Back to the range, only to find the rifle was shooting unpredictably and the diagonal stringing was back.... this time, the group spread was nearly 4".

So now suspicious of the scope mount, I went home, took off the scope and mount, looked the mount over and found rub marks on the underside near the front screw. I took the barreled action to my buddy's machine shop, locked it down in a lathe table, attached a dial indicator and tapped the mount with a plastic mallet. The rear mounting area was rock solid, but the front of the mount showed .004" movement side-to-side, while pivoting off the rear screw.

Curious what .004" over 4" between screws would do at 100 yards, I did some quick math and found it to be 3.6". <img src="/forums/images/graemlins/cyclops.gif" alt="" /> Looking at it some more, I realized that as the front of the mount moved sideways, the elevation changed due to the round mounting area. <img src="/forums/images/graemlins/cyclops.gif" alt="" /> That appears to be the reason for the diagonal stringing and the occasional wild shot around 3.5" off-target.

After doing some research on Redfield JR mounting issues, I found that while these are authentic in appearance to the old Redfield 1903A4 sniper mounts, they are now made in China and often have mounting problems - some gunsmiths will no longer install them because they've had so many problems getting them right. <img src="/forums/images/graemlins/scared.gif" alt="" />

So, I decided to pin the mount fore and aft - not the most elegant arrangement, but it should stop all movement - just required a couple more Bubba holes in the receiver. <img src="/forums/images/graemlins/notooth.gif" alt="" />

While I was at the shop, I decided to make a couple of tools - a pair of scope alignment indicators and a scope ring lapping bar so I could make certain the scope was installed correctly:


Here are the alignment bars indicating ring alignment and no shims needed at either end:


I didn't want one of the typical hand-lapping bars with a handle that you push/pull back and forth and takes an afternoon, so this one was made to be drill powered - here's the lapping bar with valve grinding compound applied, drill attached and ready to go to work:


A couple of minutes later, the job was finished and resulted in some beautifully lapped scope rings:


Now to go try again - there's a pony in here somewhere. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Frank