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Lenght of a barrel extension tube?

Posted: Wed Feb 21, 2007 9:23 am
by C-son
I am about to make a costom-made aluminium barrel extension tube (for a smallbore rifle). I am mainly looking for the "smoother" recoil-effect, rather than the sight extension. I don't want the tube to bee too long and too heavy. On the other hand not too short, since I´ve heard a short tube (100-150mm) may cause "barrel disharmony" at the shot-release. So - any ideas of the ideal lenght of a barrel extension tube? Any research done in this field?

Posted: Wed Feb 21, 2007 10:00 am
by B.T.Carstensen
First what kind of barrel length do you have 660mm or 690mm (I am going to assume that you don't have the 500mm barrel) also what kind of rifle do you have.

<>Brian<>

Posted: Wed Feb 21, 2007 3:14 pm
by Cson
Actually, its a Anschütz 2013/690 (alu).

Posted: Wed Feb 21, 2007 4:08 pm
by xcrunner8k
i have a 10" tube on my 690 barrel... i'm no expert in the technical end of it but i think it works great, i've picked up a lot of points with it. only problem is it makes for a long ass gun, though my tube is a two-piece: the mount stays on all the time and the tube itself comes off so the thing fits in the case. i think the most common lengths for the 690 are 8" and 10", at least that's what i've seen. i'm going for both an ideal sight radius and good barrel harmonics, and it works really well for me.

just my .02, sorry i don't know much more about the tech specs, but i bet you'll end up with one around 8-10"...

dan m.

Posted: Fri Feb 23, 2007 8:47 pm
by SBarn
You dont need a tube for "smooth" recoil. If your recoil is bad its because of the position, not because of the gun.

Posted: Sat Feb 24, 2007 1:27 am
by Guest
true, but we're not really talking about recoil as in the gun having an equal and opposite reaction to the bullet... it's more along the lines of barrel harmonics and the bullet's reaction to it, and what length tube will make these movements ideal. but yes, recoil can be easily fixed by tweaking the position.

anybody else got info? this stuff is getting me interested.

dan m.

Posted: Sat Feb 24, 2007 9:57 pm
by BaffledByUGuys
Maybe your time would be better spent building battle bots rather than trying to build gun with the "right length tube". Take a look at the best shooters in the states and in the world, and when I say in the states Im not talking about peole who shoot well at NRA I am talking about the ones that shoot well at the Olympic style events. There are a ton of different tube lengths on just as many different barrel lengths. Their guns all shoot great, its not because they have the exact right length tube on their gun. You people amaze me with thinking there is one answer to make a gun shoot great. Theres not. Plain and simple. Each gun is different each barrel is different. If you want to shoot better take the time away from trying to figure out the right length tube and all that mumbo jumbo and actually LEARN TO SHOOT. PRACTICE.

Posted: Sun Feb 25, 2007 2:47 pm
by C-son
BaffledByUGuys wrote:If you want to shoot better take the time away from trying to figure out the right length tube and all that mumbo jumbo and actually LEARN TO SHOOT. PRACTICE.


A tube will cost me about $300, and I want to be sure that it has the proper lenght. Thats it. By the way, my 60 shots prone average is 594 during last season after 400 hrs of practice and competitions. So please, skip your mumbo jumbo if you don't have an answer.

Posted: Sun Feb 25, 2007 6:16 pm
by BaffledByUGuys
THE ANSWER IS THERE IS NO PROPER LENGTH! If you dont want it for the reason its made which is a clearer sight picture than you dont need it. And a 594 is hardly world class, again learn to shoot! Like I said in the other post take a look at what people have at all these competitions you apparently go to. No one has the same stuff look at the AMU the OTC NO ONE HAS THE SAME STUFF!!! Want to know why? I will tell you why, because there is no one length that is correct. Add weights to your gun if you want the smoother recoil good lord its not the hard. Heres something I bet you didnt know. The tube will also cause a choke at the end of your barrel. Meaning that the tighter you tighten your tube the tighter the end of the bore will get, and if you dont believe me get air gauges and check it. I have and I have seen the proof. So theres some mumbo jumbo for a big guy that has shot a 594. WOW!! Oh wait, no thats not that good and I am not impressed. After you get your tube I am sure you will be asking how much to torque it. I will save you the time and answer that for you too. Just torque it at one and test the ammo. Although if you do that what will you do with all that time you could be practicing?

Posted: Mon Feb 26, 2007 5:18 am
by C-son
Thanks for the input. Guess "trial and error" is the right way to go.
(By the way - its was not "a 594". It was 594 in average during the last season.) Cheers!

Posted: Mon Feb 26, 2007 8:59 am
by Guest
well, if youre paying that kind of money, get the longest one you can, you can always cut a little off if its too long, but its a lot harder to put some on if its too short.

Posted: Mon Feb 26, 2007 10:16 am
by B.T.Carstensen
BaffledByUGuys wrote:THE ANSWER IS THERE IS NO PROPER LENGTH! If you dont want it for the reason its made which is a clearer sight picture than you dont need it. And a 594 is hardly world class, again learn to shoot! Like I said in the other post take a look at what people have at all these competitions you apparently go to. No one has the same stuff look at the AMU the OTC NO ONE HAS THE SAME STUFF!!! Want to know why? I will tell you why, because there is no one length that is correct. Add weights to your gun if you want the smoother recoil good lord its not the hard. Heres something I bet you didnt know. The tube will also cause a choke at the end of your barrel. Meaning that the tighter you tighten your tube the tighter the end of the bore will get, and if you dont believe me get air gauges and check it. I have and I have seen the proof. So theres some mumbo jumbo for a big guy that has shot a 594. WOW!! Oh wait, no thats not that good and I am not impressed. After you get your tube I am sure you will be asking how much to torque it. I will save you the time and answer that for you too. Just torque it at one and test the ammo. Although if you do that what will you do with all that time you could be practicing?

I would suggest that you look at the results from the World Cup Finals in Granada, Spain. Matt Emmons shot a 593 in prone and made the FINALS, and he wound up with 7th. So before you go and disrespect someone and there scores like you did, KNOW YOUR STUFF


<>Brian<>

Posted: Mon Feb 26, 2007 9:06 pm
by BaffledByUGuys
You know what? Its not even worth arguing with you guys, if you were such a hot shooter I would have seen you on the world cup circuit. However I doubt you were there. And averaging a 594 isnt winning the nationals or putting you on teams. So have fun, Im done even trying to reason with you folks.

Posted: Mon Feb 26, 2007 11:40 pm
by xcrunner8k
we know, you don't get it... you'll be rude, i'll be nice. politely leave if you haven't yet.

anyway c-son, just know that everything that was mentioned was the result of hours of testing on the bench and in position... all kinds of ammo, all kinds of barrels, all kinds of everything... olympians are olympians because they experiment and they know the technical end of their shooting to the tee. don't ever feel stupid asking a question because the answer will only benefit you and enlighten the rest of us.

i would recommend you join http://www.smallbore.us because the people there are awesome and will bend over backward to help you.

Posted: Tue Feb 27, 2007 7:43 am
by C-son
Thanks 'xcrunner8k'. There is an old Chinese saying - "It's better to ask and look stupid, than not to - and remain stupid."

$300 for tube?

Posted: Sat Mar 03, 2007 8:01 pm
by n1heu
http://www.champchoice.com/shop.php?code=TUBEMT

mount = $27.50
tube = $27.50
If you were quoted $300 for a tube you are being hosed.
Using a tube to affect barrel harmonics is not the best use of the technology. The way to change harmonic response is by ammunition experimentation.
If you are looking for recoil reduction add weight at the front end of the stock.
Extension tubes actually hurt rifle groups more than they help with a clamped rested gun. Where the tube helps is in sight radius and to help far sighted shooters better see the front sight.
If you do build your own tube be aware that repeatability in installation and the ability of the tube to be banged around a little and not lose zero will be very important. You must make it robust enough so that when you bang it off the floor getting into postion you do not change your sight alignment and keyed to the mount to ensure that when you install it every time you shoot it is in the exact same position when as you sighted your rifle last. If it does not meet these minimum criteria it will drive you slowly but surely insane and not help anything at all.
JMHO,
mike

Posted: Sat Mar 03, 2007 10:41 pm
by B.T.Carstensen
The problem with the CC mounts is that it won't fit a 2013 believe me I know. I bought the 1.013 mount first (CC said this one was what I needed)
it was too big so I got the .975 (the CC website says it will fit but IT IS TO SMALL). In the end I had to get one machined to fit my barrel.

-Brian-

Posted: Mon Mar 05, 2007 1:36 pm
by n1heu
A shooter on my team has a new 2013 with a 690mm stainless anschutz barrel. This 10" tube set works on his fine.
???

Posted: Tue Mar 06, 2007 9:53 am
by B.T.Carstensen
n1heu wrote:A shooter on my team has a new 2013 with a 690mm stainless anschutz barrel. This 10" tube set works on his fine.
???
Thats odd that mine didn't work then (I've got the SS 690mm barrel as well)
Would you happen to know what size mount he is using??

-Brian-

Posted: Thu Mar 08, 2007 6:32 am
by n1heu
He has the M975 part number, he says it fit perfect.