Rifle Scopes Burris scope with oddball feature. Gimmick or functional ?

[lma]

Recently bought a rifle carrying a Burris Signature USA 3-12x 45 (?) that has an adjustable iris like a manual camera. In a camera the iris (f stop) is used in conjunction with the shutter speed to adjust the proper exposure and control the depth of field (which items will be in focus). In an old Burris booklet I found reference to the iris as being a way for the shooter to control the light entering the scope and thus "obtain the best image". As the scope has an AO, depth of field is no issue and insofar as I can tell (shooting at a white target, over fresh snow in bright sun) I could see no difference regardless where the iris was set from wide open to fully stopped down. It is the first scope I have seen that has any gizmo to control (especially reduce) the light entering the scope. The emphasis has always been on getting in more light, not less. Of course, no scope maker has embraced this idea and Burris has dumped it as well. It is a fine scope that side by side with a 4.5-14 Conquest performs as well.
Just a gimmick or a lost secret of superior performance ?

 

[cnwrobb]

Pics would help, and I have never seen one.

 

[squishee]

i found these on the net.

 

[Davis]

The idea is to cut down on glare in bright situations when you have more then enough light. I used to have a 6-24 Burris Sign. that had an iris on it. Looking through it in your situation with snow and sunshine there is probably so much light you wouldn't be able to tell much difference. Don't know how much you will use it....I left mine wide open all the time, but it is a good idea in theory. I think the scopes are bright enough that they need the iris to get smaller to have the desired effect....at least that seemed to be the case on mine, and seems to follow with the results you are having.

 

[JMGlasgow]

Those are pretty good scopes for their heritage. Heavy but a good scope. Those iris's were a pain in the ass to rebuild.

 

[lma]

Thanks for the info. Burris told me it has the lifetime warranty and was made up to about 2000. Can't see it does anything so guess I'll just leave it open.

The Pawn Shop "deal" was a sporterized nickel steel 03' in 30-06 with a rotten bore, this scope and Leupold mounts. The price was $250.00. Figured I could "part it out" and make a few bucks. Turned out the rifle had been fitted with an 03A3 4 groove Remington bbl, converted to 300 WinMag, with a filthy but unrusted bore. The scope's lenses turned out to be perfect and it and the mount look brand new.
After a few hours with Hoppes and JB bore shine, the bore looked 99.9% and the no go headspace gauge would not go. Loaded up 20 new cases with a moderate load of W760 and 165 Nosler BTs. A quick bore sighting and a few @ 50 put me on the paper. Out to 100 and 3 5 shot groups all 1" or less. Just what I need another 300 Magnum ! ( 4 300 H&Hs and 1 other 300 WinMag)

A'int no beauty but she shoots !

 

[JMGlasgow]

I think you have a pretty nice setup there. Whoever sporterized that rifle did a pretty good job.

 

[lma]

It's a Fajan stock with the "60s look" about it. The checkering and bolt engine turning is horrible and it looks like 5 coats of spar varnish on the wood. Oddly enough, the inletting is a perfect job. Given the 1X wood quality, I'm not sure spending the time and money to refinish it, straighten out the checkering ,replacing the plastic forend tip with Ebony and putting a nice pad on it would ever bear fruit. Also needs a reblue and proper sights. May just bead blast it, paint it, sell the wood stock on Ebay, throw a Ram Line stock and a ProStaff Bushie on it and use it as a truck gun.