Hard cast bullets with BP

[SlimPigguns]

I want to try BP in my 45/70 (H&R BC). The only projectiles I have are 405gn hard cast moly coated. Can they be used with BP ?  Also I have fffg powder that I use in my c&b revolvers. Would it be suitable for the 45/70 ? - Pete

[Lead pot]

Slim.

There is no alloy that makes a magic bullet for every rifle shooting BP.
just make sure it is the proper diameter. A hard bullet to small in diameter will most likely strip lead for one reason or nother.
The Molly will do nothing for BP fouling control. It would be best to run them through a lube sizer or pan lube them with a lube designed for BP if your bullets are a grease groove or knurled.

Lp.

[John Boy]

Slim:  Lead Pot has given sound advice: Proper diameter - Proper Lube
The BC has these bore dimensions:
•   Bore -  0.450 and 0.456 grooves ... Factory Spec
•   Bore – Actual 0.4525 and 0.454 grooves - Actual on mine
You may want to verify your land - groove dimensions for your rifle

Measure the base diameter of the 405 gr bullets.  You'll need a diameter about 0.003" greater than the rifle groove diameter for the bullet to obturate (expand into the grooves).  The 405's are probably .459 to .460 base diameter which is OK

The equation for obturation is Bhn (bullet hardness) x 1440 = PSI
Guessing the hardcasts are Bhn 16, you'll need a PSI of 23,040 to obturate the bullet.  This is on the high end of velocity
So, relube them for for better fouling control, make 10 reloads for trial with 62gr and 65g FFFg.  This FFFg granulation has a higher burn rate that will achieve a higher velocity... yielding a higher pressure
Shoot them and see how they group.  You may be surprised.  One of my best 100yd targets was with Postell bullets that were Bhn 14

As for bullet hardness, they really should have an alloy ratio in the 1:15 to 1:20 range ... IMHO

 

[SlimPigguns]

Thanks for the info, I will give it a go- Pete

[zrifleman]

Be prepared to mine lead out of your barrel.

[Nobade]

I have tried air cooled wheelweight bullets in my BPCR, they leaded the bore pretty bad. Then I tried oven annealing them - 450 deg. F for an hour, turn off the oven, and let them cool as slow as possible. That makes them pretty soft and they shot quite qell. Still not as good as 30:1, but acceptable for practice and very minimal leading. It's worth a try if wheelweights are all you can get.

Now back to the original poster, if you annealed those bullets and either lubed the grooves if they have any, or used a grease cookie under them like you do with paper patch, you would probably have some success. I don't know how moly and BP fouling would interact, but I would clean the devil out of the bore after you're done because you don't want a layer of moly with anything under it sitting in the barrel. If you have a way to do it, sizing them down to .450 or so and paper patching back up to size would likely be the best bet, with the grease cookie under it. That way they never touch the bore and you don't care what they're lubed with.