I've got a 7X57 Kreigoff Mauser (pre-WW2). When shooting factory ammo in the rifle the primers back out + or - .015 of an inch. I was told by a gunsmith??? that the gun had excessive headspace. I have necksized the once-fired cases and shot them with no backing out of the primers at all. Am I flirting with disaster or is what I am doing kind of like fireforming the cases. I realize .015 stretch is a little much on the cases and have taken a paper clip (bent on the end) and ran it inside the cases to feel for separation. ALL help and advice will be greatly appreciated. Thanks, Mike
Posts: 920 | Location: USA | Registered: 22 May 2002
Yes what you are doing is fireforming the cases. I'll let someone more knowledgeable than I tell you whether or not it is safe to do with factory ammo. Me, I wouldn't do it not because it may be unsafe but it might be hard on the gun. I would fireform empty cases with cornmeal, then neck size those. If you didn't have a neck sizing die you could experiment with just backing out a full length sizing die but it sounds like you do. It is just easier on the gun this way.
Posts: 7786 | Location: Between 2 rivers, Middle USA | Registered: 19 August 2000
Used to have an old .30/06 Mauser 98 that did that. Reloads with neck sizing were no problem. With factory ammo I used to partially pull the bullet (in one of those hammer type pullers), then reseat so they just touched the lands. Solved the problem no worries.
FT, I am by no means a gunsmith. If it were mine I would bring it to a real smith and have it checked out. They have the proper tools and gauges to tell you if you have a problem and exactly what it is. JMHO
Posts: 268 | Location: God's Country, East Tex. USA | Registered: 08 February 2002
The chamber should be checked with a proper headspace gauge to find out exactly what the headspace is. There is every possibilty that the HS falls within acceptable limits. The primers back out because the case expands laterally and shortens up as a result. The pressure of the factory loads is insufficient to overcome the elastic limit of the brass. If your reloads produce higher pressure the cases will stretch back and reseat the primer. This is not an ideal situation since the brass is stretching and may be starting on it's way toward a head separation. Do have it checked with a guage and if it is long have it corrected. Regards, Bill.
Yes friend, you have excessive headspace. The primers backing out are a classical sign. You, however, WILL NOT blow yourself up if you insist on using the rifle. Yet.
If you load your own and only necksize, you most likely will not have a problem. Your ammo WILL NOT fit any other rifle chambered for that cartridge, including another of yours. You may have a problem that may continue to get worse, or you may just have a rifle that was made that way.
I would bet that a "NO GO" gage will "GO" in your rifle. As I said, you may MOST LIKELY be able to continue to us it, but why not get it fixed? Original issue on body parts is just that. One time issue.
