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P-64, DAO modification

Posted: April 22nd, 2006, 3:16 pm
by dutchuncle
The P-64 meets my needs for a self-defense pistol, but I had always been concerned by the tremendous disparity between the DA and SA pull, especially with the 17# Wolff spring "fix". The SA pull is now about 3#. In a stressful encounter, the adrenalin would increase the risk of an unintentional discharge after the first shot, which could have disastrous consequences and serious legal ramifications. (This is why most police dept's mandate DAO pistols.)

I had a brainstorm I want to share with you all. By removing a few small parts, I have converted my P-64 to and excellent DAO pistol, with the option of quickly restoring it to original configuration if I wish.

If you remove the slide and look down, you will see a small coil spring riding on a guide rod. This spring puts tension on the SA sear. By driving the small cross pin out, you can remove the sear and sear spring. The guide rod now flaps around loosely. I remedied this by cutting a small finishing nail (.072 diam.) to just shy of 5/8" and inserting it in place, effectively preventing the guide rod from moving. You can't use the original pin, as it will cause the guide rod to impinge on the front edge of the hammer.

I just returned form the range after putting 100 rounds of Wolf, Brown Bear and S&B through my new DAO, and it functioned flawlessly! With the hammer quickly following the slide into battery, I was concerned about the possibility of a slam fire, but this didn't happen. I examined about 20 of the chambered rounds, and saw no dimpling of the primers.

I am not a gunsmith, and don't even play one on TV, so I can't warrant this modification. You will proceed at your own risk. Still, this procedure is for me and elegantly simple way of making my P-64 and effective DAO handgun for self defense.

P-64, DAO modification

Posted: April 22nd, 2006, 4:18 pm
by abwehr
dutchuncle,

Thanks for sharing this information, there may be others that want this modification.

Remeber, that any modification to a firearm is done at your own risk!

P-64, DAO modification

Posted: April 22nd, 2006, 8:21 pm
by amd6547
As some have had broken safety issues, I would be concerned that the hammer might be impacting the safety. I havnt changed my springs and wont. I am not a fan of double action only, it limits your potential accuracy. As you are concerned about "liability", what about a lawyer claiming your modified pistol caused the miss that hit an innocent?

P-64, DAO modification

Posted: April 23rd, 2006, 8:38 am
by butch50
That is an interesting idea - can you by any chance provide a photo or two to go along with your description?

P-64, DAO modification

Posted: July 31st, 2006, 5:00 pm
by pshootr
DUTCHUNCLE wrote:
<If you remove the slide and look down, you will see a small coil spring riding on a guide rod. This spring <puts tension on the SA sear.

I would have a problem with this modification for the following reason: The "SA sear" is the sear, period. It engages the single action notch in the hammer for SA firing, true, but it also engages the safety notch in the hammer when the hammer is down. Try this with your P-64: After checking that the pistol is unloaded and the chamber is empty, press forward on the hammer and note how far forward it goes. Now pull the trigger all the way thru, dropping the hammer, and without ever releasing pressure on the trigger push the trigger all the way forward again. Note that the hammer now goes further forward. This allows the hammer to contact the firing pin. In the first example the hammer is stopped by the safety notch engaging the sear. In the second example the trigger has released the sear and the hammer is free to travel forward and contact the firing pin. If you remove the sear there is nothing to keep the hammer from striking the firing pin if you were to drop the pistol on it's hammer or otherwise strike the hammer a hard blow from the rear, unless the manual safety is engaged. Also, if you dropped the pistol muzzle first there is nothing to keep the hammer from moving forward under the influence of inertia and striking the firing pin.

P-64, DAO modification

Posted: July 31st, 2006, 5:04 pm
by bzinggg
PshootR,

Thanks for that excellent post.