Triple 7

[Blacksheep]

Ok for you Triple 7 guys I have a problem or issue that’s vexed me for three years. Now off the bat I’ll say I find this powder to be a very accurate powder in the Fffg version for the first 40 100 gr charges in a bottle then groups open. I alway use the foil seal and tighten the lid tight on unused powder. But I’ve seen it time and time again groups open I’ll even gently turn bottles over to move fines around

The only two rifles that don’t exhibit this a Wolverine or a Wolf usually I can get 10-20 more shots from them I kinda think that is a function of breech plugs putting powder closer to the primer.

Any thoughts similar experiences?

 

[HC]

I’ve never had 777 powder in the bottle go bad. T7 pellets yes, probably because they were not stored properly.

 

[smokepolehall]

I have not had either 2f or 3 f T7 go bad. It may let all the real fine kernels shift to the bottom n that maybe casing it. I don't fool with pellets at all n never have.

 

[Philgumbo]

I've always used T7 powder, never pellets.

 

[WP79Vet]

Ok for you Triple 7 guys I have a problem or issue that’s vexed me for three years. Now off the bat I’ll say I find this powder to be a very accurate powder in the Fffg version for the first 40 100 gr charges in a bottle then groups open. I alway use the foil seal and tighten the lid tight on unused powder. But I’ve seen it time and time again groups open I’ll even gently turn bottles over to move fines around

The only two rifles that don’t exhibit this a Wolverine or a Wolf usually I can get 10-20 more shots from them I kinda think that is a function of breech plugs putting powder closer to the primer.

Any thoughts similar experiences?

A month ago I got some very erratic performance with huge velocity variations from a bottle of T7 3F which had been open for 7 or 8 years, and which was nearly used up. When I switched to a new bottle of T7 3F, the same powder charge and bullet gave fine performance, so I'm pretty sure that something was wrong with the old powder.

When I increased the charge of the new T7 3F, I got a wide range of muzzle velocities again. I suspect that with the heavier charge of T7 3F, I was getting some odd burn dynamics. When I went to the same charge of T7 2F, muzzle velocities were consistent again.

For the full details, see Range Report 2.0: .50 Renegade with sized Hornady Great Plains Bullets and Range Report 3.0: .50 Renegade with Sized Hornady Great Plains Bullets

 

[Blacksheep]

A month ago I got some very erratic performance with huge velocity variations from a bottle of T7 3F which had been open for 7 or 8 years, and which was nearly used up. When I switched to a new bottle of T7 3F, the same powder charge and bullet gave fine performance, so I'm pretty sure that something was wrong with the old powder.

When I increased the charge of the new T7 3F, I got a wide range of muzzle velocities again. I suspect that with the heavier charge of T7 3F, I was getting some odd burn dynamics. When I went to the same charge of T7 2F, muzzle velocities were consistent again.

For the full details, see Range Report 2.0: .50 Renegade with sized Hornady Great Plains Bullets and Range Report 3.0: .50 Renegade with Sized Hornady Great Plains Bullets

I have to say when I was weighing my charges I was shocked to see the same volume charge was upwards of three grains + and it didn’t matter if it was the first or last charge . I really don’t remember this variance in BH 209.

 

[WP79Vet]

I have to say when I was weighing my charges I was shocked to see the same volume charge was upwards of three grains + and it didn’t matter if it was the first or last charge . I really don’t remember this variance in BH 209.

All the charges I shot while doing load development were weighed for just this reason. Before deciding to weigh charges, I measured 10 charges of T7 3F with a TC measure, and found that they varied about plus or minus 2 grains. When you add that to the systematic errors in setting a variable powder measure, it's easy to be off by up to 5 grains - way too much, even for black powder.

 

[MrTom]

When I increased the charge of the new T7 3F, I got a wide range of muzzle velocities again. I suspect that with the heavier charge of T7 3F, I was getting some odd burn dynamics. When I went to the same charge of T7 2F, muzzle velocities were consistent again.

T7 fffg is way hotter than T7ffg so I can see some erratic behavior in a bumped up load.

 

[smokepolehall]

I use a dry pack in my container once i open it. Also i doubt i have a lb of it longer than 3 years

 

[Blacksheep]

A month ago I got some very erratic performance with huge velocity variations from a bottle of T7 3F which had been open for 7 or 8 years, and which was nearly used up. When I switched to a new bottle of T7 3F, the same powder charge and bullet gave fine performance, so I'm pretty sure that something was wrong with the old powder.

When I increased the charge of the new T7 3F, I got a wide range of muzzle velocities again. I suspect that with the heavier charge of T7 3F, I was getting some odd burn dynamics. When I went to the same charge of T7 2F, muzzle velocities were consistent again.

For the full details, see Range Report 2.0: .50 Renegade with sized Hornady Great Plains Bullets and Range Report 3.0: .50 Renegade with Sized Hornady Great Plains Bullets

Did you

A month ago I got some very erratic performance with huge velocity variations from a bottle of T7 3F which had been open for 7 or 8 years, and which was nearly used up. When I switched to a new bottle of T7 3F, the same powder charge and bullet gave fine performance, so I'm pretty sure that something was wrong with the old powder.

When I increased the charge of the new T7 3F, I got a wide range of muzzle velocities again. I suspect that with the heavier charge of T7 3F, I was getting some odd burn dynamics. When I went to the same charge of T7 2F, muzzle velocities were consistent again.

For the full details, see Range Report 2.0: .50 Renegade with sized Hornady Great Plains Bullets and Range Report 3.0: .50 Renegade with Sized Hornady Great Plains Bullets

Did you happen to look at the sabot cup I’ve been getting some unburnt powder which I find odd with a 209 primer unless it is coming off the charge before the fire gets to it.

 

[WP79Vet]

Did you

Did you happen to look at the sabot cup I’ve been getting some unburnt powder which I find odd with a 209 primer unless it is coming off the charge before the fire gets to it.

I was shooting full-bore conicals... no way to check for unburnt powder, but there did seem to be more than usual fowling in the barrel when I swabbed between shots.

 

[Blacksheep]

A month ago I got some very erratic performance with huge velocity variations from a bottle of T7 3F which had been open for 7 or 8 years, and which was nearly used up. When I switched to a new bottle of T7 3F, the same powder charge and bullet gave fine performance, so I'm pretty sure that something was wrong with the old powder.

When I increased the charge of the new T7 3F, I got a wide range of muzzle velocities again. I suspect that with the heavier charge of T7 3F, I was getting some odd burn dynamics. When I went to the same charge of T7 2F, muzzle velocities were consistent again.

For the full details, see Range Report 2.0: .50 Renegade with sized Hornady Great Plains Bullets and Range Report 3.0: .50 Renegade with Sized Hornady Great Plains Bullets

Did you

All the charges I shot while doing load development were weighed for just this reason. Before deciding to weigh charges, I measured 10 charges of T7 3F with a TC measure, and found that they varied about plus or minus 2 grains. When you add that to the systematic errors in setting a variable powder measure, it's easy to be off by up to 5 grains - way too much, even for black powder.

Do you think that even if you weigh the charges that the fines or broken pieces changes the burning rate hence pressure and velocity?

 

[WP79Vet]

Did you

Do you think that even if you weigh the charges that the fines or broken pieces changes the burning rate hence pressure and velocity?

The burning rate of any powder is a function of exposed surface area. Black powder is ground to different levels of fineness (fg, ffg, fffg, etc) for that reason, and nitrocellulose ("smokeless") powders come in many different grain shapes for that reason too. Fines and broken pieces will therefore change burning rates, and therefore pressure and velocity. However, powder burn rates are functions of many other things - like temperature, pressure, humidity, moisture content of the powder, chemical makeup and purity of the powder, etc - so I have no idea whether the presence of fines and broken pieces in T7 is important enough to make a noticeable change. My guess is that the two most important sources of degradation in T7 are increased moisture content of the powder due to exposure to air, and chemical instabilities in the powder that slowly change its burning characteristics. However, that's just a guess.