Sleaving barrel

[batmanacw]

I am kicking around the idea of shrink fitting a sleave on my mini. I would make it out of aluminum and flute it to increase surface area and reduce weight. I will probably make it to .001" under and heat it up to slip it on. It would not move at all under recoil. The hardest part would be boring a hole that deep to maintain concentricity.

I am sure someone has done it already. Any thoughts?

[TBolt]

That is exactly what I am in the process of doing right now! I bought some aluminum tubing 1 inch o.d. and 1/2 inch i.d.. I have taken measurments on my series 580 barrel and drawn out the prototype. Mine will have a pattern of cooling holes in the aft portion and the foreward 2 inches will be 7/8 inch and no holes. I can post pictures of the design after I get off work tomorrow if your interested. With this design you can maintain your factory sights as the sleave will end just behind the fromt sight.
One of my co-workers works part time at a machine shop and is going to handle the machining for me.
As an experiment I took a piece of the tubing and placed it in the oven for an hour at 450 degrees. The center hole expanded .004 of an inch. I was thinking of going .002 inch under barrel size. I'll keep you posted on my progress.

[Wong-one]

I have a couple neat pictures of my Mini with a sleave but can't figure out how to post the picture.

[tri70]

I have a couple neat pictures of my Mini with a sleave but can't figure out how to post the picture.

did you click the manage attachments at the bottom of the screen, then click browse to find them in the right folder?

[mini-mizer]

One thing to be aware of is galvanic corrosion.
http://en.wikipedia.org/wiki/Galvanic_corrosion

I made a steel threaded type device for my mini, works
very good.


MM

[batmanacw]

The machinist who made this barrel was very, very drunk, or maybe retarded!

The dia. close to the block is .015" thinner than half way to the front sight. The dia. at the front sight is .003" thicker than the other end! This means that truely accurate sleaving is not possible.

I am going to have to tension it as originally planned. It will consist of two clamping end caps, with one having external threads, so the tensioning tube will be able to push them apart. I am bummed, because the sleave would have been easier. I will probably make the tube of aluminum, and the caps of Steel.

[TBolt]

Well, I've tried posting pictures of the design I have in mind but I can't seem to get it to work. I'll have to have my son help me, he's the computer man in the family. batmanacw, I know what you mean about the differing diameters on the barrel. Mine would require 2 different internal diameters and probably need some JB weld to stabilize the rear portion. I still plan to go ahead with the project. After all, that's one reason this site is here, to try different things and see how they work, then share results with others.

[gunrun45]

The machinist who made this barrel was very, very drunk, or maybe retarded!

The dia. close to the block is .015" thinner than half way to the front sight. The dia. at the front sight is .003" thicker than the other end! This means that truely accurate sleaving is not possible.

I am going to have to tension it as originally planned. It will consist of two clamping end caps, with one having external threads, so the tensioning tube will be able to push them apart. I am bummed, because the sleave would have been easier. I will probably make the tube of aluminum, and the caps of Steel.

Couldn't you put it on a laythe and machine it down fora tighter tolerance? Just curious, please pardon my ignorance of modern machining.

[batmanacw]

I do not want to thin out the thicker section as this will just decrease the mass even more. I also don't want to pull the barrel. If I was going to do that, then I would just buy another, thicker barrel. I am trying make it better without spending much time or money.

[gunrun45]

Gotcha! Sorry for my ignorance, really. I have never used a metal laythe or some of the more advanced tools in gun smithing. I was just curious.

[guncats]

the Mini-14 pencil barrel not only have uneven OD, it might not be true either. When they were made they might be straight enough but after a while all the internal stress shows and the barrel starts to warp......

So the sleeve might not work for all mini's, due to this warping. Should help on a mini with straight bbl though:)

[tri70]

I don't know if you could make a split sleeve that would tighten with a couple of bolts. The split in the length of the sleeve would make it easier to get over the uneven barrel machining. Or maybe clamp down with oversized flashlight barrel clamps. You may want to sand the machining marks on the barrel smooth if you go ahead with a sleeve idea.

-tri

[lobo creek]

The accu-strut works as a barrel stiffener so I think that a barrel sleeve would not necessarily have to have full contact with the barrel along its entire length. You could use a 1" o.d. aluminum pipe with a 3/4" inside diameter and use 3/4" o.d. bushings bonded to the inner ends of the outer pipe. These bushings could be made to closely fit the barrel diameter. A compound such as Loctite 680 could be used as a bonding agent for bushing to pipe and for bushing to barrel. The ends of the pipe could also be drilled and tapped for set screws. The sleeve would be easier to remove with the Loctite compound than if something like J.B. Weld was used.

[lobo creek]

I should have mentioned that Onlinemetals.com sells aluminum pipe to fit the application.

[rutro]

Maybe what you guys are looking for is a Tenisioned Barrel Sleeve. I just need some range time to check this one out and the north wind is howling 30+ MPH right now. Here's a link if you think you're interested, http://www.perfectunion.com/vb/showthread.php?t=52813, so far it's the only mod that has made it to the MOA club.

[batmanacw]

This is what I am going to end up doing. The aluminum for the tube is currently on my lathe, but haven't finished boring it or internal threading on one end. I will post pics once I am done.

[p35bhp55]

The machinist who made this barrel was very, very drunk, or maybe retarded!

The dia. close to the block is .015" thinner than half way to the front sight. The dia. at the front sight is .003" thicker than the other end! This means that truely accurate sleaving is not possible.

I am going to have to tension it as originally planned. It will consist of two clamping end caps, with one having external threads, so the tensioning tube will be able to push them apart. I am bummed, because the sleave would have been easier. I will probably make the tube of aluminum, and the caps of Steel.
Maybe not, my lathes at work are so wore out I have to do the last passes backward so my parts don't look like ice cream cones. I wonder if our bbls are even machined tho.

[P-Shooter]

batmanacw, Yes someone has done as you suggested. I drew one up and had a machinist make it for me. It is rectangular in section, 1/1/8" wide x .94" high x 9-7/8" long. It has four 1/8" wide flutes. One on each side of the bore and two along the top at a 45 degree angle. the botton has a 1/16" slot the full length and there is six 8-32 socket head machine screws along the bottom to squeeze this sleeve tightly to the barrel. It extends 1-7/8" passed the muzzle and I had three 1/4" holes drilled at 1/2" spacing on the top and the sides to create a built in flash hider. I did this before I joined this forum and started my thread in the accurizing section. I have not been successful in posting a photo yet. Does it work? Maybe, I really can't say yet. It does work great as a heat sink. I need to shoot it after dark to check the flash hider. I recently found a few stock bedding problems and solved them. I shot my 196 Mini the other day with Wolf ammo and I am not getting much better than 3 inch groups at 100 yards. What mistifies me is that it shot much better right out of the box with no mods by me and the heavy trigger. That was about 800 or so rounds ago. I am looking at the rifling and it doesn't look that distinct compared to my other rifles. I will try reloads next. Sleeving still seems like a good idea. Mine is 6061 Aluminum and it fits tight, I had to draw file the hump from the barrel for it to slide on. I haven't given up on it yet. Just remembered that it weighs close to 11 ounces.