How many FPS to not lead up the barrel?

[Clippers]

I ordered some 45 Colt SWC 255 grain and some 357 SWC 158 grain bullets from MBC, both with a Brinell of 18. I looked at their equation to figure out Brinell and FPS but math is definetly not my thing. Does anyone have some experience with loading these two bullets and know the optimum FPS to keep from leading the barrel and still obturate to seal the bore? Thanks.

 

[Anmut]

I used to worry about leading, then I bought some Chore Boy pure copper scrubbing pads. $3 on Amazon. Now I shoot as hot as I want in my 44mag and after the range I wind some of that copper scrubber around the brush and after 30 seconds all that lead is in a dust pile on my bench and the bore is nice and shiny again!

 

[Tomcat47]

Gas Checks!

http://www.hornady.com/store/45-Cal-Gas-Checks/

I loaded many a magnum 357 44 with gas checks casting our own bullets! It is a very good viable option.

As you see above I checked Hornady and they are available for your 45 Colt.

PS: You can get over a 1000 FPS with the checks in either of your above bullets! Check the load data for using a Gas Check?

Maybe someone on here has some load data using Gas Checks for the 45 Colt. Buffalo Bore sells Gas Checked 255 Grain. Here is there specs. (Standard Pressure Heavy .45 Colt - 255gr. Gas checked soft cast bullet (1000 fps M.E.566 ft. lbs.)

Im still looking for data for 45 Colt, and I can find 1050 - 1100 fps data but they are not denoting GC... But I know they are. In 38/357 I always Gas Checked when load data reached 750-800 fps or above. Some may agree or not, but that is what we were doing with good results.

 

[flipajig]

Boolit size is everything. When sized to your bore leading will be minamal Boolit size should be .001 over your bore size. Slug your barrel and it will tell you what size your Boolit should be. As to your question I'm shooting a 44 mag two different Boolits one a 310 grn RNFP at 1260 fps with no leading the other is a 260 grn GC SWC at over 1400 fps with no leading. Do some home work Cast Boolits is a great sight with lots of info about Cast Boolits
Flip.

 

[Clippers]

I did forget to mention that the 45 is a Ruger Blackhawk with a reamed cylinder and the 357 is a SP101 snubby.

 

[USSR]

Boolit size is everything.

Yep.

When sized to your bore leading will be minamal Boolit size should be .001 over your bore size. Slug your barrel and it will tell you what size your Boolit should be.

Nope, not when you are talking about revolvers. With revolvers, you want to size your bullets to be slightly larger (up to .001") than your cylinder throats.

Tomcat47,

You don't need gas checks to run your .45 Colt bullets at 1050-1100fps. I run my cast 265gr SWC HP's with an alloy of 20:1 (BHN of about 10) at that velocity, and don't use gas checks.

Don

 

[Certaindeaf]

.PS: You can get over a 1000 FPS with the checks in either of your above bullets!.

I don't see where he indicated or how to check what he referred to are gas checkable/heeled bullets. To be able to gas-check a bullet, it must be designed to accept one.. it'll have a heel/step on the base to allow one to be affixed.

And 1000fps for GC'd slugs? ha. more like 2400fps

 

[Jesse Heywood]

Every gun is different with respect to bore leading. I have pushed the BHN 10 DEWCs to 1,400 fps without significant leading. The same for the MBC 357 Action, BHN 18 pushed in the 1,200-1,300 fps range.

45 Colt I rarely push beyond 1,000 fps due to gun limitations. As stated, a snug fit in the cylinder has a lot to do with preventing leading. Also bullet lube, but MBC uses some of the best.

For cleaning I use Shooter's Choice lead removal formula and a Lewis Lead Remover tool when things get bad.

 

[kgpcr]

A good alloy and a good lube with a properly sized bullet and you wont have to worry about leading.

 

[Tomcat47]

I was just offering GC as a viable option to prevent leading...... (which it is!)

Maybe someone on here has some load data using Gas Checks for the 45 Colt.

 

[ArchAngelCD]

There are so many factors that will determine whether of not you will lead the barrel or not. They have been covered above except for pressure. It's not really excessive velocity that causes leading, it's pressure but because we have no real way to measure pressure we have to go by velocity and hope the two cross paths in a good way.

One note, you will lead the barrel easier and worse by using a bullet that's too hard for the pressures you're generating than using too soft a bullet at higher pressures. If you use a very hard bullet at low pressures the bullet will not expand and fill the barrel preventing the hot gases from traveling up the side of the bullet and melting lead leaving lead streaks all the way down your barrel. Try to match the bullet hardness to the velocities/pressures you will generate.

Under 900 fps you can use a bullet ~12 BHN without leading. I have used an 18 BHN 30-30 bullet from Missouri Bullets at over 1400 fps without any leading at all.

 

[Kerf]

USSR has it right...

by measuring your cylinders using plug gauges and sizing to that spec', you'll avoid leading your barrel and get the best accuracy. Well worth the effort. Hopefully, they'll be the same size, and if not, at least you'll know what you're dealing with.

kerf

 

[Coffeeguy]

Bullet hardness

Second that. With 18 BHN in pistols, velocity won't be much of an issue. Bullet diameter is, though, and key is to use what works best, through testing, in your gun. There are useful formulas out there for determining the 'optimal' BHN, but there are so many variables (cylinder throat size, barrel diameter, bullet alloy used, whether the bullets are heat treated and/or water-quenched, how long ago they were cast, chamber pressure, muzzle velocity, et cetera) that nothing can be construed as 'gospel'.

I think (and this isn't necessarily gospel either) that two (three) things are very useful: First, check your cylinder and bore dimensions through slugging. Second, check your bullet dimensions for .001 to .002 oversize. Third, if you experience leading, look at it: Does it occur toward the breech only, or throughout the bore? If toward the breech, that indicates either too hard a bullet for the chamber pressure, or an undersize bullet, causing gas cutting. Throughout the length of the bore is more of a velocity issue. Personally, I don't worry too much about it; a few seconds' cleaning with either the Chore-Boy method or using a Lewis lead remover makes it a moot point unless you've got sheets of lead building up in your barrel, which I've seen happen, in which case I just go to a harder bullet.

Cast bullets as opposed to jacketed are by nature dirtier and require a little more elbow grease but they're so much cheaper that I don't mind.

 

[jjjitters]

I just about gave up worrying about hardness, I make sure all my boolits(proper term) are over barrel size(still have to make sure the barrel isn't bigger than the cones or throats on revolvers) and hardness is almost unimportant(almost).

You can put GC's on non-GC bullets with certain GC's even without the step, but it isn't common.

 

[flipajig]

USSR. I stand corected you are right the throat size .001 over.

 

[Sam1911]

It's not really excessive velocity that causes leading, it's pressure but because we have no real way to measure pressure we have to go by velocity and hope the two cross paths in a good way.

Amen. However, the manuals usually DO give pretty decent estimates of pressure for a given load. That's where you should be looking to fill in the blank in Brad's equation about pressure -vs.- hardness.

USSR has it right...
by measuring your cylinders using plug gauges and sizing to that spec', you'll avoid leading your barrel and get the best accuracy. Well worth the effort. Hopefully, they'll be the same size, and if not, at least you'll know what you're dealing with.

Sort of.

You really need to balance THREE things. Bullet diameter, cylinder throat diameter (should be right at bullet diameter, maybe 0.0005" under) and then the BORE diameter, which should be 0.0005-0.001" tighter yet.

Bullets should pass through the throats with minimal resistance, and then be a snug fit in the bore itself, so they don't have to obdurate (get bumped/swell up) to seal the bore.

You can buy bullets of different diameters if you really need that, but the most important thing to check is throat diameter. If it is too tight, compared to the bore, the bullets will get swaged down to UNDER-sized for the bore and then you'll get gas blow-by which leads barrels badly. If too tight you can get the throats reamed just right for very little money. Unfortunately some manufacturers build their guns with tight throats, apparently assuming they'll only see jacketed ammo.

 

[USSR]

Bullets should pass through the throats with minimal resistance, and then be a snug fit in the bore itself, so they don't have to obdurate (get bumped/swell up) to seal the bore.

Yep. Bullets coming out of your throats slightly larger in diameter than your bore size is not a big problem; they will be swagged down to size in the bore. Worst case is having your cylinder throats be smaller than your bore size.

Don

 

[DeadFlies]

Amen. However, the manuals usually DO give pretty decent estimates of pressure for a given load.

This is why I like Modern Reloading. Lots of pressure data. There is a formula for it but it's much easier to just look at a chart.

 

[blarby]

Who said we don't need a lead sub-forum ?


Anyway.......

Your velocity that causes leading is going to depend on your size, and your hardness.

Undersized, soft bullets with hot powder ? Smear city.

Oversized extrahard bullets that won't obturate and a too slow powder ? Smear city.

Don hit it pretty much on the head- you will need to do a little fiddlin around.

I would start with .001 over throat, with 18 BHN for a bullet going over 1000 FPS, and go from there.

 

[ljnowell]

I shoot the MBC 357 action bullet at 1400fps with no leading. I also shoot the cowboy#9 255lswc at crazy velocity out of my blackhawk with no leading.

 

[RhinoDefense]

Variables that cause and prevent leading:

Alloy hardness and bullet obturation
Bullet sizing
Lube quality and quantity
Powder selection
Bore condition

It takes a certain pressure and velocity in order for a gas check to perform its best. A great majority of the time it's not needed, but is a quick solution, albeit expensive. A gas check is the last answer and should only be considered when all other variables are exhausted. A 3 cent copper diaper is a niche necessity, not an overall solution.