Repair Advice Appreciated H&R Top-Break 22lr

[John Kloehr]

I have this H&R top-break 22lr DA/SA 9-shot revolver:

 

 

Serial numbers and markings indicate 1940 production or a bit earlier. Last three digits of serial number match cylinder markings. I get soft strike/misfires shooting it DA, but not when shooting SA. The hammer does come much further back when cocked for SA than when if falls shooting DA.

 

With careful testing at the range, I found misfires were more common if I shim the cylinder forward, and did not occur if I shimmed the cylinder back. Difference is 0.011".

 

 

 

 

 

Is it reasonable for me to make a 0.010 washer/shim at the front of the cylinder (see arrows)?

 

 

Or is there another problem which might cause the misfires?

[Sgt. C.J. Sabre, SASS #46770]

I don't know anything about this gun, but given its age, it might be that the firing pin has been worn down a few thousands of an inch. Shimming it back might cause clearance issues. 

[Pat Riot]

Is that a model 999?

 

Gun Parts Corp has firing pins for the 999

https://www.gunpartscorp.com/gun-manufacturer/hr/revolvers-hr/999

[John Kloehr]

20 minutes ago, Pat Riot said:

Is that a model 999?

No, the hammer strikes the cartridge directly, no separate firing pin.

[Subdeacon Joe]

4 minutes ago, John Kloehr said:

No, the hammer strikes the cartridge directly, no separate firing pin.

 

I'm reading that as having the firing pin integral with the hammer.   It could still be that the firing pin has worn just a bit.

[John Kloehr]

17 minutes ago, Subdeacon Joe said:

 

I'm reading that as having the firing pin integral with the hammer.   It could still be that the firing pin has worn just a bit.

Sure, and this gun may have been dry-fired to the point of failure.

 

But welding and grinding the hammer to add material is both beyond my skills and tools, and the gun is not worth enough to pay a qualified smith.

 

If I can learn to figure out if this is the problem, I am always happy to learn something.

Edited February 4, 2024 by John Kloehr

[Rip Snorter]

Why not try to make a moon clip of the correct thickness?  Easy, cheap and the gun is not altered.

[Chantry]

It could also be the hammer spring.  You may want to to try a shim for the spring first

[The Original Lumpy Gritz]

There are tools to stretch(swage)the front of the cylinder. 

Look at Brownells. 

[Subdeacon Joe]

1 hour ago, John Kloehr said:

But welding and grinding the hammer to add material is both beyond my skills and tools, and the gun is not worth enough to pay a qualified smith.

 

Maybe find some place on it where you can get a good measurement on the length of the firing pin.  Take the hammer out and take it to a welding shop.  It might not cost that much to get one bead put on that you can take down with a file.

 

But, thinking about it, a 0.006" shim (roughly half the difference) might be the way to go. Use leather punches to cut it from a feeler gauge.

[Sgt. C.J. Sabre, SASS #46770]

You say that the firing pin is integral on the hammer? What are the chances that you could remove the hammer from the frame, and just peen the end of it just enough to lengthen it enough to work?

[J.D. Daily]

The Numrich exploded view diagram of the 999 shows the firing pin as a separate part.  Besides replacing the firing pin it wouldn't hurt to replace the firing pin & center pin catch spring & to be safe the firing pin retainer pin.

[Buckshot Bob]

More than likely it is the cylinder end shake that is causing your misfire problems. Lumpy is on the right track . Colt DA cylinders have the same type of set up . In gunsmithing school we all made what we called gas ring stretchers for taking the enshake out of colt da revolvers . You would probably be money ahead to find a local gunsmith that can do it . A shim would work but is not what I would consider the “best” fix .

This is the general concept of the tool but it can be achieved in a few different ways 

https://www.brownells.com/tools-cleaning/gun-tools/handgun-tools/single-action-gas-ring-stretcher/

[Buckshot Bob]

Or if you have access to a lathe you can make a new bushing and press it in the cylinder but that’s making the repair more complicated than it needs to be 

[Kid Rich]

Try Triggershims.com. I just purchased some cylinder shims from him.

kR

[Charlie Harley, #14153]

I think your original idea of a shim at the front of the cylinder would work. Cut it from a feeler gauge and see what happens. 
 

This isn’t a gun deserving of too much overthinking. 

[John Kloehr]

Found some stainless washers on Alibaba. Just not a lot of selection on Amazon or McMaster or the other usual machine part distributors.

 

0.1 and 0.2 mm thick, 10mm ID, 12mm OD, 50 count of each. Less than $6 with free shipping.

 

Paid with credit card through PayPal. Should arrive by the end of the month.

 

So until then, thanks for all the input and I will post again in March when I see if they help. Or even if they do not show up. Or if dimensions not as advertised. Whatever, I'll come back to this thread in a month.

[John Kloehr]

Update:

 

Alibaba delivered. On time, as promised, and my payment account has not been hacked.

 

Dimensions are as advertised, I checked both sizes:

 

 

And installed a 0.2mm washer:

 

 

This was so much easier than buying shim stock and cutting and drilling my own part. Next up, does this solve the problem and does the gun run well now... Will update again soon.

 

 

[J-BAR #18287]

Redneck ignition test:

 

Pull/twist the bullets out of a few .22 cartridges with pliers, dump the powder.  Take your gun with the primed brass into the garage.  Wear eye and ear protection and test fire with the garage door closed.  Your neighbors will never hear it.  Saves gas for a range trip in case your fix doesn't work.

[Abilene Slim SASS 81783]

In what kind of shape is the detent in the recoil shield? If it’s peened, that might be the source of you problem. 

[John Kloehr]

Well, one misfire. But found out the gun needs cleaning, the cartridges are not easily dropping in the cylinder bores.

 

SA still runs fine, (sample size one cylinder), DA had one misfile which went bang on the second try.

 

I'll clean the gun and try again, and may also try shimmying to 0.3mm after that.

 

I will also post up pics of the hammer, breech, etc to see if one of you spots something. This might be as soon as tomorrow,

 

Long video (3:30) from the test firing, have a good laugh at least watching me fumble with getting rounds in and out, and forgetting if I was trying to shoot DA or SA:

 

On edit: The second strike on the last round was exactly on top of the first strike.

Edited March 2, 2024 by John Kloehr

[John Kloehr]

1 hour ago, J-BAR #18287 said:

Redneck ignition test:

 

Pull/twist the bullets out of a few .22 cartridges with pliers, dump the powder.  Take your gun with the primed brass into the garage.  Wear eye and ear protection and test fire with the garage door closed.  Your neighbors will never hear it.  Saves gas for a range trip in case your fix doesn't work.

Just felt like getting out of the house, I can shoot in my yard.

 

But all things considered, 2 cylinders of .22lr combined with the drive to the range was enough for today. I'll post up a bit on this in a new thread. I think I'll title it "A Good Day To Be Alive."

[Eyesa Horg]

You are a very lucky man, John.