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The advice here is good!  Do plan on at least a couple stuck bullets... it does happen and is no problem.  Going to the range prepared for such an eventuality is good counsel!

If having to load at home, then go to a pay to enter range, I would load them at 2.2g Bullseye, and let 'em go!  

That should get you into the ballpark.  Do make sure that your bullets are oversize to start with! And too that the cylinder throats are also larger than groove diameter as mentioned earlier here.

Enjoy!

God Bless,

Marshall
 

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The best rule of thumb in fire-lapping is to use the lightest charge possible without sticking a bullet.  What happens when using higher velocity rounds to lap with is rather difficult to explain, but basically the faster and harder that the lapping bullet hits the barrel steel, the more aggressively it will work the metal of that barrel.  At higher velocities, rather than only lapping the surface of the bore, the extra energy from the harshness of the those higher velocities actually works the metal deeper than the surface, which in turn work-softens the steel primarily in the throat area.  Down the not-to-distant road, the throat of that gun will be in very poor shape.  Now I  am speaking of this in the extreme, because there are a couple of companies that are advocating using abrasive compounds to lap firearms at normal, full velocities, even in .22-250's and 300 Win Mags!  

I've seen the barrels of three guns that were fire-lapped this way.   The owner of two of them was so very proud of his accomplishments that he wanted me to come over and look at his finely polished and lapped bores... one a 6mm Remington, the other a .30-06.  He had used one of the "kits" advocating treating ordinary jacketed bullets at full snort.   Indeed they did look nice, they were shiny, and smooth.   He showed me targets as well... there was a marked improvement with the before and after targets that were fired from the same box of shells in each respective rifle.

As Paul Harvey would say...Now, for the rest of the story!

This gentleman who had lapped these two rifles began warming them up on Rock Chucks that spring.  Shooting, according to him, less than two hundred rounds through the .22-250 (A Winchester M70 XTR) and around a hundred and fifty through the .30-06 (A very nice Husquavarna), the accuracy had gone to near paper plate sized 100 yard groups!   Upon examination, the first 3" of the barrel in that .30-06 was totally devoid of any sembelence of rifling!   The .22-250 was worse!  It had nothing for nearly 5" of the barrel immediately ahead of the throat... it was all throat!

Subsequent to this, I used two VZ24 8x57 Mausers, lapped one with the method that I recommend in our Technical Manual, the other with the same grits, only at 1800 fps velocities.   Upon initial inspection, both barrels looked the same, I polished them the same in the final steps as outlined in the Tech Guide, and gave the same breaking routine for each.  (By the way, the 1800 fps method did the job with 1/3 the total lap rounds, it was quicker)  Then, I set about shooting each with bulk packed Remington .323" 185g PSP jacketed bullets at 2400 fps.  Fairly conservative loads by anyone's rule.

Upon shooting nearly 150 rounds in the "Quick Lapped" bore, the groups began opening up measurably (beginning with 2" average with the issue sights), after a total of 200 rounds groups off the same sandbag rest, at the same range, from the same lot of ammo loaded on the Dillon, groups averaged something over 5".  By 250 rounds, an 8" paper plate at 100 yards was a challenge, and the barrel was all throat for the first 3+" looking like the described .30-06 barrel above.

Conversely, the VZ24 lapped with my more conventional, and conservative practices, as detailed in the Technical Manual, consistently shot 1.5-2" groups throughout the entire 250 round marathon shooting session.  I even intentionally got the barrel very hot (something I was cautious not to do with the "Quick Lapped" gun), by fast repeated gunfire.  Never did I hurt the gun, and the throat looked perfect after cleaning, following the 250 round shooting session.

Wow, sorry to get carried away, but I wanted you to know that there is a very definite reason for lapping slowly!  Precision takes time... haste makes waste!

Now, about that '86 .45-70, I'll wager to say that you'll have constrictions under the dovetail cut for the rear sight, and perhaps where the front barrel band is located.  Lapping the .45-70 is no more difficult than your .45LC.  With the bullet seated so all bearing surface is located within the brass in the loaded lapping round, use 5.0g Red Dot for a lapping charge... this should get you to the velocities you want... be careful to make sure each and every bullet leaves the bore... this is a light load and might just possibly stick a bullet... only time will tell.

Hope this helps!

God Bless,

Marshall
 

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Jeff,

I specifically prefer Red Dot for all my lapping projects.  I was asked about charges for Bullseye, and that's why you see data for the Bullseye powder, it 's what he had on hand!

I like Red Dot, as it seems to be more predictable in performance, and not as volatile as Bullseye.  If you must buy one or the other for lapping, go for the Red Dot!

Does this help?

God Bless,

Marshall
 
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