Holding the barrel in a rail gun

JerrySharrett

JerrySharrett

Senile Member
So as to not hyjack Jeff's thread about 8208XBR and Gary's rail gun I had ask the question of how Gary;s barrel was held in the rail upper. I had heard Gary has been working on a different holding method than the often used double vee-block that can distort the barrel as it heats up.
 
Jerry

Considering some of the phenominol aggs that have been shot, it is probably not as big a problem as many suspect.

I have played with three different configurations. First was the barrel 100 percent epoxied inside a 1/4 inch wall thickness steel tube. I had the best success with that set-up, won a National 100 yard with it, and still hold the Gulf Coast Region five 10-shot record at 100 with a .211 agg. The barrel assy was clamped in a simple V-Block.

Because of the work involved, I tried a barrel block with a round 2 inch hole and a non metalic sleeve to isolate the 1.450 barrel. As I said before, I have my doubts.

I have now gone back to a V-Block, but turned the barrel as round and truly straight as I can, and lapped it into the V-block. I also am using a ridiculously light torque on the bolts, only 50 inch pounds, but it seems to be shooting quite well.

I did not get to look at Tony's Rail at the Nationals. Is he using a Delren, or similiar sleeve, to isolate the barrel??. It sure shot good........jackie
 
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I agree

It does look like a V-Block.

I have heard that some shooters are using a V-Block, but also using a "skim" bedding so that the block cannot clamp down on the barrel in an irregular manner. I am thinking my lapping the barrel in the block would serve the same purposes

I am tempted to just go back to the barrel in a tube, but that is a LOT of work. The worst thing is to go through all of that effort, only to find the barrel to be "average". Been there and done that more than once.........jackie
 
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Tony uses the standard block that Don Powell used on his rails. It has a upper half with a rectangle cut and a bottom half with a "V". Barrels are turned straight to fit the block.

Hovis
 
jackie schmidt said:
It does look like a V-Block.

I have heard that some shooters are using a V-Block, but also using a "skim" bedding so that the block cannot clamp down on the barrel in an irregular manner. I am thinking my lapping the barrel in the block would serve the same purpose..........jackie
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The skim bedding and lapping might work. I know I can lightly clamp a barrel in a 4 bolt barrel vise and feel where the vise is with a lead slug.

I don't even shoot a rail though, I just continued the subject to see what other ideas people had so as to get ideas for a 600 yard HG I may build. 2009 is the first year I didn't shoot UL/HB at either of the nationals. Arthritis!!
 
My first setup was a barrel glued in a block, I felt that was about as
stress free as it could get. Still believe that, but as Jackie says if its
not the barrel, lots of work ahead
 
Here is the setup I use to attach the forend on my Metal Mayhem stock. The threaded sleeve has a .250" shoulder at the back that takes the place of a recoil lug.

On a rail gun you could make the sleeve much longer and with a thicker shoulder. Also wouldn't need threads, just the typical rail gun vee block. With this setup the bbl is fully free floating and is easy to change.

erectorsetthreadedsleeve.jpg

erectorsetcouplingcloseunscrewed.jpg

erectorsetcouplingclosetightened.jpg
 
Perhaps an answer

JerrySharrett said:
The skim bedding and lapping might work. I know I can lightly clamp a barrel in a 4 bolt barrel vise and feel where the vise is with a lead slug.

I don't even shoot a rail though, I just continued the subject to see what other ideas people had so as to get ideas for a 600 yard HG I may build. 2009 is the first year I didn't shoot UL/HB at either of the nationals. Arthritis!!
Click to expand...



is to set the barrel up in the clamp and them lap the restriction out of it. That might be easier than most other things one could do. There must be folks around who know how to lap barrels, eh?
 
crb said:
Here is the setup I use to attach the forend on my Metal Mayhem stock. The threaded sleeve has a .250" shoulder at the back that takes the place of a recoil lug.

On a rail gun you could make the sleeve much longer and with a thicker shoulder. Also wouldn't need threads, just the typical rail gun vee block. With this setup the bbl is fully free floating and is easy to change.
Click to expand...

crb, is the .250 shoulder the only thing that supports the action/barrel assembly?
 
I once saw a barreled Panda action screwed and glued to the top of a square block which was bolted to the rail top. The barrel was 1.250 and as I remember this setup shot quite well. The scope was mounted on the Panda dovetail in normal fashion. This would seem to eliminate any problem of the barreled action shifting in relation to the scope.
 
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A tube with an internal shoulder which imitates a recoil lug would
work great for smaller barrels , then clamped in a V-block.
like maybe testing factory barrels. NEAT---
 
Gene

One of the more accurate Rail Guns I ever saw was one that had a Kelbly Polar action bolted to the top, the barrel was just free floating as well, the scope mounted on the top dovetail.

I have often thought about getting one of those old Polars, (if any are around), and trying that myself. That thing was very consistant.....jackie
 
jackie schmidt said:
One of the more accurate Rail Guns I ever saw was one that had a Kelbly Polar action bolted to the top, the barrel was just free floating as well, the scope mounted on the top dovetail.

I have often thought about getting one of those old Polars, (if any are around), and trying that myself. That thing was very consistant.....jackie
Click to expand...

Another way is to glue a large diameter round action into a solid bored block and have the barrel free floating. With the scope mounted on top of the block there is not much chance for things to move as the barrel heats up with firing. With this setup, you can use a 1.450 dia. barrel because of the added support of the heavy action. Not so sure about that heavy of a barrel on the Panda or even a Polar.
BTW, Lowell Frei once told me that the most consistant barrel that he ever had on his rail was a 1.250 dia. but I don't know if that was in a v-block or if it was mounted with a different method.
 
JerrySharrett said:
crb, is the .250 shoulder the only thing that supports the action/barrel assembly?
Click to expand...


Jerry,
This isn't a rail, see pic below. I was just thinking that if you made the shoulder 1/2" or thicker then you would have plenty of strength for the bbl and action to float.

Ray

metalmayhemviperassembledlhfront.jpg
 
JerrySharrett said:
How about the BAT 50BMG25. It is 2.5" diameter and has a 1.5 x 16tpi tenon.

The old Stolle Teddy has a longer tenon than the Panda.
Click to expand...

I think the BMG action thread size would be too big for a 1.450 dia barrel but the model "L" 2 inch dia would work just fine. It has a 1.250 thread dia which would work with the 1.450 dia barrel. With the BMG you would have to have about a 1.750 dia barrel made up (expensive) and then need a cherry picker to move the top around. Not good at the Nationals!
I know the Teddy and the Polar have a longer tenon than the Panda but don't know if a 1.450 dia barrel will fit into the shroud just ahead of the action face.
Gene
 
JerrySharrett said:
So as to not hyjack Jeff's thread about 8208XBR and Gary's rail gun I had ask the question of how Gary;s barrel was held in the rail upper. I had heard Gary has been working on a different holding method than the often used double vee-block that can distort the barrel as it heats up.
Click to expand...


Hi Jerry,

For the longest time Gary has been using a close fit cylinder sleeve barrel block setup with various different types of cyclinder sleeve materials, starting out with a lead shot/epoxy material mix and then other material substances.

I am not sure what the latest material experiment is but is probably along the same lines................Don
 
Gene DeLoney said:
Another way is to glue a large diameter round action into a solid bored block and have the barrel free floating. With the scope mounted on top of the block there is not much chance for things to move as the barrel heats up with firing.
Click to expand...
Here is a photo of Gary Sinclair's rail. As I understand it, the action in glued into a solid bored block as Gene noted above. I don't know all the spec's on this rail; however, I am fairly sure the barrel is free floating.

DSC01005.jpg
 
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