Glass for a thumper

boxhitch said:
yes....;)
maybe lay a lapping bar or 1" rod of sorts in the rings to try and see that they are in-line properly?

3x with the same symptom in the scope must be a record, did Hirsch offer any clue? bent or crushed tubes?
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That’s what I thought as well, 3x seems pretty odd. It happen twice on a 375-338, same scope twice (vxiii 2.5-8x36), and once on my H&H and its scope (vx3 1.75-6x32). Each has their own talley light weight mounts on them.

I do test with line up bars when mounting a scope, but I have not lapped any mounts.

Korth fixed the vx iii both times, I sold it after the second time. The vx3 I sent in, it came back worse then it left. I sold it as a broken scope that needed re work. All 3 scopes they stated they replaced the reticles iirc, I don’t remember (I don’t think) anything else was replaced. They didn’t mention anything about distorted or bent tube

I use the line up pins to be sure both mounts are in line, but haven’t used the lapping bar. Next time I mount a scope in one I will try lapping first maybe.

AB3006 said:
This^ Check the rings for a burr or uneven spots that create pinch points and uneven stresses. A 1" or 30mm hardened steel machining dimension rod would be helpful. Put the rod in each of the rings, and check if you can see light between the ring and the rod. If you can, the ring is misshapen/distorted or has an uneven spot - all of which can affect the tube differently, especially under the thump of the 375, and possibly the internals or seals of the scope as well. Check both rings separately, and together.

EDIT. Also, level the rifle using the rail or bases you have as your even point. Put on the rings at the same spacing as for the scope. Tighten them down, place the test bar in them and measure to see of it's level. If not, then you may have to engage in some shimmage or ring lapping.

Next, measure the actual diameter of your tube. Your "very near" (Vernier) calipers you use for reloading should be good, but a mic would be better. The tube should be exactly 1 inch or 30mm (depending on the variant. While I would trust the 30mm to be 30mm, the 1 inch might well be 25mm not 25.4, so the torque may affect it differently - you may be getting pinch points or eccentricity, or it may not be holding it tightly enough and the scope is accelerating with each thump.

Then, I would take and check the eccentricity of the problem tubes. Make a pencil mark on the top of the tube to clock your measurements. Measure diameter in the vertical direction and then at 90 degrees to that (horizontal). They should be within a thou or two, else your rings are likely distorting the shape of the tube, weakening it and possibly applying stress on the inside. The interior of the scope is sealed and under pressure with gas (N2 or argon). If you distort the tube enough, the seals may... unseal and let moisture inside.

Finally, I'd check the tube for high/low spots. Take two parallels, place them on a flat plane. Make sure the parallels are taller than the height of the turrets. Place the scope so that the tube rests on the parallels. Roll the scope slowly through 360 degrees. Look for uneven rolling or a jump. If there is, this should give you an indication that your rings are distorting the tube in some way. A surface plate and machinist's parallels would be best, but any kitchen counter and two identical bars of material will do.

Of course, if you have access to a machine shop and dial indicators, you can make all this more exact than this, but that is what I would do.
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Thank you for taking the time to write this!! Really appreciate it! A few thins here I’ll look into.

I don’t have any of the previous scopes any more, but am looking to top one of these .375’s right quick and try again before moose season.

I will give these mounts a go though again, maybe I’ll hit them with the lapping bar just to be sure there are no burr’s
 
No problems with my prostaff 7 2.5-10x50 Nikon, although I recently upgraded to a S&B.

I wouldn’t really call the 9.3x62 a thumper though, not magnum size cartridge with magnum cartridge powder behind it.

I’d say it kicks less than any 300WM.

If your launching slow and fat lead maybe you want a lower mag range optic, but you can get 250 grain NAB’s in or close to the 2700fps range. So it’s no 45-70 for trajectory, it can move like a 308w
 
AB3006 said:
That was my little joke. I referred to a Husqvarna 1640 in 9.3x62 mounted in a skinny little schnabel stock. I had her out at the range on Sunday, and without the limbsaver pad it's a shoulder hammer.
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Yes, they are. Mine is a Husqvarna (FN 98) also with a light beech Schnabel stock; it weighs just over 7 lbs without the scope, empty weight. If I am shooting more than 10 rounds, I use the slip on limb saver, and I have a wearable recoil pad as well. With both, I can pound a couple boxes down range before I've had enough. Without the pads, 3 rounds will raise a contusion. LOL

Thumper often refers to a large diameter heavy bullet, usually moving slow. I would say that a .366 bullet that weighs over 280 gr moving not so slow, does indeed qualify. I have also heard the term "spud" or "Potato" gun.
 
cody c said:
I wouldn’t really call the 9.3x62 a thumper though, not magnum size cartridge with magnum cartridge powder behind it.

I’d say it kicks less than any 300WM.

If your launching slow and fat lead maybe you want a lower mag range optic, but you can get 250 grain NAB’s in or close to the 2700fps range. So it’s no 45-70 for trajectory, it can move like a 308w
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That may have more to do with the stock design and weight. Any of the recoil energy charts I have looked at show rifle weights at 9+ lbs, not a bit over 7 like most huskies. One chart with an 8 lb 300 Winmag and a 9 lb 9.3 list the 300 at 24 lbs force vs 30 for the 9.3. However, with the Huskies, the drop at the comb is said to contribute to felt recoil.
 
AB3006 said:
what would you suggest as a minimum eye relief on a moderately thumpy rifle?
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The recommendations I had always read were for as close to 4" as you could get. This prevented getting bit, especially when crawling the stock in your excitement of shooting at game , or shooting from prone, uphill.
Many scopes do not provide 4" of eye relief, but there are a number that will provide 3.5-3.75". Lower power scopes or variables on lower power, also provide a little more relief.
And since most 9.3s are not used for longer distance shooting and do have more recoil, the fixed low power, or lower power range variables are best bets for overall performance and satisfaction for the larger/heavier game (moose, bear, elk, bison, buffalo, eland, etc.) that would be typically hunted with this chambering. (Not saying that it wouldn't work fine on smaller animals such as deer/antelope if this is what you have in hand when a shot opportunity arises. It has done so for generations in Africa.)

"Both rifles use talley light weight mounts and torqued with a fat wrench." (Sorry couldn't figure out how to get the second quote here properly.)

Talleys are great mounts, but there was a period they went through when it seemed like most of them required lapping to help with alignment issues. This can definitely cause scope issues on harder recoiling rifles. Using your tools should have helped, but until you run the lapping tool and compound you won't know how far they are out for certain (it is an eye opener - pardon the pun!).
 
My 9.3x62 used to be a Husqvarna Model 649 - so probably a "beavertail" stock (?). I have only used it with an M8-3X Leupold scope. I used to load 286 grain PPU and 286 grain Nosler Partition - latest loads are 250 grain Nosler Accubond. There are some 9.3 mm 320 grain for it, but I have done nothing with them - never loaded or fired them.

I just weighed it - 8 pounds 3.4 ounces without cartridges. Last time I had it out with my Model 70 Winchester in 338 Win Mag (225 grain Accubond) - my recollection is that they "bucked" similarly.
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Meroh said:
That may have more to do with the stock design and weight. Any of the recoil energy charts I have looked at show rifle weights at 9+ lbs, not a bit over 7 like most huskies. One chart with an 8 lb 300 Winmag and a 9 lb 9.3 list the 300 at 24 lbs force vs 30 for the 9.3. However, with the Huskies, the drop at the comb is said to contribute to felt recoil.
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Sure… but if we’re bending definitions because of stock design, than a 243 with a super crap stock and not butt pad is also a thumper. We’re splitting hairs here a bit.

This is the start of a bit more of a thumper build, well, mid way maybe, it will need thumper glass. M-17, eddystone, RKS gain twist, 458WM, flattened floor plate, Timney, NECG front band.

Actually, I have something more helpful to the topic.

My 9.3x62 (Steyr model M)
I swapped from a Nikon prostaff 7, 2.5-10x50 in favor of a S&B Klassik 2.5-10x56

The S&B has a longer rear bell section and a bit less eye relief, it handles the recoil well enough but I did just barely have it kiss my brow shooting at the bench. It’s not a problem but a reminder for me.

Longer eye relief scopes that don’t have a really long rear bell should be considered a necessary requirement to be considered “thumper” glass in my opinion
 

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I run a Discovery Optics FFP 1-8x ED scope on my 375 Ruger. It holds up perfectly, has never lost zero with 300 rounds down the pipe. And I'm running the 350 grain Woodleigh's with a very stout load of reloder 26. It's an extremely affordable scope, with very good glass, and a great zoom range for the caliber.
 
cody c said:
Sure… but if we’re bending definitions because of stock design, than a 243 with a super crap stock and not butt pad is also a thumper. We’re splitting hairs here a bit.

This is the start of a bit more of a thumper build, well, mid way maybe, it will need thumper glass. M-17, eddystone, RKS gain twist, 458WM, flattened floor plate, Timney, NECG front band.

Actually, I have something more helpful to the topic.

My 9.3x62 (Steyr model M)
I swapped from a Nikon prostaff 7, 2.5-10x50 in favor of a S&B Klassik 2.5-10x56

The S&B has a longer rear bell section and a bit less eye relief, it handles the recoil well enough but I did just barely have it kiss my brow shooting at the bench. It’s not a problem but a reminder for me.

Longer eye relief scopes that don’t have a really long rear bell should be considered a necessary requirement to be considered “thumper” glass in my opinion
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Not bending definitions, but defining why experience may vary for some.

Sorry, you did not understand what I wrote; the point I made was that these recoil charts mean very little because 1. Rifle weights are inconsistent caliber to caliber. 2. they may not represent your rifle, and 3. To the shooter, felt recoil is what matters.

Hi bore axis on a Husky Stock designed for aligning an eyeball with iron sights will also have more muzzle jump and more risk with a short eye relief scope than a low bore axis on a similar rifle in a chassis. (eg. a 9mm CZ 75 has less muzzle jump than a Browning HP has the same recoil but the browning jumps more than the CZ with the lower axis).

The 7 lb Husky is going to have a lot more "felt" recoil than the same caliber in a heavy chassis that weighs a total of 12 lbs..

I don't know about you, but felt recoil is more relevant to most shooters than theoretical (text book) recoil, since it is the recoil that they feel.

Newtons second law of motion proves that if force is the same, but mass (weight) increases, acceleration decreases (less felt recoil) and therefore, with the same force, if the decreases, acceleration increases (more felt recoil).
https://www.calculatorsoup.com/calculators/physics/force.php
 
ya, i still don't get it. Your either validating that smaller calibers are still qualified as thumpers based on felt recoil, or your just commenting off topic about felt recoil in a thread about optics for a thumper. Your not wrong about the factors that affect felt recoil, but its easy to make an argument of apples vs. oranges and that itself is pulling away from the glass. As an alternative to requiring "thumper glass" I must have missed the part where better stock/pad was reccomended.

You can get a boyds with a good butt pad on the 7lb husky to fix that problem and we can get back to optics selection.
 
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