M1917 scope mount ID?

[clanker]

I was lucky to inherit my great-grandfather's M1917 after getting my PAL. It shows signs of being sporterized, like the top of the handguard being removed, and the two "wings" that protect the rear sight being removed and sanded smooth.

The rear sight has also been removed. In it's place is a tiny tapped hole, and a recessed hole clearly intended to be used for securing/anchoring an optic ring of some sort. I am looking to see if anyone here can hopefully ID what style of scope mount this would be, or if it's a custom job from 50+ years ago. Thanks.

 

[tazzman]

I was lucky to inherit my great-grandfather's M1917 after getting my PAL. It shows signs of being sporterized, like the top of the handguard being removed, and the two "wings" that protect the rear sight being removed and sanded smooth.

The rear sight has also been removed. In it's place is a tiny tapped hole, and a recessed hole clearly intended to be used for securing/anchoring an optic ring of some sort. I am looking to see if anyone here can hopefully ID what style of scope mount this would be, or if it's a custom job from 50+ years ago. Thanks.

View attachment 939223

Watch this, it's really interesting.

 

[tiriaq]

Those holes have nothing to do with mounting a scope. They are artifacts from original production.
If you want to mount a scope, perhaps the best way would be to have the rear bridge recontoured to match the radius of the M700 Remington. and holes drilled and tapped to mount a M700 bridge mount.
Cannot suggest a gunsmith who is doing this, though. Reworking Enfields into sporting rifles isn't something that is being done very often these days.

 

[nowarningshot]

Without watching the video.

I know it's not drilled for it now. But, I've owned a bunch of m1917. All were set up for m98 bases, very very common to find. IIRC that would be weaver #45&#46. That could be a Leupold twist in .....square juice boxy kinda thing.

Getting a receiver drilled and tapped is very low level gunsmithing, simple and cheap. Probably cost you less than a good set of rings.

 

[tiriaq]

45&46 are the standard Mauser bases. The front receiver ring can be drilled and tapped, and the base installed. The trick then is to fit a base on the rear bridge that matches the height of the front base. A rear base contoured for a Mauser bridge isn't going to fit a flat bridge, and heaven only knows if the height would be close enough. Perhaps a rear base could be altered. Note that there is only room for one hole on the rear bridge - that is why I suggested a bridge mount. Drilling and tapping can be low level gunsmithing, made easier by use of a Forster jig. The holes have to be positioned correctly, in line, etc. There is also the issue of the nature of the steel, whether it can be easily drilled and tapped, or if spot annealing is necessary.

 

[fingers284]

etting a receiver drilled and tapped is very low level gunsmithing, simple and cheap. Probably cost you less than a good set of rings.

Not for any P14/17 that I ever did...those bridge rings are HARD and take a pile of work carefully done to anneal where the holes must be and tap breaking was a distinct possibility.
Making that back bridge match the front ring is a real problem on these, you cant just chuck up in a lath & turn the back to match...the bottom trigger mounts wont allow it to spin so you need to build a sort of wobble cradle that allows a cutter to remove steel while you wobble it back and forth....but before you do that weld that big hole up full so that when you cut the base contour it is cut to match.
custom manuf of a custom rifle from a P17 donor can leave you with a very well deserved sense of achievement BUT it is a pile of work without some very expensive power tooling.

 

[Potashminer]

OP - from your picture - that single hole in the rear bridge was used to anchor the flat spring for the original rear sight - in American terminology that would have been the "rear sight base spring screw" - in British terminology that would have been called the "backsight spring screw" (as per Charles Stratton book) - page 88, that screw is identical between P14 and P17 - 0.14" diameter by 0.30" long with 37 threads per inch - I did not look that up - could be an Enfield series thread or a BA series? - most definitely NOT 6-48 or 8-40, and most definitely NOT originally used to mount a scope base.

That oval cut-out is normally below the flat rear sight spring - you do not normally see it in a full dress military rifle. Not all rifles (or maybe not all years) had that oval cutout. When BSA sporterized these actions, I think they milled a "plug" that was soldered into that cavity - then they placed their logo on that plug and also drilled and tapped a second scope mount base screw into that "plug" - the original screw hole was filled (plugged with weld) - then a second scope base hole drilled and tapped - the result was a BSA "sporterized" rifle with 6-48 holes drilled and tapped along centre top of the receiver (and other holes, drilled and tapped, in other places). I think there used to be longish one piece bases available - two holes into the top of the front receiver ring, then one or two holes for rear screws - since the rifle was to be loaded one cartridge at a time, that one piece base was likely considerably in the way of access to the magazine for loading - I have never used them, so do not actually know - the original P13, P14 and P17 were designed to be loaded with "chargers" - five rounds at a time through the top - but can not do that when a scope is installed, unless using a side mount "hinged" mount system that allows the scope to be swung off to the left of the rifle to use a "charger" - Pachmayr used to sell them as "Low Swing" Scope mount - they had a screw adjustable "stop" and the scope would "click in" when you swing it back into alignment..

For a virtually identical rifle some years ago (my Dad's) - I drilled and tapped four 8-40 holes into the side wall left side and installed Weaver #1 base, then used a Weaver 1H ring unit to hold that scope - there may be some fussing involved to get the scope set correctly - if the scope has a "boss" for the turrets, and the mount does not have clearance for that "boss". He used that rifle many years with a Tasco 1.5-4.5 scope - I am not sure that he ever turned it off of 3X once I had it sighted in for him.

 

[Potashminer]

Not for any P14/17 that I ever did...those bridge rings are HARD and take a pile of work carefully done to anneal where the holes must be and tap breaking was a distinct possibility.
Making that back bridge match the front ring is a real problem on these, you cant just chuck up in a lath & turn the back to match...the bottom trigger mounts wont allow it to spin so you need to build a sort of wobble cradle that allows a cutter to remove steel while you wobble it back and forth....but before you do that weld that big hole up full so that when you cut the base contour it is cut to match.
custom manuf of a custom rifle from a P17 donor can leave you with a very well deserved sense of achievement BUT it is a pile of work without some very expensive power tooling.

An option? I note that the Remington 788 rifle uses just one screw on the rear base - Weaver #76 - I have installed several of them and have two Rem 788 rifles in 308 Win that have those "one hole" rear scope mount bases. I have some spare "rear sight base spring screws" on hand. It is my intent to attempt to drill one rear Parker Hale base and use that original screw hole with just the one screw, then two 6-48 holes drilled and tapped into the front receiver ring - but that is predicated on finding two bases that result in a "plane", on top, to each other - which has not happened yet. An alternative, for me, is to re-drill that existing hole and re-tap it to 8-40 thread, although I would rather not try to tap into that receiver. I am not married to the PH bases, but there is an assortment here, as well as some RALS.3 and RAHS.3 rings to go with those bases - sort of seems to me to be appropriate to that era of rifle?? If I end up with an older European scope - 26 mm body - I would have to come up with the appropriate rings for that, which might affect my choices for bases.

 

[Potashminer]

An option? I note that the Remington 788 rifle uses just one screw on the rear base - Weaver #76 - I have installed several of them and have two Rem 788 rifles in 308 Win that have those "one hole" rear scope mount bases. I have some spare "rear sight base spring screws" on hand. It is my intent to attempt to drill one rear Parker Hale base and use that original screw hole with just the one screw, then two 6-48 holes drilled and tapped into the front receiver ring - but that is predicated on finding two bases that result in a "plane", on top, to each other - which has not happened yet. An alternative, for me, is to re-drill that existing hole and re-tap it to 8-40 thread, although I would rather not try to tap into that receiver. I am not married to the PH bases, but there is an assortment here, as well as some RALS.3 and RAHS.3 rings to go with those bases - sort of seems to me to be appropriate to that era of rifle?? If I end up with an older European scope - 26 mm body - I would have to come up with the appropriate rings for that, which might affect my choices for bases.

CHIT!! a double post in error!!