Velocity or Pressure?

[BW460]

I'm shooting a Model 460 with a 5" barrel. I made up some cartridges in .454 Casull with a 255 grain standard cast bullet and I push them at about 900 fps out of my 460. No problems, no leading, all is good. Now, my latest purchase was a Rossi lever gun in .454 Casull. If I shoot these same cartridges in the 16" barrel rifle, I should pick up something like 300 to 400 fps. Now, instead of 900 fps, I could have 1300 fps. General wisdom is to not push standard cast lead bullets at over 1000 fps or you will get leading problems. Basically (as I undestand it), the pressure would be about the same for my 460 and the Rossi, but the velocity is greater in the longer barrel. So, my question is this - is it strictly the velocity that I have to worry about for leading issues? Or, is it really the pressure? Do I need to tune these loads back so that my velocity is still under 1000 fps in the rifle or would they be OK in the rifle since they dont lead the 460 at this same pressure? Make any sense? For whatever it's worth, the Bhn value for the bullet is listed as 16.

 

[OKFC05]

General wisdom is to not push standard cast lead bullets at over 1000 fps or you will get leading problems.

Well, right there we part company.
I regularly shoot hard cast lead bullets over 1000fps with no leading problems.

 

[BW460]

Hmmm, well, I didnt say "hard cast" I said "standard cast". I agree with you, in fact I have ordered some very hard cast 340 grain bullets that I should be able to push over 2000 feet per second without a gas check. However, I have this box of 1000 bullets that are not hard cast. So, while I do appreciate your response, maybe someone could respond to the question that I did ask.

 

[OKFC05]

I don't think your Bhn 16 bullets will lead the bore of your carbine if it is smooth and free of all copper deposits. If it is rough or copper-fouled, all bets are off.
If it does lead, I don't think it will be because of the added velocity, which only occurs toward the muzzle. Most leading occurs either near the breech or at point of greatest acceleration.

 

[k22fan]

While you wait for an authority to come along I'll make a few comments.

First, the 300-400 fps velosity increase sounds reasonable for loads like traditional 240 gr. .44 magnum but you'd get a much smaller increase from traditional .45 Colt or .45 acp loads. My guess is your 900 fps load probably would top out between 1,000 and 1,100 fps. Do you have a manual that shows your load in both a rifle and pistol?

Second, If leading increased as bullets got further down a barrel due to their speed building up, we'd see that as a recuring pattern of barrels leading worse towards their muzzel ends and we don't.

And finally, why aren't you at the range testing your load rather that asking your computer how well your gun shoots?

 

[DonD]

First, the 300-400 fps velosity increase sounds reasonable for loads like traditional 240 gr. .44 magnum but you'd get a much smaller increase from traditional .45 Colt or .45 acp loads. My guess is your 900 fps load probably would top out between 1,000 and 1,100 fps. Do you have a manual that shows your load in both a rifle and pistol?t asking your computer how well your gun shoots?

I agree, no way you'll get 300-400 fps gains. You might well get 300fps with a hot load but not something mild like the one you described. Enjoy the blaster, they're great. Don