9mm Kimber Micro9. I'm getting this odd brass spot in the firing pin indent. I get these in CCI SP but not in what I assume to be Winchester in some reloads from a small commercial reloader; or if I do its hard to see in the brass-colored primers. My theory so far is the firing pin strikes, bounces back, or is pushed back and the primer metal flows into the channel, then the nickel plating is sheared off as the case is ejected. Anybody seen this?
Last edited by alfadan; 02-03-2021 at 05:48 PM. Reason: words are hard
Could it be a brass primer cup and guilding being smeared off under pressure?
Check to see if you are finding shavings in the firing pin channel or other parts of the action. If these are from your reloads you might double check the data if this is a fast powder.
That's the strangest spent primer I've ever seen. Notice it still has the radius...
Two options that may or may not be related. First is an over size firing pin hole and or over pressure with the load. The primer is blanking enough so that the plating is getting wiped off and the original firing pin indent is being closed.
Primer blanking is an issue that needs to be addressed. If it only does it with loads from the one small commerical loader I would start there. If it does it with a variety of loads it needs of go back to Kimber.
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A couple more details. The odd looking ones are my reloads, with 3.5gr 700x 124gr rn at 970 fps. I've taken the pin out and found two very tiny slivers of brass. Next step is to measure the pin and hole. I've never seen this before even with milsurps that have primer flowing.
+1 Primer smearing.Originally Posted by Soundguy
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They don't look hot, or they'd be flattened without the radius...
Running my clubs indoor range I find a lot of factory ammo with primers that look like the one you found. Oversize firing pin hole allows brass to flow around the firing pin and gets wiped off on extraction.
Near as I can tell, the spot is about 40mil bigger than the firing pin hole. The pin is a very good fit.
Is there a difference between primer smear and wipe?
I have read and seen the patterns discussed above, and the explanations for them seem reasonable, but I've also seen "comma" shaped FP marks described as wipe in pistol rounds, and the explanation offered was under springing the recoil spring (a common mod in action pistol) along with a high pressure, high velocity load.
Normal for a hot loading.
Firing pin not in contact with primer, on yours.https://www.thehighroad.org/index.ph...er-swipe.2998/
Last edited by 243winxb; 02-04-2021 at 04:21 PM.
You have a odd one. First thought was brass on the firing pin but your pictures show otherwise. The only thing I could think of is the extractor is letting the case move forward on impact and the primer balloons backwards then is flattened when the pressure peaks. The only other thing I could thing of is weak firing pin spring or hammer spring. Check the extractor and springs. When you find the problem please do let us know.
Never seen that before and I've looked at a lot of brass over the years.
Speer data.. I am loading 700X @ 3.2 grs with Lee 356-120-TC .3568" diameter. OAL 1.045" WSPM. My primes not as bad as Rem factory ammo.
My firing pin hole.
Last edited by 243winxb; 02-04-2021 at 03:23 PM.
Been reloading a very long time and that pic is a first for me. I won't hazard a guess as I don't have the pistol in hand, but can you pry the brass piece/smear off the primer? I'd try picking it off with a dental pick sorta tool. Might help determining if the primer is "flowing" or a piece of brass is being deposited on the primer...
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Deprive.. Check the cup.. What is it made of vs others not doing it. Tinned brass cup?
I picked at it and it wont come out. I then filed it and ended up with just flat brass with no perceptible indent. Deprimed cup looked normal. The brass spot is the cup metal with the nickle plating sheared off.
Most of my cases plunk deeper than the barrel hood and read an average of .741 sized. I think these reloaded cases are a bit short allowing case movement.
I used magnum primers, WSPM for my 700X -3.2 gr loading & Lee 356-120-TC . Less chance of primer problems @ 38,500 PSI +P loadings. If you load hotter.
Seating depth , a shorter OAL, is said to greatly increase pressure in pistol rounds. Plastic frames are not KABOOM friendly.
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