I've finally sussed out a second Achilles heel in the scopes we are offered now.

My country cousin gave me a Burris 1.75-5×21 scope he had wrecked by stumbling and falling against the ocular housing. It had been his favorite scope and, having no objective bell, sat low on the rifle with little tube extending beyond the front ring. Looking at the scope shows no outward sign of damage.

Taking it to bits I now see that in pushing down the ocular slightly (hardly enough to measure), he ovalled the alloy tube, causing the SFP vertical crosswire to buckle. Unfortunately, this would be beyond warranty and I can't squish it back into service.

This problem could be avoided in a scope with the reticle in the first focal plane, because the reticle is between the rings and on a loose-fitting assembly in the outer tube.

However, the thinness of 1" alloy tubes is a problem out there, too.

Sixty-five years ago most scopes had steel tubes, which in the same diameter are much stronger than aluminum. The Germans had realised the lack of strength in alloys and made their dural tubes a millimetre or two thicker, to compensate. Also, most of their alloy scopes had mounting rails that stiffened them against twisting.

When the American and Japanese makers went to alloy, though, they kept the 1" diameter. The new scopes were much lighter than steel and European alloy models but came with a problem in mounting almost equal to that of the old reticle-movement type.

If you just plonk one of these scopes into any old mounts and tighten the screws, there's every chance you'll bend the tube. Considering image-movement lives on the concept of bending light paths, I find bending the scope no sillier - but target-shooting experts disagree. They generally insist on aligning scopes to boresight with the reticle optically centred, in rings lapped to remove any stress.

There is a simpler answer, of course: the use of the Signature swivelling/eccentric ring inserts sold by Burris, which ironically take us back to where we don't need constantly centred reticles at all

'NEVER MIND THE QUALITY, FEEL THE WIDTH'



Whatever you think of Leica and 30mm tubes, sambarman338 likes the thickness their of body material.



As requested by SM338 I am hosting the above pics.

Thanks Gryphon, much appreciated!

Never a great fisherman, it is time for me to spread some self-effacing burly.

As you can see in the top photo, second from left, it was in fact the horizontal crosswire that buckled. I asked my cousin about it and he said that actually he'd dropped the rifle and it fell butt first and then on its side.

The threaded sleeve on that Burris is all of 29mm across but it's only one or two mm thick and the reticle cell is equally thin.

The first-focal-plane Nickel reticle cell (left) however, is much thicker and never likely to be bent in service. (That this one looks slightly wonky is because I showed it to a guy at a gunshow, suggesting he could push it down against the spring beneath to feel its strength. However, he pushed the #1 reticle in instead).

Sorry, installing an emoji at that point somehow aborted the rest of my long post. I will try to find or rewrite it tomorrow.

Meanwhile, in the centre is the Nickel's 27mm central body with solid erector set. Those two items on the right are from an old Tasco Pronghorn 3-9x

Paul, the old K-series Weavers built in El Paso may have had dim lenses, but their steel tube construction did make them hell for stout!

Thanks Bill, I've got a steel Weaver K2.5 from 1947 that is both clear and sound. It has some of the best field blending and 'eye box' characteristics I've seen, even from Zeiss and Nickel.

Like Nickel, Weaver's waterproofness could have been better, but I like this one very much.

I've hunted most of my adult life with steel scopes like Kahles, Pecar and Nickel and have never had a mechanical problem with them. Though the eye relief could be longer, my old Kahles Helia Super 27 was so tough over 33 years I can still hardly believe it. One day I slipped down a dry but greasy cascade and used the rifle and (mainly) scope as a brake in case it changed to a waterfall below me. The alloy ocular and turret caps got well scratched but the scope was only put out by two MOA, not enough to miss a sambar in our bush.

I'm still looking for that lost text from yesterday. Does anyone know how to retrieve it?

Regarding that missing text, though I've previously happened on lost stuff like that later, I can't find that draft now.

As I recall it concerned the 'cost' of makers aiming at the lightest possible scopes. Though these may have benefits in ease of carrying the rifle and limiting recoil inertia to stop scopes moving in the rings, the unseen dangers within the scope can be worse.

Beyond the possibility of bending or denting thin alloy bodies and thus damaging internals, many makers now make the erector tubes of aluminum, too, as in the Tasco's (above right). While this reduces the moveable mass subject to recoil inertia compared with brass, it is less able to withstand the beating that does result if the tube bottoms out, let alone damage from it slamming back against the turret screws under spring pressure and the second recoil pulse caused by your shoulder pulling up the rifle's rearward/upward motion.

Equally worrying is aluminum's tendency to gall from movement in a variable's power scroll. A side-on photo of the Tasco's erector tube that has also failed to appear (and may not now get a guernsey) shows slight burring that gave trouble enough for the owner to cull it, even from his .22-250.

Being a greasy metal that lubricates without smudging lenses, brass won't do that. The Burris scope that began this thread is actually heavier than expected and I assume that is because they favored brass erector tubes there, as they apparently have used in their scopes with Posi-Lock. (Brass makes a lot of sense in variables and Posi-Lock appeals to me because it would stop the heavy erector tube reacting under recoil.)

Another point of weakness in all variables that change the power via a collar in front of the ocular housing is the long slot linking it with the power scroll. While modern O-rings should limit the possibility of moisture getting in there, only the power ring guards the remaining tube from bending in case of an accident such as killed that Burris. The slot in the Tasco Pronghorn covers three-quarters of the tube's circumference but was shorter on the Nickel, which had a more-limited power range.

For this and waterproofing reasons, I prefer the Zeiss/Hensoldt and Kahles outlook where the magnification is changed by twisting the entire ocular. Chuck Hawks doesn't like this design because it messes with hinge-up scope covers - but I don't trust that crap when quick shots are needed, and rarely waste precious time cranking up magnification in the field for long shots.

The second picture, of a dissected Leica variable, shows that 30mm tubes are not just to give increased elevation when raising aim for long shots. The body of that scope was just as thick as the one on the Nickel scope I cut up.

The Germans have long used 30mm bodies on their 1.5-6x variables, even when they had reticle-movement. In those days extensive reticle adjustment was irrelevant because it needed to be close to centre for symmetry. Some, as I recall, only provided about 20 clicks of movement.

Perhaps they needed some extra space for the 4x power multitiple but my guess is most of it went to reinforcing the body.

FYI,
I've discovered that Nickel may have made the odd dural model with a light body, too. This thought comes from my latest acquisition, an early 4x30 Supralyt which only has a 26mm tube and no rail or front bell, yet has a 23mm clear objective (according to Colin Shadbolt's 1966 table). This gives an exit pupil of more than 5.5mm (approx .22cal ), which should be enough for any daylight shooting by most older hunters, at least.

This means that the metal around the objective lens is a bit thin, however. Hopefully, it is thicker farther in. When it was made, maybe in the late 1950s, many American scopes had only 7/8th-inch tubes yet boasted enormous fields of view, so perhaps Nickel gave this scope innards designed for 22mm models.

quote:

Originally posted by sambarman338:
FYI,
I've discovered that Nickel may have made the odd dural model with a light body, too. This thought comes from my latest acquisition, an early 4x30 Supralyt which only has a 26mm tube and no rail or front bell, yet has a 23mm clear objective (according to Colin Shadbolt's 1966 table). This gives an exit pupil of more than 5.5mm (approx .22cal ), which should be enough for any daylight shooting by most older hunters, at least.

This means that the metal around the objective lens is a bit thin, however. Hopefully, it is thicker farther in. When it was made, maybe in the late 1950s, many American scopes had only 7/8th-inch tubes yet boasted enormous fields of view, so perhaps Nickel gave this scope innards designed for 22mm models.

Buy a March scope!

Thanks Butch,
The guy who brought that Tucker conversion to my notice said that he found March and NightForce scopes much more reliable than Leupolds. His belief was that this related to their having brass erector tubes.

I can understand brass being much better in variables because, being greasy, it is less likely to gall in the power scroll. The Leupold scope we were concerned with was a fixed power, though, and I would have thought aluminum less likely to cause trouble under recoil inertia.

I know that NightForce tumble their erector springs for hours to prevent snagging on the outer tube but have no idea what makes March scopes so good.

Maybe everything is gold-plated