M95 mannlicher + 303B barrel

[quentin]

Hi,
Have been told that a SMLE 303 barrel will screw into a M95 straight pull bolt mannlicher action.

Anyone got one of each to test this out?

cheers
Q
ps. I'm aware that it won't headspace - I just want to know if it will fit at all. Easy smithing job if it does, which would be incredibly popular down here.

[Buckshot]

...........The threaded shank of an 1895 Steyr straight pull is:

14 TPI 'V' type, shank OD 1.020" x .693" long

SMLE is:

14 TPI 'V' type, shank OD .997" x .688" long

..............Buckshot

[quentin]

Hi Buckshot

With thread depths running about 0.130 the 0.022 difference seems small.

If tensioned on the barrel shoulder would the gap be acceptable ?

Q

[Buckshot]

Hi Buckshot

With thread depths running about 0.130 the 0.022 difference seems small.

If tensioned on the barrel shoulder would the gap be acceptable ?

Q

...............Actually that .022" is a bit misleading. The barrel has to thread into the receiver so the actual difference could be a few thousandths more then what a book shows the component parts to measure, given a bit of clearance in the receiver threads. Manufacturing tolerances however might have your SMLE barrel and M95 action being a bit tighter. The again, maybe a bit looser too. Taking the figures I posted, that's 0.011" all around.

I'm not proffessionaly trained in anything having to do with firearms repair/re-furbishing so I won't say. [smilie=1:My suggestion would be to talk to someone who is, and then get a 2nd opinion.

...............Buckshot

[Linstrum]

A good many of the European rifles of World War Two and earlier age, usually going back to the 1880s, have Whitworth Threading System threads that use the Whitworth 55º thread profile that has a radiused root. Making radiused threads is difficult for a home machinist (like me and Buckshot) to make a thread cutting tool for to cut on a barrel. Even Mosin-Nagants made in Russia have Whitworth threads, as do Mausers. Because of this difficulty, U.S. and Metric threads do not have radiused roots and tips. There is no demonstrated difference in strength, by the way.

So, if by chance you have a barrel that will screw into your receiver, the pitch diameters are correct, and the barrel shoulder butts up just right, use a thread gauge to check out the thread profiles to be absolutely sure that the two mating parts also have the same thread angle. On simple threaded parts where thread pressure is low you can get away with using Whitworth threads on 60º profile U.S. threads. But on high thread pressure precision applications like wheel lug nuts/bolts and gun barrels, you can't mix 55º Whitworths with 60º U.S. threads because the threads will become badly damaged and won't hold. You don't need a barrel blowing out of the receiver. That has the potential for eyes disappearing and fingers ending up a block away as soon as the trigger is pulled.

rl 1,057

[Ballistics in Scotland]

I've only just seen this three year old thread while googling for something else. However it does have the potential for serious harm.

I believe the figure reference books copy from one another for the M1895 Mannlicher are incorrect. Certainly they sometimes are. I have seen two of them dismantled, and one rebarrelled by turning away the rear surface of an M98 Mauser thread on the replacement barrel. The threads were very close to the 1.06 x 12 found on the Mannlicher-Schoenauer.

I think that may be a 27mm. thread (1.0629in.). Simple measurement won't tell us, because it is the flanks that matter, not how much the roots and crests are truncated. I suppose it may have been 2mm. pitch, but this is a lot less certain. 12 tpi would be about 2.11mm., and I don't believe the person doing the work experienced the loosely starting but tightening up of a thread that far out.

It may well be a true 12 tpi, for Mauser 98 threads were. You set the diameter by simple adjustment of the lathe, but changing from Imperial to metric requires special gears or a special leadscrew. I'm pretty sure that by 1895 the Austrians had long since abandoned buying British or American machine tools. But the Lee-Enfield thread derives from the Martini-Henry, and I wouldn't be surprised to find it in the Snider. The Mannlicher threads might also go back a long way.

There isn't necessarily much harm in using 60 degree male threads in 55 degree female ones. American gunsmiths do it all the time with the Mausers. But they make them a close fit, and screwed up really tight. But the sort of clearance between the Lee-Enfield and Mannlicher threads would be another matter entirely, even if they had the same pitch. There would not only be less engagement, but engagement on the thin crests, rather than the much thicker roots of the threads. I think vigorous use of the barrel wrench would strip them without a shot being fired.