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Thanks for this!

An order for a Wheeler Engineering laser bore sighter was entered yesterday. (After all these years without.) Lever action, pump action and now an in-line muzzle loader besides upgrading scopes pushed me over the edge.

MD, thanks for the tip on that Wheeler Engineering bore sighter! It’s exactly what I needed. It works great.

I forget, "What's the drawback for a scope having a longer eye relief?"

Smaller field of view--everything else being equal.

Thanks.

Optical physics.

DF

I took a course in optical physics once. But memory is a sister to Mother Nature. (Bitch)

Yep, for sure...

DF

John,
What is an accurate scope bore sighter that won't break the bank?

Ralph

John,
Have you or anyone you know had a chance to test or use a Maven RS2 riflescope. I’m interested in hearing about any experience with these scopes....thanks, John

anothergun,

The Sightmark laser models only cost around $20, depending on where you buy them. But they're essentially chamber-specific cases that only fit a rifle chambered for the .223 Remington, .243 Winchester, etc. If you want to use a collimator for rifles in several chamberings, you're money ahead when buying a more universal model, whether a laser or optical type.

gbear,

Sorry, no I haven't.

when it comes to 4x scopes i just can`t see how people can claim they can shoot small groups at 100 yards ,i have tried and with a 6x it can be better but to be honest 9x or higher really helps most of us. > Mule Deer what power scope setting for seeing how well a rifle shoots do you use ? i also have been told if you have a 3-9 scope you should sight rifle in on 6x so its more equal accuracy on 3x and on 9x is that true ?

John,
Have you or anyone you trust done a field test on the Sig BDX system?

Pete,

There's a very simple optical rule for the potential amount of aiming error with a scope of a certain magnification.

The average human eye (meaning 20/20 eyesight, whether "bare" or corrected) can resolve about 1 inch at 100 yards in a black-and-white test, which involves looking at a sheet with alternating black-and-white lines of equal width. At 100, 20/20 eyesight can see alternatiing lines 1/2" thick, but not very far beyond 100 yards the same lines merge and appear gray (just like a zebra in the distance).

Magnification allows our eyes to resolve B&W lines at longer distances, and also allows us to resolve smaller lines at shorter distances. A 4x scope allows us to resolve 1/4 inch at 100 yards, if the optics in the scope are decent, which means a 4x scope will result in 1/4" of aiming error--in addition to other inherent errors in rifle/ammo accuracy. (This is leaving out parallax, wind, and our hold and trigger pull.)

The same rule applies to higher magnification. A 6x scope allows 1/6" in aiming error (.1666 inch), a 3-9x set on 9x .1111 inch (a little over a 1/10th), and a 25x scope .04 inch.

The quarter-inch error in 4x scopes really isn't much. I have several medium-bore hunting rifles with 4x scopes, and the most accurate will regularly shoot 5-shot groups averaging an inch with the right loads. Which means they should average .85 inch with a 3-9x set on 9x, or slightly over .75" with a 25x. In reality that isn't much error.

I suspect most of the problem many people have with shooting small groups with a 4x scope is due to inappropriate targets. Most commercial targets these days have pretty small aiming points, because so many hunters use at least a 3-9x variable. While a 4x scope ideally results in only 1/4" of aiming error, most aiming points don't allow us to hold as closely as possible with 4x.

There's also potential parallax, which many hunters don't even know how to check for, or correct. But 4x scopes normally don't have any perceivable parallax at 100.

Hear! Hear!

From another thread:

Thanks John...

I have a bushnell with the plastic insert on the end of the unit, for different calibers, and they seem to be touchy, and have to be set in the barrel just so, in order for the laser to be where it needs to be.

So the ones that look like a casing seem that they aren't as finiky?

Have never used that model. The laser bore-sighters that shoot through the bore are much less touchy.

I've also had very good luck with the Wheeler laser model, available from Midway and others, that attaches to the muzzle with a strong magnet. It's useable on everything from .17's to 12-gauge slug guns, but like all laser bore-sighters, requires some room in front of the muzzle to work usefully, in my experience at least 20-25 feet. It's also relatively pricey, around $80, but that's the sort of price you pay for versatility and reliability.

back to 4x scopes yes i understand a bigger target is needed to shoot some what smaller groups ,but i myself do better with more scope power and yes most of my targets do have smaller squares all 1 inch mostly . i like a bigger hunting scope for another reason so i can judge the size of the antlers on a deer ,at my age of 66 i don`t see a reason to shoot little deer anymore its just a personal thing for me, but i do enjoy young people shooting a deer no matter the size for them,for me just watching deer is alot more fun and less work too. scopes i guess the power you use is just a personal thing but i see a advantage to more power than 4x too, yes some will criticize me on here that`s ok, but when i only always carry a 257 Weatherby Mag. single shot i don`t plan on missing if i take the safety off either. Tim the toolman and me believe the same thing more power !

This one???

https://www.amazon.com/Professional-Magnetic-Connection-Gunsmithing-Maintenance/dp/B07L6YYTM7

Good stuff... thanks again John.