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Discussion Starter #1
ok, so now I know that I need to lap my barrel to get performance out of cast bullets, but what do I need for it...solvent? lapping screw setup thingamajig? and bullets for fire lapping?  I understand the solvent and the thingamajig, as I looked 'em up on the site, but what about the bullets for lapping?  What are their purpose?  I need to know before I can order the guide and the bullets themselves so I can throw 'em into the shooping basket as well.  Any help will be appreciated

Thanx and God Bless,

-shooter  
 

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Shooter,

You didn't specify what firearm(s) you are considering lapping, so I can't be specific in my reply, but I will cover the generalities here for you.

The lapping compound giving the most gratifying results is a Clover, 1A 320 Grit silicone Carbide suspended in a grease mix.  There are a whole host of other abrasives out there of comparable grit size, but the silicone carbide provides the best lapping performance to all others. ( I go into this in some detail in our Technical Guide).  One 4 oz. can will do half a gunsafe full of firearms.   One can is all you need for several firearms.

The Lap Bullet Seating Screw will facilitate seating the abrasive treated bullets into your cases without fouling or harming your conventional reloading dies.  The best part is, that it will work for all calibers and you never have to get the lapping compound near your reloading dies when using the lap bullet seating screw!

The bullets are caliber specific, and you'll need to order them according to your needs.  They are deliberately cast to a BHN 11-12 for the sole purpose of fire-lapping barrels.   This hardness allows aggressive lapping action in tight constricted portions of a barrel, yet does not have a residual memory to "spring-back" to a larger diameter after passing through these constricted portions of barrels (ie. under dovetail sights, roll stamping, barrel bands, barrel shanks on revolvers).  Thereby you end up with aggressive cutting action on those tight spots and not in the looser portions of the bore, consequently you effectively lap out those constrictions without affecting the dimensional aspect of the remainder of the bore.  

As a general rule of thumb, for most long guns 30-50 lap loads are sufficient, blued revolvers 100 usually suffice.  Stainless revolvers 100-150 will do the job unless that stainless revolver happens to be a Ruger... then figure on 200+ lap loads to get any constrictions out of the bore, as they are extremely abrasion resistant barrels!

Fire these lapping loads at a modest air-gun velocity for best lapping action and superlative barrel finish, NO FASTER!!!!

I hope this generalization helps familiarize you with the lapping process and the components used to accomplish the task.   With more information I can be more specific.  Please feel free to post your questions here, that's what we are here for!

God Bless,

Marshall
 

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Discussion Starter #3
Finally I get to talk to the man himself <!--emo&:)--><img src="http://beartoothbullets.com/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'><!--endemo-->  I've posted a couple times asking .444 advice hoping to get a gem from you, but got just as good advice telling my about where to find your pet load recipe...I own the Marlin 444SS, and I bought it used...micro groove barrel...shoots like a dream with the 240gr factory ammo (remington), but I want to try the 330gr load to see what she can do.  Barrel is well broken in, and I just talked to a barrelmaker for HS precision and he didn't recommend the lapping if the barrel is already broken in.  In turn, I said I'd talk to you, since you're the .444 junkie.  I would love to get the 330gr cannonballs you guys make, but only if I know I'll get good performance from 'em...So, in short, Is it worth lapping the barrel if it's already broken in?  

Thanx for your info,

God Bless, shoot straight, and all that other good stuff <!--emo&:)--><img src="http://beartoothbullets.com/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'><!--endemo-->

-Ben
 

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Ben,

Your Micro-Groove .444 will handle those 330g pills superbly as is!  Lapping might enhance performance a tad, but you won't be disappointed with accuracy out of the barrel the way it is either.  Just make sure to remove every trace of jacket fouling from the bore prior to shooting the cast alloy bullets.

Bullet diameter you will need is .432", contrary to popular beleif, those Marlin Micro-Groove barrels are superb for cast bullets.... the only reason that previous "experts" bad-mouthed them with cast bullets over 1600 fps is the fact that they didn't slug the bores and shoot bullets appropriate for the guns, use hard enough bullets and high enough quality lube for the tasks at hand!

Put all the right variables together, and those Marlins shoot like gangbusters!  Take the .432"-330g LFNGC/56.0g H335 (compressed load)/WLRP/Rem Brass and you'll have a winning load the first time to the range!  That's a promise... one that's been fulfilled time and again by many folks!

Hope this clears the air for you just a bit!

God Bless,

Marshall
 

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444Shooter,

I too have a 444S bought new in 1981. I've run quite a number of jacketed bullets through it over the years. It has the Micro-Groove rifling also.

I've never lapped the bore but, before switching over to cast bullet shooting, I cleaned every speck of jacketed fouling out of it with a good copper fouling solvent. I then swabbed the bore well with some JB Bore cleaner followed by more solvent to remove that.

It does very well with cast bullets so far. The key is for you to slug your bore to determine the groove and throat diameters. Marshall usually recommends a .432" bullet for the Micro-Groove barrels, if I'm not mistaken, as a rule of thumb.

I have been shooting a .430" bullet in mine but I know it is a bit undersize. The bullets are gas checked though and may be saving the bullet from stripping in the bore. These are generic sized bullets I bought a while back but are an LBT design. (280gr WFN) Best to slug your bore for the proper diameter from the start.

I also would highly recommend Marshall's Handbook on shooting cast bullets. There is a ton of info in it and you can read it at your leisure.

FWIW


Regards


:cool:
 

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Discussion Starter #6
Wow, thanx guys...
Now, how do you slug a barrel?  Or is that in the guide as well?  I was going to order the .432 bullets anyways, as Marshall has advocated and the guide along with them.  Any recommendations on the type of copper fouling remover to use?  

Thanx again, and God Bless

-Ben
 

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You put on a heavy leather glove and haul off sock the side of the barrel near the rear sight. :biggrin:

Actually Marshall's Guide illustrates how it is done quite well.

A cursory explanation of it is to carefully drive a SOFT lead slug into the muzzle end of the barrel an inch or so, then drive it out. Then drive a SOFT lead slug into the barrel from the breach end just past the throat, then drive it out. Then drive a SOFT lead slug just into the throat itself, then drive it out. Compare diameters.

Ideally, the throat should be the same diameter or slightly larger than the groove diameter of the barrel. The barrel groove diameter should be the same throughout the barrel or slightly taper down toward the muzzle end.

Sometimes there are constrictions at the barrel threads near the reciever and at the dovetails for the sites and mag tube.

I myself am just going to check the diameter of the throat and at the start of the rifling with some Cerrosafe. I'll then check the groove diameter near the muzzle with either some Cerrosafe or a SOFT lead slug and then I'll go from there.

You yourself could probably get away with just slugging the throat diameter and if you felt like it the bore also. The throat basically supports the bullets journey into the rifling. Get the bullet diameter as close as possible to the throat diameter and you have most of the battle won. The rest is load development, which is fun anyway.

Sorry for the book. :biggrin:

Oh as far as bullet lube, Marshall uses his own mix and I use some LBT Blue that is now a finite resource. I have heard good reports on Lyman's Orange sludge and Moly sludge also. Many concoctions to choose from here.

Regards

:cool:
 

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Discussion Starter #9
well then...
should I slug the barrel to make sure, or is it safe to go with Marshall's word that the .432 will shoot great?  I have limited resources and limited time, and I would like to get bullets and load 'em ASAP.  

Thank you guys very much for all of this info, I appreciate it more than you know.
 

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444shooter,

I've never seen a triple-four that didn't shoot .432" pills very, very well.   If you're pushed for time, and resources, just go with the .432" and don't look back.   They'll shoot great.... that's a promise I'll stand behind.  If your gun doesn't shoot the .432" bullets after thoroughly cleaning the copper fouling from your bore, I'll refund your money!   Enough said?

God Bless, and happy shooting!

Marshall
 

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*sniff* I think I'm gonna cry <!--emo&;)--><img src="http://beartoothbullets.com/iB_html/non-cgi/emoticons/wink.gif" border="0" valign="absmiddle" alt=';)'><!--endemo--> You guys are some of the nicest darn people I've met.  Thank you all very much for the info you graciously give out, especially when you are also busy making bullets and developing loads for guys like me...I will order the .432's soon, and keep you posted on how well they shoot.  Although I'm confident that you will hear nothing but praise from me.

Again, thanx for everything, and happy easter
"for god so loved the world that he gave is only begotton son..."
-Ben
 
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