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Extension Tubes - How long?

Posted: Thu Jul 28, 2011 11:11 am
by matchguy
Hello,

Was looking at latest pictures from Camp Perry Smallbore Prone and noticed majority of shooters have extension tubes on their rifles for metal sights. I know some have short barrels with long tubes and some have std barrels with tubes.

How long are these top people making their rifle barrels with the extension tubes to help out their eyes? 30"? 34"?

http://www.nrablog.com/?tag=/smallbore

Thanks

Posted: Wed Aug 10, 2011 11:33 pm
by Flashmo
You are typically aiming for around 30" +/-. Don't bother adding length to your sight radius until you are shooting at a high level regionally (Expert - NRA, or at least B USAS...in competition) because it will introduce a whole new set of issues to work through.

It makes quite a difference if you are ready for it...if you are still working out bugs in your game it will be a big monkey wrench for you.

Posted: Thu Aug 11, 2011 9:56 am
by Barney
If your long sighted it doesn't really matter what level your are, It will at least give you more clarity in the front sight element thus helping you align it around the target.

Posted: Thu Aug 11, 2011 10:54 am
by KennyB
There's also an added bonus that the longer the sightbase, the less parallax error there is if you get your head in the wrong place...

However, you can see a lot more movement with a long tube attached which can sometimes be disconcerting and detrimental.

FWIW, I've had a 12" aluminium tube on my 26" barrel but the extra weight up front has caused me to change to a 10" carbon fiber tube which works very well.
I also have a stubby 4" one for when the wind is buffeting the rifle and disturbing the hold.
I know of one chap with a 26" barrel, 12" tube AND a 6" hammerhead extension who shoots very well over here in the UK.

I've also seen it suggested that the tube can exhibit a "tuning" effect on the barrel and that there will most likely be an optimum length/weight for any particular barrel - that depends on whether you have access to many batches of ammo for testing with your rifle or whether you have few batches available and have to tune the rifle to the ammo.

K.

Posted: Sat Aug 13, 2011 2:22 pm
by GaryD
KennyB wrote:There's also an added bonus that the longer the sightbase, the less parallax error there is if you get your head in the wrong place...

However, you can see a lot more movement with a long tube attached which can sometimes be disconcerting and detrimental.

FWIW, I've had a 12" aluminium tube on my 26" barrel but the extra weight up front has caused me to change to a 10" carbon fiber tube which works very well.
I also have a stubby 4" one for when the wind is buffeting the rifle and disturbing the hold.
I know of one chap with a 26" barrel, 12" tube AND a 6" hammerhead extension who shoots very well over here in the UK.

I've also seen it suggested that the tube can exhibit a "tuning" effect on the barrel and that there will most likely be an optimum length/weight for any particular barrel - that depends on whether you have access to many batches of ammo for testing with your rifle or whether you have few batches available and have to tune the rifle to the ammo.

K.
Hi All,
This is my first post on this forum, although I have been lurking for about 6 months or so.
I would like to start by asking KennyB where he got his extension tubes from.
Were they sourced from the UK

Posted: Sat Aug 13, 2011 2:47 pm
by KennyB
GaryD wrote:I would like to start by asking KennyB where he got his extension tubes from.
Hi Gary,
no problem, The 12" and 4" come from Barry Nesom in Yorkshire. I expect I'll be seeing him next week at Bisley as I need a collar made for my newly acquired barrel.

The 10" Carbon Fiber Tube came from a young man called Brian Johnson in the US who advertised on this very site.

http://www.targettalk.org/viewtopic.php?t=27173

Regards,
Ken.

Posted: Sun Aug 14, 2011 7:16 am
by GaryD
Hi Ken,
Thanks for the infomation.

I will be at Bisley tomorrow (Monday) for the day, batch testing some ammunition.

But no doubt I wiil be wandering around so I will have a lookout for
Barry Nesom while I am there.
Cheers
Gary

Posted: Wed Aug 17, 2011 11:14 pm
by matchguy
Flashmo wrote:You are typically aiming for around 30" +/-. Don't bother adding length to your sight radius until you are shooting at a high level regionally (Expert - NRA, or at least B USAS...in competition) because it will introduce a whole new set of issues to work through.

It makes quite a difference if you are ready for it...if you are still working out bugs in your game it will be a big monkey wrench for you.
Boy, I thought I wasn't going to get any responses to my question and now there's a bunch. Thanks.

I'm not looking for a bloop tube to gain a competitive edge. I may be getting near the end of my open sight days at longer distances (highpower) and this was my last option to try. Don't have real problems yet at 100yd smallbore or closer. Since originally posting this I got a 6" extension and I'm back in the 190's in prone HP. You are correct, initially I had to get used to it but by the end of the day with some aperture adjustments the sight picture was considerablly better with it. The reason I went with 6" is it was the longest I could get to fit in my case with the butt colapsed without removing it.

I just thought it was odd that most of the ISSF videos I've watched on Youtube showed most of the upper shooters had tubes on their guns. Didn't think there were that many shooters with their eyes going south on them.

Posted: Wed Aug 17, 2011 11:38 pm
by WesternGrizzly
I am 19 and I use a 12 inch tube on a 500mm barrel. I really wish it was longer but I would have to go carbon fiber.

I use a tube because it increases my ability to see very small changes in sight picture. I dont use it for vision.

I am assuming that the majority of the top shooters use them for this reason.
Matt

Posted: Thu Aug 18, 2011 6:46 am
by sbrmike
The bloop tube serves 3 main functions. They are all important but which is more important is an individual thing.

1. This permits the use of a shooter barrel which means less dwell time. This also reduces the weight out front.

2. The tube yields a longer sight radius which magnifys aiming errors. A little low with a longer sight radius isn't very low at all compared with the same amount of low with a shorter radius.

3. It can enhance the sight picture for aging eyes.