91/30 PU Mount Elevation Screw

[beartracks]

A buddy of mine wanted me to sight in his PU Sniper, so he brought it to work today. Its missing one of the mount's elevation adjustment set screws. I pulled the remaining one out and measured it. Seems non-standard, and I'm a little surprised at the pitch.

It measures .232 on the thread OD = 5.89mm, so I am guessing its a 6mm. The thread count however is 16 threads over .314" (7.98mm~8mm). Gives me a pitch of 2 threads/mm? I matched up a .020" piece of shim stock to the thread points and verified point to point it looks like a .5mm spacing, so 2 threads per mm.

Ever heard of this? I can find M6 x .75 and M6 x 1 as standard metric fine threads, but not M6 x 2.

Please correct me if I've botched the math on this (you'll have to assume my measurements were accurate ) I suppose a very fine pitch is necessary or elevation adjustments would be too gross. This is the first time I've ever closely examined the PU mount.

Probably have to order this specific screw rather than hitting the hardware store.

Thanks,
BT

Information

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[vintage hunter]

Check ebay, believe I remember seeing a set not long ago. Search Mosin Nagant sniper.

[Patrick Chadwick]

Ever heard of this? I can find M6 x .75 and M6 x 1 as standard metric fine threads, but not M6 x 2. Please correct me if I've botched the math on this (you'll have to assume my measurements were accurate )

Metric threads are always designated by the pitch, so the correct designation is M6x0.5 (0.5mm pitch).
This is one of a fine thread series: ISO - DIN 13-3. Taps and dies are available - at a price!

[beartracks]

Thanks guys. I did order some off ebay.

BT

[bill-may]

never mind-normally mosin nagant PU snipers had 6mX0.75 threads. never mind, i was seeing mount to receiver screws.