Swedish M96 bolt interchangeability
- Thread starter Steiner
- Start date
Maybe .... maybe not.
Headspace should never be taken for granted.
Just because a bolt will cycle and close does not indicate the rifle is safe to fire.
In checking many Swedes, i've seen headspace of well over 20 thou., and at the other extreme, a bolt that would not close even on a empty chamber.
Best way to check yours would be headspace gauges, but I've used the RCBS precision mike, and in a pinch, even shims between the boltface and case head of new or f.l. sized brass. Measure the shim that will allow the bolt to close with light resistance.
For me the measured max. H.S. that has shot well and given reasonable case life is 9 thou., but, I'll never F.L. size brass fired in a chamber that long, and am not suggesting you do as I have done. YMMV.
Best bet is to have a gunsmith look at it, .... and take backyard bubba internet advice like the above with a grain of salt. Bad things can happen if a case holding 50,000 plus P.S.I. ever lets go inches from your nose.
BTW, if you ever find an extra Swede bolt f.s. ...
Headspace should never be taken for granted.
Just because a bolt will cycle and close does not indicate the rifle is safe to fire.
In checking many Swedes, i've seen headspace of well over 20 thou., and at the other extreme, a bolt that would not close even on a empty chamber.
Best way to check yours would be headspace gauges, but I've used the RCBS precision mike, and in a pinch, even shims between the boltface and case head of new or f.l. sized brass. Measure the shim that will allow the bolt to close with light resistance.
For me the measured max. H.S. that has shot well and given reasonable case life is 9 thou., but, I'll never F.L. size brass fired in a chamber that long, and am not suggesting you do as I have done. YMMV.
Best bet is to have a gunsmith look at it, .... and take backyard bubba internet advice like the above with a grain of salt. Bad things can happen if a case holding 50,000 plus P.S.I. ever lets go inches from your nose.
BTW, if you ever find an extra Swede bolt f.s. ...
Quoted for emphasis. Excessive headspace can produce a very dangerous situation with the potential to destroy the rifle and seriously injure or even kill the shooter. OP, take this very seriously and have a gunsmith (or knowledgeable tinkerer with the correct tools) check it before trying it out at the range.
Mark
A proper headspace gauge is very cheap insurance. For a bolt gun shooter a "field" gauge will suffice as a safety check. For a semi-auto shooter both a "go" and a "field" gauge are necessary. If you are into rebarreling, a "no-go" gauge is essential to allow you to set things up a little tighter. These gauges are available from Brownells @ $30 or less. Give up a couple of visits to Mc Dildoes or Booger King and you've got it covered.
Complete nonsense, and the dramatics of the alleged risk is the worst I've seen. The "Great Satan" Headspace has been debunked many times. If this gets your back up, please explain the chain of events that will lead to "a destroyed firearm and a dead shooter". I'm all for safety, but it starts with facts, not ages old myths.
While it is unlikely that anyone has been killed on account of excessive headspace, the implications of this are not something that should be dismissed out of hand.
The primary implication of an excess headspace condition is that the ctg case will expand (lengthen) to seal the chamber on firing. With a minor degree of excess this means nothing at all, except to the handloader who should then necksize in order to avoid excessive case working as a result of repeated case stretching and then compression in subsequent firing/resizing cycles. I once had a 7x57 Mauser with excessive headspace and managed the condition by neck sizing only after initial firing.
If headspace is sufficiently excessive, cases may stretch to the point where case separations can occur on firing resulting in the head portion of the case being extracted while the portion ahead of the separation remains lodged in the chamber. Apart from unreliability in a hunting situation, repeated case separations do admit hot propellant gases into the chamber which is not a good thing. In some cases there is no dramatic result, but in other cases gases can escape into the rifle and blow back into the shooter's face. Personally I would not fire a rifle where headspace was sufficiently excessive to cause repeated case separations. This is not an acceptable situation when you dealing with a 50,000 PSI pressure bloom a few inches in front of your face.
There are conventions on headspace with a min, max, and field measurement established for each ctg. It is an accepted norm that rifles where headspace in in excess of the "field" measurement, should be withdrawn from use until the situation is corrected. That was the arbitrary military rejection standard. Using the .30-06 as an example, the minimum, or "go" chamber length is 1.940. The maximum for newly rebarreled rifles, or "no-go" measurement, is 1.946, and the maximum or "field" measurement where rifles are withdrawn from service for overhaul is 1.950.
There is an interesting discussion of excessive headspace in Hatcher's Notebook where the author progressively reamed out the chamber of an M1917 Enfield to a measurement of 1.965 w/o encountering a case separation.
There is another variable here which can arise when a new bolt is swapped in. Should one lug not be bearing equally, what may initially appear to be a safe condition may change as the non-bearing lug is worn down to a point of full contact. Everyone is entitled to their own beliefs and tolerances on this topic, but if advising others, I would always urge staying within the established "field" measurement for a particular rifle-as determined by a headspace gauge.
The primary implication of an excess headspace condition is that the ctg case will expand (lengthen) to seal the chamber on firing. With a minor degree of excess this means nothing at all, except to the handloader who should then necksize in order to avoid excessive case working as a result of repeated case stretching and then compression in subsequent firing/resizing cycles. I once had a 7x57 Mauser with excessive headspace and managed the condition by neck sizing only after initial firing.
If headspace is sufficiently excessive, cases may stretch to the point where case separations can occur on firing resulting in the head portion of the case being extracted while the portion ahead of the separation remains lodged in the chamber. Apart from unreliability in a hunting situation, repeated case separations do admit hot propellant gases into the chamber which is not a good thing. In some cases there is no dramatic result, but in other cases gases can escape into the rifle and blow back into the shooter's face. Personally I would not fire a rifle where headspace was sufficiently excessive to cause repeated case separations. This is not an acceptable situation when you dealing with a 50,000 PSI pressure bloom a few inches in front of your face.
There are conventions on headspace with a min, max, and field measurement established for each ctg. It is an accepted norm that rifles where headspace in in excess of the "field" measurement, should be withdrawn from use until the situation is corrected. That was the arbitrary military rejection standard. Using the .30-06 as an example, the minimum, or "go" chamber length is 1.940. The maximum for newly rebarreled rifles, or "no-go" measurement, is 1.946, and the maximum or "field" measurement where rifles are withdrawn from service for overhaul is 1.950.
There is an interesting discussion of excessive headspace in Hatcher's Notebook where the author progressively reamed out the chamber of an M1917 Enfield to a measurement of 1.965 w/o encountering a case separation.
There is another variable here which can arise when a new bolt is swapped in. Should one lug not be bearing equally, what may initially appear to be a safe condition may change as the non-bearing lug is worn down to a point of full contact. Everyone is entitled to their own beliefs and tolerances on this topic, but if advising others, I would always urge staying within the established "field" measurement for a particular rifle-as determined by a headspace gauge.Thanks for the replies and info. Well I got the rifle. The fellow knows he has the bolt 'somewhere in the house'. He said he'll contact me when he finds it. I'll wait for awhile and hope he is has success in tracking it down. If nothing by spring then I'll check the issues mentioned and decide then what to do. Thanks guys.
Well Andy,
Ever had a case head separation (or partial, or blown primer) in a M94 Swede actioned rifle?.
Do you wear shooting glasses?.
The very first time your face gets peppered with gasses, metallic particles, and all the debris from inside the action .... your 'great satan' headspace debunking theory will be revised in a FLASH.
You claim to be "all for safety", better bone up on the headspace related mishaps that have befallen others before advising recklessness on a public forum.
I've got a Bubba'd mismatched m-98 ( I know ; 3 lugs vs 2 on M-96 ). The bolt didn't match, so I trying to answer the same question. An aquaintance showed me a trick; which may or may not be valid. He dis-assembled the bolt and inserted it minus the back workings. Upon closing the bolt ( he claimed ), you can feel if it's right.
I really wouldn't be able to verify this without an assortment of similiar Mausers to try the theory though.
Stay Safe
I really wouldn't be able to verify this without an assortment of similiar Mausers to try the theory though.
Stay Safe
Well Andy,
Ever had a case head separation (or partial, or blown primer) in a M94 Swede actioned rifle?.
Do you wear shooting glasses?.
The very first time your face gets peppered with gasses, metallic particles, and all the debris from inside the action .... your 'great satan' headspace debunking theory will be revised in a FLASH.
You claim to be "all for safety", better bone up on the headspace related mishaps that have befallen others before advising recklessness on a public forum.
Oh my! Did I say that headspace was not important, or that it didn't matter? It does, but not because your gun will blow up and you might die - you won't. "Purple" and many other experienced reloaders understand it and you can too. The only life that is threatened by excessive headspace is that of your brass, and yes that can then lead to casehead separations and that's why we all wear shooting glasses. Reloading 101 talks about extending brass life by partial F/L and neck sizing and to watch for incipient casehead separations - good advice. Did you know that even with perfect headspace they can occur - the 303 Brit is a familiar example. Be safe and base your actions on knowledge.
Again, good points. Happily the fellow found the bolt! He said it's been 15yrs since he's seen it. Found it under his basement stairs wrapped in cloth and stuffed between some boards. Got to love humanoid squirrels.
So the Swede story has ended well for me.
I do recall switch bolts on between Mosin Nagants with no ill effects. Never reloading for them, just shooting surplus ammo. We did have one of those Russian go/no go guages and it appeared (when using the guage) bolts would interchange fine between the couple of rifles we had on hand, but only one had a missing bolt. I didn't do the measuring, some experienced old Ukrainian WW2 vet did the judging.
So the Swede story has ended well for me.
I do recall switch bolts on between Mosin Nagants with no ill effects. Never reloading for them, just shooting surplus ammo. We did have one of those Russian go/no go guages and it appeared (when using the guage) bolts would interchange fine between the couple of rifles we had on hand, but only one had a missing bolt. I didn't do the measuring, some experienced old Ukrainian WW2 vet did the judging.
