Barrel Slugging questions

[Bored1]

So I picked up some soft lead cast bullets to use as slugs from a forum member awhile ago and finally got around to slugging the barrel on my norinco sks tonight.

The slug measured .312 beforehand and .313 when it came out of the chamber, pushed through from the muzzle end, with light rifling marks on the sides.

So does this mean I should use a .312 mold to cast for this rifle of .314? I think the slug probably shortened on the way through but not sure what to do @ this point? Did this twice with the exact same results.

[cajun shooter]

I would use the .313 as that is the size it bumped up to to fill the bore. Now not knowing the composition of your bullet alloy, I would try one more time using a lead fishing sinker that is egg shaped. They are for the most part pure lead and may give you a better reading, if not then you will be sure your figures are correct.
Just take your mike with you to the store and find the size you need which should be larger than something that is very close to actual bore size. Oil the bore very heavy and the same with the sinker before starting. Later David

[Mohavedog]

If you are only getting "light rifling marks" on the boolits after pushing through the bore, I don't think you are getting the correct dimension of the grooves. You should be seeing full strong rifling that shows that the boolit is actually getting sized to the full groove diameter.
You need a slightly larger slug of soft lead. Mohavedog

[MBTcustom]

If you are only getting "light rifling marks" on the boolits after pushing through the bore, I don't think you are getting the correct dimension of the grooves. You should be seeing full strong rifling that shows that the boolit is actually getting sized to the full groove diameter.
You need a slightly larger slug of soft lead. Mohavedog

I agree, take another boolit and crush it slightly until it measures .318 and do it again. You should see clean rifling marks all the way around the slug. Until you do, you do not have the correct measurement.

[Bored1]

OK, I will try it again and see what happens. Thanks for answering guys.

[MBTcustom]

You bet.
Also, I might mention how important it is that the end of the rod that touches the slug must be flat and square. If not, you will rue the day that you tried this.
Also, remember to keep an oiled barrel. If you do not oil before every slug, you are in for trouble.
PM me if you get "stuck".

[ukrifleman]

Or you could slug the bore using candle wax, which also gives you a chamber cast.
ukrifleman.

[Oreo]

How dimensionally stable is candle wax as it cools? That's the whole point behind cerosafe- that it melts at low temp so as to not cool to a smaller size.

[MBTcustom]

I wouldn't think that candle wax would give an accurate piece to measure.

[blackthorn]

Even with Cerosafe, if you do not measure at the one hour post cast point, requires knowledge of the math formula to deal with changes to the casting! A Sulphur/Graphite cast however does not expand or shrink ever.

[Oreo]

Sulphur / graphite cast? Got a link to info on that per chance?

[gandydancer]

So I picked up some soft lead cast bullets to use as slugs from a forum member awhile ago and finally got around to slugging the barrel on my norinco sks tonight.

The slug measured .312 beforehand and .313 when it came out of the chamber, pushed through from the muzzle end, with light rifling marks on the sides.

So does this mean I should use a .312 mold to cast for this rifle of .314? I think the slug probably shortened on the way through but not sure what to do @ this point? Did this twice with the exact same results.
www.meisterbullets.com slug your barrel kits. check it out. best dang kit on the market.

[MBTcustom]

Flowers of sulfer can be had at your local farm and home supply store. Just melt in a normal ladle with low heat and pour into your chamber like cerosafe.

[Bored1]

Ok, so now I have more questions! Why would you cast your chamber?

[John Boy]

I would try one more time using a lead fishing sinker that is egg shaped. They are for the most part pure lead and may give you a better reading, if not then you will be sure your figures are correct.David, in today's market, I wouldn't trust sinkers anymore to be pure lead.

Not all the shooters of lead bullets are casters, so it's tough unless they have a friend who is. In Bored's case the bullet he was given was soft but to a smokeless shooter that could mean any Bhn less than hardball of 18 and account for the 'light' marks or the bullet was too small

If I was Bored, I'd slug the bore again. Bullet nose in the muzzle - flush the bullet with the end of the muzzle with a brass hammer, then drive the bullet to the breech using multiple 6-8" cut sections of a wood dowel rod

The fist step though is ... what is the base diameter of the bullet being used for the slug?

[John Boy]

Chamber cast elapsed time measurements:

Contraction expansion factor versus time, measured in Inch per inch compared to cold mold dimensions. Test Bar x x 10
2 minutes - .0004"
6 minutes -.0007"
30 minutes -.0009"
1 hour + .0000"
Tests have proven that 1.5hrs = +.0000
2 hours +.0016"
5 hours +.0018"
7 hours +.0019"
10 hours +.0019"
24 hours +.0022"
96 hours +.0025"
200 hours +.0025"
500 hours +.0025"
http://www.rotometals.com/SearchResults.asp?Search=chamber+casts

[Bored1]

The fist step though is ... what is the base diameter of the bullet being used for the slug?[/QUOTE]


The bullet or slug was .312 before it went through the barrel. I did make it flush using the mallet before using the dowel rods. Don't this the first rod was exactly square either though.

The slugs where cast using pure lead. Its soft enough I can smash one using a rubber mallet if thats any indicator on how soft it is.

[.22-10-45]

Hello, everyone. I have used beeswax to make a chamber cast..granted the stuff shrinks..though if chamber is warmed..it doesn't shrink all that much..in fact it takes a smart tap to get it out. And of course..it's too soft to "mike"..but I wasn't after a diameter..I was only interested in length. I was checking a .255 Jeffery rook rifle..chamber seemed off from published info.
This rifle has a spring powered ejector...two guide rods..and lots of little crainies where with my luck..cero-safe would probably find its way...the reason for the b.w.
Anyway..I soon found I didn't need to trim cases as short as book said..and shoulder was farther forward..less case work than I thought.

[MBTcustom]

Well dad-gum, you said you were after a barrel slug, not a chamber slug.
For what you were actually looking for, you did exactly right. Good deal.

[blackthorn]

I am just on my way out the door---back day after tomorrow (or sooner) and I'll post what I have then on the sulphur/graphite casting.

[blackthorn]

Well here we are. Just got back from Vancouver this afternoon. Here is what i have on sulphur/grapgite casting:

SULPHUR CAST:

An alternative to using Cerrosafe or the pounded slug method is to make a sulphur or a sulphur/graphite cast. To do this, make up a mixture containing a ratio of approximately two-thirds sulphur to one-third powdered graphite. Sulphur requires a much higher melting temperature than Cerrosafe but it has the advantage of neither growing nor shrinking once the cast has set. As noted, a chamber cast can be made using just sulphur but these casts tend to be somewhat hard to remove and they tend to be brittle. The addition of graphite in the casting makes it less brittle and easier to remove once it is hard.

A four pound. sack of sulphur can be had cheaply at the garden centre. Clean and degrease the chamber, put a paper plug about one half inch into the rifling, drop a piece of cotton string into the chamber, do not use synthetics, have a wood dowel longer than the barrel and of smaller but as close as possible to the inside diameter on hand. Alternately, you can make a barrel plug out of cork or other stiff material, attach the required cotton string through the plug and push it into the chamber/barrel. Place some sulphur in a small pan with a pour spout, using, preferably an electric hot plate, slowly heat the sulphur until it melts, do not let it catch fire, the smoke is () poisonous. Stir in the powdered graphite and pour in enough of the liquid mix to just fill the chamber, wait until the cast is completely hard, this will depend on how large the chamber is, which governs the mass that has to cool down. Carefully push on the cast with the dowel while firmly pulling on the string; it should come out easily once it starts to move.

As noted, unlike Cerrosafe, sulphur cast dimensions of the chamber do not change at all over time, so how soon after casting you measure the cast is not important. Sulphur is one of the few elements that do not change dimensions when going from a liquid to a solid state. Casts made with sulphur do not change shape or dimensions even after many years. Molten sulphur can also be used to set machinery anchor bolts in concrete.

The inclusion of graphite allows the casting to release very easily after it cools. These castings can be remelted for re-use or they can be marked for identification and kept for future reference.

Have a good day!

[Oreo]

Excellent! Thanks for that!