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howdy Marlin lovers, i just got a previously fired 30 30 and I have a couple of questions. should I assume the barrel has copper fouling in it? Can I see copper fouling in the barrel? And once I get the barrel clean should I slug my barrel or assume a .311 cast bullet will work the best? If I slug the barrel should I just push the ball in a couple of inches from the breech or crown or both. I appreciate the help thanks!
 

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I use fishing lead sinkers and I just stick them in the muzzle and push with wooden dow rod..
 

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yup make sure you use some SOFT lead (fishing sinkers) and it will work pretty easily, and yes, most of the time you can see copper fouling. if your barrel has a greenish tint down the bore it needs a thorough cleaning.
 

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Use most any copper solvent, wet swab the bore, stand rifle on muzzle on some newsprint, copper fouling will stain the paper green. I just keep wet swabbing the bore, let is stand, dry patch, reswab until not green tint is evident on the paper.

I have a take on slugging a 30-30 and thats using a .32 cal muzzleloader round ball, I drive it in the muzzle with a mallet. I then take a heavy stainless ramrod I have with a blunt end on it and use it like a slide hammer against the ball while having the muzzle resting on a steel plate, it forces it to swell into the grooves.

Bottom line, .311 should work I use .310 in two I have.
 

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If you think you may have copper fouling, run a dry, white patch on an appropriate jag from the chamber to within about 1/4" to 3/8" from the muzzle. Tip the rifle muzzle up, under a good light (flourescent lights seem to show fouling the best, IMO), and take a peek into your bore. Copper fouling is readily visible on the lands of the rifling if present.

For getting rid of copper fouling, most folks on this site have their favorite, tried and true approach. Mine happens to be Bore-Tech "Eliminator" solvent. Even bores that I thought were copper free, using Butch's Bore Shine, Sweets 7.62, Barnes CR-10, a couple of foamers, and a myriad of others really surprised me when a I tried the Bore-Tech. A buddy of mine that does a lot of the varmiter bench-rest shooting suggested I give it a try - - I have not used anything since, when it comes to copper fouling.
 

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So what is "slugging" and what does it do? Is this something I need to do before I shoot my cast after copper jacketed?

Lost in the weeds,
Matt
 

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Hi Matt--

Slugging is a process used (as described above) so you can truly tell what the exact dimension is in the rifling of any firearm that has rifling.

Here's a crude explanation of what actually happens when a cartridge is fired in your gun.

As the hammer hits the primer a small explosion ( bomb) is set in place, the primer ignites the powder and as it's ignited there is fire and gases that are formed by the ignition. First thing is the case expands in all directions, it can't expand any more to the rear because of the locking mechanism you have on your gun ( bolt) but because the cases are usually brass they will and have to expand both in length and in diameter. The gases and fire keep expanding in the brass until there is sufficient pressure to blow the bullet out of the end of the case and into the barrel.

Once the bullet hits the barrel it has been swollen from the rear by all the force generated at ignition. ( Think of a spit ball and a straw--the more force the further it goes out the end of the straw) Once the bullet hits the rifling it starts to turn and spin down the barrel. This is when and why slugging is important.

As the bullet goes spinning down the barrel it has expanded from force and is supposed to make a seal in the barrel to keep any fire or gases from escaping around the outside diameter of the bullet. ( Think of it like this--take a small round ball of cookie dough--lay it on the counter--know push your thumb right in the middle of the dough and watch it expand--if that same round ball was in a cookie cutter shaped like the rifling in your barrel it would expand to the outer edge and make a perfectly tight shape/form of the cutter it was in and a seal would be formed between the dough and the cutter.)

If this seal is not formed, fire and hot gases can escape around the outside edges of the bullet and go down the barrel--this is when leading occurs. The hot fire and gases escaping around the bullet actually heat the outside edges of the lead and softening it to a point where it actually adheres itself to the inside of the barrel causing what is called leading.

By slugging the barrel you get the exact inside dimension of the barrel by forcing a soft piece of lead into it and after it comes out you then Mic it to see exactly what the dimensions are. Like a .45 Colt--it could slug out to be .452 up to .458. Once you know the exact OD of your barrel you can then either size cast bullets to your needs or buy cast or jacketed to match your barrel requirements.

Think of it like this--if you shot a .452 bullet in a barrel that's .458 the bullet could wiggle itself like a snake going down the barrel until it exited and your accuracy would be terrible. Most people that cast their own lead bullets will oversize the bullet by about .001 to ensure the seal and accuracy--some vary from this but that's usually pretty close.

Here's probably the dumbest thing I have personally ever done before I knew better. I had a beautiful S&W 586--.357 that I loved to shoot. Got some ammo at a gun show and went to the range to burn em' up. Now previously this gun , from a bench rest was a tack driver, I loved it. Shot a couple of rounds and it was all over the place--moved the target back to 25 yds.--just as bad--adjusted sights and did everything I could think of and I was getting 3" groups at 25 yds. from a rest, Horrible. So I figured the gun was done--sold it. Months later after learning about slugging a barrel I decided to check the ammo I used in the 586 that I had so much trouble with--they Mic'd at .354 in a barrel that was probably closer to .359--it was PMC Ammo and it's now gone.

Sorry this is so long winded but I hope it helps you understand what slugging is and why it's so important.

Steve
 

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Keep it simple!
When you buy a gun, give it a thorough cleaning! It takes less time to clean a barrel than to worry about it. The next day push a patch through the bore, if it has green streaks ( copper fowling ), clean it again.

Slugging the barrel measures groove diameter. A cast bullet should be about .001" to .002" greater than groove diameter.
M.
 

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Having slugged many barrels, I have this to offer. Use a "lead" egg sinker. Make sure it is lead. Egg sinkers are the fishing weight with the string hole through the longitudinal axis of the sinker. Lead is elastic, with a small bit of return or bounce back to it when it is crushed. That small hole through the sinker will relieve this property and deliver the diameter.

Everyone seems to live by the bore/groove diameter, a good rule, but throat diameter and profile is more important. That is not so easy to measure and is larger. If this area is not filled, combustion gases will get ahead of the bullet no matter what the bore fit is like. Personally, I at least fit the throat in diameter where the freebore/throat meets the bore and match the angle at that point with the bullet profile. This area is a bit easier to model with lead wire of the appropriate diameter.

I have slugged many, many 336s chambered in 30-30. My rule of thumb is to use a:

.311" bullet with pre-cross bolt safety rifles
.310" bullet with cross bolt safety rifles

It has been a while since I've visited with Marshall at BTB but I believe his measured results have been the same. I've since added an additional rule of thumb...

For rifles with the serial number stamped on the side of the receiver, you will need a .310" bullet but will use a much shorter cartridge OAL than is traditionally used. My measurements indicate that the step, throat, and leade is different in these rifles to better accommodate the FTX bullet. The same will be found when working with a cast bullet in the 308 Marlin Express. A totally different bullet profile is needed to provide the perfect fit. I have been working on that bullet, off and on this year, and plan to hunt with it this year in both my 336BL and 308MX. Here is what the comparison in the actual bullets look like to fit the chamber profile.



Imagine the case being up to the crimp groove and then how short the bullet on the left comes up. The problem with the new 30-30s and 308ME is the amount of freebore cut in the throat. The bore needs a .309" bullet but not filling the gap of the freebore results in very poor performance. The bullet band forward of the crimp groove and bullet body is sized to .310". This is the only bullet that I've been able to get to shoot out of the 308ME and it shoots very well while matching the FTX in pressure and velocity without the new fangled powder. My present 30-30 bullet will shoot well out of by BL but the nose profile isn't right. The freebore requires a .310" body but not having a bore riding nose causes the cartridge OAL to be much less than it should be.

If I wasn't interested in designing bullets, the first thing I would do with my BL would be to have it rechambered with an SAAMI spec reamer. I don't know what Marlin did but they did something to accommodate the FTX.

These are the ramblings of someone that has gone quite mad!
 

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kalifornia said:
howdy Marlin lovers, i just got a previously fired 30 30 and I have a couple of questions. should I assume the barrel has copper fouling in it? Can I see copper fouling in the barrel? And once I get the barrel clean should I slug my barrel or assume a .311 cast bullet will work the best? If I slug the barrel should I just push the ball in a couple of inches from the breech or crown or both. I appreciate the help thanks!
Hi Kalifornia.

Don't let all this confuse you. If you want to shoot cast bullets (not boolits) just buy some that are sized to .309 or .310 and bang away. You should be good to go with that size. After all the slugging monkey motion you will arrive at that size anyway.

.
 

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JBledsoe said:
Hi Kalifornia.

Don't let all this confuse you. If you want to shoot cast bullets (not boolits) just buy some that are sized to .309 or .310 and bang away. You should be good to go with that size. After all the slugging monkey motion you will arrive at that size anyway.

.
Probably so--you never know though ::) ::)

Steve
 
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