Good, you know the history of it. Did your grandfather ever fire it and did he save the brass? A fair amount of useful information can be gathered from fired brass if you can locate any of it.
So, the major issue on firing pin protrusion is that it should be .060" +/- .005=.055 to .065" from the tip of the firing pin to the bolt face when the firing pin is pushed out by hand. If it is too long, it can pierce primers which is bad, if too short, you won't get reliable operation and firing. The next thing is whether or not your extractor tension is enough to hold the cartridge straight from feeding. Mausers are designed to feed from the magazine, not by placing a round on top of it and push feeding it. The magazine is designed so that the extractor grabs the cartridge as the magazine follower and spring hold it at the proper position. If the magazine spring is weak, then feeding can be an issue, especially on a full magazine. If the extractor is worn or altered or loose due to the extractor ring's keys (the prongs that hold the extractor), the cartridge can droop a bit and miss the chamber.
What Slamfire was talking about is that some hunters, annoyed with the Mauser controlled feed, like to feed individual rounds by sitting them on top of the magazine and then have the extractor "snap" over the head of the case. Then they alter the extractor by beveling a corner of the extractor to allow it to bypass the magazine feeding if desired. In a similar way, some folks swap magazine followers (the platform that the bullets sit on in the magazine as the standard 93 Mauser follower is designed to lock the bolt back on an empty magazine. To make it able to close on an empty chamber, one has to bevel the back of the follower or more simply get a Chilean 95 Mauser follower which is the right design from the get go for closing the bolt on an empty chamber.
The next issue is that of headspace, the Mauser cartridge head is not supported at the breech end and thus the Mauser system is susceptible to getting hot gas from a cartridge separation into a bad place where it can harm the rifle and/or yourself. Older rimmed cartridge systems versus the "rimless" design were developed in the era where brass metallurgy was not that dependable and the rim seals the firing chamber on firing which can eliminate gas events in the bolt lug area. Mauser came up with the rimless for his new Mauser series where the back of the chamber allows the brass to stick out a bit--this is where the system can have issues.
Thus, firing a cartridge in a chamber-bolt relationship--rimless cartridge headspace is measured from a reference point set by the mfg at the time but later by SAAMI or CIP (ammunition and gun makers) of the shoulder of the chamber to the bolt face. Headspace gages are carefully calibrated by their makers to conform with the SAAMI or CIP standards so that commercial ammo can be safely manufactured, guns can be made to fire this ammo safely, and older rifles can be checked for their suitability to fire ammunition safely.
https://infogalactic.com/info/Headspace_(firearms)
Three gages are made, a go gage which is used to set the minimum length chamber for a cartridge--this is only really useful for people assembling a new firearm or changing barrels, bolts, etc., the next gage is a no-go gage that is set at the maximum chamber shoulder distance to the bolt head for a new firearm. Thus, a new gun's headspace should be between a go-gage and a no-go gage at the point of purchase. The field gage is used, primarily, on old military surplus firearms. That is the maximum safe distance without risking cartridge head separation, between the bolt head and the reference point on the chamber shoulder. The military does not reload brass so firing brass in such an overly long chamber will cause it to stretch so brass life will be shortened and firing one repeatedly in such a state will often require a case extractor on hand as the case head can often be pulled off when trying to extract an fired case. It can sometimes result in some gas getting out and causing damage to the chamber and bolt face over time--pitting, etc. and gas leakage from the chamber. At a minimum, shooting glasses are strongly recommended and protective gloves are recommended for firing old milsurps, especially Mausers. New factory ammo is another thing to use if you have headspace greater than a no-go but shorter than a field gage. A lot of folks will simply chalk one up to being a wall hanger if the headspace is greater than a no-go or they have the barrel set back one thread by a gunsmith with a lathe and the chamber is then rereamed to be within a no-go gage. This is requalifying a barrel and requires the proper tooling and equipment to do right. Last, but not least, is putting a new barrel on it and finish reaming it to perfect headspace. As far as accuracy goes, this is the superior alternative.
Some folks know that their old rifles have too long headspace and artificially form cases for their rifle which is an advanced reloading technique for experienced folks. They then only neck size the brass so as to prevent additional case stretching and use that brass only in that particular rifle and they should know signs when reloading that brass is unsafe.
Last, but not least, these are old actions that saw considerable wear and tear and were not regarded as particularly strong actions as Mauser himself developed the 98 action to be stronger on purpose. If you reload, use the beginning charges in the reloading manuals--these are not safe actions to hotrod despite what is scattered around on the internet by folks that will not be paying your medical bills if things go south. Accept them for what they are--a living piece of history, honor your grandfather, and preserve the rifle for future generations by treating it gently and keeping it in good mechanical order.
Sorry for the long post.
