DIY Slug-o-Tron: barrel slugging machine

[Boris]

Acknowledgements: big thank you to a lot of members on another forum: RKG, 50BMG, Slowdive and EddieCoyle on awesome insight and ideas for this little adventure, also to (<>) crew.

greeting comrades. Some time ago, never mind how long, I came across problem of slugging many barrels of most glorious Mosin rifle. It is true that you should slug your Mosin barrel as many vary anywhere mostly from .310 to .315. Thus, selecting ammo to fit rifle will provide you with accuracy. Sniper rifles were selected for two parameter: one is how straight the bore was, the other was how close it was to factory ammo (since no sniper ammo existed during WWII)

http://i1178.photobucket.com/albums/x368/_ak_74_/sot12.jpg~original

Before you hunt me down and cut my hands off, keep in mind:

1. These are not ... some of ... my barrels ;)
2. I did not mutilate these most glorious rifles made in defense of motherland :-(
3. They will all be restored to most awesome glory and fire many cartridge of ammo in future! :smile:

Anyway, many barrels, very long time to slug all. Thus I made this machine and call it "Slug-o-Tron" Basically, this machine could slug a barrel in 15 sec and provide more information on which I elaborate later.

Here is my original setup, it is a 110V wench that drags steel cable with slug attached to it.

http://i1178.photobucket.com/albums/x368/_ak_74_/sot11.jpg~original

To make slugs, I cut up a bunch of #8 bolts. You can probably make that from a threaded rod, but at my HD the rod was as expensive and I need to have good threads one end.

http://i1178.photobucket.com/albums/x368/_ak_74_/sot5.jpg~original

Before casting, I screw the threaded piece into a 1/4 brass rod:

http://i1178.photobucket.com/albums/x368/_ak_74_/sot6.jpg~original

The mold body is made from scrap aluminum and three drill bits. I drill 1/4 hole all the way through. Then start with 5/16 and round leading edges on another to finish drilling:

http://i1178.photobucket.com/albums/x368/_ak_74_/sot3.jpg~original

The brass plug is inserted into mold like this:

http://i1178.photobucket.com/albums/x368/_ak_74_/sot7.jpg~original

and we are almost ready

http://i1178.photobucket.com/albums/x368/_ak_74_/sot8.jpg~original

[Boris]

I make top from a piece of scrap metal similar how bullet molds work:

http://i1178.photobucket.com/albums/x368/_ak_74_/sot4.jpg~original

using the spacer under the mold, once soft lead is cast, I tap the top off, tap the mold on the ground and slug comes out like this

http://i1178.photobucket.com/albums/x368/_ak_74_/sot9.jpg~original

the slug is attached to the steel cable of wench like this:

http://i1178.photobucket.com/albums/x368/_ak_74_/sot14.jpg~original

now you know why #8 threaded rod is used. I use length of 3/16 steel brake line, it is perfect for cable and is perfect to tap #8 inner threads.


why is slug drugged by the wench? Because slugging from muzzle can give you one thou variation vs. slugging from the chamber.

in addition, I added a load cell to measure the tension on the cable continuously

http://i1178.photobucket.com/albums/x368/_ak_74_/sot10.jpg~original

some barrels are airgaged (French did first airgaging) and this can very accurately measure barrel internal diameter and also variations in caliber inside, flat spots etc. The theory is that when wench pulls boolit through barrel, tension will drop at the increased dia and tension will increase once boolit passes into a tight spot:

http://i1178.photobucket.com/albums/x368/_ak_74_/sot16.jpg~original

I slagged a couple of barrels and I could see that each barrel has its own, unique "signature" that is repeatable every time. Here are four graphs of slagging two barrels. You can see that each barrel has very unique pattern.

http://i1178.photobucket.com/albums/x368/_ak_74_/sot2.jpg~original

here are three more graphs of three other different barrels:

http://i1178.photobucket.com/albums/x368/_ak_74_/sot15.jpg~original

Since slugs are good for any rifle in the most glorious (7.62) caliber, I slugged several AKs:

http://i1178.photobucket.com/albums/x368/_ak_74_/sot1.jpg~original


Romy AK is f-up, I don't even remember what it slugged as, not very accurate at all. Arsenal is ok, it slugged at around .312 and shoots acceptable. Polish AK slugged at .309 and is very accurate despite flimsy collapsible stock.

I will post more pictures of the setup. I don't think that tension graph tells you something dramatic as to decisively determine accuracy of rifle, but it does corroborate the evidence of good shooting rifle. In short, there are many of factors to make rifle shoot well and bore is one of them.

Also, for people who lap their bores, tension graph may be useful to gage results of work.

[brtelec]

What an ingenious solution to a problem.

[Artful]

Welcome Boris - good of you to posted this.

Excellent Idea and work - What inspired you?

I could this something like this as something you could offer to anyone buying
a rifle from you to inspire confidence that the barrel is in good shape.


- but I will admit you bring out the spelling Nazi in me.
Wench
http://3.bp.blogspot.com/_8SQ4Wf6Crw0/SeZf0OHWHOI/AAAAAAAACB0/qdcmODMnn28/s400/medieval_wench.thumbnail.jpg
Winch
http://www.harborfreight.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/i/m/image_22135.jpg

Drugged
http://cdn.theatlanticwire.com/img/upload/2012/05/25/Picture%2084.png
Dragged
http://1funny.com/wp-content/uploads/2011/05/dragged.jpg

[Garyshome]

Great idea.

[mikeym1a]

Very neat idea. Well thought out. Congratulations!!!!! :D

[waksupi]

Очень хорошо сделано! Поздравляем!

[M Hicks]

Nice waksupi.

Very nice way of getting it done Boris. It seems like a lot of great info can be had from something like that.

[xs11jack]

This demonstrates why we have the best website in the world, bar none!!!! Thanks Boris.
Ole Jack

[Fishman]

A 110 volt wench. Hmmmm.

In all seriousness, a really interesting setup and really thinking out of the box.

[W.R.Buchanan]

Boris: Great work sir! I can easily adapt this concept to a manual version.

Art: Great explanation of the English language.

Randy

[Southern Son]

Boris, mate, that is brilliant.

I do want to see more photos of the Wench. Any Wench that can drag a slug through a rifle barrel is somethng I want to see!!!

[Artful]

Boris, mate, that is brilliant.

I do want to see more photos of the Wench. Any Wench that can drag a slug through a rifle barrel is somethng I want to see!!!

http://magiccitycyclechix.files.wordpress.com/2013/02/wine-wenches-and-wrenches2-sized.jpg

[W.R.Buchanan]

Is that similar to sucking a golf ball thru a garden hose?

Seriously a strap winch off a truck trailer with a padded stop in front to stop the gun from moving towards it would easily drag a slug from breach to muzzle on an assembled rifle, and the whole thing could be assembled on a 4x4 with a padded cradle for the gun to rest in. clamp it in a vise and you are ready to go.


Also if you don't want to cut off screws you can buy a box of long 8/32 x 1" set screws for about $4.00 at any industrial bolt supplier.

Randy

[DCM]

Durn it Randy you just had to come up with an economy model for the average Joe.:kidding:
Now I have a Bad case of gots to have its!