SBH Hunter Weigand Mount Failure

[98Redline]

Took my SBH Bisley Hunter out to the range yesterday to take a couple of verification shots prior to the regular firearms opener here in PA. 6 shots all on the mark. The gun was dialed in so I put it back in the case and left.

Getting things packed up today to head out for my hunting ground I noticed that the Weigand scope rail seems to have slid forward so the screws are now only halfway grabbing into the ring cutouts on the barrel. My sharpie alignment marks also show a forward shift of about 1/8".

All mount screws were torqued per the Weigand mounting instructions and locktite applied.
When I removed the rail, the bottom of the mount looks identical to the pics in this thread
http://www.rugerforum.com/phpBB3/viewtopic.php?f=3&t=163812&p=1646230&hilit=weigand#p1646230

The roll pins have elongated the holes in the mount and are now sitting with a rearward slant. I haven't removed the rings and red dot yet, but being that I have the same rings as Iron Mike Golf I would expect to see the same issue.

The gun sees a steady diet of 300+ gr top end loads but nothing that is above published limits.
Anybody other than Iron Mike seen a failure like this?

 

[mike7mm08]

Any cross slot base can encounter this problem. Not only is torque important but the placement of the rings in the slots. If the rings were not slid all the way forward in the slots movement can result. Under recoil the scope will want to move forward. Once movement starts it is only a matter of time before the mount will fail. If you have the scope slid all the way forward it is unlikely any movement will occur. Now how does this relate to the base itself moving. Simple in the scope is moving on the base it in essence acts like a slide hammer battering the base eventually causing movement of the base and deformation of the roll pin.

All that said as much as I like the weigand mounts I think they are little on the soft side. I run one on a Smith 29. I am running four rings instead of two and keep the loads to sane levels. Have had no issue. Also had one a 500 smith. I am the reason that weigand now offers the x frame mount in steel. I destroyed several before weigand realized that it was the mount not my mounting technique that was causing failure.

 

[Iron Mike Golf]

Well, I had rings jammed forward and shot 205-255 gr bullets using near max of published loads (0.5 to 1.0 gr below max) out of a 7.5 inch 44 Mag Redhawk. I feel the rail metal is too weak and the roll pins have inadequate contact area and possibly too weak as well. Roll pins are hollow and they start to collapse, allowing forward movement.

The round surface of the threads of the cross-bolt concentrates force where it contacts the side of the cross slot.

You shot several loose on an X-Frame. Have you shot one of these mounts on a 44 hunter-style BH or RH?

 

[mike7mm08]

No experience on the Rugers. The mount on my 44 smith has been just fine. Of course it does not have the roll pin just three screws. The x frame mounts I trashed in the manor I described. Scope started moving despite having it mounted forward in the slots and the mount then began to deform around the screws. The rings broke off before the base totally went to hell. After several attempts I replaced the whole deal with a dual dovetail leupold mount.

Think the Ruger mount is just depending on clamping pressure to much. No mechanical lock like screws leave to many things open to possible shifting. Once something starts moving anything can happen.

Could also be the recoil. For some reason the recoil impulse might do something to the mount and ring set up. Have a a friend with a taurus raging bull 454. We have yet to find a mount that will hold up or rings that a scope does not slip in. Some kind of wierd physics is at play I would guess.

 

[98Redline]

I completely get what you are saying about the scope acting like a slide hammer however in my case I don't think it was the scope moving. I am running an UltraDot Match dot with 3 rings. I don't see any evidence of the rings shifting on the rail or the dot sliding through the rings (all of my alignment marks are still aligned). It appears that the only place the mount shifted was on the mount to barrel interface.

I tend to agree that the mount relies too much on the clamping force of the screws. I would like to see them get rid of the roll pins and use something more like a key that fills the slot in the frame as opposed to bearing only on the outer edge of the pin. I suppose another option would be to extend the rail all the way to the rear of the frame and use the rear sight notch as a recoil lug like they do on the SRH 480/454 mount.

Hopefully their customer service will give me a hand on Tuesday (Monday is our opening season).


BTW: Jeff, did Weigand replace your mount?

 

[mike7mm08]

Weigand was great for me when I had the issues with the X frame mount. Hope you can get something figured out.

 

[Iron Mike Golf]

I never contacted them. Just went with Ruger rings. Holds my scope just fine.

He needs to use:

1. Steel rail
2. Solid pins or a key
3. Rail hold-down screws that are either harder or use Torx
4. Cross-slot screws that are squared where they ride in the slot and that fill the slot.

Mine was not the current Weigand-tinny design.

It'd be interesting to see what his testing procedure was for this design.