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In this issue:
Cataract surgery?
Re: Recommend SCUBA setup for a team
Re: Recommend SCUBA setup for a team
Re: Recommend SCUBA setup for a team
Re: Recommend SCUBA setup for a team
Re: Recommend SCUBA setup for a team
Re: Recommend SCUBA setup for a team
Re: Recommend SCUBA setup for a team
Re: Vision and Shooting
Re: 30 degree rule
Bloop tube or not?
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Hi Michael
A quick query. I have been asked by a member of our Association whether anyone has knowledge of the effects on shooting vision of cataract operations. He is concerned about the possible effects of scarring on the eye from the operation which might be visible when looking through a small peep sight.
Any views welcome.
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Michael,
As for Air Systems and Cascading, check with your local Fire Department. It
is the same system and they will likely fill your air tanks for free (so long
as they are within Hydro). If nothing else, they will be able to show you
what they have and how they fill their tanks.
Roy
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1. Everyone should provide their own adapters, so you should only need to
provide the standard yoke that holds them.
2. Even with 2 tanks, there is enough trouble at matches I have seen that I
would not recommend just buying tanks for use by a lot of people. You really
need a pump that can keep them topped up; preferably with an automatic
switch (and a safety valve is of course mandatory). Air guns use a lot less
air than scuba divers, so a small pump should do if you can find one.
- Benjamin
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Hi Michael,
We have two eighty cubic foot aluminum air tanks for 5 shooters. Practice at the range is once a week, most fill up when they arrive and before they go home. I have to fill the tanks two or three times a season (October-June). Adapters are available from Champion's Choice, Pilkington and Nygord. If you purchase a tank with a 200 DIN fitting instead of the std American, you won't need an adapter.
In Wichita,
Cost for 80' aluminum tank with std American fitting- $160.00
Cost for 80' aluminum tank with 200 DIN fitting- $180.00
Ralph Goodwin
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I'd suggest you contact a couple of local dive shops and tell them what
you're doing. Suggest they become your team/club's 'SCUBA air headquarters
and official air supplier.' They fill your team's large tanks for free, and
offer a discount to your individual members for fills.
In return you put their shop's banner up in your range, an ad or notice in
your club newsletter, an ad or note in the match program and a framed photo
of the team or display on the dive shop wall.
Everyone wins at minimal cost.
Scott Engen/Utah, USA
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Michael,
r.e. your CA request. Saw an airgun specific compressor rig at Camp Perry's Commercial Row this summer - seems like a better solution than lots of heavy tanks to transport. Maybe another reader will remember which vendor. You will need a couple of tanks for road trips unless you are assured of good air at the destination (aluminum 80s are the norm). Use the two tanks sequentially - meaning label the tanks # 1 and #2. First do a basic fill off tank #1 then top off from tank #2. That way you'll retain tank #2 at a higher pressure for longer periods and you won't have to get the tanks re-filled as often. Hope this helps.
Floyd Houston
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Michael,
I recently set up our Air Rifle Team for CA. Your best bet is AL 80 CUFT tanks. There are many other sizes and volumes, but the AL 80s are the cheapest (because that is the most common size made for the diving industry).
On the FWB P-70 Juniors, I can get 10 to 15 rifle cylinder fills out of a single full 80. If you then have a second SCUBA tank, you can use the first SCUBA tank for another 10 to 20 starts and get 15 to 30 fills from the second tank before its pressure drops and it becomes the tank to start with and the the original one needs to be filled. With two tanks (and depending on how low the rifle cylinders are when you have to fill them) you can count on 20 to 30 fills per SCUBA cylinder refill (with a two SCUBA tank system). I have never had a full rifle cylinder need to be changed during a match. You can use cylinders as low as 2,000 psi (130 bar) for practice and just change them during position changes.
I retrofitted the SCUBA tanks with DIN valves. If I had to do it again, I would get the yoke that Pinkerton makes and stick with the regular SCUBA valves. You might ask around, we had 3 tanks donated to the team (people who had stopped diving) and all we had to do was was get them Hydroed. That's when I replaced the valves and it would have been cheaper to go with the yokes (if only I had known). Also, if you do not replace the valves you will not have to remember to bring the fitting that goes in the DIN valve to get them filled at the dive shop. Each of the air rifle manufactures have their own adapter (they needed a good System Engineer). I would recommend two yokes with adapters for each kind of of rifle tank you are filling. I would get two spare yokes, but not an adapter for the rifles you do not have. People who bring rifles should have the adapter that fits their rifle.
I am recommending two yokes and adapters because when filling a rifle cylinder you never want to remove; the rifle cylinder screwed into the adapter, or the rifle cylinder screwed into the adapter and the yoke from the SCUBA tank. The adapter depresses the valve in the cylinder and if you remove a yoke with an adapter and cylinder from a SCUBA tank you will blow the O ring in the tank and empty the rifle cylinder (with the accompaniment of much noise). You also don't want to have to unscrew the adapters any more than necessary. They only need to be hand tight, but if they are overtightened, you will eventually mess up the O rings and get leaks. Have spare O rings for the SCUBA tanks.
Tom Ciarula
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Michael -
At MIT, where we are getting more and more CA guns, rifle and pistol, we
currently have 3 80's. They drain steadily, and need to be refilled
about 2X during the season. I am considering getting a large volume
tank from BOC gasses. They have 500cu' tanks for about $125, plus about
$5/mo. to rent. But, and a big BUT, they require a reducing regulator
to go from 6Kpsi to 3Kpsi, and it costs about $300. My guess is that
you could use air or nitrogen, or even, possibly, helium.
My other option is picking up a couple of extra tanks, but 100's instead
of 80's. They hold about 25% more air and cost about 25% more.
Also, consider what type of valves you want on the tanks. I have a
combination of DIN and standard K valves. The Ks need an adapter which
can be had for $40-100, depending on model/options.
Hope this helps.
Will
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Has Stan looked in to Doctor Alan Toler's Custom Sight Picture Service, http://home.earthlink.net/~agtjragt/index.html ?
Richard Ashmore
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Gerald,
Michael is correct in stating that "In general" lower is better, to a point. If the position gets too low, more muscle gets involved as the sling and angles formed cease to provide adequate support.
Now lets address how the 30 degree angle is best measured. First of all, in a competition the range officers and/or jury members have little time to assess a position, therefore a precise measurement is not practical. Yes, triangulation would be very precise, but not practical in competition. Remember it is the officials determination as to what is legal or not. An official tries to look at all shooters positions to assure they are legal in the pre-prep and prep time. Sometimes this just can't be accomplished and a shooter that is in clear violation of a position rule must make adjustment during the actual event time limit.
In using a 30/60 degree triangle or template, try to get as close to the shooter as possible without disturbing him/her or any other competitor. Also make sure the baseline is as near parallel to the floor as possible, and make sure that the triangle or template is "in plane" with the shooters forearm i.e. rotate it on the vertical axis until it is parallel with the shooters forearm. Now the fun begins, you must be able to judge where the centerline (axis) is from the hand to the elbow point while the shooter has a jacket on (see ISSF rule 7.6.1.1).
As an ISSF judge and USAS official, my best teacher has been time and experience looking at a lot of positions. If you have the opportunity look at a shooter with a jacket on and off and use a standard triangle the way I described. You will develop a knack for "seeing" a legal or non-legal position, within reason.
As an official, my job is to make sure the rules are followed and that no shooter has an artificial advantage over his fellow competitors. As a competitor you or your coach have the right to protest anyone's position you feel violates the rules. Just remember that during a competition it is sometimes a judgment call on the part of the official.
Over the past ten years or so of officiating at National and World Cup competitions, I have observed the prone positions getting higher not lower. Most of the top prone shooters in the world are nowhere near the 30 degree line.
Hope this helps.
Allen Harry
USAS 50m CRO
ISSF Rifle Jury member
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In Reply to: Re: Extension tube or not? posted by Josh Peters on August 28,
2001 at 10:47:32:
The tube or bloop tube as you will, changes the focal length of the physical
eye in relationship to the sights and bull. And, if you are using glasses to
correct then the whole thing is off for your use. If you are using
corrective glasses the eye becomes excessively tired and that make it much
harder for the physical eye to work for you. So the bloop tube is not of
much use except to make you feel better about tiring your physical eyes and
adding additional weight to the overall rifle. Don't forget that the
additional weight also imbalances the rifle so you will have to rebalance
which causes changes in the adjustments of the rifle stock. What a mess to
install something that really does not help you in the least. Wouldn't your
time be better spent learning the perfect position and shooting technique.
There are no short cuts so stop trying to find any. There is no gimmicks to
find either. you have to apply yourself to the shooting technique that wins
and meets your shooting goals. Bloop tubes and gimmicks just will not make
it.... Also remember that the rifle recoil must jump straight up and down to
prove your position correctness and perfect balance. The additional weight
of the bloop tube will change this aspect and will inversely effect the
rifle recoil movement. Recoil in any type of shooting technique is our
friend by telling us many things about our shooting technique and position.
As a shooting athlete you are responsible for the removal of all errors of
technique and errors of the shooting position.
Chet Skinner, Coach
Entity Sports International
http://www.geocities.com/colosseum/dome/4512/index.html
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End of UIT Mailing List #26
Michael Ray - DBA & Systems Engineer
Rose-Hulman Inst. of Tech. Rifle Coach
UIT Shooting Page - http://www.geocities.com/Colosseum/1190/index.htm
