[mreish]

I'm building a rail gun kinda, sorta, similar to the one below. The barrel is .920 in diameter. My question is how big should I make the whole in the clamp? .921?

Thanks for any guidance!

http://accurateshooter.net/Blog/xbr01.jpg

[txcncman]

Do you want a slip fit? If you are actually going to use this and you make the hole larger than the barrel, when the round fires, the recoil will drive it out of the clamp. Even with a press fit, you may see resulting movement. At some point of clamp compression, you will get deformation of the barrel which will effect accuracy. I would suggest the slip fit you noted, but adding a recoil damping system with a limitation on how far the barrel can travel. This could all be worked out in physics if you wanted, but not something I would want to get into without some type of compensation.

[Delw]

With rail guns your accuracy is critical obviously.
On a bore for a rail gun I would do 2 things.
one have the barrle gound to an exact dia where the clamp will hold on and 2 have the clamp HONED to the exact dia +.0001 maybe .0002 of the barrel dia.

the problems most guys have building there own rail guns is the clamp and barrel are not perfect and under recoil the barrel will move due to high and low spots.
if the clamp and barrel mate perfectly then you can rule that out for any problems will accurcay.
example
you have a bore in the clamp and it has some high spots the barrel will actually cant(sp) change position)
other things to do mainly due to the amount of contact with the barrel is but grooves in the clamp, this will help if your barrel or clamp tends to heat up in one area. but it still must be ground or honed exactly to barrel size that is ground.

hope all that makes sence.
Delw

[Delw]

the other thing I can see that needs to be improved in your picture, is the scope mount.
that needs to be made like an "A" frame attached to both sides of the clamp so to speak not like the picture. those arent very accurate and they due vibrate.

Delw

[mreish]

Good info and thanks, everyone! I should have been more clear.

The rifle is a Ruger 10/22 (.22lr) with a heavy 18" bull (.920 muzzle to breech) barrel so recoil is very minimal. I have a drill press, a band saw and not much experience. This is more of a fun experiment and learning exercise than anything.

The max range I'll be shooting this at is 100 yards but the vast amount of shooting is at 50 yards.

I appreciate the info! Keep it com'n!

[fizzissist]

Are you married to rimfire??
just wonderin', the 10/22 are fun, and cheap....but ..
6.5 Creedmore isn't that much bigger....

[mreish]

For this experiment, yes, I'm married to this rifle and this barrel. If I was doing this for 'real' I'd probably go with 6mm BR in a Pierce action.

[Delw]

Good info and thanks, everyone! I should have been more clear.

The rifle is a Ruger 10/22 (.22lr) with a heavy 18" bull (.920 muzzle to breech) barrel so recoil is very minimal. I have a drill press, a band saw and not much experience. This is more of a fun experiment and learning exercise than anything.

The max range I'll be shooting this at is 100 yards but the vast amount of shooting is at 50 yards.

I appreciate the info! Keep it com'n!

Thats some damn fine work for a drill press and a band saw.
if thats the case, I would put some plastic shim stck on both sides of that clamp, that will be more than enough to make up for any errors. plus it will keep the temps from variing(sp) your point of impact during hot and cold.

I always wanted to do a .300 winmag and a 50 for a rail gun. mainly the 300 win mag to test loads with. Used to watch guys shoot rail guns down here in the valley, it was always an interesting concept. plus it beats the heck out of a ransom rest when testing new fire arms that you build.

[mreish]

Whoa. Whoa. Whoa.

That picture is not me or my rifle. It's an example of what I'd like to do.

I wish I could build something like that.

[Delw]

I knew that wasnt a 10-22 thought that was one of your other rail guns you were trying to duplicate for a 10-22.

you can also buy a small brake hone to hone the rail clamp for your barrel dim. and you can also make/modify the clamp out of accurglass from brownells that way it matchs perfectly
like bedding a rifle stock

[fizzissist]

For this experiment, yes, I'm married to this rifle and this barrel. If I was doing this for 'real' I'd probably go with 6mm BR in a Pierce action.

I was just playing with 6xc, 700 action and Bartlein barrel.... borrowed from a friend for a 1000yrd match.... Inspired me to build my own set up, considering I placed 3rd and I'd never shot the set up before.. (the credit belongs to the gun on this one!!)

But a 10/22 platform? ... that does sound like fun!

[mreish]

I was just playing with 6xc, 700 action and Bartlein barrel.... borrowed from a friend for a 1000yrd match.... Inspired me to build my own set up, considering I placed 3rd and I'd never shot the set up before.. (the credit belongs to the gun on this one!!)

But a 10/22 platform? ... that does sound like fun!

That sounds like a fun time, was that in F-Class? I have a friend who keeps trying to get me to shoot with him in F-Class but I'm really having a fun time with the smaller stuff this summer. Maybe next year.

I'm doing this project as a learning experience in trying to make an accurate semi-auto .22lr and to increase my electronics knowledge. I'm placing vibration sensors in various places to see if I can a) measure vibrations accurately, b) save the data for future analysis and c) use the data to place the barrel clamps (or bloop tubes, etc.) to increase accuracy.

ps: since starting all this, I picked up a Savage MK II (that's a bolt action for the non gun guys) that will probably end up as part of this experience too.

pps: I'm posting this in the RFQ section as well.