37 posts · August 23, 2018 to February 1, 2020 · Archived from the original AirgunWarriors.com forum
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I recently acquired a PCP that needs fully-adjustable two-piece scope-rings or single-piece scope mounts for a dovetail groove.
All I can find are high or extra-high scope-rings/scope mounts.
The scope I'm using has a 40mm objective and 30mm tube.
As such, medium rings would work just-fine for me.
Does anyone manufacture fully-adjustable (elevation, windage, lateral) medium rings/mount for dovetail grooves?
Weaver? Dovetail? 1"? 30mm?
The most durable adjustable mounts are the Burris Zee mounts with the eccentric “Pos-align” inserts. They are proud of them, however.
If cost is a concern, Sun Optics makes adjustable mounts that have threaded posts for elevation and a gimbal mechanism for windage. They won’t deal with bumps and scrapes as well as the Burris. They’ve worked great for me but I always handle my rif carefully.
Approximately how much correction do you need? X inches of elevation and Y inches of windage at Z yards?
The most durable adjustable mounts are the Burris Zee mounts with the eccentric “Pos-align” inserts.
Burris Rimfire and Airgun Rings not available in 30mm rings
Here's a table for the Sun Optics rings. From your description, model SM0130 would be the one...
https://www.amazon.com/Sun-Optics-USA-Elevation-Adjustable/dp/B002K7A2LI
| Model | dia. of scope tube |
type | height | rail type | adjust-able |
| SM7701 | 1 in | 1 pc | high | 11mm or 3/8" | Y |
| SM7101 | 1 in | 1 pc | medium | 11mm or 3/8" | Y |
| SM7702 | 1 in | 1 pc | ultra-high | 11mm or 3/8" | Y |
| SM7130 | 30 mm | 1 pc | medium | 11mm or 3/8" | Y |
| SM0037 | 1 in | 2 pc | high | 11mm or 3/8" | Y |
| SM0101 | 1 in | 2 pc | medium | 11mm or 3/8" | Y |
| SM0201 | 1 in | 2 pc | medium | weaver | Y |
| SM0137 | 30 mm | 2 pc | high | 11mm or 3/8" | Y |
| SM0130 | 30 mm | 2 pc | medium | 11mm or 3/8" | Y |
| SM0230 | 30 mm | 2 pc | medium | weaver | Y |
What are the circumstances with the 1720T that requires adjustable rings? The nature of its construction does not lend itself to needing lots of compensation in the scope mount.
Using Sun Optics adjustable rings By Jason (nervoustrigger)
CORRECTION
Sorry, I was mulling two airguns in my head ... the adjustable mounts will be used on a .177 Gauntlet that I'll be shooting at near 50-yards.
The scope has a 30mm body diameter and will be mounted on a dovetail grooves.
When zeroed at 20-yards, the rifle is impacting approximately 3-inches high and 5-inches to-the-left at 40-yards
CORRECTION
Sorry, I was mulling two airguns in my head ... the adjustable mounts will be used on a .177 Gauntlet that I'll be shooting at near 50-yards.
The scope has a 30mm body diameter and will be mounted on a dovetail grooves.
When zeroed at 20-yards, the rifle is impacting approximately 3-inches high and 5-inches to-the-left at 40-yards
You only need adjustable mounts when you rut out of adjustment on your turrets.
It's more likely that you have some cant errors.
You only need adjustable mounts when you rut out of adjustment on your turrets.
It's more likely that you have some cant errors.
Awww, when zeroed at 20-yards, my POI at 40-yards is 3-inches high and 5-inches left.
When I zero at 40-yards, my 20-yard POI is low and to-the-right ... I conclude the scope is not aligned with the bore.
I'm thinking fully-adjustable mounts/rings will solve the problem for me.
Here's a table for the Sun Optics rings. From your description, model SM0130 would be the one...
nervoustrigger ... Are the adjustable Sun Optics mounts "Made in the USA"?
I don't know but I doubt they're made in the USA for those prices.
what scope are you using, the reason a ask is that this problem has been chew on like a dog and a bone and if you Google it there are many answers but most state that if the scope is of good quality and is mounted correctly it should not happen in any big way
and your is shifting in big ways, would buying a set of magic ring fix the problem, my guess is no, if you can zero the scope and it would shoot fine day after day at the power you were using but then you change the power and it shooting way off the mark, how are the rings go to fix it, they are not
are you going to readjust the rings, I don't think so
should you have to readjust the scope at different powers, maybe a little
You only need adjustable mounts when you rut out of adjustment on your turrets.
It's more likely that you have some cant errors.
Awww, when zeroed at 20-yards, my POI at 40-yards is 3-inches high and 5-inches left.
When I zero at 40-yards, my 20-yard POI is low and to-the-right ... I conclude the scope is not aligned with the bore.
I'm thinking fully-adjustable mounts/rings will solve the problem for me.
If you are leaving everything on the scope the same when changing ranges......magnification, AO adjustment, etc.... Then more than likely the dovetails are not milled parallel with the bore of the gun. The vertical movement is more than likely caused by the offset of the scope to the bore. If you can find the adjustable mounts that you want you'll have to treat them like "open" sights and adjust accordingly. Then you'll have to get the vertical cross hair pointed to the center of the bore. Cant can cause error but IMHO, you would have to lay the gun on its side to get 5" of change when moving the target out an additional 20yds.
Is the gun new? You might want to talk to the customer service people and see if they can help you out.
I've used the Burris rings and they give you a lot of adjustment but you might have to use an adapter to go from dovetail to weaver. They would be worth a hard look though. Good Luck.
You only need adjustable mounts when you rut out of adjustment on your turrets.
It's more likely that you have some cant errors.
Awww, when zeroed at 20-yards, my POI at 40-yards is 3-inches high and 5-inches left.
When I zero at 40-yards, my 20-yard POI is low and to-the-right ... I conclude the scope is not aligned with the bore.
I'm thinking fully-adjustable mounts/rings will solve the problem for me.
If you are leaving everything on the scope the same when changing ranges......magnification, AO adjustment, etc.... Then more than likely the dovetails are not milled parallel with the bore of the gun. The vertical movement is more than likely caused by the offset of the scope to the bore. If you can find the adjustable mounts that you want you'll have to treat them like "open" sights and adjust accordingly. Then you'll have to get the vertical cross hair pointed to the center of the bore. Cant can cause error but IMHO, you would have to lay the gun on its side to get 5" of change when moving the target out an additional 20yds.
Is the gun new? You might want to talk to the customer service people and see if they can help you out.
I've used the Burris rings and they give you a lot of adjustment but you might have to use an adapter to go from dovetail to weaver. They would be worth a hard look though. Good Luck.
I have had excellent results using the, (UTG low pro snap in adaper) when using Weaver/piccatanny mounts on my airgun dovetail grooves. What I love about them is the fact that they only add about 1/16th of an inch to the height of your mount.
Only $10.00 a pair. Many places sell them, just Google it.
Have fun,
Scott
You only need adjustable mounts when you rut out of adjustment on your turrets.
It's more likely that you have some cant errors.
Awww, when zeroed at 20-yards, my POI at 40-yards is 3-inches high and 5-inches left.
When I zero at 40-yards, my 20-yard POI is low and to-the-right ... I conclude the scope is not aligned with the bore.
I'm thinking fully-adjustable mounts/rings will solve the problem for me.
Alignment is corrected by adjusting the turrets.
You don't have an "alignment" problem. You have a "cant" problem.
I'll draw a picture for you:
Do me a favor: rotate the scope in the rings a few degrees CCW. Rezero it. Shoot the target again taking care to hold the reticle vertical.
That is how you fix "crossover". It's really a scope cant problem.
Alex, I think the culprit here is the scope -- not the mounts -- so adjustable rings will be of no help.
The symptoms indicate a scope with a faulty AO, that shifts the POI when you adjust for 40yds vs 20yds. I suggest setting the AO to 30yds and leaving it there while you rezero, then shoot at different ranges without touching the AO.
If you do, I predict the POI shift will disappear.
Very interesting replies here.
Years ago I had a Marlin bolt action 22mag that when zero'd at 100 yards would impact a few inches to the right at 25 and if zero'd at 25 would hit around ten inches left at 100. I concluded that the receiver grooves and barrel weren't aligned properly and sold the rifle.
I've always been super anal about cross hair alignment and always take lots of time using a level, the horizon, and level horizontal reference lines to be sure my scopes are as perfect as one can make them. That 22mag was the only rifle I've ever had do this. Airgun or otherwise.
Cross hair alignment alone does not prevent "cant" error. The rifle has to be leveled first and then the scope leveled so that they are both level with the ground (gravity) and with each other. Brownells sells a brilliant tool that, when used in conjunction with a plumb line, assures both are square and level with each other.
If cant is not the problem and you have a bent barrel or grooves that are not true with the bore, B-Square makes a multi-adjustable mount that will adjust both windage and elevation. Since the objective len(s), ocular lens, and the lenses in the erector tube need to be in perfect alignment for the focal points to work as designed, it is generally best to stay as close to optical zero as possible and use as few clicks as possible to zero your rifle. At least this is my experience and opinion.
The requirements to eliminate cant error are:
1. Align the scope's reticle with the rifle's barrel.
2. Hold the reticle level when shooting.
Item 1 deals with scope cant...i.e. mounting the scope incorrectly.
Item 2 deals with gun cant...i.e. holding the gun incorrectly.
Here's the easiest way to eliminate cant errors. The great part is you don't need any special tools. All you need is a mirror. Set the mirror at a distance of, say, 5 yards and set your AO to 10 yards. Look through the scope at your reflection in the mirror. Twist the scope in the mounts until the vertical bar of the reticle simultaneously bisects both the muzzle and objective bell. Then lock it down. At this point you have eliminated scope cant (item 1). If it's hard to see your muzzle, add a little dot of White Out or take a dot from a hole punch and tape it to the muzzle with clear tape.
Now to eliminate rifle cant, install and use a level. View a known good plumb line (e.g. hanging string) through the scope and orient the rifle so it precisely aligns to it. Now affix your level so it shows level. From now on when you're shooting, hold the rifle so it shows level and you can be sure you've eliminated both potential sources of cant error.
By the way, don't buy a level that attaches to the scope rail. There is no guarantee it will show level. Instead, get one that attaches to the scope tube so you can rotate it and lock it down where it shows the proper level.
Cross hair alignment alone does not prevent "cant" error. The rifle has to be leveled first and then the scope leveled so that they are both level with the ground (gravity) and with each other. Brownells sells a brilliant tool that, when used in conjunction with a plumb line, assures both are square and level with each other.
If cant is not the problem and you have a bent barrel or grooves that are not true with the bore, B-Square makes a multi-adjustable mount that will adjust both windage and elevation. Since the objective len(s), ocular lens, and the lenses in the erector tube need to be in perfect alignment for the focal points to work as designed, it is generally best to stay as close to optical zero as possible and use as few clicks as possible to zero your rifle. At least this is my experience and opinion.
...If cant is not the problem and you have a bent barrel or grooves that are not true with the bore, B-Square makes a multi-adjustable mount that will adjust both windage and elevation....
The OP is able to zero his scope at 20yds and at 40yds. So it appears that he has not run out of elevation or windage adjustment. Until he runs out of elevation or windage, adjustable mounts will do no good. Either his scope is mounted incorrectly (canted) or the scope is bad.
Question for Alejandro: How much windage and elevation adjustment do you have remaining when your scope/gun is zeroed at 40 yards?
Adjustable mounts allow you to stay close to optical zero. The more you click, the more you move away from the sweet spot where you are looking through the center of all the lenses. If you run the windage or elevation completely out, you will be looking through the edges of the lenses in the erector tube. Shim stock in .001 increments on scope bases or in rings will accomplish the same kind of external adjustment allowing you to take full advantage of your scope's optical quality.
Adjustable mounts allow you to stay close to optical zero. The more you click, the more you move away from the sweet spot where you are looking through the center of all the lenses. If you run the windage or elevation completely out, you will be looking through the edges of the lenses in the erector tube. Shim stock in .001 increments on scope bases or in rings will accomplish the same kind of external adjustment allowing you to take full advantage of your scope's optical quality.
"...you will be looking through the edges of the lenses in the erector tube...."
That is not true. You still look down the center of the erector tube. The only time you look near the edges is when you use stadia marks (mil-dots, etc) that are near the edges.
The rest may be true to some degree but it won't fix the OP's problem.
---------------------------
Field target shooters that click often run a full turn from center. As long as you have more than 1/2 turn or more remaining, any decent scope will still function fine. I would rather crank my elevation turret up a little before I would put shims on the scope rings.
Crosman Center-Point 3-12X44, side-focus parallax adjustment, MOA Retice, Model LR312SFT2. High Center-Point Picatinny-rings on UTG #DTP (Leaper’s) 11mm dovetail-to-picatinny rail adapters. One thing I noticed, the adapter can be inserted into to scope-base in one direction only - reversing the adapter does not allow the fixed-side of the base to mate with the moveable-side of the adapter ... there’s a gap showing.
Did I mention, I don’t like using adapters from one MFG with another MFG’s scope base. I’ll probably try-out my scope using 11mm base/30mm rings on another airgun first and see if I continue to have sighting error.
Moreover taking a shot-in-the-dark, I turned-around the rear scope-base and re-zeroed at 20-yds. Then, I took some shots at 40-yds. The elevation was still high as I had expected. However, the windage error was reduced to approximately 3-inches ... a definate improvement. Windage correction was only 5-to-6 clicks to-the-right instead of the former approximately 10 clicks.
Alignment is corrected by adjusting the turrets.
You don't have an "alignment" problem. You have a "cant" problem.
I'll draw a picture for you:
Do me a favor: rotate the scope in the rings a few degrees CCW. Rezero it. Shoot the target again taking care to hold the reticle vertical.
That is how you fix "crossover". It's really a scope cant problem.
I zeroed my scope at apprx 40-yrds ... corrected with 5-clicks down and apprx 10-clicks right. After reseting my zero at 40-yds, I checked POI at 20-yrds, the POI was low and to-the-right ... consistent with the correction I dialed-in at the 40-yrd mark.
Alex, I think the culprit here is the scope -- not the mounts -- so adjustable rings will be of no help.
The symptoms indicate a scope with a faulty AO, that shifts the POI when you adjust for 40yds vs 20yds. I suggest setting the AO to 30yds and leaving it there while you rezero, then shoot at different ranges without touching the AO.
If you do, I predict the POI shift will disappear.
Steve, this afternoon after work I sighted-in my Gaunlet at approximately 30-yds. I didn’t have time to take shot a group at 20-yds. However, I put my Gauntlet away without touching the side-focus. I’ll try to shoot a group at 20-yds in the next coming days - work and my chores permitting.
Steve, this afternoon after work I sighted-in my Gaunlet at approximately 30-yds. I didn’t have time to take shot a group at 20-yds. However, I put my Gauntlet away without touching the side-focus. I’ll try to shoot a group at 20-yds in the next coming days - work and my chores permitting.
I'm honored, Alex, that you've elected to invest your valuable time to try the experiment I suggested.
Alignment is corrected by adjusting the turrets.
You don't have an "alignment" problem. You have a "cant" problem.
I'll draw a picture for you:
Do me a favor: rotate the scope in the rings a few degrees CCW. Rezero it. Shoot the target again taking care to hold the reticle vertical.
That is how you fix "crossover". It's really a scope cant problem.
I zeroed my scope at apprx 40-yrds ... corrected with 5-clicks down and apprx 10-clicks right. After reseting my zero at 40-yds, I checked POI at 20-yrds, the POI was low and to-the-right ... consistent with the correction I dialed-in at the 40-yrd mark.
Did you: "rotate the scope in the rings a few degrees CCW" before you re-zeroed it?
Without that, you corrected nothing in your setup.
Did you: "rotate the scope in the rings a few degrees CCW" before you re-zeroed it?
Without that, you corrected nothing in your setup.
One thing at a time ... Steve’s suggestion was the quickest and easiest to implement. After I check the POI at 20-yds and 40-yds without adjusting the sidefocus. Then, I’ll adjust the sidefocus at the same respective distances. I might-add, my Gauntlet was shot by several persons before I came into my hands. John Swenson of New England Airguns and one of his friends fired the Gauntlet at 42-yds to ensure my air rifle was reasonably accurate. Translated, they found no problems with my Gauntlet. As such, I’m thinking along the lines of scope base alignment (mixing components of different MFG’s ... base and the adapters) or the scope itself being the problem.
Did you: "rotate the scope in the rings a few degrees CCW" before you re-zeroed it?
Without that, you corrected nothing in your setup.
... I’m thinking along the lines of scope base alignment (mixing components of different MFG’s ... base and the adapters) or the scope itself being the problem.
If you still have usable adjustment remaining in the turrets, then it is not a problem with scope base alignment. How much turret rotation do you have remaining? If you have a full turn in both direction, you are definitely good. Even half a turn is usually sufficient.
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If you still have usable adjustment remaining in the turrets, then it is not a problem with scope base alignment. How much turret rotation do you have remaining? If you have a full turn in both direction, you are definitely good. Even half a turn is usually sufficient.
After I test-fire the Gauntlet according to Steve’s instructions ... I’ll check for remaining turret adjustment.
To bring-to-mind my prior actions ... I initally set-zero at 20-yds. Then, I fired some shots at apprx 30-yds and estimated through my scope my group shift was 3 1/2 inches to-the-left and 3-inches high. I’d like to issue a correction, after using a spotting scope to take closer-look at the 30-yd group ... I estimate the shift the be apprx half of what I initially stated. The group was closer to 1 1/2 inches too high and 1 3/4 inches to the left.
After rezeroing at 30-yds, I shot the Gauntlet at 20-yds with the sidefocus set at 30-yds and the rifle zeroed at 30-yds.
However, I first warmed-up and then set the Gauntlet on a makeshift but solid rest. Took three shots that formed a nice tight group. Shot #4 did not change the group size - neither did shot #5. The group was less than the size of a pea. and was 1 1/2 peas below POA and 1/2 -a-pea to the right.
I adjusted focus and the POA became much more clear. I fired three shots all landed in a very tight group 1/2 a pea above the original group. With the same outcome, after three-shots the group size didn’t increase ... #4 and #5 made no discernible difference. After ten-total shots, the full group size was still sub-pea size.
The only reason I can think the POI shifted 1/2–pea UP was because after adusting focus the POA was much more clear. Moreover, there was not lateral shift in the POI after the 20-yd focus was properly set. As such, the off-set of the 20-yd group was inkeeping to the scope adjustments I made at 30-yds to zero-out the Guantlet - apprx 5-clicks down and abut 6-clicks right. I shouda kept notes on this ... just like I do with my springers ... but, I didn’t.
Couldn’t try shooting at 40-yds as the wind began to pick-up.
Shot my Gauntlet at 20-yds with the sidefocus set at 30-yds and the rifle zeroed at 30-yds....
...I adjusted focus and the POA became much more clear. I fired three shots all landed in a very tight group 1/2 a pea above the original group. ...
Target is at 20yds, but parallax adjustment set for 30yds?
If the parallax adjustment (focus) is not set correctly, eye position then becomes critical. If parallax is adjusted wrong, and your eye is not centered perfectly, your POA will change. When the parallax is set correctly, you should be able to move your eye around without any change in POA.
Shot my Gauntlet at 20-yds with the sidefocus set at 30-yds and the rifle zeroed at 30-yds....
...I adjusted focus and the POA became much more clear. I fired three shots all landed in a very tight group 1/2 a pea above the original group. ...
Target is at 20yds, but parallax adjustment set for 30yds?
If the parallax adjustment (focus) is not set correctly, eye position then becomes critical. If parallax is adjusted wrong, and your eye is not centered perfectly, your POA will change. When the parallax is set correctly, you should be able to move your eye around without any change in POA.
YES ... focus initailly set at 30-yds. After a five-shot-group. I adjusted focus at 20-yds and shot another group with the same POA. No lateral shift in POI. Vertical increased by 1/2-a-pea ... attributed to the more clear POA.
I checked the adjustment remaining on the turrets ... was able to rotate both turrets in both directions
as least one full-turn.
Wasn't able to shoot at 30 or 40 yards ... winds too gusty.
I checked the adjustment remaining on the turrets ... was able to rotate both turrets in both directions
as least one full-turn.
Wasn't able to shoot at 30 or 40 yards ... winds too gusty.
That's a good indication that the mounts are not the problem. Your alignment is fine for your current zero distances.
Well, I finally fixed the problem with my .177 Gauntlet.
I replaced the scope with a Crosman/Centerpoint FFP 3-12X44 Spectrum.
And I installed the telescopic sight with a Sun Optics medium fully-adjustable two-piece mounts.
Been wanting to try-out a fully-adjustable mount.
However, the expense of the Sportmatch versions seemed way-too pricey for me and way too-tall to-boot.
Anyway, I spent the afternoon aligning the scope/mount with the rifle-bore.
This IS NOT an easy task.
I finally got-done and fired a few three-shot groups to finalize zero.
So-far, it appears that that mysterious POI-shift has been eliminated.
Gonna install the removed CenterPoint 3-12X44 PLT scope on another rifle.
To-see if the optic was the root-problem.
Scope Mount · Adjustable · Dovetail