Re: Bolt face dent's? Savage 338 lapua
This looks like an overpressure situation. The primer flattening and difficulty opening the bolt indicates overpressure. In a semi-auto gun (like my LaRue OBR .308) you get "pressure swiping" which is a mark on the case head as the case sticks in the chamber for a fraction of a second as the bolt turns to eject.
The most likely cause for this is that your chamber throat is a few 10/1000s to short, and/or the chamber is very slightly undersized.
One of the keys to accuracy in either a bolt or semi gun is how far the projectile has to "jump" to contact the lands in the throat of the barrel. Extreme high precision shooters who handload will use various methods to determine exactly what the maximum overall length of the cartridge must be in order for the ogive of the projectile to just barely NOT touch the lands. I use Dykem steel bluing (a purple marking liquid painted on steel when laying out and scribing lines and holes on steel) and a set of dummy rounds using ONCE-FIRED and carefully resized and trimmed cases to determine the exact bullet seating depth that keeps the ogive just off the lands.
If the overall length is too long on any specific cartridge, when you close the bolt the ogive is physically jammed against the lands, and this, for reasons I don't clearly understand, can cause a massive increase in chamber pressure as the round goes off, sometimes to dangerous levels.
The marks on your bolt face and the primer flattening are clearly indicative of overpressure and I suspect that what you have is a "tight" chamber and throat that doesn't handle factory-loaded ammo well because of the manufacturing tolerances in OAL that occur with all factory ammo.
You can test this by using a precision micrometer OAL length gauge that simulates the throat where it contacts the ogive of the projectile on a new box of factory ammo.
Mike every round and record the precise OAL on a matrix chart showing which round is which. Systematically load and shoot one round at a time, placing the empty case back in the same position, and record any other evidence, such as difficulty in opening the bolt.
When you've shot the entire box, inspect each case for primer flattening or pressure swiping (if it's a semi) and note the evidence next to the OAL measurement for the respective round on the matrix chart.
I'm betting that you will find a correlation between "long" OAL's and indications of overpressure.
In precision rifles the manufacturers tend to make the chambers and throats "tight" as compared to an ordinary combat weapon precisely to enhance accuracy, and they probably assume that anyone who is really interested in precision shooting knows about the effects of OAL on accuracy and chamber pressure, and they expect real shooters to hand-load their ammo to very precise specifications that take advantage of the precision of the chamber to maximize accuracy.
As good as factory "match" ammunition may be, there is simply no substitute for a worked-up load for your specific rifle, which will give you both maximum accuracy out of THAT weapon and will also give you the very best possible repeatability.
You can also get a glue-on stress gauge and reader that allows you to expoxy (temporarily) the stress gauge to the outside of your chamber and record the actual chamber pressure as indicated by the bulging of the metal. This can be expensive, but it can also give you good data on the accuracy of your hand-load and the overall spread on velocity/pressure differences, which can help in diagnosing accuracy problems that may be solved by changing primers, powder, cases, projectiles, seating depth, sizing and all the other parameters that high precision shooters must consider when working up a load.
You should also chronograph each round you fire and record those results as well when trying to diagnose problems or work up a load.
You're not likely to damage your barrel/chamber with minor overpressure, you'll wear out your bolt first. As you can see, whatever was between the bolt face and the cartridge head was hard enough to dent steel. This can be caused by debris, from carbon buildup to grains of sand or metal shavings finding its way onto the case head or bolt face. This would also change the headspacing and serve to push the round further into the chamber than normal.
Cleanliness is next to accuracy, and something as simple as a tiny grain of sand on your case head can cause real problems.
Remember that it's not just the bolt face that takes a pounding in an overpressure situation, it's also the locking lugs on both the bolt and the chamber. Shoot overpressure rounds too often and your bolt lockup will loosen enough to affect accuracy.
Short of checking and perhaps re-seating any commercial over-length rounds using a properly adjusted seating die, the only solution is to hone he throat a tiny amount to allow a few 10/1000s of an inch more space between the maximum OAL spec for the ammo you use and the lands. It doesn't take much reaming/honing at all, so don't overdo it. There are folks who manufacture and sell chamber/throat reamers in specific sizes just to deal with these sorts of problems. They are quite expensive however, and you'll only use it once per rifle.
That's why checking each round for OAL and reseating the bullet even in commercial ammo is a necessary step for precision shooting.
And when you do that, you should also measure, rate and segregate ammo according to its concentricity, which means the amount of "runout" in the projectile as it's seated in the case. You do this by chucking the round in a trimmer or other holder and using a dial gauge meter to measure how close to the centerline of the case the widest part of the ogive is.
I segregate my commercial .338 Lapua Magnum rounds into three categories
< 0.001 runout; 0.002 to 0.003 runout; and > 0.003 runout.
The small runout rounds, after being checked for OAL and reseated (and rechecked for runout after reseating), are designated as my critical high-performance rounds. The mid range are my general accuracy shooting range ammo, and the > than 0.003 are used for playtime and plinking where maximum accuracy is not a factor.
Consistency in your ammunition is absolutely critical to accuracy, and factory ammo is not nearly as precise as it could be, even the expensive "match" ammo, which has higher standards than regular ammo, but which still has manufacturing tolerances that are greater than a true precision shooter can tolerate.
I hope this helps.