Carbon Build Up Question...

[Exodus11]

Quick question. i have an old WW2 German Mauser Mod. 98, and I have been having some issues with the round jamming after discharge. (meaning, it is INCREDIBLY hard to get the bolt to cycle to expel the round).

I did not have this issue when i first got the rifle (i think) because i used the good winchester 8mm Mauser rounds. I started having this problem after i found some cheaper surplus ball ammo (manuf. date is 1951?) from a local dealer. now before i get preached at, i KNOW ... "dont use old corrosive ball ammo" ... i wont make that mistake again.

but the question remains, will carbon build up in the area just AFT where the round enters the chamber cause the bolt to be difficult to cycle? or is it just the old ammo being nasty?

ok...i guess i should say, i found last night an unhealthy amount of carbon in this area...just an FYI...

[sdw308]

It possibly could be carbon build up. But more than likely its the old ammo creating too much pressure on the chamber. Just my $.02

[120mm]

Also, you need to get the chamber checked. Something you should do with all surplus arms, imo.

[Exodus11]

@sdw308 ... good call! i was kind of thinking that MAY have played a part...although i wasnt sure..i was thinking that maybe the cartridge was expanding after it was fired but after checking it against the ammo i know worked, it didnt seem to be that.

@120mm ... i was very hesitant when i bought the first batch of Winchester stuff. i did alot of homework prior to purchasing it and it seemed that it was either a 7mm or 8mm. i took the weapon down to the 'Sportsman's Warehouse' near my home, one of the knowledgeable bolt action guys said it was PROBABLY an 8mm so thats what i went with. like i said, the winchester 8mm worked flawlessly so thats what i bought when i found the cheaper surplus ammo. thanks for the recommendation though!!!


having too much pressure in the ammo would cause a vacuum seal type of thing happen after the round is fired correct???

[Alpha Sierra]

having too much pressure in the ammo would cause a vacuum seal type of thing happen after the round is fired correct???

No.

Too much pressure expands the brass past its elastic limit and the brass case stays stuck to the chamber ID instead of springing back from the chamber walls like it is supposed to.

[Exodus11]

No.

Too much pressure expands the brass past its elastic limit and the brass case stays stuck to the chamber ID instead of springing back from the chamber walls like it is supposed to.

well g'd@mn....

thats what i thought was happening but i couldnt find a justification in it beyond comparing the two types of ammo.

Thanks for the feedback guys!
know anyone who wants 60 rounds of 8mm Mauser ammo from the Czech Republic? haha

[rickp]

you can check the brass for signs of over pressure, like flat primer etc...

R.

[justapod]

I am pretty sure it is excessive pressure and the brass is being stretched beyond its limit of elasticity and not shrinking back as Alpha Sierra suggests. In addition to flattened primers split case necks or shoulders a bright line in the brass just above the case head indicating severe stretching and incipient case failure.