A different method of mounting Rail Gun barreled action.

[jackie schmidt]

While laying in bed the other night, I was thinking about the various methods of mounting a Barreled Action to the top of a Rail Gun Top. Barrel Blocks are the most successful it seems. And they work once you arrive at the proper tension of the clamping screws.

For some reason, recoil lugs popped up in my head. I see thick ones on big rifles, so what if you incorporated a stress free way to mount the barreled action with a precision machined mounting block that was in reality a huge recoil lug.

This is what I came up with. The block is machined from 17-4 PH at H 1050. It was bored and faced on the same setup to insure it is dead square. The barrel is machined to match it. The fits have .001 clearance in the bores of the block.

The block is secured with two 3/8 24 bolts

I’m going to try this,.....just because.

http://benchrest.com/attachment.php?attachmentid=23693&stc=1&d=1592528120

http://benchrest.com/attachment.php?attachmentid=23694&stc=1&d=1592528163

http://benchrest.com/attachment.php?attachmentid=23695&stc=1&d=1592528226

http://benchrest.com/attachment.php?attachmentid=23696&stc=1&d=1592528279

http://benchrest.com/attachment.php?attachmentid=23697&stc=1&d=1592528380

 

[Zebra13]

Jackie,

I'm glad to hear I'm not the only one who lays in bed at night thinking of rifles and such...

Very interesting and inventive. I'm extremely curious as to how it will shoot. I assume the barrel is a known quantity, being a current barrel for your rail. If so, how did it shoot prior to altering for the recoil lug set-up?

You mentioned the proper tension for barrel block screws. What would that be, approximately, in foot pounds? And is there any concern about bore distortion caused by the clamping of the barrel block?

Justin

 

[JerrySharrett]

If a barrel is carefully slugged a UL barrel in a barrel block anything over about 65 in/lb you can feel the restriction.

Does it effect accuracy??


.

 

[jackie schmidt]

The barrel was the current one on my Rail and seemed to be pretty good.

 

[jackie schmidt]

If a barrel is carefully slugged a UL barrel in a barrel block anything over about 65 in/lb you can feel the restriction.

Does it effect accuracy??


.

Yes. We had a discussion quite a while back about barrel blocks, so I tested mine. Anything over 60 inch pounds and the groups opened up. I never slugged, it, but figured it was affecting the ID.

I settled in on 25 inch pounds. I bought a little 25 inch pound “clicker” to tighten the bolts. That held it firm with the 10 5/16 28 bolts, without closing the bore.

This thing I am doing now is just an experiment, mainly seeing if the assembly can be mounted stress free, producing more consistent performance. The barrel, a new Krieger for this season, shot pretty good. Since the block has to be made from steel or a similar material that won’t compress, weight would be an issue in anything but a large long Range Heavy Gun application.

Here is kinda of a scale drawing of the assembly

http://benchrest.com/attachment.php?attachmentid=23698&stc=1&d=1592574162

 

[R.G. Robinett]

Cool concept!

You'd maybe probably get some more teeth pulled, Jackie - cool concept!RG
P.S. R U already thinking about testing with metal-to-metal & with damper between lug and base-plate??

 

[Lee Martin]

Slick concept Jackie and I can't say I've seen anything like it on a rail. Please keep us posted.

Speaking of rails, I finally finished mine this week. Hope to play with it soon. I'm going to start around 20 in/lbs and go up to 50 or 60. Quick question. Do you tune the load first, then start torquing? Or have you found it better to find the block setting first, then adjust loads?

-Lee
www.singleactions.com

 

[jackie schmidt]

Slick concept Jackie and I can't say I've seen anything like it on a rail. Please keep us posted.

Speaking of rails, I finally finished mine this week. Hope to play with it soon. I'm going to start around 20 in/lbs and go up to 50 or 60. Quick question. Do you tune the load first, then start torquing? Or have you found it better to find the block setting first, then adjust loads?

-Lee
www.singleactions.com

Lee, if you torque the barrel block too tight to where it actually distort the barrel ID, no load will shoot. It amazed ho light a torque will do that. In truth, the only way you can actually ascertain this is by slugging the barre. Or shooting it

Start at 25 inch pounds.

 

[geo.ulrich]

Well Jackie, at least someone is thinking. here are pictures of mine, last time I shot it was 2013 ubr nationals. I shot it at Kansas City nationals before that so I'm guessing 12-15 years ago.....

 

[Zebra13]

Jackie,

If your idea shows promise...

You mentioned the block needing to be made of steel and the resulting weight issue. Do you think an aluminum lug with a pressed/pinned steel insert would be a viable alternative?

Justin

 

[jackie schmidt]

Jackie,

If your idea shows promise...

You mentioned the block needing to be made of steel and the resulting weight issue. Do you think an aluminum lug with a pressed/pinned steel insert would be a viable alternative?

Justin

The reason I mentioned steel or another high strength material is you are Putting in compression the barrel block between the action face and the shoulder of the barrel. Considering the torque involved with insuring a adequate joint, I doubt aluminum would be up to the task.

Perhaps Titanium. But then that is getting into a whole different ball game when considering doing something just for the fun of it.

And then, I didn’t have a big enough chunk of 7075 T-6 Aluminum laying around, but I did have this piece of 17-4 left over from a previous job.

 

[geo.ulrich]

Jackie, After looking at your sketch mine is alittle different. 4" long and I used two 1/4 " dowel pins front and rear with 6 1/4 20 screws to hold to plate. Also I went down in dia. to 1.125 the nice part is you don't need a shoulder where barrel is just thread up and use block to determine h.s..... An alum block would work fine you would need to counterbore both ends and use a steel washer maybe 1/4 " thick at both ends to sandwich alum block. The first I can recall discussing this was with Micky Coleman around 1999 we threw the idea around until I decided to try it ....

 

[jackie schmidt]

Well Jackie, at least someone is thinking. here are pictures of mine, last time I shot it was 2013 ubr nationals. I shot it at Kansas City nationals before that so I'm guessing 12-15 years ago.....

This goes to prove George, nothing under the Sun is really ever new.

Heck, this concept might be put in the closet with many of my other ideas that “seemed like a good idea at the time”. Hopefully I can get to the range Sunday and see.

That being said, my barrel mounting block would be a great paperweight

 

[BillBrawand]

jackie, after looking at your sketch mine is alittle different. 4" long and i used two 1/4 " dowel pins front and rear with 6 1/4 20 screws to hold to plate. Also i went down in dia. To 1.125 the nice part is you don't need a shoulder where barrel is just thread up and use block to determine h.s..... An alum block would work fine you would need to counterbore both ends and use a steel washer maybe 1/4 " thick at both ends to sandwich alum block. The first i can recall discussing this was with micky coleman around 1999 we threw the idea around until i decided to try it ....

with all the bbls i put on rim and cf i just put piece of flashing on top and bottomof bbls in block seems to work quite well

 

[jwv2001]

Layman's quesstion

First of all, I would classify myself as a layman's layman, but I find myself drawn to these discussions because they are so interesting. I mean I read the rudder shaft thread backwards and forwards. Maybe it was just the pictures. Same here maybe.
Some things were discussed and a question immediately popped into my mind. If somewhere between 25 and 60 inch pounds of torque on a barrel block will potentially alter the inside dimension of a barrel, why wouldn't removing .201 of the o.d. also have an effect on the inside dimension. I mean everything has a cause and effect. Please enlighten me.

 

[geo.ulrich]

It wouldn't be any different then when they turn barrels down during mfg. after rifling....except a shorter length...

 

[BillBrawand]

with all the bbls i put on rim and cf i just put piece of flashing on top and bottomof bbls in block seems to work quite well

block of steel

 

[jackie schmidt]

First of all, I would classify myself as a layman's layman, but I find myself drawn to these discussions because they are so interesting. I mean I read the rudder shaft thread backwards and forwards. Maybe it was just the pictures. Same here maybe.
Some things were discussed and a question immediately popped into my mind. If somewhere between 25 and 60 inch pounds of torque on a barrel block will potentially alter the inside dimension of a barrel, why wouldn't removing .201 of the o.d. also have an effect on the inside dimension. I mean everything has a cause and effect. Please enlighten me.

On this case, there is no cause and effect.

There is a theory floating around for years that if you turn the OD of a button rifled barrel, the ID will be affected because of the stresses induced in the bore by the extruding of the lands and grooves. Most barrel manufacturers dispute this.

Since this is a cut rifled a Krieger, none of that supposed stress is present. I shoot nothing but cut rifled barrels.

 

[OliveOil]

stress/strain on 1.06 dia

Seeing your sketch, there will be quite a torque applied on the 1.06 "ring" due to barrel weight being full forward. That's a complete different storry than the usual barrel block.

Have you run some stress calculation and compare from what you get from tension at tightening action/barrel ?



Question from the stupid :

I read above that depending on the torque applied on the barrel block screws, a presumely goog barrel can shot poorly. As far as I understand, you are giving a go to a solution with no screws to "block" the barrel.

What about a design with a LONG 25 tpi thread on the barrel at barrel block location, grind the thread top to create a surface of contact, bore a barrel block to almost ground thread OD and have 2 barrel nuts aka Savage to secure barrel on barrel block ?

No compression on barrels.


I do not know about RailGun Rules, but I would also imagine the same "screw-less" barrel block with 2 O"'Rings (front and back),, a recess/cylindrical chamber machined all along the block except at the O'Rings location (idea is to have the barrel floating in/along the block), slightly tighten the "Savage" barrel nuts (with washers, elastic or not), then, using a cartridge grease pump, feel the block with a flexible adhesive (some 1/25" air vent holes somewhere, greasing point the opposite ), let cure and full torque on the nuts, or ... for a short BR round ... remove the nuts.

ORings are here as a soft shim to keep the barrel axis on the block axis, & dampen vibes. Yes they are on a treaded part but no, they have no sealing purpose.


OK, OK, I go back to my shop and hide.

 

[jackie schmidt]

I do not possess the math skills to ascertain the stress level experienced by a barrel when mounted this way. In practice, it is no different than a standard action/barrel attachment with a recoil lug sandwiched between the shoulder of the barrel and the action. I torqued the barrel the same as I do any of my Rifles.

I am not an engineer. My skills center around the machinist trade.

As for the ground thread idea, I have no means on hand to grind threads. I can turn and polish to within a couple of “tenths”. Tightening in the linear plain does not affect the barrel ID at the lands and grooves as much as the compression exerted by standard V thread. The inward closure exerted by the the action thread is over the chamber where there are no lands and grooves, so I consider it of no consequence.

When I first built my Rail years ago, I had the barrel 100 percent encapsulated in a steel tube with aluminum pourable Devcon being used. The Barrel/ Tube assembly was mounted in a standard V Block. The idea was to completely deaden the barrel. I gave it up because while it shot well, the work involved did not seem worth the effort. Plus, you go to all of that effort and the barrel turned out to be mediocre, you have wasted a lot of time and material.

I”ll try this particular idea first. The good thing is, if it turns out to be a crap shoot, I can just go back to the V block.