Are bloop tubes legal in biathlon??

Levergun59 · Post by **Levergun59** » Sun Dec 12, 2010 4:31 am

My son is using a modified Biathlon Basic. I hve a 6" bloop tube mounted on the barrel for 100yd Palma. Are bloop tubes legal or do I have to take it off? Thanks in advance.
Chris

Kevin6Q · Post by **Kevin6Q** » Mon Dec 13, 2010 10:33 am

I don't recall reading anywhere that bloop tubes are illegal. Biathlon rules tend to be pretty vague. Having said this, they interpret them to be"if we didn't specifically say no, then it must be okay". Here is a link to the rules

http://www.biathlonworld.com/en/downloads.html

I think you want section 3 and the annex section 4.

weilers · Post by **weilers** » Sat Jan 01, 2011 1:38 pm

I'm not really sure how and where you'd use one, but it somehow seems to defeat the whole idea of a snow cover.

RonBott · Post by **RonBott** » Tue Jan 11, 2011 9:30 am

I have never seen a bloop tube in biathlon, which then leads me to the conclusion that:

1. They are not legal

2. They do not work

If they were legal and did make a difference, then everyone would be using them.

Levergun59 · Post by **Levergun59** » Sun Jan 16, 2011 3:13 am

I have seen pictures of quite a few Biathletes with long barreled Anschutz rifles. My son is a lightweight at 105lbs. At 14, he doesn't have to ski with the rifle but the extra sight radius with a bloop tube will increase the number of hits. It is the same as shooting a 24" shotgun barrel in Trap. That extra 6" of sight plain will break more birds. Also, since weight for him is a major consideration, a carbon fiber bloop tube would cut down the weight on the muzzle end of the rifle. Since the sight is located at the end of the bloop tube, the muzzle cover could be expanded to fit the 1" bloop tube hole. I could actually chop the barrel and use a 12" bloop tube for even more weight savings.
Chris

peterz · Post by **peterz** » Sun Jan 16, 2011 9:08 pm

Sorry to horn in, Levergun59; I'm not a biathlon shooter, but I am a parent. Your son is likely to grow astoundingly fast, and could be bigger and stronger in a season or less... Maybe before you can even get a bloop tube delivered.

-pz

Levergun59 · Post by **Levergun59** » Mon Jan 17, 2011 1:45 am

Yep,I'm 6'4" 230lbs and I was 5'2" the beginning of my sophomore year and finished growing by the end of my senior year. Still, shorter barrels do not distort from barrel harmonics as much as longer barrels and are more accurate. Also, Bloop tubes tend to shoot better in a wind. Possibly the bullet is allowed to stabilize faster as it exits the barrel and gets a clean run down the bloop tube. Whether that is fact, I can't tell you for sure, but all the Highpower shooters have noticed it. Barrel tuners are also another way to go. Just about everyone who shoots 50 yard benchrest has one. Just my take.
Chris

mkVsten · Post by **mkVsten** » Fri Mar 04, 2011 9:41 am

Just thought I would chime in here. My Son is 14 years old and competes in Biathlon. I cannot see why adding a bloop tube would really give him an advantage at 50m, there are just too many other factors in the sport to reach the podium. I personally think with everything involved in Biathlon, a good training program would more then make up for the use of one. Dry fire Dry File Dry Fire + rounds down range. Get on a good program and it will rerally improve his shooting.

Levergun59 · Post by **Levergun59** » Fri Mar 04, 2011 5:27 pm

Wow, if that is your son, he is rather large compared to mine. The only reason my son has a bloop tube is that he used this rifle in men's indoor 4p and outdoor 22 Palma He also has a bloop tube on his Winny 52 and his 6.5X47 Lapua chambered NRA and Palma gun. At 108lbs its a little hard to hold out a heavy barreled rifle for a series of standing shots. Boots Obermeyer contoured his rifle barrel to reduce the weight on his highpower rifle barrel and cut it short at 24". Most if not all Palma shooters shoot a 28, 30 or 32" barrel as they need the sight radius for shooting 1000yds. I made a snow cover for the barrel and front sight using a 1" scope cap and some cut plastic epoxyed to the cover. A few years ago, Anschutz made a few bloop tubed Biathlon rifles and showed them to the U.S. biathlon team, so it is not an original idea by any means.
Thanks for the responses
Chris

moigy · Post by **moigy** » Wed Jun 20, 2012 12:34 am

What are Bloop tubes?

Levergun59 · Post by **Levergun59** » Wed Jun 20, 2012 6:10 am

It is a tube attached to the end of the barrel that is hollow. It allows an extended sight radius for more precise shooting. There is usually a locking ring that attaches to the barrel, and the tube has a pin to relocate it back in the same position. Easy to take off for cleaning with no change in zero when you put it back on. Hope this helps.
Chris

ShootingSight · Post by **ShootingSight** » Wed Jun 20, 2012 6:41 am

The real advantage of a bloop tube is that it extends the sight radius to better match your depth of field.

Aiming a rifle is all about depth of field. You use a small rear aperture to get as big a depth of field as possible, in the hopes that you can get a sight picture where you can see both the target and the front sight clearly at the same time.

The lens formulas that calculate lens power are based on the inverse of the distance (in meters). Changes in target distance have a very low impact on the result, so 1/50 meters versus 1/100 meters are 0.02 diopters vs 0.01 diopters; both small numbers, but if you push the front sight from 0.85m to 1.0m with a 6" bloop tube, you go from 1.18 diopters to 1.00 diopters, which is noticeable. The human eye can generally see differences in focus as small as 0.125 diopter steps.

Another thing you might consider doing is adding a +0.50 lens to his sight picture. That will move the eye's relaxed focal point from infinity, back to the hyperfocal distance of the front sight, effectively centralizing his depth of field between the target and the front sight. For biathlon, I would think that adding a lens into the actual rifle sight is risky, because if it frosts or fogs, it will do more harm than good, but adding a lens into his safety glasses or goggles might work.

I used to run Summer Biathlon, and we just wore safety glasses to shoot. I've never really tried or tested any lens solution in the cold. What do biathletes wear for eye protection while shooting in the cold?

Art

Levergun59 · Post by **Levergun59** » Wed Jun 20, 2012 9:45 am

Usually biathletes wear sunglasses so they don't get snowblind. Just out of curiosity, Champoins Choice has a Gehmann Microsight Superfilter, on page 78 in their catalogue. Have you had any experience with these? It is proported to allow focus on both the front sight and the target at the same time. It has no magnification or optical characteristics. In Biathlon, we have snow covers for the front of the rear and front sight, so they are protected somewhat. Thanks,
Chris

ShootingSight · Post by **ShootingSight** » Thu Jun 21, 2012 1:36 am

The MicroSight uses a novel diffractive zone plate lens, which is able to deliver two focal points, so in theory, you can see the target and the front sight clearly together.

However they have only come out with one strength of lens, so how well it works for you is determined by your sight radius, as well as by the condition of your eyes. Various shooters have reported mixed results ranging from near-miracle, right down to pulling it off the rifle and reverting to a decent lens.

Understand about the sight covers, though the sunglasses thing I had not thought about. Do they flip the sunglasses up to shoot? You want as small an aperture in back as possible, to maximize your depth of field. Normally, the limit on how small you can go is driven by available light. If you are starting out with really bright light, you might be able to go very small in your aperture.

Kevin6Q · Post by **Kevin6Q** » Thu Jun 21, 2012 6:15 am

By rule, optical magnification is not allowed. Practically, having anything to catch a snowflake or condense moisture is not good. Very often snow flakes get into the sights and the clearing method is to blow them out. Sometimes the humidity in breath condenses on the flake and can foul the sight pic. Biathletes won't use front plastic discs for the same reasons.

Most biathletes take the glasses of to shoot. Fogging is a huge issue. Many use a blinder attached to the rear sight and this does an excellent job of protecting the eyes.

ShootingSight · Post by **ShootingSight** » Thu Jun 21, 2012 7:43 pm

All of that makes sense, and is what I expected, except for not using plastic discs in front.

The iris and target image come through a hole in the disk, so even if there were fog on the front disk, you can still see and center the target. It is only the image outside the ring that is blurry, however, 'minor' issues like making sure you are shooting at the right target could be impaired.
Cross firing does actually hurt your score ...

As a side thought - I wonder if you could add an electric heater to the front sight ....