Thread: Cratered Primer

So I'm wondering if this is an issue for me in terms of my gun or the load because even my factory load primers don't appear to be much different. My bolt since new with factory ammo has always been firm to close. 1st photo is factory round, 55g federal sp and the reloads are 35.5g AR2206h with federal primer.

I'd say it's normal an agressive firing pin spring, with good protrusion and a little clearence around it in the hole in the bolt face.

Since you get it with factory ammo, your rifle probably has a firing pin that is a bit of a loose fit for the hole in the bolt face.
Though in the photos the reloads look a bit worse, and you are at max load on the ADI website, which may be above max for your rifle. Zooming in, it looks like there is an ejector mark on the bottom case too - where the 25 is in the 250 part of the headstamp.

Other more qualified people may have different comments.

brand of firearm?

Note also federal brass is often thicker than most brands, so book max plus federal is possibly getting into overload territory. Does look like an ejector stamp so time to back off I’d say.

Greetings Charliehorse,
A good question would be what was the velocity and was this in line with the ADI/ Hodgdon data. If it was then your pressures should match theirs reasonably well. The slight mark on the lower case looks like a stamp mark to me. You get these with plunger extractors where the edge of the extractor hole is a little rough. I can't see a shiny rub mark though that would indicate a high pressure load. Have a look yourself in good light. You may also wish to check that the projectile is not too close to the rifling. This or a tight chamber or bore should show up on the chronograph. I wouldn't read too much into the primers.
Regards Grandpamac.

Originally Posted by greghud

brand of firearm?

It's a Bergara HMR, I dont have a chronograph so have no exact way other than trying the crude 100-300m drop with a ballistic calculator. Be a real shame if I have to drop this load but if that saves my gun and myself then so be it. I'll go through my brass tomorrow after work. Would the shiny rub mark be consistent on all cases?

Maybe .3-.5 gn over but I'd inspect a few then fire them and re inspect. Could be from load development or near max and the odd one with .1-.2 more than others.
As for the craters that is the same as my bergara although different caliber. They copied remington a little to well including some of their faults. Be careful setting your dies up for full length sizing as your verniers and head space gauge will be measuring the raised crater not the base so you won't be getting a true or accurate measurement for bumping the shoulder back and/or over working your brass. De-prime a few first to set your dies correctly. As others have said doesn't look like impending doom but just do the usual checks. Nice group by the way

Greetings Again,
I sure would not be in any hurry to meddle with any load that shoots that well and especially not based on the dubious art of reading primer appearance. I suggest that once the current pandemonium has subsided find someone with a chronograph and chronograph the load. This will tell you if the pressure is hot or not. I believe from a previous thread that you may be neck sizing your cases. 22-250 cases become tight in the chamber quite quickly due to case taper so if you are getting two loads or more before full length sizing becomes necessary then pressures are moderate. Federal .308 cases are indeed heavy with reduced capacity but Federal .223 cases are the lightest available. A shiny rub mark due to high pressure would show up on most cases but I just don't see one in the photo.
Grandpamac.

Thanks all. I'll have a suss out tomorrow

My 300 Rum craters everything, factory and reloads, some rifles do most don't. Dropping your reload by .5 grain my stop the slight ejector mark and may not affect the accuracy. It sure shots that load you have got very well.

I did wonder when I saw the possible ejector mark if it might be from an earlier loading, as the marks are normally shiny. But also could be dull if it's a while since that round was fired.

I had similar concerns with a rifle many moons ago. Like yours, it had the primer-flow around the pin, with nothing on the edges (primers still nicely-rounded rather than flattened to edge of pocket). It was suggested back then, to have the pin-length relieved slightly, as the first and simplest (also cheapest) attempt to remedy things. It did work, primers looked much better, with very mild flow. All mine looked like your 3rd pic (bottom one), or even a tad worse. Any gunsmith could do this, without compromising the pin-function, going by the depth of penetration your pictures show

Okay so had a look at my twice fired brass and of the 30 odd theres 4 with decent ejector marks and a couple in the 3x fired

I've gotten through a fair few loads in the last 2 weeks so I will pre inspect the 2 loads I have ready to go and give them a good going over after firing. Find the culprit load and start backing off.

Read a few US forums last night and theres also chat on there about the primer issue with Bergara.
.

Further suggestions are more than welcome. FL sizing?

There seems to be a lot of clearance around that firing pin either that or its an optical illusion