from my home, so it takes a little bit to get there and back. These pictures are not my best. I will set up some lighting and get some good macro shots perhaps tomorrow. I hope these give a few clues.

And by the way (now where is that "embarrassed" emoticon when you need it?) The rifle is a 550-I, and I owe apologies for anyone who wasted time looking for a model -H. I should have been wearing my glasses.

Anyway, here are the pics, I hope.








Comments more than welcome, and if closer, clearer pics are desired, I can definitely furnish. I have a decent camera and some macro lens capability. I was just fatigued from doing more moving today than accustomed to. I spent two months basically on the sofa, sleeping in a recliner. Does wonders for muscle tone.

 

[TonyWells]

Is it possible that the sear spring is incorrect? It sure seems strong when held in place outside the gun. Long spring, lots of compression. Both sear edges seem to be sharp enough, but I'm not against ordering a few new parts, such as the sear spring housing, the sear spring, the upper sear and lower sear. Everything else seems to be low wear and tight. That's mainly why I suspect the PO messed something up.

 

[Vern Humphrey]

A 550 A would have a sheet metal cartridge case deflector mounted above and behind the ejection port.

The sears seem to be a bit worse for wear.

But your first photo shows a bolt-over-base stoppage. This is usually a feeding failure and the elevator (the part that brings the cartridge into the bolt path) may be the culprit.

 

[TonyWells]

Vern, so the worn sear(s) might simply not be catching when the bolt cycles? At least on that part. I will look closer at the elevator.

 

[Vern Humphrey]

That could be. The sear affects timing in this rifle, and the feeding system is always a good suspect in stoppages like this.

 

[TonyWells]

Well, I think I will address the sear issues first, then see what comes of the feed stoppage. Is there anything you can think of that would interfere with the bolt movement so that it would not make the full length travel back beyond where the sear would engage? It seems smooth, both with and without any springs in place.

 

[rcmodel]

If you have a 550-1, it has a Williams Floating Chamber.

It may be carboned up and stuck so bad you can't see it.

But I can assure you it has one.

If the floating chamber is stuck in the barrel, the bolt will not receive enough power to operate the action.

Look harder for it!!

Then remove it and clean it completely..


http://stevespages.com/pdf/remington_550-1.pdf

rc

 

[TonyWells]

It does have the floating recoil chamber, or whatever some people call it. I have found different references to it. It is free in the barrel. I saw no need to remove it since it was already free, but I can and probably will. I'll have this rifle scattered completely before I resolve this, I imagine. But that was one of the first things I checked.

Thank you very much for the link. I'm sure I'll find that useful!

 

[TonyWells]

While I am waiting on parts.....something else crossed my mind. I'm sure most of you are familiar with the common problem with this particular rifle of cross threading the sear spring housing. This one was a little cocked when I got it, so I suspect it has been a problem for the PO. Even with no spring, and no sear in place, I find it difficult to get started straight, from the damaged threads. Is there an accepted method of correcting the threads in the receiver? By a couple of quick measurements, I make the thread to be 3/8-32. I hesitate to simply run a tap through it, because I might not hit the original thread and make a bigger mess of it.

Has anyone made a replacement insert and milled out a pocket and TIG'd it in place with good threads in it? I've got about 40 years of experience as a machinist, and a pretty well equipped shop (I own the business) and could do that with little trouble if you guys think it would be worth it, and there isn't a better way. I realize it's a bit labor intensive, but it seems to me to be a solid fix.

 

[TonyWells]

Well, it took a while to get all ironed out, but all is well with this little rifle. A new sear spring, sear spring housing and a lot of honing rough edges and it works beautifully.

As expected, a complete disassembly was executed to facilitate a thorough inspection. Polishing here and there where obvious rough edges and surfaces existed and a proper cleaning and reassembly seemed to cure all the problems.

Thanks to all for the suggestions and help. Now on to the next problem child, a Savage MK II......starting with a teardown. Might need some help on it if I cannot find the problem. But that's for another thread!

 

[Dave Markowitz]

A 550 A would have a sheet metal cartridge case deflector mounted above and behind the ejection port.

A lot of them were removed and went missing over the years. The 550-1 I picked up a few years ago was missing its case deflector. I got a replacement from Numrich.

 

[TonyWells]

Well, I spoke in haste. Although it does shoot more reliably, it still suffers from the bolt-over-base stoppage. It has improved to average 1 of 10 rounds, better with high velocity ammunition than standard. When I examine the bolt face when this happens, the FP is "loose", as in not engaged with the sear. I did not replace the sears. I cleaned them up with a fine stone and they have nice sharp edges and a crisp release.

Seeing the FP not engaged when I get the jam makes me suspect that either the bolt is not moving rearward enough to hook the sears for some reason or it simply isn't connecting.

On the stoppage, I am not sure what to look for when examining the cartridge stop, or cartridge stop detent. They both move freely, are not bent and I can see no evidence of wear (shiny spots). Part of me suspects the carrier tension spring. Is that what controls how hard the cartridge stop lifts the round being chambered?

Is there an area of the receiver insert that it prone to wear? I'm running out of ideas. I have run the rifle dry, oiled, greased, and dry-lubed.....all making no difference. I would appreciate any comments on what to look for. Oh, and I can get some better pictures now if they would help.

Tony Wells