Rail gun/barrel block

jbhotrod

jbhotrod

New member
Howdy yall, Blake here.

I know theres quite a few rail shooters so I was wondering if i could ask a few things.

For one, have yall found a way to get rid of the squeezing effect on the bore when clamping it down in the block? (Maybe an epoxy sleeve or lapping it in the block like Mr Schmidt talks about)


Also, is it certain that the squeezing down on the bore has a negative effect on accuracy?

How often do yall encounter a barrel that simply wont shoot, or a bad barrel? Maybe a better question would be how often do you encounter a really good barrel?

Has anyone ever tried a block that ran the full length of the barrel? Or is it better to use around 8-9" block for tuning purposes?


And would yall say the Heavy bag guns are competitive with rails?

Thanks so much sirs.
Blake.
 
A light gun is competitive with rails- until the wind or mirage gets goin good. There are plenty of v-block rails out there that squeezes on 3 points of the barrel. Id venture to say 10 to one has a v block and that equates to way more winning rail guns having a v block and out of those v blocks 99% you can feel the tight spot with a proper fitting patch. Of course for the sake of argument i do not have a forum opinion but I do actually shoot rail guns.
 
Dusty,

Have you ever clamped a 1.450 barrel in a v block with the same tension you would use when shooting, and put a pilot on a long rod and checked it? I've done this with pilots that I had (.0002" increment) and have not been able to determine any tightness difference between clamped and unclamped. I always heard about the tight patch theory, but I'm skeptical that could be felt in a blind test.
 
I feel it every time I run a patch thru a young rail. it doesnt seem to affect accuracy as most winners shoot one.
 
but no to answer your question- I'm sure you have way more actual testing experience. I can feel roll marks on some barrels with ivy rods but cant with deweys so my experience is skewed.
 
jlcprec said:
Dusty,

Have you ever clamped a 1.450 barrel in a v block with the same tension you would use when shooting, and put a pilot on a long rod and checked it? I've done this with pilots that I had (.0002" increment) and have not been able to determine any tightness difference between clamped and unclamped. I always heard about the tight patch theory, but I'm skeptical that could be felt in a blind test.
Click to expand...

Any chance you(or anyone else) have ever slugged an unclamped barrel and then slugged the same barrel while clamped and measured the difference, if there was any sir?

Thanks so much yall.
Blake.
 
im a shooter. I dont do anything like that. im from the school that a barrel maker can lap a barrel better than I can. I dont want to push foreign objects down my barrel or repoint a bullet that a bullet maker sent out. I cant see the tightness on the paper which is all I care about. so no ill leave that up to someone else!
 
I have two rail guns, in fact one is built by JLCPrecision. They both shoot well and have earned sapwood for me.
The only way I would feel any tightness would be with a patch or a brush and I haven't. I've never tried running a slug down the barrel.
In my experience, the rail has all the advantage over a bag gun in heavy mirage.
A good shooter with a tuned bag gun will leave the rail in his dust in switchy winds as the rail shooter will either have to shoot fast in a condition or go back to the sighter to figure out the next condition. Bear in mind that most unlimited matches are 10 shot instead of 5 shot. This will tend to get the bag gun (LV or HV) a hot barrel.
 
Agree

jlcprec said:
Dusty,

Have you ever clamped a 1.450 barrel in a v block with the same tension you would use when shooting, and put a pilot on a long rod and checked it? I've done this with pilots that I had (.0002" increment) and have not been able to determine any tightness difference between clamped and unclamped. I always heard about the tight patch theory, but I'm skeptical that could be felt in a blind test.
Click to expand...


(Just to be clear, I am in no way trying to debunk anyone’s findings here), I put a 1.25 (Not 1.45) barrel in a Rail gun V block and tightened the rat *&% out of it and pass a pilot from a reamer thru it (jlcprec Idea), Increments of .0002 between bushings, So I was able to find a snug one in the bore tightened the block down (tight, real tight) the bushing had the same amount of pressure to push it all the way down the bore, I even try it with only a ½” of contact on each point of the barrel to see if it would change (nope) I believe that if the barrel had crushed any that bushing would not have moved, I would think a cleaning patch even a tight one would still have enough give in it to pass down the bore without tightening up, Just my 2cents but again. (Just to be clear, I am in no way trying to debunk anyone’s findings here),….J
 
I'd take a good shooting rail gun any day over a bag gun. Windy or not. Maybe I just can't handle a bag gun, but I can still hold off with a rail if I need to, and if the condition does stay, I know I can shoot a little faster to take advantage of it.

Jim
 
Blake, saw that your kind of new here. Just in case you didn't know, Jim and Jay very good rail builders. If they were concerned about V blocks they would do something different.

Good luck!
 
Still trying to figure it out

I haven’t had my Rail Gun very long. Still trying to figure it out. I can definitely say that if you don’t have the Vee Block tight enough,the Barrel will slide.:) A rail gun barrel that moves,shoots some whopper groups.

A good while ago,a friend of mine showed me how to “slug”(Hope I’m using the correct term) a barrel. I got in the habit of slugging Every new barrel blank I bought. Just for nothing else but to satisfy my curiosity.

I could feel irregularities(Tight spots) in every barrel I slugged. Some of those barrels shot like crap,some shot Ok and a few shot excellent. Don’t know if the tight spots had anything to do with the way the barrel shot. The slugging exercise did generate some interesting responses from advocates of the procedure.

If a too tight Rail Gun Vee block can cause a $600.00(installed) rail gun barrel to shoot like s..t, I need to know at what point do I stop tightening the screws.:D I’ve tried everything from, light torque to heavy torque. I can't tell where torque affects the tune. Maybe I just don't know what I'm doing. I suspect that I might have one of them barrels that just wont shoot. I’ve owned a few of those.


Glenn
 
Tighten the block such that the barrel won't move and I suppose no more. If it won't shoot well, move the barrel in the block within the limits where something touches. If it still won't shoot well....start looking for another barrel.
 
I'm not a rail gun owner or shooter but find them interesting and will likely own one once I am retired and have more time for shooting. Wouldn't adjusting the block's torque be part of the tuning process. If too much/little torque is used the target should provide the answers you seek?

Jet
 
My gunsmith told me to start at 25 inch pounds and go up to 80 inch pounds in 10 inch pound increments to find a torque tuning as he called it. He shot his way into the HOF with a rail and said some will like a certain amount of torque. Mine didn't like the light torque but anything from 45-80 inch pounds made no difference.

I have owned several LV barrel block scoville guns. You can feel a restriction in the bore with that setup when you reach about 45-50 inch pounds. At 50-80 inch pounds and above, it will almost stop a patch. However, I have never had a change in accuracy except below 40 inch pounds, this was because the barrel would want to move on occasion.

Hovis
 
Dave Coots said:
Mark is correct Blake. BTW...Haven't I seen you hanging out on the 409 forum?

Later
Dave
Click to expand...

Hmm. No sir wasnt me. Im not much into 409s. Id love a 427 Cammer or a Boss 9 if you got one you wanna give me though! LOL speaking of:

http://www.jonkaaseracingengines.co...-custom-built-boss-nine-and-p-51-engines.html

No sir dont get much purtier than that.

As much love as I got for some of the Ford engines, my uncle runs a 565ci Brodix Big Cheif headed Chebby putting down 907 hp @ crankshaft.

If Im gonna be honest though, my first choice for a serious max-effort race car would start with this:
http://www.prolineracing.net/engines/plr-526-572-481x-4000-hp

Throw in two Precision or Garrett 94mm turbos and Id be on my way to building a pro mod. Thats what I really want to do when I get the money, hook up with Proline(who represent my great home state of GA quite well) and build a Pro Mod, Outlaw 10.5, or Outlaw Drag Radial car depending on finances. Tim Lynch and Steve Petty and crew build the fastest turbo cars in the world hands down. Wont be long and they`ll be dominating Pro Extreme(no rules run-what-you-brung door slammers), and take all the records away from the screw blown cars.

Highest 1/8mi trap speed by anyone, ever, in a door slammer. And before people start calling 1/8mi races gay, please keep in mind no big organizations will sanction these cars to run 1/4mi all out on account of they dont want drivers getting killed on their track. Basically, would be willing to do 260 or 270mph in a door slammer every time you hit the track? Note that these things arent made for that type of speed and youre taking your life in your own hands. Theres smaller races like Shakedown @ E`town that allow them on the 1/4 but these are few and far between. Yes NHRA does Pro Mod but its limited to 88mm turbos and has a minimum weight. ADRL and XDRL have no weight minimum, no maximum turbo size, AND they allow full-tilt screw blowers.
http://youtu.be/QH6Djm3kgJY
 
Ive read that one can tune the rifle by moving the barrel within the block fore and aft, have yall ever had to do this during a match? Or is it something that you set once and leave it?

Also, does anyone know who builds the ammunition test rail guns for Sierra?

One more thing, do yall know what a Mann Accuracy device is? Basically a 1.25" barrel screwed into a 1903 action(usually), with 2 rings on the barrel . The rifle is turned upside down and rides loose in a huge V-block. Have any of yall ever tested a setup like this?

Post #7 in this thread shows a close-up photo of the rig. Real old-school stuff, I guess you could call it the railgun`s pap:

http://forums.thecmp.org/showthread.php?t=6338

Also, is there a reason blocks arent longer? Ie could you make a rifle shoot, that had a block the full length of the barrel?

Or having two smaller mini-blocks mounted at different points along the barrel?

Like this:
http://benchrest.com/showthread.php?84233-New-stuff-we-are-playing-with-in-the-F-Class-game
 
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