Shorten the hammer spur on a NAA Mini Revolver?


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David Sinko
January 30, 2012, 02:14 PM
For years I've had a.22 LR NAA Mini Revolver. Ignition has always been somewhat spotty, with about one in 15 rounds failing to fire using various brands of ammo. I was looking at this revolver today and wondering if shortening the excessively large hammer spur could make the hammer fall faster and improve ignition. Any thoughts on this? Over the years I have removed the hammer spurs of S&W DA revolvers of J, K and N Frame sizes with no negative effect on ignition. Same for a couple of Ruger DA revolvers. Is there any reason to think this would not work with the Mini Revolver?

Dave Sinko

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drsfmd
January 30, 2012, 02:23 PM
Hmmm... I've never heard of this being done before. I wonder if the bobbed hammer would have enough mass (and inertia) to reliable ignite primers?

David Sinko
January 30, 2012, 03:00 PM
I had the mass and inertia discussion with Hamilton Bowen years ago when I ordered a Redhawk Alpine Conversion. I requested that he remove the hammer spur and he was reluctant to do so, saying I was the first customer to ever ask him to do it. He believed it would compromise ignition for these same reasons. I explained that I have seen some S&W revolvers with extreme hammer mass reduction and this process in and of itself does not compromise ignition, though at the time I wasn't so sure if the same applied to transfer bar ignition. In the end, Bowen did completely remove the spur and the gun fired DA and SA just fine. I don't own any other SA revolvers so I'm just wondering if I might be missing something from the SA aspect.

Dave Sinko

drsfmd
January 30, 2012, 06:29 PM
Dave, there's a huge difference in mass between a S&W Hammer and that little bitty chunk of sheet metal that makes up the hammer of a NAA...

I would suggest you call NAA and ask them if anyone has done this. Our experience has been pretty good with their customer service from them.

25cschaefer
January 31, 2012, 12:10 AM
I think, with that itty bitty hammer, I would look at the springs first.

David Sinko
January 31, 2012, 07:34 AM
Sheet metal??? That's a bit harsh. Whatever it is, it was made in a mold. You can see the mold line.

Are my expectations too high? After all this is a .22 rimfire. Is it normal to get one misfire every few cylindersful with one of these things?

Dave Sinko

dsink
January 31, 2012, 08:55 AM
I have one in 22 mag, granted I havent shot it alot but I have never had a misfire. You will probably want to look at the springs and leave the hammer alone.

Old Fuff
January 31, 2012, 09:15 AM
.22 ammunition can be part of the trouble, because sometimes the entire circumference of the rim doesn't get filled with priming compound, and this is especially true of the cheaper bulk brands sold at big-box stores.

It is also harder to set off rimfire ammunition vs. centerfire primers. For that reason .22 and .22 Magnum revolvers have stronger mainsprings, all other things being equal. However stronger springs are difficult to fit inside a mini-revolver.

Another approach is to check and see to be sure the hammer isn't rubbing something so the added resistance softens the blow.

Were I to decide to lighten the hammer (which is unlikely) I'd drill a series of holes in the body rather then shorten the spur and make it harder to cock.

drsfmd
January 31, 2012, 09:22 AM
Sheet metal??? That's a bit harsh. Whatever it is, it was made in a mold. You can see the mold line.

I know, I know... I was being illustrative, but apparently it didn't work.

Is it normal to get one misfire every few cylindersful with one of these things?

No, but again, what you are proposing will make it worse, not better.

David Sinko
January 31, 2012, 09:39 AM
What exactly is this hammer made of? Is it stainless steel? I have successfully modified forged S&W hammers, MIM S&W hammers and cast Ruger hammers. Is it possible that the material is not one of the above?

I don't see any rub marks anywhere on the hammer.

Frankly I believe the spur is excessively large. Even if the grooved portion is removed there should still be enough spur left behind to effectively cock the hammer when the gun is drawn from a pocket. And then I'd be able to actually see the sights too!

Dave Sinko

murf
January 31, 2012, 05:52 PM
are your misfires all with the same chamber, or random? could be a problem with the cylinder.

murf

351 WINCHESTER
January 31, 2012, 07:29 PM
Before you do anything to the gun try different ammo as rim thickness will vary. Magnums are harder to set off than centerfire as are the .22 rimfires.

reppans
January 31, 2012, 09:28 PM
I just picked up an NAA Wasp...

Only fired 100 rounds so far, but I did have one light primer strike on a .22 mag. The indentation on the rim was noticeably lighter than the rest of the hammer strikes. I'm almost certain that mine was due to the fact that the shell was not fully seated in the chamber so that when the hammer struck, the whole shell/rim traveled the last 0.05" along with the hammer, effectively absorbing much of the ignition blow.

After 20 or so rounds the chambers start fouling and I'd have to push the rounds in to make sure they were fully seated... didn't have another instance after doing that, but I wouldn't say that's foolproof due to recoil potentially dislodging them again. It's best to keep this gun clean if it's going to be used for self-defense duty, period.

btw, I also noticed a propensity for this gun to keyhole when dirty. After cleaning it, I can clearly hear the shells freely sliding back and forth that 0.05" when you shake the gun.

pss, I was absolutely amazed at how accurate this little gun is (once you figure out how to hold it). I initially bought it as a novelty item, but I now think I want trade my LCP in for another one :D.

cerberus65
February 1, 2012, 07:18 AM
You should definitely call NAA about it. I've got a bit over 500 rounds through 2 of their .22 LR guns and the few rounds that failed to go boom all cooperated the second time once I rotated the round and tried again.

reppans, I'd be curious to hear how you hold it. One of mine has the folding grip and I'm way more accurate with it than the other. So I'm always looking for ideas. And I suspect I'm not alone.

reppans
February 1, 2012, 10:58 AM
cerberus65, would be happy to.

OK just for reference, a finger has 3 knuckles with the 3rd being the big one where it joins the hand. Also, I think it's agreed that only real control issue with the NAA is upward muzzle flip.

I use a strong-hand one-fingered grip with my middle finger at the bottom of the grip, 2nd knuckle pointing forward toward target and underneath the trigger.... not up high behind the trigger (which interferes with the trigger pull). Ring finger is curled up underneath the grip. Then I use the very tip of the index finger for the trigger pull .... it gives the best feel for me.

Now wih the weak hand, I use the first knuckle of the index finger to support the bottom strap, leaving just enough room for the trigger finger behind it... (make sure you're far back enough from the cylinder/barrel gap so you don't get burnt, not hard with the mag cylinders but may be difficult with the LR and short cylinders). Then I use the weak thumb to cock the hammer - but here's the important part - after cocked, I use the weak thumb to put downward pressure, as much as I can, on the backstrap just behind the cocked hammer.... it's the only place to put downward pressure to counteract the muzzle flip that doesn't compromise sight picture or ignition.

Here's another idea that I want to try at the range, incorporating someone else's method of holding.....

With the weak hand, use a 2 fingered grip with the index finger tucked up high behind the trigger, with the flat spot between the first and second knuckle directly behind the trigger so it doesn't interfere with the pull. Then again use the thumb diagonally across the backstrap to apply the downward pressure.

Then lay the strong hand thumb over the weak hand thumb to cock, and then move it to form a "V" around the cocked hammer for a second downward pressure point on the backstrap. Once again, use the very tip of your strong hand index finger on the trigger.

As you can tell, I think the key to accuracy with this gun is to apply as much downward pressure on that backstrap, as close to the hammer as possible.

Let me know if either of these work for you.... have fun..

BTW, here's a 10 shot group @ 30 feet with that hold..... (I flinched on one or two ;)) CLICKY (http://farm8.staticflickr.com/7004/6777276243_e296d46b8d_z.jpg)

David Sinko
February 1, 2012, 11:35 PM
I think I'm starting to figure this out. It seems the cleanliness of the chambers is the key. When the chambers were dirty I was getting at least one misfire per cylinder. With a clean chamber I can go at least four cylinders without a misfire. It seems that the slightest bit of fouling does indeed absorb the energy of the hammer fall. And to think I have been hating this gun all these years!

I have concluded that the hammer is MIM. In addition to the mold marks, there are "sprue" circles on each side. I guess the hammer could be shortened a bit but I don't think I'l bother. The part that obstructs the view of the rear sight is the hammer nose, not the spur. No way to fix that.

This afternoon my friend showed me his earlier dual cylinder model. He cocked the hammer and the cylinder spun freely without stopping. Definitely not normal. The cylinder stop stays in the down position and will not snap up to lock the cylinder. I don't know what he did to it, but it looks like he'll have to send it back to the factory. At least now mine seems serviceable and reliable.

Dave Sinko

cerberus65
February 2, 2012, 10:31 AM
Glad you got it figured out!

I wonder though if maybe your chambers are really tight. The cylinders on my minis aren't super loose but if you turn them upside down all the unfired rounds will fall out. Does your do that?

reppan, thanks! I'll give those two ways a try the next time I get to the range.

reppans
February 2, 2012, 11:50 AM
I think I'm starting to figure this out. It seems the cleanliness of the chambers is the key. When the chambers were dirty I was getting at least one misfire per cylinder. With a clean chamber I can go at least four cylinders without a misfire. It seems that the slightest bit of fouling does indeed absorb the energy of the hammer fall. And to think I have been hating this gun all these years!


hmmmm, guess you never had the chance to read my post #13 above? :confused:

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