cratered primers

[thelaw]

has anyone ever noticed if there is a difference from one brand of primer to the next when it comes to the "softness" of a primer associated with cratering? i use winchester large rifle primers for all my rifle loading. i have recently started loading for a TC encore in .260 which has a very strong hammer. i am well below the listed max on my loads and still getting cratered primers. the rifle has a 26" barrel and my velocities are below advertised velocities for a 22-24" barrel. i know cratered primers are a sign of high pressure, but i wondering if my primer just might be too soft. last night i got some federal210s last night to try. andy advice on this?

[huntswithdogs]

I've noticed this same thing with my Encore. Tried different primers, becuse like you, I was not anywhere near reaching a pressure problem with my loads. After trying different brands,I've reached the conclusion that its just a overlong firing pin. The only other thing would be the shell coming back against the frame when firing before the pin can retract.
I quit worrying about it eventually. Now you had to ask this and I'll start to think on it every time I shoot! OH WELL! That just means I need to go to the range for some more therapy this weekend!!


HWDl

[Patriot_1776]

Cratered primers can be tell-tale signs of pressure.  But, as you stated you are still getting them without even approaching maximum loads.  With that, I would say then it could be just the way the primer reacts to the discharge.  Cratered primers alone should not be construed as high pressure; look for other signs with it.  If your primers are cratered and flattened, the face of the cartridge looks "smashed" (or unusually shiny when fired in a bolt gun) to some degree, seemed stuck when you tried ejecting it, or any other oddity you don't see as normal, then high pressure could be certain.  In other cases it could just be a headspace problem, but that is for another subject.

Heh, even if those signs are present when your not near the maximum loads, it just may be the way your gun is.  There are some in which you can't get near the max without severe pressures signs, and there are others which are able to shoot maximum loads, and all looks well.  Its all a matter of how well you know your gun, what your looking for in a load, and how you can or want to get the job accomplished....safely!!!

[dubber123]

I believe CCI's are about the hardest commonly available primers, Winchesters are soft.  I am currently loading both, and you can really feel the difference when seating them, in fact it is pretty easy to crush the Win primers.  As mentioned, besides high pressure, a long pin can cause cratering, and I feel the biggest culprit is an oversized firing pin hole.  This gives the primer more room to flow rearward around the pin, and is a fairly common occurence in old style S&W's that have a lot of miles or abuse on them, as the older hammer mounted firing pins can eventually enlarge the pin hole.  I had to file a pretty large burr off the inside of the frame of my old mod 10 after about 40,000 rounds, (and about the same amount of dry firing).

[thelaw]

i really don't know if i should be concerned about it or just load up to near the max and go shoot. i just looked at my fired cases and the primers are not flattened, but they all have the cratering. all of the fired primers still have the rounded edge on the butt of the primer.  i have some brass from my buddy's .25/06 encore, which was bought at the same time my .260 was. the .25/06 brass is from some federal premimum accubond loads which i know know were hot because all of the cases have distinct flattened primers (no rounded edges or cratering) and they clocked 100fps. more than the factory specs for the round out of a 24" barrel. i'm going to try see if there is a difference between primers, win.(what i use in my 260) vs fed. (what are used in the 25/06). if you can think of anything else, please chim in. thanks

[thelaw]

also i might add, all the 260 cases are sized and measured to .0015" headspace, which is i see all the "pro" encore shooters recommending.

[PaulS]

has anyone ever noticed if there is a difference from one brand of primer to the next when it comes to the "softness" of a primer associated with cratering? i use winchester large rifle primers for all my rifle loading. i have recently started loading for a TC encore in .260 which has a very strong hammer. i am well below the listed max on my loads and still getting cratered primers. the rifle has a 26" barrel and my velocities are below advertised velocities for a 22-24" barrel. i know cratered primers are a sign of high pressure, but i wondering if my primer just might be too soft. last night i got some federal210s last night to try. andy advice on this?

Before I make any comment on what the problem might be I would ask you to share your load.
There is a difference between the deep impact that an over-extended firing pin would make and a cratered primer. A cratered primer has a ridge around the pin strike that is raised above the primer cup on the outer diameter of it. A deep pin strike has a deeper than normal (.060") indent in the cup but no other deformation of the cup metal. A cratered primer is a sign of over pressure when the primer cup is pushed into the firing pin hole by pressure which makes the cup metal flow into the hole and around the pin. If the hole in your breach for the firing pin is oversized then even at normal pressures it might flow into that gap and cause a crater look. Cratered primers are usually accompanied by the loss of or reduction in the radius on the outer edge of the primer cup after firing.
So, what are you shooting: bullet, powder, case, overall length - tell me all you can about your load and what book you are using and the start and maximum listed loads. Then I can tell you more about what might be causing your condition.

[thelaw]

here you go,
hodgdon website:
.260rem. with 24" barrel

rem. 9.5 primer & rem. case
120gr. speer/COL 2.780"
H4831               50.0C
H4350               46.5
H414                 45.5

My load:
260rem with 26" barrel

win. stan. rifle primer & rem. case
120gr. speer (col 2.775)
120gr. nosler bt (col 2.810)
H4831               48.0
H4350               44.5               (all of these still show the crater effect)
H414                 44.0

i really wonder if its not gun. wouldn't the primers still want to flatten out if they were hot loads, because mine certainly don't?

[beemanbeme]

a cratered primer in and of itself came mean a lot or very little.  A cratered primer is a sign of high pressure only if it is associated with other signs.  If you still have a radius on your primer shoulders, the case extracts easily, no extractor marks on the case head, and you are below book limits (a chrony would come in handy here) then I wouldn't worry about it.  Its not a problem in itself.  Changing to another --harder-- primer that doesn't crater doesn't fix the "problem".

[thelaw]

i am using a chrono and most of my velocities are below the book numbers. the only thing i notice about extraction is that when i open the breech(remember its an encore) the cratered primer can be felt scrapping the breechface slightly as you open the action.

[PaulS]

thelaw,

in the Speer #13 manual these are the maximum listed loads for the 260 Rem, 120 grain spitzer-sp, at an over-all length of 2.720

H414 listed 42.5 to 44.5 with top velocityies from a Rem. 700 24" at 2895

H4350 was not listed in the Speer#13 only IMR4350 - totally different load so I will omit it

H4831 wasn't listed specifically but 4831SC was listed at 45.0 to 47.0 with top velocity of 2762
none of these powders recommended compressed powder charges with this Speer Bullet

Overall Speer recommends lower charges than you list from Hodgdon - up to 3 grains less. At this point I would call Thompson (or look at the load information that came with the gun) to find out what they recommend as a load with that combination of components. Sierra is another good place to call for information when you get "wierd oozing from a load".

From your description of the primers you are getting pierced primers NOT CRATERED primers and at the very most it can damage your gun. By all means go to a heavier primer - thicker cup - and see if all the symptoms go away.
Take a look at your firing pin through a magnifier (at least 10x) to see if it has a sharp point or as it should, a nice round radius. Measure the primer protrusion - it should be no more than .060". Check the hit between the pin and its hole in the breech - it should fit very close - You can measure the diameter of the pin tip and with a taper guage measure the hole - anything over about .005" clearance is more than you want.
At this point- with the information that I have I would bet that the pin hole is too big and that is where your problem is. Whether TC will do anything about it is another question - write them and ask how big the pin hole should be and what the pin clearance is - if yours is sloppy then send it to them to fix - or just find and use a primer that is tough enough that it is no longer a problem.

[thelaw]

i inspected the firing pin and it is nice and rounded. i got almost the exact same measurement for the pin as i did the pin hole in the breech face. all the loads i've loaded (some 12-15 different ones) are below listed max for the data i got. i'm about ready to chunk the encore. i'm going to contact tx monday and see what they tell me. i may just sell the barrel and try another one.