What causes/fixes primer drag?

D

dyl

New member
I don't have a problem with primer drag. I don't have a sig p365 (known for primer drag). But I do have a Kahr CM9 which is smaller yet doesn't have primer drag.

Here's how I imagine it happens: after firing the barrel starts unlocking / dropping down while the firing pin or striker is still extended outward. The case stays in place because the extractor claw and the chamber walls hold the brass oriented facing forward and tight to the breech face. Then the striker has a chance to retract at some point while the case is extracted from the chamber. Then later the back of the casing hits the ejector and end of story.

So is this essentially "early unlocking"? The larger p365 XL doesn't exhibit primer drag. Did the extra weight of the slide delay cycling speed, or did they delay the unlocking process? How did they fix it?
 
H

HisSoldier

New member
In the 1911 this is known as a symptom of firing pin problems I think. following are two discussions;
https://pistolsmith.com/reloading/2334-firing-pin-drag-marks-primers-45-a.html
https://forums.1911forum.com/showthread.php?t=239619

I'm also "partsproduction" in some forums, and I'm the one who suggested possible undue elongation of the FP hole over time. I know this does occur because I've seen fixing the hole mentioned, but it must take a heck of a lot of firing over a long time and is probably an extraordinary occurrence.

I agree with Dave Berryhill that it's probably not a big deal. Easy check, buy a spare FP and shorten it .010" (round the end the same etc after) and see what that does. It shouldn't cost too much to try that, or even cheaper, try a slightly stronger firing pin return spring.
 
G

gnystrom

New member
Well I do have a couple of P365's and both have what is termed primer drag or primer swipe. One has 7000 rounds the other is less than 1000. Both are early manufacture guns and personally I don't care what the spent primer looks like as long as the gun goes bang every time I pull the trigger. So far, both do.
 
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