Thread: Slipping scope

hi guys and gals. I'm brand new here, but wanting some advice. I bought a 1952 sporterised 303 with a 4 x 32 tasco scope. When trying to zero in the scope, I discovered that after about 5 rounds, the scope had moved to the rear of the scope rail. Another 2 rounds saw it sliding right off. Put the darn thing back on, checked the tightness of the screws, but 5 rounds later, the scope was at the back of the rail again. Has anyone else experienced this, or has a suggestion on a fix, short of welding the scope to the rail? Cheers.

Sounds like the rings are too wide for the base or they aren't tightened up enough.
Are the rings and bases Parker hale. If not what are they. Photos explain a lot so maybe put one up which will help in figuring out what wrong.

The rifle is still in Burnham after my trip up the Lees valley. Once I get it back I'll check. Thanks. However, they were as tight as I could get them without stripping a thread.

Originally Posted by misha2001

hi guys and gals. I'm brand new here, but wanting some advice. I bought a 1952 sporterised 303 with a 4 x 32 tasco scope. When trying to zero in the scope, I discovered that after about 5 rounds, the scope had moved to the rear of the scope rail. Another 2 rounds saw it sliding right off. Put the darn thing back on, checked the tightness of the screws, but 5 rounds later, the scope was at the back of the rail again. Has anyone else experienced this, or has a suggestion on a fix, short of welding the scope to the rail? Cheers.

Yes, i see this often on customers guns, mainly older ones with dubiuous ring/mount-base combinations.

The tension from the side clamps alone will not stop the scope from shifting forward on the rail, no matter how much you tighten them up. There must be a mechanical recoil stop-pin or stop-shoulder system to prevent the rings sliding on the bases. Depends on what rings/bases you have on there. If you can post a pic that would help, or you can email or pm me.

Dean.

If you haven't a recoil stop pin on your rear mount you may have to drill and tap a reasonable sized hex head screw or even a grub screw, cut to the appropriate length, in the rail behind the rear mount.

Better off getting the proper mounts if you can find some.

Hiya. Thanks for the hints guys. Still waiting for the rifle to wend its way up from down south.

Hi again. My poor old 1943 LE finally made its way home. Having looked at previous hints, I have taken some shots of the scope mounts and the rail. I cannot find any name on the mounts. There is no stop pin on the rail, so it looks like I have a bit of work to do. I think I will get some better mounts - are Weaver mounts OK? I am new at the whole scope thing, as I come from an iron sights background.

Im no expert but that looks like a rimfire 3/4 dovetail mount with a home jobbie set up, I stand by to be corrected.

+1

As above I am no expert either but there is a problem there.
There is no way for the mount to clamp the dovetail without bending the mounting screw....there must be a mismatch of parts even China is not this bad surely?

Originally Posted by JRW87

Im no expert but that looks like a rimfire 3/4 dovetail mount with a home jobbie set up, I stand by to be corrected.

I had exactly the same rings arrive on a 2nd hand 22 I bought. They got removed and tossed in the rubbish. Replaced with Burris 22 rings. Couldn't see them hacking the pace on a CF.

Originally Posted by zimmer

I had exactly the same rings arrive on a 2nd hand 22 I bought. They got removed and tossed in the rubbish. Replaced with Burris 22 rings. Couldn't see them hacking the pace on a CF.

Oh? Seems an illogical design, it looked like someone had chopped up some curtain rail but the bottom ring looked factory.

You need some Parker hale rings to match the base.
The base looks like a Parker hale base. I could be wrong.

These rings were sold under the Zero brand in the '80's & 90's. They are very weak and I have seen several instances where the clamp screws have been over-tightened, stripping the threads and having the whole scope and ring set jump off the rifle with recoil. The smart move would be to have a weaver style base fitted and use far better, though still inexpensive weaver style aluminium rings. Warne make steel rings to fit the BRNO 19mm dovetails which would work very well on the existing base. The recoil projection on one ring would need to be ground off, and a screw fitted into the base of the ring to engage the recoil stop hole in the rear of the base plate. All this is assuming that the .303 has a decent barrel and is worth the effort!

Originally Posted by gundoc

These rings were sold under the Zero brand in the '80's & 90's. They are very weak and I have seen several instances where the clamp screws have been over-tightened, stripping the threads and having the whole scope and ring set jump off the rifle with recoil. The smart move would be to have a weaver style base fitted and use far better, though still inexpensive weaver style aluminium rings. Warne make steel rings to fit the BRNO 19mm dovetails which would work very well on the existing base. The recoil projection on one ring would need to be ground off, and a screw fitted into the base of the ring to engage the recoil stop hole in the rear of the base plate. All this is assuming that the .303 has a decent barrel and is worth the effort!

Just about to go to bed and hadnt learnt something new today, haha, cheers gundoc!