Will switching scope with Ruger M77 rings hold zero?

tpcollins · December 20, 2017, 04:34 PM

I want to mount 2 scopes in dedicated Ruger M77 rings. I would set them forward in the slots, tighten them down and then mount the scope.

If I did that with another set of rings and a different scope, how well would they hold zero when switching back and forth between the two scopes? Thanks.

Smoke & Recoil · December 20, 2017, 04:57 PM

The two would hold zero (zero), close, but no cigar.

Art Eatman · December 21, 2017, 10:56 AM

Two assumptions: The bases are six inches apart, and they're off by only 0.001 inch.

100 yards = 300 feet. So 2 x 300 x 0.001" = six-tenths of a foot, or 7.2 inches off from point of aim.

BillM · December 21, 2017, 11:06 AM

Quote:

Two assumptions: The bases are six inches apart, and they're off by only 0.001 inch.

100 yards = 300 feet. So 300 x 0.001" = three-tenths of a foot, or 3.6 inches off from point of aim.

Ummmm-- 6" apart and off by .001 (one thousandth). 100 yds=300 ft, or 600x6"
600x.001 is .600. 5/8 of an inch is .625. So off a little less than 5/8" in 100 yds.

Picher · December 21, 2017, 11:47 AM

Only one way of knowing for sure. Actually do it, and check each swap by shooting at the range, off a good set of rests.

Don Fischer · December 21, 2017, 11:51 AM

Sound's like you want to switch scope's now and then. Why do that in the first place?

tpcollins · December 21, 2017, 02:11 PM

Quote:

Sound's like you want to switch scope's now and then. Why do that in the first place?

Yes at times. I do it all the time with my AR. I have an illuminated VX3 1.5-6x20mm and a SWFA 3-15x40mm - both set in Bobro mounts and I interchange them often with no appreciable notice of poi at 100 yards.

If I have 2 scopes zeroed in with their respective rings, not sure how you assume they'll be off .001". The issue is basically whether they can seat back into the Ruger style rings or not.

BillM - my math agrees with your .6". There a shimming table that indicates a 1" poi change at 100 yards for every .001" shim, based on ring spacing of 3 1/2". So there would be less than a 1" poi difference due to the longer 6" spacing.

.

FrankenMauser · December 21, 2017, 02:26 PM

The Ruger ring design returns to zero better than I had expected. I've had to remove scopes from my Rugers a few times for gunsmithing jobs, and the return-to-zero was quite decent for something never designed with it in mind.
I don't think I saw more than 3/8" change in POI at 100 yards.

Give it a shot with the existing scope, and see how it does.

jmr40 · December 21, 2017, 03:39 PM

I've done so many times with both Ruger rings and Weavers. Never had zero off enough for me to detect it. I have scopes on my AR's with back up irons that mount below the rear of the scope and flip up when needed. I take the scope and mounts off the rails and practice with the BUIS quite often. When I return the scope it has always maintained zero.

As long as you use care and mount them exactly the same every time you won't have any issues. During recoil the rifle moves back toward the shooter. The scope and mounts want to move forward toward the muzzle. When mounting initially always move the mounts as far forward as possible before tightening them down. Do the same when returning them after they have been removed.

Scorch · December 21, 2017, 11:21 PM

Quote:

how well would they hold zero when switching back and forth between the two scopes?

I've seen it done, and return to zero was pretty darn good. Will yours do the same? Who knows? Try it if you want to.

Quote:

Sound's like you want to switch scope's now and then.

I'll tell you what I tell my customers: pick one, mount it, leave it alone. If you do that, it will always hit where it's sighted to hit.

Pathfinder45 · December 22, 2017, 01:47 AM

I believe in using a decent scope, mounted once, mounted correctly, and dedicated to that rifle, never to be removed unless damaged. I have one brother and a friend that have never entertained such a notion. They are always switching scopes from one rifle to another and both of them have so darned many rifles that they end up putting cheaper scopes on rifles that deserve better. Consequently, neither of them shoot as well as they could if they would just stop messing around.

Picher · December 22, 2017, 10:27 AM

Weaver Quick Detachable Top Mounts allow scope swapping with no variation in impact. Some people take an extra scope, all sighted-in when going on a long hunting trip. Others may remove the scope and put it in their other luggage, because some airport baggage guys purposely slam gun cases around.

Most of my rifles have Weaver Detachable Top Mounts. Sometimes I swap scopes when doing load testing, using higher-powered scopes for shooting groups and haven't noticed any change in impact when going back to the other scope.

Art Eatman · December 22, 2017, 07:08 PM

I guess that better precision in machining has made a difference. QDs often had a bum rap, back some fifty years ago.

Rifletom · December 24, 2017, 01:45 PM

Post #5 is your answer.

**44 AMP** · December 25, 2017, 04:16 AM

All you are really asking is how well will each scope hold its zero when removed then replaced.

Generally speaking pretty well (unless the scope gets bumped) if you are consistent about the position and tightness of the rings on their bases when you reinstall the scope.

Don't expect it to be perfectly "on" though it should be pretty close.

December 20, 2017, 04:34 PM	#1
tpcollins Senior Member Join Date: February 18, 2009 Location: SE Michigan Posts: 558	Will switching scope with Ruger M77 rings hold zero? I want to mount 2 scopes in dedicated Ruger M77 rings. I would set them forward in the slots, tighten them down and then mount the scope. If I did that with another set of rings and a different scope, how well would they hold zero when switching back and forth between the two scopes? Thanks. __________________ What direction did that last shot at Kennedy come from?

December 20, 2017, 04:57 PM	#2
Smoke & Recoil Senior Member Join Date: August 23, 2008 Location: East shore of Lake Michigan. Posts: 714	The two would hold zero (zero), close, but no cigar. __________________ Sent from my Tandy 1000

December 21, 2017, 02:26 PM	#8
FrankenMauser Senior Member Join Date: August 25, 2008 Location: In the valley above the plain Posts: 13,424	The Ruger ring design returns to zero better than I had expected. I've had to remove scopes from my Rugers a few times for gunsmithing jobs, and the return-to-zero was quite decent for something never designed with it in mind. I don't think I saw more than 3/8" change in POI at 100 yards. Give it a shot with the existing scope, and see how it does. __________________ Don't even try it. It's even worse than the internet would lead you to believe.

December 21, 2017, 03:39 PM	#9
jmr40 Senior Member Join Date: June 15, 2008 Location: Georgia Posts: 10,806	I've done so many times with both Ruger rings and Weavers. Never had zero off enough for me to detect it. I have scopes on my AR's with back up irons that mount below the rear of the scope and flip up when needed. I take the scope and mounts off the rails and practice with the BUIS quite often. When I return the scope it has always maintained zero. As long as you use care and mount them exactly the same every time you won't have any issues. During recoil the rifle moves back toward the shooter. The scope and mounts want to move forward toward the muzzle. When mounting initially always move the mounts as far forward as possible before tightening them down. Do the same when returning them after they have been removed. __________________ "If you're still doing things the same way you were doing them 10 years ago, you're doing it wrong" Winston Churchill

December 25, 2017, 04:16 AM	#15
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,820	All you are really asking is how well will each scope hold its zero when removed then replaced. Generally speaking pretty well (unless the scope gets bumped) if you are consistent about the position and tightness of the rings on their bases when you reinstall the scope. Don't expect it to be perfectly "on" though it should be pretty close. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

December 21, 2017, 10:56 AM	#3
Art Eatman Staff in Memoriam Join Date: November 13, 1998 Location: Terlingua, TX; Thomasville, GA Posts: 24,798	Two assumptions: The bases are six inches apart, and they're off by only 0.001 inch. 100 yards = 300 feet. So 2 x 300 x 0.001" = six-tenths of a foot, or 7.2 inches off from point of aim.

December 21, 2017, 11:47 AM	#5
Picher Senior Member Join Date: December 14, 2004 Location: Maine Posts: 3,694	Only one way of knowing for sure. Actually do it, and check each swap by shooting at the range, off a good set of rests.

December 21, 2017, 11:51 AM	#6
Don Fischer Senior Member Join Date: March 2, 2017 Posts: 1,868	Sound's like you want to switch scope's now and then. Why do that in the first place?

December 22, 2017, 01:47 AM	#11
Pathfinder45 Senior Member Join Date: January 7, 2008 Posts: 3,224	I believe in using a decent scope, mounted once, mounted correctly, and dedicated to that rifle, never to be removed unless damaged. I have one brother and a friend that have never entertained such a notion. They are always switching scopes from one rifle to another and both of them have so darned many rifles that they end up putting cheaper scopes on rifles that deserve better. Consequently, neither of them shoot as well as they could if they would just stop messing around.

December 22, 2017, 10:27 AM	#12
Picher Senior Member Join Date: December 14, 2004 Location: Maine Posts: 3,694	Weaver Quick Detachable Top Mounts allow scope swapping with no variation in impact. Some people take an extra scope, all sighted-in when going on a long hunting trip. Others may remove the scope and put it in their other luggage, because some airport baggage guys purposely slam gun cases around. Most of my rifles have Weaver Detachable Top Mounts. Sometimes I swap scopes when doing load testing, using higher-powered scopes for shooting groups and haven't noticed any change in impact when going back to the other scope.

December 22, 2017, 07:08 PM	#13
Art Eatman Staff in Memoriam Join Date: November 13, 1998 Location: Terlingua, TX; Thomasville, GA Posts: 24,798	I guess that better precision in machining has made a difference. QDs often had a bum rap, back some fifty years ago.

December 24, 2017, 01:45 PM	#14
Rifletom Senior Member Join Date: February 11, 2011 Location: So-Cal Posts: 786	Post #5 is your answer.