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8x63mm Swedish question
- Thread starter smle2009
- Start date
Bockscar
Well-Known Member
Tony,
A comparison check carried out across the diameter of various unfired Swedish 8 m/m x 63 and German 7.92 m/m x 57 projectiles in my collection reveals them to be the same diameter, i.e - 8.18m/m. (.322" give or take a thou'!).
Interesting, as I had never thought to size them myself.
Robert.
A comparison check carried out across the diameter of various unfired Swedish 8 m/m x 63 and German 7.92 m/m x 57 projectiles in my collection reveals them to be the same diameter, i.e - 8.18m/m. (.322" give or take a thou'!).
Interesting, as I had never thought to size them myself.
Robert.
smle2009
Well-Known Member
Hi Robert,
Thanks for your reply,never been able to understand the actual measurements of bullets myself,one that has always 'got' me is;
7.62 nato = .308" Win & .303" = 7.7mm(7.70mm)??? It has been explained to me that different parts of the planet measure the bores diffrently ie across the rifling lands or from a land to a groove but I can not see how this affects quoted bullet diameters?
I have been unable to find any reference to the change of calibre from the Geman 8mm as used in commision rifles ect to the 7.92mm,which could be why the U.S refer to the later 7.92 as 8mm?:hmmmm2:
Tony
Thanks for your reply,never been able to understand the actual measurements of bullets myself,one that has always 'got' me is;
7.62 nato = .308" Win & .303" = 7.7mm(7.70mm)??? It has been explained to me that different parts of the planet measure the bores diffrently ie across the rifling lands or from a land to a groove but I can not see how this affects quoted bullet diameters?
I have been unable to find any reference to the change of calibre from the Geman 8mm as used in commision rifles ect to the 7.92mm,which could be why the U.S refer to the later 7.92 as 8mm?:hmmmm2:
Tony
Bockscar
Well-Known Member
Tony,
When you write that 7.62 Nato = .308 & .303" = 7.7m/m, what you are seeing is both the metric and imperial designations for the same projectile. I agree that it can be confusing if you are only familiar with one system or another, but it is only another way of describing the same thing.
I remember once describing a fellow shooters ammunition as 7.7 m/m x 56R......."No, its not! - its .303"!" He replied. Discretion being the better part of valour,I left it at that!
I myself, have no idea concerning the 7.92m/m / 8m/m designations. I would like to know now though! I am sure someone on the site shall have the answer.
Robert.
When you write that 7.62 Nato = .308 & .303" = 7.7m/m, what you are seeing is both the metric and imperial designations for the same projectile. I agree that it can be confusing if you are only familiar with one system or another, but it is only another way of describing the same thing.
I remember once describing a fellow shooters ammunition as 7.7 m/m x 56R......."No, its not! - its .303"!" He replied. Discretion being the better part of valour,I left it at that!
I myself, have no idea concerning the 7.92m/m / 8m/m designations. I would like to know now though! I am sure someone on the site shall have the answer.
Robert.
TonyE
HONOURED MEMBER RIP
.303 is the bore diameter and converts to 7.7mm.
.30 (whether Nato or .30-06) is also the bore diameter and converts to 7.62mm
.308 is the groove diameter of a .30 barrel and actually converts to 7.82mm
The military generally measure the bore diameter whilst the US commercial manufacturers often use groove diameter.
As an aside, when the FN rifle was being developed into the L1A1 there were a lot of problems with accuracy in hot and worn barrels so although the NATO spec for barrels is I believe .3005 +- .0005 the British elected to go for a .296 bore diameter.
This link should tell you most of what you need to know about the 7.92x57 variants.
http://en.wikipedia.org/wiki/8x57_IS
Regards
TonyE
.30 (whether Nato or .30-06) is also the bore diameter and converts to 7.62mm
.308 is the groove diameter of a .30 barrel and actually converts to 7.82mm
The military generally measure the bore diameter whilst the US commercial manufacturers often use groove diameter.
As an aside, when the FN rifle was being developed into the L1A1 there were a lot of problems with accuracy in hot and worn barrels so although the NATO spec for barrels is I believe .3005 +- .0005 the British elected to go for a .296 bore diameter.
This link should tell you most of what you need to know about the 7.92x57 variants.
http://en.wikipedia.org/wiki/8x57_IS
Regards
TonyE
Bockscar
Well-Known Member
Tony,
Ah yes, I see what you are saying now! - too early in the morning for me!
As you rightly say, the bores can be measured across the top or the bottom of the lands on the rifling - in which case .303" across the top becomes .311" ( interestingly this is 7.9 m/m) across the bottom of the lands. It seems that the nominal diameter of .303" was accepted as the calibre as this was the way it was done in smoothbore days! You know all this of course but it still doesnt explain why .303" is given as (correctly) equating to 7.7.m/m when .308" is given as equating to 7.62 m/m when it is actually 7.82 m/m.
Is it just a case of rounding up - or in this case down? I shall look out Hatchers book later and see if he says anything on the subject.
Robert.
Ah yes, I see what you are saying now! - too early in the morning for me!
As you rightly say, the bores can be measured across the top or the bottom of the lands on the rifling - in which case .303" across the top becomes .311" ( interestingly this is 7.9 m/m) across the bottom of the lands. It seems that the nominal diameter of .303" was accepted as the calibre as this was the way it was done in smoothbore days! You know all this of course but it still doesnt explain why .303" is given as (correctly) equating to 7.7.m/m when .308" is given as equating to 7.62 m/m when it is actually 7.82 m/m.
Is it just a case of rounding up - or in this case down? I shall look out Hatchers book later and see if he says anything on the subject.
Robert.
smle2009
Well-Known Member
Ah the mud is starting to clear a bit!
Thankyou very much to both of you. Anyway I found a bit of a funny story about the 8x63mm while trying to find info about it;
originaly made for a heavy?? MG it was later used in rechamberd WW2 stock K98's by the Swedes,the recoil was so violent that muzzle brakes had to be fitted to these rifles,but the recoil was still bad enougth to 'shake' the recoil brakes off and people who fired it once did not want to play a second time!
All the best
Tony
Thankyou very much to both of you. Anyway I found a bit of a funny story about the 8x63mm while trying to find info about it;
originaly made for a heavy?? MG it was later used in rechamberd WW2 stock K98's by the Swedes,the recoil was so violent that muzzle brakes had to be fitted to these rifles,but the recoil was still bad enougth to 'shake' the recoil brakes off and people who fired it once did not want to play a second time!
All the best
Tony
smle2009
Well-Known Member
Hi Robert,
just heard back from Chris at the Swedish ammo site and the 8x63 is 7.92mm the same as the 7.92x57 round,proof of the pudding is apart from measuring,as you did,is those converted K98's which were only re-chambered,the bore and rifling were unalterd.
Tony
MissingSomething
Well-Known Member
Bockscar
Well-Known Member
Tony,
Thanks for the update on the M/40 rifle and its 8 m/m x 63 ammunition. I tried to contact my Swedish expert on this matter but havent had a reply from him yet. I suppose it would be an easy job just to re-chamber the rifles for the new case and just keep the rest the same. It does seem that they were really nasty things to fire though.....I know for sure that I find the standard K98 in 7.92 m/m x 57 a bit hard going on the shoulder - more padding required I think!
Missing Something,
Thanks for the link to the website, I actually came across this when looking for info' to Tonys question. An interesting site indeed, with the historical bit an added bonus.
Robert.
Thanks for the update on the M/40 rifle and its 8 m/m x 63 ammunition. I tried to contact my Swedish expert on this matter but havent had a reply from him yet. I suppose it would be an easy job just to re-chamber the rifles for the new case and just keep the rest the same. It does seem that they were really nasty things to fire though.....I know for sure that I find the standard K98 in 7.92 m/m x 57 a bit hard going on the shoulder - more padding required I think!
Missing Something,
Thanks for the link to the website, I actually came across this when looking for info' to Tonys question. An interesting site indeed, with the historical bit an added bonus.
Robert.
smle2009
Well-Known Member
Thanks Robert and Missing something,
Found this site,general Swedish ammo but loads of info on the 8x63mm
The Swedish Military Ammunition Site
Cheers
Tony
Found this site,general Swedish ammo but loads of info on the 8x63mm
The Swedish Military Ammunition Site
Cheers
Tony
Bockscar
Well-Known Member
Tony,
Well done on being the first one to pick up on the Erewhon tag! I wondered how long it would be before someone asked about that!
Not a Samuel Butler fan per se, but I had read the books synopsis many many years ago and came across a 1923 edition printing at a car book sale for 1.00 so it got snapped up right away! an interesting read......
Sorry for the late reply, but im on holiday at the moment and access to the net is very limited indeed.
Be back in about a week
Robert.
Well done on being the first one to pick up on the Erewhon tag! I wondered how long it would be before someone asked about that!
Not a Samuel Butler fan per se, but I had read the books synopsis many many years ago and came across a 1923 edition printing at a car book sale for 1.00 so it got snapped up right away! an interesting read......
Sorry for the late reply, but im on holiday at the moment and access to the net is very limited indeed.
Be back in about a week
Robert.