Do you know the gehmann numbers of the set up?
Bill

Sportslube, the Gehmann number is PH-530 which I think is the standard model. Mine came with an adapter for the Parker-Hale base. I bought it through Creedmoor Sports in Alabama. It was special order for that mount but only took about two weeks from Germany. They were very helpful all around and I would buy from them again. 

Redsetter, I knew about the ones from back in the Schuetzen days and that is what sent me looking. I have an implant from an eye injury that keeps me from seeing even with glasses but the combination of focus and iris seems to do the job. It's like I have a teenage eye again. And that is with no prescription glasses.  That's why they call me "ratseye".

I have one of those as well.  I found that the sight picture overall is much better if I use just safety glasses and not my prescription glasses.  You may find a different solution.

Dave

Is it allowed to have a lense in the rear or front sight when shooting "Iron sight" class in ASSRA and ISSA Schuetzen?


Yes you are allowed to have a diopter lens in either the front or rear; but not in both, because that would be making it a telescope.

With the adjustable diopter you can focus so both the front sight and the target are sharp.

However you are better to back the focus off so the front sight is sharp but the target is not as sharp.

This forces your eye to continue to concentrate on centering the target; as opposed to focusing back and forth from the front sight and the target.

This slight out of focus adjustment will cut your group sizes to a third the size.

Advice provided to me by Lones Wigger; former  top US shooter, former Olympic Coach and only shooter in the U.S. Olympic Hall of Fame as well as a member of the USA Shooting Hall of Fame .

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ratseye wrote on Nov 24^th, 2018 at 7:40am:


You are not alone!

Schuetzendave wrote on Nov 24^th, 2018 at 12:32am:


Don't see how that's optically possible, though if the muscles controlling the eye's lens are flexible enough (i.e., young enough), the illusion of sharp focus can be created by the eye's rapid re-focusing between front sight & target.

But as you pointed out, a slightly blurred target can be advantageous for aiming. 

Don't see how that's optically possible


It will be very obvious if you ever try it by playing with an adjustable diopter.
Maybe someone can lend you one and you can test it.

I have been using a Gehmann adjustable iris c/w an adjustable diopter since 2005.

Using it I was the International Schuetzen Benchrest Champion even though I had cataracts at the time.

I have an adjustable diopter with my Gehmann adjustable iris with colour filters and dual polarizer.

I also have an adjustable diopter with my Gehmann adjustable iris with only a dual polarizer.

Found adjusting light and focusing with the adjustable diopter was all I needed to improve my declining eyesight that comes with age.

I no longer use the colour filters or the polarizer.

The big knob closest to the sight is for adjusting the diopter.

I watch the wind with my left eye and sight with my right eye - so I always have both eyes open.

I have always mounted my sights high so my head is vertical and I always have the same Point of Aim.

As we age and macular degeneration occurs; we may need to adjust how we look through the sights to use the best part of our eyesight that remains.

You must have the right amount of light to your eye so an adjustable aperture is number one.

You can improve your scores by selecting the right focus or balance of sharpness between your front sight and the target so I believe the adjustable diopter is essential.

Every time I have tested using the colour filters or the dual polarizer; I always got better scores using straight light to my eye, so I do not value these add ons.

These other addons make you believe you are seeing a better sight picture.
However the apparently improved sight picture did squat for improving my scores; rather they actually slightly decreased my scores after numerous trials.

Then the precision of adjustment of your sight is the next most important thing.

I strongly believe it is better to have 1/8 or 1/10 MOA adjustments so you can better select your point of aim.

With a scope you can hold off but with iron sights you need the fine accuracy of adjustment if you are going to have an edge in competition.

I do not think 1/4 MOA adjustments will shoot fine enough to win competitions because there are some pretty strong competitors out there.

I screwed one of those #530's into the tube sight I built and it definitely helped my iron sight scores.  Agree with Schützendaves's views on adjustment.  I got mine from Champions Choice - believe they are $140 now.

Regards, Joe

I mostly use Baldwin sights, or did when I could see well enough. Does anyone know about thread compatibility or adaptors between the two products?

Does anyone know about or use any of the sight discs offered by the Merit Corporation? They also offer a lens disc. Has anyone ever used one of these?

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Is it optically or scientifically possible to have a lens in the rear sight and one in the front sight so this combination functions just like a telescopic sight? 

As I recall, the thread on the Gehman is an oddball metric.  It's close to a US size - maybe 3/8 - 24 ?   In my own case, that's what I used and it acted somewhat like a pipe thread - turned in two or three threads and started to tighten up - worked fine for my application.  I had no luck trying to find out the thread sizes for their adaptor (577).

California fires have not affected us this far south Dave, but the devastation up north is hard to see.

We should probably start a new thread for tube sights so as not to derail this one.

Regards, Joe

The thread is 9.5 x 1 metric.

It is very close to a 3/8 x 24, will actually engage it about 3-4 threads before it binds.

Thanks for the thread info. Interesting possibilities. At the worst, more stuff for the heirs to wonder at and toss.

I like the idea of a clamp and that would save me having to cut that oddball inside thread for an adapter. Cutting the outside 10-40 to fit the MVA on my Ballard will be easy but I am getting way ahead of myself since I haven't shot the Cadet yet with the new sight disk and that will be the proof. 

I for one would be interested in a tube sight thread if someone wants to open one. That is another area that I would to know more about. Thanks, ratseye

Do the math: 9.5 mm = 0.374" dia., 1 mm lead = 0.03937" 
0.3937 divided into one inch = 25.4 threads per inch - much closer to 24 tpi than 28 tpi.

I might add the container was also marked as being the proper MM size but that was not what was in side it was the 3/8 X 28UNF along with the note included in the box they where shipped in. If memory serves me right I gave my second tap to Jerry Hartwig? and his container might still be marked in MM's all though it was also a 3/8 X 28 UNF inside mine has since wore off the container it came in or I would have also shared it. 

JLouis

I know you are not trying to be difficult Don and I am only wanting to share what I used on all those I made for others and those I sold. The rear apretures by Gehmaan and others all screwed in very nicely. If you might feel I could be of some help with your project send me an e-mail to the below e-mail address. I still have the information for both a 28 and 30 inch tube sight in regards to the baffle placement and the various hole sizes for each of the four or five baffles I used depending on the tube length one wanted to use. The only real critical part is to insure the tube is completely black inside minus any and all stray light and how one goes about achieving that can very easily vary from one person to the next and that the tube is straight so it will center nicely in the rear mount. When done it should be the same as looking through a scope with all that you are seeing is the front apreture and nothing in between and the same as only seeing the crosshairs when looking through a scope. The way I made mine was pretty labor intensive / allot of time involved all though not at all that difficult to do. Straightining the tube was probably the more difficult part in all honesty if it required having to be done. 

johnnymlouis@gmail.com

JLouis

I might add both taps I purchased were clearly marked 3/8 X 28UNF I just double checked and had I not gifted one I would have gladly gifted it to you. Hopefully Jerry H might also chime in if they were possibly miss marked I would have not known so. If memory serves me right I got the information from Gehmaan at the time for the right MM tap size and you might also want to do the same to be safe I just simply e-mailed that question and then went from there.

JLouis

John, the tap I got from you is marked 3/8-28, on both the tap and container. I used it on a tube sight for Rich$ and it worked, but was tight.

Just going by memory (a bad thing) I once upon a time bought a Gehmann rear aperture from O.K. Weber. He loaned me a tap that he said was as close as you could get because the German threads were unique and not available as a standard tap. Pretty sure he said it was an English Cycle Thread at 3/8-26.

I'm not sure, only saying what I think I remember.

JerryH

Don the way I set my own tube sight up all though I don't recommend doing so for others I can actually line up and center up all five holes in my baffles with the front apreture yet the interior is still void of all and any stray light and something I thought would be an added benefit for myself and it has actually worked out quite well. But I had also incurred some permanent vision loss in my right shooting eye from my stroke and I was trying to make up for it as well. I'am also curently thinking about selling it along with the real nice crisp clicking Unertl mounts but minus the rear apreture due to my eye sight now haven gotten even worse. 

JLouis

Bob send me an e-mail so I can respond to your request.

johnnymlouis@gmail.com

Since we are engaged in a bit of topic drift anyway. What is the advantage of the tube sight over separate front and rear sits?

The top picture is the Anchutz 18MM Apreture Clamp Ring that I use for the Acrylic inserts that takee the M18X.5 Tap and cost only $10.00. Below it is but one of several 18MM adjustable types mine goes from 2.0 to 4.0 and by stating several I am referring to the various choices such as the cross bar shown, or crosshairs or on and on and price is very dependent on choice of Gehmann, Centra, Anchutz, Others and Apreture design. They all use the same M18X.5 thread design as do the Diopters, Sunshades and various other 18MM accessories. I might add they will all also screw into the front of the Anchutz clamp but not the various adjustable types and thus the clamp is by far the better choice for my own use. With the adjustable's you also have be careful it is not one of those used at the back of a sight as you can then see the back side of the adjustable iris and it might not appear to be round.

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JLouis

Ratseye I can only hope that something I might have shared has been somehow helpful for you. In all honesty when tapping the M18X.5 hole it has to bored very accuratly to spec. If a bit under or over due to the threads being so fine and shallow it really cannot be accomplished correctly and you end up with no threads or wiping them out while trying to tap and it really is that critical. With that being said and if possibly not having that capability I would very seriously take a real close look at Jerry H's approach and I am sure he would be more than happy to explain his entire process and what he uses on the front if so being required. One would be hard pressed to find a more willing individual who enjoys helping others and his approach would indeed be a high quality one.

JLouis

My error and miss-understanding Ratseye my having permanent partial eye sight loss from a stroke back in 2011 I thought I was on the same page as you. I was thinking about what it was I had to do for myself to continue shooting the Iron Sight matches and should have been paying closer attention to what exactly what your own needs are.

JLouis

I said I would report when I finally shot the gun with the new peep sight. Today was it and I am more than happy. I know that this isn't much in the world of real competition shooters but I was at the point of selling my iron sighted guns because of not being able to see well enough. 

The rifle is a Martini Cadet in 32-20 WCF with an excellent bore. The load is IMR-4227 in Starline brass and a CCI-LR primer, using a bullet cast from a custom CBE 130 grain heeled bullet mold with my home made lube. That bullet is quite accurate in another Cadet of .310 caliber. This was before my vision started to really nose dive. So shooting this same load that the BEST I could do before in the 32-20 was a 7" shotgun spread, today's best was 1-1/4" for five at fifty yards. THAT my friends is a significant improvement and made me a believer. I think I can do better as I work on the adjustments but being able to see the front sight clearly and the target almost as well made a huge difference. It may not work for everyone but it sure helped me. Thanks for all your input, ratseye

There are 2 mentalities in people, fixed & growth.  Fixed people think there is nothing they can do to change their condition, growth types, like Ratseye, study & learn how to respond. We can all learn from this.

I always believed that every problem has a solution if you never give up. I can attest to hundreds of ways to not do something before finding the answer. I am humbled by the level of knowledge and the willingness to share that this group has shown me. It is much appreciated. ratseye

Unfortunately that is not how mine worked with my Gehmann rear apreture and I am not sure just why? Had I known I would have gladly sent you mine before purchasing yours to use on a test piece. Other than coming from China who supposedly had the correct Metric size and the only one I could find. All though the outside of the container was correctly marked in MM but not what was inside and noted as being the same. It worked out very well for me so I am completely baffled to why?

Actually no, that's not what I am making but might be something i could use in the future. I am making an adapter to use the Gehmann peep I have on my Cody Ballard and the thread on the peep is an oddball metric. 

jlouis, no problem with the tap size because I think the issue may be related to my choice of a very tight clearance as the fit is about 74% or tighter with the drill I used. I will go up one and see how that works. No matter I can work with it and it will be so much easier to make now and will be a great help. 

Thanks, ratseye

I have 3 CPA that yes this set up, 80 year old eye needed help---------smillllin

That's the fellow Kurt but I had a different use in mind at the time.

JLouis

It holds it up pretty high but loading a cartridge isn't a problem. I have not tried breech seating yet so I don't have experience with the equipment or method to comment. The value for me is being able to see the front sight and target much better. Aesthetically, it doesn't fit at all but I'll suffer with that. Thanks, ratseye

beltfed, 

You are correct about the "tunnel" and it will cause issues with the windage cranked over. The one shown is the first attempt and I saw what you are talking about so I made another with the absolute minimum dimensions for length and maximum hole size. The bigger hole brightened things up a bit too. I am a little concerned about strength now but have a good radius at the joint so I think it will hold. It is a trade off at best. Look through an oval or not see at all. 

Has been raining and cold and now warm and raining so there will be no testing for a couple of days. 

Merry Christmas to all! 

Thanks, ratseye