Rem 550 I

[Tony Wells]

Any of you Smiths out there have a decent breakdown of the .22 semi rifle? I have one that refuses to consistently engage the sear, I believe. At least that's my guess. It will cycle by hand perfectly, but actual shooting, every few rounds, at random, the firing pin is not locked back and since it protrudes from the bolt face, prevents the next round from "sliding" into alignment with the chamber so of course it jams. I'm open to any ideas.

I know the sear spring housing is a bit tricky to get in, and I am not the first one to work on this rifle. Yes, the sear housing was crsos-threaded, but I have all of that straightened out. Since it seems to shoot normally part of the time, I believe (and best I can see) that the spring and housing are all in place correctly.

 

[Ulma Doctor]

i'm not a smith, there may be mechanical problems, but.
i had a couple old semi-auto's that were very particular as to what ammo it would accept and cycle correctly.
CCI mini mag,Remington (yellow jackets or thunderbolts), and winchester ammo is on the top of my list, for jam free op
some slow burning ammo can gum up old actions

 

[Silverbullet]

I too think some dirt is a cause. But you may have a burr or a bend in the pin or the slot hole. I have one just like it and mine digests anything and I'm betting in the past 40 plus years it's shot well over half a million rounds. One of the best 22s EVER made in my book. Shoot its not even cleaned till a thousand rounds are put thru it. Now I want to do some plinking have to call my nephews and get a couple bricks of ammo.

 

[Tony Wells]

I misstated the model number, to begin with. It's a -I, not H. I have come to the conclusion that the bolt is either not cycling back past the sear catch point, or the sear is simply worn out. I'll be ordering some new parts over the weekend. Not worth making them.

Mike, I've tried a half dozen different types of ammo, but always the same. I'm convinced it is a mechanical failure. Just have to find it.

I agree.....very fine rifle. One of the best, for sure. This one is a very nice example. I just wish some ham fisted mechanic hadn't gotten his mitts on it before I got it. It has a quirky little sear spring housing that lots of people seem to have trouble with. I had to iron that out first, hoping it would solve the problem, but no.

 

[dulltool17]

Tony- have you looked on Rimfire Central? Has all sorts of good info. I had problems with my Marlin 60 and found a solution there; perhaps there's some folk there that can help out.

 

[Tony Wells]

Yes, I did. I tried to join that forum, but technical difficulties prevailed for the time being. I saw references to "thehighroad.com" and joined there. Got some help pretty quickly. Reminded me of this place.
http://www.thehighroad.org/showthread.php?p=10293522#post10293522
Looks like I'll be ordering a couple of parts. Namely the firing pin, the lower sear, the sear spring housing, and sear spring. I think that will cure the problem of the firing pin not catching on the bolt cycle, but after posting a pic of a typical fail-to-feed, it was pointed out that the feed mechanism (elevator) may play a part as well. I know the firing pin is a definite problem, but after looking closely after a misfeed, I'm not so sure every malfunction is caused by the firing pin hanging the round. All of them don't seem to make it high enough on the bolt face to say the pin stopped them. But I will eliminate what I can, then address the elevator problem.

Thanks for the recommendation. That seems like a good site. Once I get this one going, I have a near basket case to work next. It's an old Rem 581 bolt action, and after all the mechanical is fixed, it needs serious cosmetic work. I think I will fire up my manganese phosphate tanks and see if I can get a decent version of a Parkerize. I'll be haunting both those sites, I'm sure.

 

[Rick Leslie]

My experience has been that the vast majority of FTF problems in semi rimfires is due to dirt or debris. A good disassembly and scrubbing should put things back in order. At least that will eliminate one possibility.

When I was 'smithing full time I never tried to diagnose a dirty gun. My customers understood that they would be getting a good cleaning first.

I will say that the 22 rimfire is one of the most finicky rounds to go through a semi action. Sometimes it's as simple as swapping ammo. Others it will keep you awake at night. Good luck and please let us know what you find.

 

[Tony Wells]

I know what you mean, Rick. First things first. A .22 doesn't have a lot of force to begin with, relative to larger caliber rounds, so dirt has a huge effect on function. On this particular model, it h a reputation of running CB's just fine, so with nearly any standard LR round, I wouldn't expect cycling problems. This action came to me pretty dirty, so yes indeed....a good cleaning is the first thing it got....except...there is a floating chamber in this unique rifle, which if I understand correctly, gives it the ability to reliably fire low energy rounds. Most people recommended that I remove that floating chamber, but it was already very easy to move and obviously not sticking so I did not. If the problem of not catching the sear was only with squib loads, I might buy that diagnoses, but it happens with every type of ammunition I tried (I have on hand about 6 different brands and bullet types just for this purpose). I feel justified in saying that the floating chamber is not the cause. If, after I replace the handful of parts I stated above I still have the same problem, I suppose I'll remove it and make sure, but at this point I just can't see it contributing to the problem.

Since this is a fairly unique action, and odd problem, I'll be sure and let everyone know what it took to fix it. It WILL be fixed. I put up a couple of pics on the other site, but I'm not proud of them. Seems I can't hold my good camera still enough with these nerve damaged hands, and didn't feel like setting up the tripod and getting my light set up for some good macro shots, but I will, and I'll put them up here too, and maybe someone will spot something I missed.

I would like to ask an opinion here though. Since I am supposing that the sear fails to catch on the bolt return, is it safe enough (as an experiment to prove bad sear surfaces) to take a hone and deepen them a little, and sharpen the edges to perhaps make it easier to latch? The sear spring seems more than strong enough, so I'm thinking just a few thousandths more of sear engagement would only mean a little more trigger creep.

 

[Rick Leslie]

It's worth a try. Inspection of the engagement surfaces should reveal some wear and/or rounding.

 

[Bluedog]

I'm not a smith, just a tinkerer. I worked on one a few years ago that just needed a deep cleaning. After taking it apart I discovered the difficulty involved in reassembly. I read about the option of grinding away a portion of the case and the sear lip to allow it to go together easily but I refused to do that. After a lot of cussing and dreading the thoughts of taking a box of parts to a real smith, I finally got it back together and it functioned perfectly. Probably no help here, but I have a few pages of exploded diagrams and a parts list if your interested. Probably nothing that can't be found with a Google search.

After working on this one, I was so impressed with the rifle that I bought one in good condition for myself.