What velocity does leading start in a 4" gp100?

[Geofois]

There is probably too many variables to just have a specific velocity but roughly what can I expect with 125gr cast boolits? I see cast loads in the hodgdon book with a max load of 231 5.5gr at 1157fps so will that be prone to leading or would going to a more actual magnum load of h110 powder hitting 1500fps cause leading? I will shoot 38 and 38 +P loads mainly but in case I want to try some magnum loads with the bullets I have. The cast bullets are 12 brinell and the coated cast bullets are 13 brinell.

[elk hunter]

Gas check or no gas check? how rough is the barrel? bullet lube? what is it? with good bullet lube and a gas check I would not think 1,100 fps out of that hardness bullet would cause any significant leading. I shoot softer lead faster with no problems of leading in my guns, but your gun is different.

[koehn,jim]

Bullet fit is very important. Slug the barrel and size the bullet a 1000th biger.

[Geofois]

Cowboy #17 .358 Diameter .38 Special 125 Grain RNFP Brinell 12 is the exact listing from their website. I don't think it is gas check but I'm just guessing. I'm not sure what gas check is. It is .358 vs .357 so that sounds like that would give a snugger fit. I have a ruger gp100. I'm going to google "gas check". I've read about it but it sounded like it was a more expensive lead bullet.

http://missouribullet.com/results.php?category=5&secondary=9

['ol shooter]

Hard cast runs a lot cleaner than some of the softer brands I have tried. I have settled on Oregon Trail as a well made hard cast bullet for several rifle and handgun chamberings.

http://oregontrailbullet.com/

[Win231]

I load cast bullets up to 900 fps in my GP100 with no leading. When I want more velocity, I use plated or jacketed.

[robert101]

there are a lot of variables to this question. I use a maximum velocity of about 1,200 fps as a general rule. My go to is to shot then look to see how leaded the barrel is from about 50 rounds. Shooting and then cleaning it will give you a definitive answer with that load, bullet and barrel.

[elk hunter]

Elmer Keith ran 1-16 and it is BHN 11 for his supped up pistol loads I don't ever remember him complaining about leading in his pistols. I have loaded that mix using NRA 50/50 plain base in my .44 SPL and Mag and never had leading of any kind. Gas checks are the copper cup attached to the base of a cast bullet that allow you to drive them substantially faster than without. Elmer was not squeamish about driving a pistol bullet hard like most of today's re-loaders. I don't know much about the GP100.

['ol shooter]

Elmer was not squeamish about driving a pistol bullet hard like most of today's re-loaders.

Just saw half of a chamber of one of Elmer's blown up guns on a Forgotten Weapons Youtube video. Think I'll just be a chicken and treat my guns right by following established guidelines.

[Bigman54]

Proper bullet Diameter is what is important. If a Bullet fits the chamber mouths and the barrel diameter there will be little if no leading.
And a Proper Bullet Lube is equally important.
If you have a "Hard Bullet" and It's undersized You'll still get leading.

Keith blew up handguns because He was pushing the envelope for Velocity & Power. Not because of poor bullet fit or sloppy reloading practices.

And that so called blown up cylinder that is attributed to Elmer Keith. He's been dead over 30yrs. After the advent of the .44Mag He didn't blow up any guns that I ever heard about.
And the guns he did blow up were .45Colt SAA's. That is why he switched to .44Spl's. Thicker Chamber walls.

[elk hunter]

As I remember it Elmer's "One" blown up pistol was a old Colt single action Army and with balloon head cases. A weak combination to say the least. After that I do not remember it happening again. Elmer knew exactly what he was doing and he got to where he wanted to be. I trust his load data and other decisions as much as I trust some of the other real innovators like Roy Weatherby and P.O. Ackley and others. Bottom line in this for OP is there is lots of factors involved with leading and they all have to be delt with to prevent it.

[Geofois]

Thanks guys. I was reading a bit and watching a lot of youtube how to videos. I didn't know why leading was occurring and was thinking it was just because of high velocities. One video talked about making sure the boolits are .001 larger than the exit diameter of the cylinder so the hot gases don't blow the molten lead ahead of the bullet. That was the cause of leading in the cylinder and beginning of the barrel. I forget what the cause was for the end of the barrel. I'll watch it again. One video showed how easy it is to clean out with a smaller than barrel brass brush and some strands of copper from a copper cleaning pad and the lead falls right out.