I have been reading through "Handloader" and have come to discover that vintage ~250gr 40gr black powder loads typically produce velocities under 1000fps in 7 1/5" guns.

Well, long before I knew that I was stuffing 35gr FFFg (yes, holy black not fake stuff) in a Starline case behind a lyman 454190 (pre war style) that casts out at 255gr with 20-1 mix and SPG lube with 0.010" gasket wad.

The load is accurate, because of the soft lead and ample lube as well as the gasket wad leading is minimal and in my Cimmaron 7 1/2" "Custer Cavlary" 1873 Army it clocks at 1250fps across my chrono at 10-15'

So what gives? The only thing I can think is that the origional load was with FFg not FFFg. But hey why change what works.

I'll also mention I have a decently accurate 45-70-500 load using 52gr by volume of 777 FFg that pushes it's Lyman 457125 (500gr military style bullet) at 1250 fps out of my M1888 trapdoor (the 1888 is a 84 with ramrod bayonet) And there is minimal leading with that load too.

So what do you guys think is going on? I am guessing its the granulation of the powder in the Colt load but I don't know since I don't know what they were origionally loaded with.

I agree.

I think you're way too hot. Original Colt .45 loads shooting 255 grain lead runs around 825 to 875 fps. Your Cimmaron isn't any stronger than the original Colt Peacemaker. A Ruger Blackhawk might withstand those loads somewhat better, but I think your handgun will start loosening up in short order. Maybe worse.

What brand of powder are you using? Goex may produce top velocity compared to other brands.

Remember; that the original .45 Colt was loaded in a balloon head case.
Being a solid head case you will have less room in the brass, which will increase your pressure and velocity.
Also, most loads used FFg, although Fg and FFFg were both used.

Typically, with many vintage .45 Colt Cartridges, the average powder charge was 35-37gr.

ETA: Also to note, when they loaded these they did not load by weight. They loaded by velocity. Each lot of powder was loaded to reach a certain velocity, using a ballistic pendulum, So you might find vintage cases with 28gr, and some with 38gr. Depends on the powder.

If I recall correctly, a .45 Colt was suppose to be able to shoot through a Horse at 100 yards.

One would hope that the metallurgy is substantially better than the original even if the

design is the same, but I would say that when your handloads are doing

300 or 400 fps faster than normal that is a screaming warning sign to stop and think.

He is certainly well beyond the intention of what the gun was designed for.

All of this makes me really wonder though. How is this possible at all? I'm using goex FFFg and 35 grains by volume of it. There are no pressure signs. Brass will still fall out of the chambers under thier own weight for the first few cylinders until the chambers get dirty (same with the smokeless cowboy loads I make up. And I have shot between 300 and 400 rounds of this load through the gun plus maybe a thousand more of my cowboy loads and the gun is still nearly as tight as when it was new, definately tighter than any of the four s&w revolvers I own.

Now I could understand there being real issues if I were using FFFFg. I sure wish there was better load data with pressures and velocities available for black powder loads but there inst the intrest.

How many rounds did you chrono?

Maybe your chrono is picking up pieces of powder, or a wadding, or something?

1200 is a big leap for a 250gr bullet, I would think you'd notice the recoil pretty easily.

Are the bullets definitely 250gr?

Well I'm fairly certain since that was data from a ten shot string and the SD for the ten shots was in the teens which is low for those who dont know. Yes its definately a 255gr bullet since I cast and weighed them myself.

I'll have to rechrono them when I get my house hold goods delivered from my move since the chrono is in there.

Oh an recoil was pretty decent but no more than what I expected. Its not sharp but a rolling recoil. You definately know you are shooting a powerful load. But by no means was it an ammount of recoil that seemed to be an indicatior of something wrong or dangerous.

Then again when refering to the 45 black powder magnum they arent even achiving 1050 with 48gr of powder and a 250 gr bullet in a colt walker lenght barrel 9" I guess I will need to rechrono.

I am thinking  chronograph problem also.  Goex has a load with 2F that goes 770 fps with  40grs.  I would guess 3F would be a little faster, but not 1250 fps.  If you listen close, you can tell the difference in velocity. The speed of sound is around  1087 fps. When over this velocity, you hear a crack or sonic boom from the bullet.

Perhaps I erred.

I never chronographed mine, but come to think of it, Elmer Keith used 18.5 gr.of #2400 with a 250 gr. bullet in both the .44 Spl, and .45 LC to get 1200 ft/sec.

He used the same load for both because the .45 LC cylinder walls are thinner, hence no increase in the fatter case.

There is a chrono problem.
The gun will not be harmed by full cases of black powder, it will be harmed by reduced loads of black unless a filler is used.
You do NOT want air space between the powder and bullet.

Wrong screen spacing?

Very well be a chronograph thing but consider this.

35gr volume of fffg is more powder by weight then 35gr volume ffg.

Volume is a convenient way to measure but charge weight is still most relevant.

I have used both of those loads. I have chronographed  the 44 load in a S&W Mountain Gun and got 1225 fps. I don't think the 45 Colt will approach 1200 fps and probably at least 100 fps less.

Edit--- I was using the 240 in the 44.

I started, and stopped, at 17.5 in the .44 spl with the keith 240 10:1, and it was enough for me.

It killed a snapping turtle on the bottom of a river, under two feet of water. He never moved ... rose up about a foot, turned over, slowly, and sank back to the bottom of the river.

Never chronographed it.

I guess it was fast enough.

That or lighting, or low batteries, or bad battery connection , or flyspecks on the pickup, or weird shit in general!
One thing for sure, you're not gonna get that kind of speed out of a casefull of any normal black powder.

Hell, you're only gonna get 920-940 from a round ball over 40 grains of 3f Swiss!
I think Lyman, years ago, got about 1000 fps from a round ball over 40gr 4f in a Ruger Old Army, but I would have to dig out my old book to verify.

I would bet your chrono is not accurate.

When I saw the title to this thread, my first thought was "...he's using a Chrony". Maybe, maybe not. Regardless, I'd bet the farm on a chronograph problem. I say that from a couple of decades of dealing with chronographs. I've now learned to never chronograph in direct sunlight. I always either set my chronograph in the shade of some trees or chrono in the evening and use shadows.

FWIW I'm in the middle of Keith's book "Sixguns". He did obtain 1200 fps with a ~240 gr. cast SWC in a .44 Special but only 1000 fps with a 250- 255 gr. cast bulletin the 45 Colt.

How much does black powder smoke interfere w/ chronographs?

So far it hasnt ever seemed to interfere because the chrono is far enough away. The issue may be things like the wad behind the bullet but even that doenst make sense since they will cross the chrono at a different time and even then might not cross both sensors. If anything it should cause a lot of errors like very low velocity readings and stuff like that. I did find out that gaschecks can come off in flight though as I found one lodged in my tripod leg once. But the only time I use gas checks anymore is on rifle and if I start powder coating I'll stop using them alltogether.

Large caliber handguns when loaded hot and using heavy bullets can sometimes trick a chronograph. The muzzle blast can effect the screens and give erratic results. I have used a sheet of cardboard with a circle cut through it as a blast shield with good results.