[99HMC4]

I have a PTR91 SC that has the welded rail on top. I was wondering if it was a picatinny type or a weaver type? Also what type are the handguard rails? And how can anyone tell the differance between a weaver type and a picatinny rail? And Ive heard a weaver will fit picatinny but picatinny will not fit weaver, true? Reason being Im ordering some optics and I wanted an Aimpoint with the A.R.M.S. mount....

 

[Chopstix Kid]

I can not say for sure, but more than likely they are Picatinny since Picatinny is Mil-spec and these by all pratical intent are "military" style rifles which may, at some point, have "military" style accessories added by the owner -- which are almost all Picatinny mount.

The difference is the width and spacing of the square notches that run across the top of the rail. Weaver has narrow width notches and Picatinny has wide width notches. Weaver rings will fit any Picatinny rail, but Picatinny rings will not fit a Weaver rail.

 

[tiger888]

I have a PTR91 SC that has the welded rail on top. I was wondering if it was a picatinny type or a weaver type? Also what type are the handguard rails? And how can anyone tell the differance between a weaver type and a picatinny rail? And Ive heard a weaver will fit picatinny but picatinny will not fit weaver, true? Reason being Im ordering some optics and I wanted an Aimpoint with the A.R.M.S. mount....

you are correct weaver will fit both (more slop on the picatinny though) but picatinny is slightly larger and will only fit the same.

looking at the pics of the SC, I'd wager the rails to be weaver - they do not look milspec for the scope rail, if you can wait until monday (unless someone has one to chime in with they rifle) i'd ask PTR themselves.

 

[Raufoss]

The width is 1913 (Picatinny) but the lug spacing is not. The rail was intended to be used with rings. Only an optics mount with one lug can be used.

The recoil groove width is .206 + .008 inches. The rest of the dimensions are:

 

[99HMC4]

The width is 1913 (Picatinny) but the lug spacing is not. The rail was intended to be used with rings. Only an optics mount with one lug can be used.

The recoil groove width is .206 + .008 inches. The rest of the dimensions are:

you got the A.R.M.S. mount ot fit? Even if I have to use the front slots (like I have my EOTech mounted on it now) that would be fine. So let me get this right; the rails are the same on picatinny and weaver but the slots are the only differance? If that is right whats to stop a machine shop from adding and correcting the slots on the welded rail? Possible? I would think not worth it but if the rail is weaver that really narrows my selection of mounts I can use. And I really want a quick release type...

 

[Raufoss]

The rail on your PTR is Picatinny width, period. Forget Weaver. All you have to consider is a mount with only one recoil lug. Any single lug ARMS or LaRue mount will work fine on your rifle. GG&G Accucam mounts (EOTech) are not advisable because the recoil lug is in the center of the mount forcing you to use the front position on rail, which causes the mount to overhang the rail. If the overhand doesn't bother you, tee it up.

I am sure a good machine shop could add grooves but why? PTR should have used a full rail to begin with. I am sure they got some smoking deal on a zillion rails. Who knows?