Slugging the barrel!

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ms6852

ms6852

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I have been shooting for more than 50 years and am quite embarrassed but just recently I heard the following phrase at the range a couple of times "You need to slug the barrel". What is meant by that phrase?
 
This is a distilled explanation- I'm sure others will elaborate.
But slugging a barrel is when you use a ramrod to push a slightly oversized bullet through the barrel to measure the actual diameter of the bore. By dong so, you can optimally size cast bullets which will allow improved accuracy.
 
CLP said:
slugging a barrel is when you use a ramrod to push a slightly oversized bullet through the barrel to measure the actual diameter of the bore.
Click to expand...

Yes, but:
1) Selection of a rod is critical. Slightly undersized brass is good. A wooden ramrod could be very bad.
2) not only can you measure the minimum bore size, but you might also detect a tight spot if present.
 
ms6852 wrote:
"You need to slug the barrel".
Click to expand...

In what context was this advice given?

Also, while CLP is exactly right as to what "slugging" a barrel is, it is also possible to achieve the same result using a low melting-temperature casting alloy such as Cerrosafe.

The barrel is plugged (either near the chamber or near the muzzle), the casting alloy melted and poured into the barrel. After a few minutes, the alloy solidifies and shrinks by a known amount. This shrinkage allows it to be easily removed. The cast can then be measured and the measured dimensions increased by the known amount of shrinkage.

Cerrosafe and similar alloys are available from most large shooting suppliers (Midway, Brownells, etc.) and it can be melted using a propane torch, so no casting pot is needed, but you will need to buy a casting ladle to melt the alloy in, but they can be had for under $10.
 
edwardware said:
Yes, but:
1) Selection of a rod is critical. Slightly undersized brass is good. A wooden ramrod could be very bad.
2) not only can you measure the minimum bore size, but you might also detect a tight spot if present.
Click to expand...

Why would a wooden ram rod be bad?
 
hdwhit said:
In what context was this advice given?
Click to expand...
I would be guessing as to the context but they were shooting black powder if this helps and as was mentioned by CLP it probably than involved cast bullets. They were a couple of tables down from me.
 
Havok7416 said:
Wood has a tendency to splinter and that can cause it to get stuck in the barrel.
Click to expand...

Yup. A brief search will reveal that we have a, "Help! My dowel split and my slug is stuck in my barrel!" thread about quarterly here. Sufficient persistence down that path will leave you with no options better than melting it out or tapping for a grease zerk.
 
RULE 1. DON'T slug any barrel that you can't get the slug pushed all the way and out the other end. :neener: :cuss: :what: :D

RULE 2. DO use a pure lead muzzle-loader roundball that's either slightly larger than groove diameter to start with, or "tapped" lightly with a hammer to to flatten/expand the radius.

RULE 3. CLEAN and OIL the barrel before proceeding further.

RULE 4. LUBE the ball with resizing lube.

RULE 5. TAP the ball all the way into the muzzle with a plastic/rawhide/wood hammer.

RULE 6. SHORT-START the ball further 1-2 inches with a short dowel (yeah, wood's OK at this point)

RULE 7. PUSH the ball through & out the other end with the ramrod/ (no jag). It will be relatively easy if you've followed Rules 3 & 4.

RULE 8. MEASURE ball diameter on the flats.

RULE 9. DO TWICE and take the average.

RULE 10. DON'T drink while doing this. o_O
 
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"Why would a wooden ram rod be bad?"
"Wood has a tendency to splinter and that can cause it to get stuck in the barrel. Really not a fun day I promise!"

So true. I learned this the hard way while clearing a squib a while back. Not good.
 
MEI Harvey has it right. I recommend going to Ace or another hardware store and buying long brass rods of varying diameters to do this. You can get them at Amazon or Ebay but they can be a bit higher than the good ole hardware store (never seen them at Lowes or Home Depot). The Blackpowder musket balls sold by folks like Speer are generally pure lead--you should be able to mark pure lead with your fingernail. No mark--too hard.

As hdwhit notes above, cerro safe can give you the chamber and part of the barrel--especially the throat area up to initial rifling. This area is thought to be the most significant for accuracy along with the muzzle. Slugging gives you the bore dimensions and can also tell you if you have a bore constriction somewhere in the barrel. The bore dimensions are useful to size (either actually size if using cast boolits or buying fmj bullets to best fit if possible) your reloading bullets to the bore for optimum accuracy--Lee Enfields are a notorious example where bores vary quite a bit, especially the old SMLE's. Sometimes it can tell you to use a flat based fmj instead of a boattail.

Here is an old gunboards thread about the Lee Enfield No. 4 rifle bore variances to explain,
http://forums.gunboards.com/showthread.php?199142-Enfield-No4-bore-diameter-variances

A major issue is if you have an odd number of grooves where the measurement gets more complicated.
Here is a thread from practical machinist on doing so,
http://www.practicalmachinist.com/vb/gunsmithing/measuring-5-groove-slugs-189215/
 
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