Ruger Forum

ZommyGun · September 21st, 2012, 11:20 AM

Work in progress...

Getting to this point is the easy part...

This is the 28mm scope mounted to the Weaver TO-9 rail with Weaver Low rings...the rail is .175" thick...the center of the scope has approx. .05" of clearance to top of rail with that scope/ring combo...there is approximately .240" clearance from objective to .920 bull barrel...

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This is the Leupold Rifleman Low rings modified to mount directly to the receiver with a 1" tube in place of a scope...

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Here are the rings screwed to the receiver...screws have not been recessed/trimmed...I need to drill and tap a new hole for a two screw mount on the rear ring...then fine tune the lapping until it's all perfect including gross elevation and windage centering the scope's adjustment hopefully at 100 yard zero...

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All the tuning and getting the final fitment will take a while...

Iowegan · September 21st, 2012, 01:01 PM

ZommyGun, Looks like an exercise in futility to me. Bullet drop does not change with scope height, however trajectory does. Although it is true ... the closer the scope is to bore line, the better trajectory will track up close, it is also true ... the trajectory beyond the sight in distance will shoot much lower.

When a scope is mounted excessively high, (think see-through rings where the center of the scope is mounted 2" above bore line) close up shots are going to hit too low. When a scope is mounted at a normal height (1.5" above bore line), close up shots won't be quite as low and distant shots will also be closer to sight line (best compromise). When scopes are mounted very low (1" above bore line) the trajectory for close up shots will be much better but distant shots will drop well below the line of sight.

In other words, mounting a scope as low as possible will improve the trajectory from the muzzle to the sight-in distance but is counter productive for any shot beyond sight in distance. In the below chart, if you extend the sight in distance from 50 to 75 yards, the bullet path in the middle will be way higher than line of sight, which is also counterproductive for a 22 LR.

What happens is ... the muzzle must be pointed slightly upward so the bullet will rise and intersect the line of sight at the zero-in distance. The lower the scope is mounted the less the bullet moves upward. Although this is good at closer distances (flatter trajectory), you end up paying for it at longer distances (more radical trajectory).

I have included a Ballistics Explorer trajectory chart for a 22 LR (rifle) with the same exact 40 grain bullets rated at 1250 fps and zeroed at 50 yards. The only difference in the three traces is the scope height. As you can see, the lowest mount (1") is better up close and the highest mount (2") is better at a distance whereas the best compromise for both close and distant shots is a medium mount (1.5").

Another factor is the gun's stock. If the drop in the stock is too low, you have to raise your head too high to get a good sight picture (full view, no black areas). With a straighter stock (typical for a 10/22) you can still get a good sight picture with a higher mounted scope, yet maintain a good cheek weld. Of course with a high mount, you will strain to find a good sight picture.

I guess it all boils down to what distances you plan to shoot. If you shoot primarily at 25~50 yards, then a low scope mount is better. If you shoot at distances from 35~75 yards, which is the typical distance for a 22 LR, then a medium scope height is better.

ZommyGun · September 21st, 2012, 02:22 PM

Thanks for information...I appreciate the input...however...doing what I like to do is by no means an exercise in futility even if it doesn't yield the results I would like it to...

Ballistics and theories not with standing...If you look at the first post you will see that I started out higher and with a factory stock...in fact before the picture of that 40mm scope with low rings...it was 3/8" higher than that picture...

In short...I hated it for a lot of reasons including height...the 40mm mounted as low as possible was a HUGE improvement...

The last picture with the 28mm scope mounted really low so far is definitely best...and since my eye level is still below the center of that height scope with the cheek rest set where I like it...I fully expect to like the new lowest mounting even better...of course, until its done...I won't know that for a fact...

It's a long post to explain everything why I like what I like so forgive me time is short and I have posted it all several times over...don't have time or energy to thru it all now but will try to include it all later for reference for anyone who cares...

If it turns out that 100 yard accuracy suffers a lot because of low mounts I suppose I will just not use it for that...it's not important enough to me to have a high mount scope...

Thanks again for the information...very interesting and I will certainly take it under advisement...

Iowegan · September 21st, 2012, 05:06 PM

ZommyGun, I understand your logic (I think). Experimenting is great fun and you learn first hand information ... not just some opinion by others. I just wanted to dispel another one of those "urban gun myths" that we so frequently see on the Internet .... meaning "the lower the scope mount, the better the trajectory." Fact is ... neither a low or high mount is "best" for all shooting distances. What you gain on one end, you always lose on the other so you have to figure out your shooting priorities and stock considerations for eye alignment then go with what serves you best.

Been there ... done that myself and concluded there really isn't enough difference in trajectory to warrant jumping through hoops. My approach is very simple ... buy the rings and base that make the front lens bell clear the barrel far enough to use a protective lens cap. For a 22 LR, the rest pretty much takes care of itself.

I would never use "see-through" or extra tall mounts because of other issues we haven't discussed ... recoil and bolt shock. For 22 LR rifles, recoil is not an issue like with a high power rifle but bolt shock is (semi-autos only). The farther a scope is from bore line, the more recoil or bolt shock will negatively influence the scope. Another topic for a different thread.

ZommyGun · September 21st, 2012, 07:04 PM

I'll get back with later...glad you are interested in sharing information...can't tell you how much I respect that...

For now...work in progress...

.022" clearance to barrel....016" clearance to power knob to receiver... .067" clearance scope center to receiver...working out great...need to lap for better fitment...trim screw length to clear bolt...test fire...then do final lapping and seating...

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303lithgow · September 21st, 2012, 08:32 PM

Quote:

Originally Posted by James6591

Lower is best.

I agree.

ZommyGun · September 22nd, 2012, 08:12 AM

Got a chance to check the eye-level...in a word... PERFECT...

Work in progress...

I didn't get those rings for this purpose...there is not really enough meat on the bottom to fully seat them without the objective or mag knob touching...

When done if I am happy with lowest setting will get a second set of rings and do a better/permanent job...

Look forward to finding out how it does at the range...hopefully withing a week...

Later,
ZG

ZommyGun · September 22nd, 2012, 10:13 AM

Hit the wrong button...sorry...

ZommyGun · September 22nd, 2012, 10:15 AM

Lowegan… I am sorry it took me a while to go thru your post and properly answer you before…

Quote:

When a scope is mounted excessively high, (think see-through rings where the center of the scope is mounted 2" above bore line) close up shots are going to hit too low. When a scope is mounted at a normal height (1.5" above bore line), close up shots won't be quite as low and distant shots will also be closer to sight line (best compromise). When scopes are mounted very low (1" above bore line) the trajectory for close up shots will be much better but distant shots will drop well below the line of sight.

This extremely helpful information…I didn’t have time to think about it yesterday…thank you for putting it up…if the results of the “lowest” mount for the 28mm scope yield poor results at 100yards compared where it was before I will know why and what to do about it…

All comparisons for “results” are accuracy at 100 yards… the longest shot I care about is at 100meters…I need to get 1” groups at bench rest with high velocity or standard velocity ammo…I can get that with hyper but it is not allowed…

Rounding off the numbers just a bit here for speed but they are close…

Originally had 40mm scope shown in first post mounted on TO-9 rail with Burris “Z” rings with saddle height of .5” from top of tip off rail…

Basic dimensions are this…

Barrel… .92” o.d. ____ .46” radius center of bore to top of barrel…
Top of barrel to top of receiver… .075”
Top of receiver to top of Tip Off rail… .175”
Top of tip off rail to eye-level approx. 1”

Total height from center of bore to eye level roughly 1.7” …. Results were bad for multiple reasons but height was certainly a factor…not necessarily trajectory but IDK…it doesn’t matter…I refuse to go back that high period…

The top of receiver to bottom of tube for the 40mm scope with rail/rings shown in picture is .425…
.425 + .075 + .460 + .500 = 1.46” … Results were much better and the same as the 28mm scope mounted in the pictures shown with Leupold Rifleman low rings and the lower still Weaver low rings…both on the TO-9 rail…

The 28mm scope with Rifleman Low rings on TO-9 rail were .150 + .250 + .460 + .500 = 1.360

Going to the Weaver rings drops that to 1.3”

Now what I am doing here is a dramatic drop from there…the opposite extreme of too high as you pointed out…

Without getting to much into the weeds over “final” fitment of the lowest of the lowest mounts…it is approximately as follows… .460 + .02 + .70 = 1.18”

There is no way without modifying that objective to get it any lower than 1.17” above the center of the bore… so if it works out to my advantage in the long term that is exactly where it would be … 1.17” above cob…

Let me put it this way…if the net result is poor…I will go higher…however, it is entirely possible that the theory of trajectory vs. eye level is NOT the dominant factor and might not necessarily pre-determine the outcome…we will see and I will not lie about the results…on the other hand…my testing is not that refined so the results are not deemed completely reliable by me either way at this point in time…

Quote:

ZommyGun, I understand your logic (I think). Experimenting is great fun and you learn first hand information ... not just some opinion by others. I just wanted to dispel another one of those "urban gun myths" that we so frequently see on the Internet .... meaning "the lower the scope mount, the better the trajectory." Fact is ... neither a low or high mount is "best" for all shooting distances. What you gain on one end, you always lose on the other so you have to figure out your shooting priorities and stock considerations for eye alignment then go with what serves you best.

Been there ... done that myself and concluded there really isn't enough difference in trajectory to warrant jumping through hoops. My approach is very simple ... buy the rings and base that make the front lens bell clear the barrel far enough to use a protective lens cap. For a 22 LR, the rest pretty much takes care of itself.

I couldn’t agree with you more on the big picture…however the devil is in the details…and you are wrong regarding my reason for doing this…it’s not about theory in the least…because if that were it…I wouldn’t bother modifying the rings…which is quite easy for me btw…it’s testing, verifying, fine tuning and final fitting for permanent use IF the results pan out that is the hard part and ONLY worth it if it achieves IDEAL results…which is why I am not going all out prior to test firing it at 100 yards…

Quote:

Another factor is the gun's stock. If the drop in the stock is too low, you have to raise your head too high to get a good sight picture (full view, no black areas). With a straighter stock (typical for a 10/22) you can still get a good sight picture with a higher mounted scope, yet maintain a good cheek weld. Of course with a high mount, you will strain to find a good sight picture.

My purpose for doing this is 100% ergonomics for offhand shooting…you are NOT going to believe me at first when I tell you this but as it sits in the last picture it is the IDEAL eye-level for head erect as can be with rock-solid cheek-weld absolutely perfect grip with no stress on wrist…eye relief locks in tight and perfect as can be…comfort level is finally exactly where I want it…AND THIS OCCURS AS NATURALLY AS CAN POSSIBLY BE WITH ZERO CANT...a small but very important imo detail...

One thing to not also with regard to that SBS rules don't allow cheek weld to rise above bore center line and I don't like it that high anyway but if it works out that a higher mount is needed I will set the rest at exactly that height and that is where the scope eye level will have to stay...hopefully it will work out at 1.2"...

But that sir is another thread…I am just sharing what I am up to with anyone interested and very glad you presented me with this information and your personal experience with it…

Note that I have the same stock you have only w/o the adjustments…I can tell you where you have gone wrong with yours but I bet you are so set in your ways you won’t change over… LOL…

Now I have another thread where I could SERIOUSLY use some help with barrel/ammo accuracy…scope type and height not withstanding of course….

Iowegan · September 22nd, 2012, 01:03 PM

ZommyGun, Before this turns into a discussion of what's right and what's wrong with either of our techniques ... I just want you to know our priorities are obviously different. What may be right for you may be wrong for me and vise versa. The point I was trying to make previously was ... from a trajectory point of view, the old wives tale about a scope having to be as close the the bore as possible, just isn't true. However from an ergonomics point, it all depends on the shooters physical characteristics. All of us don't have the same shaped head and our eye balls aren't the same distance to the chin for cheek weld.

My goals with a 10/22, is to get good accuracy from 25~75 yards with good quality ammo. I seldom shoot any 22 LR at distances beyond 75 yards nor closer than 25 yards so my priority is to find the optimum conditions (such as scope height) that will take advantage of a 22 LR trajectory between these two distances. Also because I shoot at multiple distances, I insist on having proper magnification and parallax correction for each and every distance within "normal" 22 LR limits (variable power and adjustable objective lens or side dial). With the scopes you pictured, it doesn't look like you considered the important factor of parallax. High power rifle scopes are parallax corrected for 100~150 yards and really suck at closer distances. Rimfire scopes are parallax corrected for 50 yards and are far from optimum at longer distances. When parallax is not correct for the distance you are shooting, just the cross hair drift from being in different focal planes can open up groups several inches. For 22 LR scope magnification, I use the "1x for each 10 yards" rule. When the magnification is set properly for each shooting distance, you will get the same sight picture as if you were shooting at 10 yards. This makes a 1" aiming dot the same size and enables you to "calibrate" for hold over/hold under at any distance within the normal range. My favorite 22 scope is a Nikko Sterling 42mm, 3~10x, with a side dial for parallax correction. This gives me a usable range of 30~100 yards for magnification and I can dial in for parallax correction at any of these distances. Eye relief is good, and the scope height matches my natural hold. Because of the fairly large objective lens, this center of this scope is 1 3/4" above bore line and misses the barrel far enough where I can use the supplied spring loaded lens cap.

If you clamp down a rifle in a device much like a Ransom Rest for handguns, you will eliminate the human factor and will see what the optimum accuracy is for that particular gun and ammo. These devices do not use sights or scopes for precision aiming ... rather they return the rifle to the exact same position for each shot. No scope or creature comforts like stocks or trigger pull can improve accuracy beyond the the mechanical limits of the rifle (bore, crown, chamber, headspace, etc). I have done this with my 10/22 build and found at 75 yards, my groups with CCI Mini-Mags was 3/4". I don't doubt this could be improved if I used expensive match grade ammo, however that's the ammo I normally shoot and it performs good enough for my purposes. In theory, a 3/4" group at 75 yards should be 1" at 100 yards but I found with my 10/22 build, using the same ammo, groups opened up to 2" at 100 yards. With 10/22s, it's impossible for cartridges to feed from a magazine without a little bullet distortion so groups would improve if cartridges were "single loaded" but that's not the way I shoot this rifle. Again, distance amplifies imperfections. In this case, just a tiny difference in bullet shape, bullet weight, or velocity will show up at extended distances, not to mention the slightest breeze.

The challenge is to see if I can muster enough skill to get as close to Ransom Rest groups as possible. To do this, I need every advantage I can get ... nice trigger pull, good scope, well fitting stock, etc. My 10/22 must be set up pretty good because I can almost always drill a 1" aiming dot the fist shot at any distance from 25~75 yards. To do this, I print a chart from Ballistic Explorer and use the trajectory trace to compensate for hold over/hold under.

Any decent scope can be zeroed in at 100 yards on a 22 rifle. That's not at all what I was referring to and has no impact on trajectory if that's the only distance you shoot at. However, if you shoot at multiple distances and zero at 50 yards, the error correction for the low mounted scope in my above chart is 6" versus 5" for a high mount scope. Neither have a bearing on the issue if you zero at 100 yards.

Quote:

I can tell you where you have gone wrong with yours but I bet you are so set in your ways you won’t change over…

I'm all ears ... tell me where I went wrong.

ZommyGun · September 22nd, 2012, 01:36 PM

I was razzing about the stock if you can't tell...

You are wrong about my assessment of the scopes and if you look at the 40mm scope you will see that it is an AO/TT and the parallax adjusts down to 10 yards...

At 2x at the closest range I will ever use the other one at it not a problem and I have used it at 100m at 7x without any problem as well...

If higher magnification, higher mount, and adjustable objective were my priorities I had that covered 10 years ago...wasn't happy with that...

I checked my cheek weld...it was already at the center of the bore which is the max allowed (I thought I still had room to go higher but I was mistaken) and it was not high enough for the 28mm scope mounted on the lowest rings available on the lowest rail available...now the eye level and relief are both perfect so I hope it doesn't cause accuracy problems due to being too low...

Anyway...thanks once again for tips about the height it is valuable information...

ZommyGun · September 24th, 2012, 12:00 PM

Lapped the profile tighter to the receiver...shimmed the rear ring base with aluminum .004" thick while lapping in the profile for an additional 3-5MOA of elevation...once that tilt was in the profile I removed the shim and seated a little more...used the seem in the tube to align gross windage while lapping...

Reassembled it...set the scope cross-hairs for dead center on windage and elevation...but the bullet-style laser bore-sight in and checked it at 50'...

Laser POI was 3MOA high and 3MOA left...not bad at all...

It currently has .013" clearance to barrel...so I still have room to add more elevation to the final fitment if need be...however...based on bore-sight I think it is already way, way better gross elevation and windage than of the rail/ring/scope combinations I have used so far...the elevation is typically not so far off center but the windage previously with tip off rail and weaver style rings has typically been off by a lot...

Now all I have to do is test fire it at 100 yards and make sure the gross windage and elevation are where I want them...then drill and tap the receiver for a second screw in the rear ring...

I really hope the trajectory/ballistics is not a problem because the eye level is perfect as can be...

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ZommyGun · September 26th, 2012, 08:34 AM

It's not as perfect as I would want it for permanent installation at this point but more than adequate for test firing...if it shoots half as good as it feels I will go all out on a perfect/permanent installation...

Wish me luck...

Later,
ZG

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NY Ruger · September 26th, 2012, 12:59 PM

Lower the better....

Nice job!

Consistent cheek weld is the key.

Biggest problem when scoping a 10/22, with a oem stock or stock with the same profile, the sighting plane is very low.

I have a scoped 10/22, and went thru the pains to get it as low as possible.

The fixed power weaver I went with looks very very close to the same as the last pix.
But not as low, since I"m still using a rail.
Picked it for the better optics so I could live with a smaller dia lens.
But one still has to look through the center of the optics, which is much higher than the original designed sight plane.

After all of that, still need to add a check pad to raise where the cheek weld lands and get it naturally up onto the center of the optics.

I found this worked great on the oem 10/22 stock. For my daughter I have keep it filled with all pads, for me I can take out 2 of the pads.

BlackHawk Tactical Cheek Pad - Adjust HawkTex 90CP01BK FREE S&H 90CP01BK. BlackHawk Weapon Accessories.

It's night and day when shooting.... if your truly scoring, the points tell the story.
For just knocking soda cans down... ah, probably wont notice. But consistency is the key to accuracy , and a bad / inconstant cheek weld takes down the rest of the proper shooting foundation.

ZommyGun · September 26th, 2012, 06:00 PM

I couldn't agree with you more and that looks like a good product...I made mine out of foam and stretch wrap for now...going to sculpt one later and cover with leather...

I almost got a fixed 4x...glad I didn't...reason is I really like having the 2x...the 7x is not all that great at 100m anyway...and of course the lack of parallax adjustment doesn't help at that distance...so today I just used it at 2x at 100m and liked it...my accuracy was no better or no worse at 7x vs 2x...but with iron sights...forget it...can't see worth crap...

Anyway...ran about 300 rounds thru it today...not at range...not on paper...but did shoot standing at rest on tool box and off hand both from 100' to 100 meters at small targets...

The scope and modified rings couldn't have been better...

Regardless of rings/rail I wanted to get the scope centered at 100m for mini-mags...

The scope has 80moa elevation and windage...set it exactly 40/40 at home...went out to shoot...turns out that +39 moa is the elevation it was set on when I got back...which was for super-x 1435fps...and right before that I was shooting Game Shock and Mini-mags that were 2-3moa more elevation...

For the gammit of a variety of hv ammo (three types of bulk plus two types of mini-mags plus game shock) and the super-x at ranges from 100' to 100 meters I can say I never adjusted the elevation more than +/- 5moa the whole time I was out there...

I will take quite a bit of credit for doing an excellent job of lapping in the elevation and windage of the rings onto the receiver...but have to say I feel like I got very lucky overall with it being so, so, so dead on...

AND also very lucky that the trajectory vs eye-level didn't bite me in the butt...

This set up is so stone cold perfect I can't believe it......something finally went according to plan with the gun...

Yes my cheek is set absolutely perfect for it...the ONLY problem I had was to remember to quit lifting my head up off the cheek rest...bad habit from having to do it for so long before...

Couldn't be happier with it...

Which is good...because the way it went with ammo and mags today...if the scope/mounting had f/d up I think I would have take out my glock and shot this gun to pieces...

Fortunately the only thing that had to get shot in anger today was my bx-25 mag...it is officially dead...25 times over...I confess to murdering the sob in cold blood...