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9.3x57 to 9.3x74r

This topic can be found at:
https://forums.accuratereloading.com/eve/forums/a/tpc/f/9411043/m/6011008532

07 October 2017, 11:46
yumastepside
9.3x57 to 9.3x74r
I picked up a 9.3 barrel (9.3x57 chambered and threaded for large ring M98 ) off fleabay for $300 delivered and its huge !! New, unfitted and unfired, 26 inches long and just over 3/4 of an inch at the muzzle. My thoughts were, as its not a super high pressure round ( and it was cheap ), I might be able to use it for my P14 Enfield 9.3x74R project.
Now my question is.... if I recut the thread to a smaller diameter and screw a new sleeve over the top with the correct square thread, how much length would I lose to get the x74R reamer to clean up the x57 chamber. I realise this is a frowned upon method but I have done it before with a threaded and silver soldered sleeve on my 8-06 RCBS M98 with no problems this past fifteen or so years......????????

Roger
07 October 2017, 17:19
farbedo
To get past the shoulder on the 9.3X57, my quick calculation says you will be cutting 1.5-1.6" off the shank.

No need to make an adapter, you will be cutting the existing threads plus a bit off. The 9.3X74R is long with a slow taper.

Jeremy
07 October 2017, 20:05
dpcd
Your P14 will stand that 74R loaded up to the gills; far more pressure than original. Have fun.
If you have enough meat in front of the existing chamber, then just re thread it. You need 1.125 for the threads and a little for a shoulder, but you know that.
08 October 2017, 03:43
yumastepside
....I'm just a fitter and turner with too many gunsmith books, too much imagination and not enough money Whistling

The barrel thickness at the end of the case mouth, if I remove the existing barrel thread, is .299 per side ( 7.6mm )...is this enough ??

By my measurements ( digital vernier ) I should only need to remove .3" to get the 74 case forward enough to clean up the 57 mm chamber....which would be the best way to go ??

yours truly...dazed and confused...well and truly....

Roger
08 October 2017, 04:43
dpcd
I know the feeling....
.299 per side of barrel wall thickness is plenty of meat; look at some double rifles in 9..3 and they have very thin walls.
I just measured a Chapuis and the barrel OD at the chamber mouth is .730 which gives a barrel wall thickness of way less than you have. (.182)
Chrome moly steel is wonderful stuff and has made modern firearms very safe.
As for cutting off the end; do whatever is easiest to machine. No need to make work.
08 October 2017, 09:00
yumastepside
.....thanks for that, looks like I'll cut off the old thread and start from scratch.......cheers!

Roger