300 mag marking?
- Thread starter Oneshotadam
- Start date
- Location
- Western Manitoba
An acquaintance has a left hand rifle - from factory, the barrel was stamped with "30-06" - looking at rear end of barrel - is re-chambered for a belted round - bolt face has been opened for a belted head size - the "6" has been crossed out - leaving "30-0" - so we assume a 300 of some sort, from the magazine length. From era of that rifle - I know of 300 Winchester Mag, 300 H&H Mag and 300 Weatherby Mag. A 300 Win Mag case chambers; a 300 H&H and a 300 Weatherby Mag does not - so we presume it is a 300 Win Mag - but another acquaintance advises there was many "custom" shapes, based on 300 Win Mag, done "back in the day" - so our intent is to use a start load for 300 Win Mag - fire it, and see what that fired case looks like compared to an unfired one. I suppose we could do a cerrosafe cast of that chamber, and then measure it. There was also a 308 Norma Magnum at that time - preceding the 300 Win Mag - but the barrel stamps on a Parker Hale Model 1200 rifle here indicate "CAL 308 N Mag" (no "periods" or "dots" that I can make out). All five of them - 30-06, 300 H&H Magnum, 308 Norma Mag, 300 Win Mag and 300 Weatherby Mag will have .300" bore diameter and .308" groove diameter - or should have.
At one time, there were many "300 Magnum" - all based on the then "new" "short magnum" Winchester case for 458 Win Mag, 338 Win Mag or 264 Win Mag - most common I think was a variation called "30-338 Magnum" - about all went defunct when Norma introduced that 308 Norma Mag, and then Winchester probably killed off that one, with their 300 Win Mag - better advertising, better distribution and availability of rifles and factory ammo.
Reviewing your picture of that stamping on the barrel - the "." might be significant, but I do not know - appears to be ".300 Mag" on that rifle.
I simply do not know the era of that Interarms rifle - if it was sold out of England, there will likely be Birmingham proof marks on the barrel, at the chamber area, under the wood line - would give you a clue to the date of manufacture - or at least the year of the "proofing" - from the codes on the crossed pennants mark - then to discover what commercial ".300 Mag" existed at that time.
The 300 WBY is perhaps 1/4" longer than 30-06 - so was a fussy thing to fit into a standard Mauser 98 length action, although it was apparently done, with the .375 H&H, which is same length cartridge. I think 300 WBY introduced circa 1944?? 300 Win Mag circa 1963? If the rifle dates before 1963-ish, can not be 300 Win Mag, nor 300 Norma Mag - I am pretty sure, at that time, (pre-1963) the only ".300 Mag" was by Weatherby, or perhaps the much older 300 H&H Magnum.
But really no telling what a "home guy" might have done with it once in North America - there never was a requirement to "proof" a new chamber or barrel here, and as I indicated - at least one example where somebody altered a centre fire rifle chamber for a different cartridge, without accurately re-marking the barrel. There is also two Stevens Favourites here - both are marked "25-Stevens" on the barrel. Both have had the bores drilled out and Redman liners installed and re-chambered to 22 Long Rifle - yet I have not found any "new" cartridge markings on those barrels - and the "25-Stevens" cartridge designation has not been crossed out or removed.
I also have a Schultz and Larsen M60 rifle chambered to 7 mm Sharpe and Hart - was a thing that I read that it was reasonably common to have those re-chambered to use more common to buy 7 mm Rem Mag - especially in Alberta (?), and no doubt some exist that still say "7x61 S&H" on the barrel, despite them being chambered for 7 mm Rem Mag, and despite the Norma ammo head stamp on the cases saying different (7x61 Re or 7x61 Super) - although I have never owned one re-chambered like that.
The foregoing was presuming that is the original factory barrel - if that InterArms rifle was made in the 1970's, it could have been "out in the wild" for over 50 years - and about any barrel could have been installed at some time and chambered to whatever.
It may not be relevant to your question or to that rifle, but I recently acquired a Model 70 Winchester - serial number seems to indicate made-in-1988 - barrel roll stamp says "300 H&H Magnum" - so seems to be what that rifle is still chambered for. Full Length resized 300 H&H cases do chamber - F.L. resized 300 Win Mag and 300 Weatherby do not.
At one time, there were many "300 Magnum" - all based on the then "new" "short magnum" Winchester case for 458 Win Mag, 338 Win Mag or 264 Win Mag - most common I think was a variation called "30-338 Magnum" - about all went defunct when Norma introduced that 308 Norma Mag, and then Winchester probably killed off that one, with their 300 Win Mag - better advertising, better distribution and availability of rifles and factory ammo.
Reviewing your picture of that stamping on the barrel - the "." might be significant, but I do not know - appears to be ".300 Mag" on that rifle.
I simply do not know the era of that Interarms rifle - if it was sold out of England, there will likely be Birmingham proof marks on the barrel, at the chamber area, under the wood line - would give you a clue to the date of manufacture - or at least the year of the "proofing" - from the codes on the crossed pennants mark - then to discover what commercial ".300 Mag" existed at that time.
The 300 WBY is perhaps 1/4" longer than 30-06 - so was a fussy thing to fit into a standard Mauser 98 length action, although it was apparently done, with the .375 H&H, which is same length cartridge. I think 300 WBY introduced circa 1944?? 300 Win Mag circa 1963? If the rifle dates before 1963-ish, can not be 300 Win Mag, nor 300 Norma Mag - I am pretty sure, at that time, (pre-1963) the only ".300 Mag" was by Weatherby, or perhaps the much older 300 H&H Magnum.
But really no telling what a "home guy" might have done with it once in North America - there never was a requirement to "proof" a new chamber or barrel here, and as I indicated - at least one example where somebody altered a centre fire rifle chamber for a different cartridge, without accurately re-marking the barrel. There is also two Stevens Favourites here - both are marked "25-Stevens" on the barrel. Both have had the bores drilled out and Redman liners installed and re-chambered to 22 Long Rifle - yet I have not found any "new" cartridge markings on those barrels - and the "25-Stevens" cartridge designation has not been crossed out or removed.
I also have a Schultz and Larsen M60 rifle chambered to 7 mm Sharpe and Hart - was a thing that I read that it was reasonably common to have those re-chambered to use more common to buy 7 mm Rem Mag - especially in Alberta (?), and no doubt some exist that still say "7x61 S&H" on the barrel, despite them being chambered for 7 mm Rem Mag, and despite the Norma ammo head stamp on the cases saying different (7x61 Re or 7x61 Super) - although I have never owned one re-chambered like that.
The foregoing was presuming that is the original factory barrel - if that InterArms rifle was made in the 1970's, it could have been "out in the wild" for over 50 years - and about any barrel could have been installed at some time and chambered to whatever.
It may not be relevant to your question or to that rifle, but I recently acquired a Model 70 Winchester - serial number seems to indicate made-in-1988 - barrel roll stamp says "300 H&H Magnum" - so seems to be what that rifle is still chambered for. Full Length resized 300 H&H cases do chamber - F.L. resized 300 Win Mag and 300 Weatherby do not.
Last edited:
Zastava rifle, given the age, likely yes. - dan
I don't know the date of manufacture of this rifle, so my comment probably doesn't apply, but there was a time when "300 Mag." meant 300 H&H. I believe the early-60s Sako L61R rifles chambered in 300 H&H, for example, were marked simply "300 Mag." I'm guessing that other early 300 H&H rifles were similarly marked. If this Interarms rifle, made in the Balkans, was manufactured prior to, say, 1964 (the .300 Win. Mag. arrived in 1963), it may be a 300 H&H, although, from its appearance, it looks more recent than that.
- Location
- Western Manitoba
Is very possible that is a longer than "normal" Mauser action - there was a Brevex and a Dumolin, I think, that were Magnum length - was often needed for the 300 H&H and 375 H&H and similar. Was a "project" in a gunsmithing book by Roy Dunlop to cut two normal length Mauser 98 actions - long front end and short rear end on one - long rear end and short front on other - then weld the two long ones together to make a longer than normal action and weld the two short ones together to make a shorter than normal action - and of course, the fussing with the bolt body, extractor and firing pin to go along with that. I believe a gunsmith guy in Ottawa did that - I can not imagine the cost to pay someone these days to do that - maybe he did that for his own use?
Last edited:
- Location
- calgary alberta
Only a chamber cast will tell you for certain.
Well, if it's a 300 H&H, a 300 Win Mag or 300 Wby won't fit. If a 300 WM fits, but a 300 Wby doesn't, then it's a 300 Win Mag. - dan
Last edited:
