Technical question about loose BP

[Havicman]

I recently got a .58 Hawken am going to be using loose powder. I already own a TC Omega that I shoot with pellets. Since I'll only be using loose powder in the Hawkens I decided that I might as well use loose powder in the TC Omega also. When I checked the powder charges in manual that comes with the Omega, the max charge is 150Gr for either pellets or loose. The muzzle velosity and energy, though, are different for each. The muzzle velocity/energy for 150Gr of pellets is 2249/2696. For 150Gr loose powder it is 1879/1882. I'm wondering what causes the difference between the pellets and the loose poweder. Does the loose powder burn quicker, causing higher pressures? As I said I would like to use the loose powder in both of the rifles, but I don't realy want to be shooting a max load if I don't need to. I only hunt whitetail deer at 100 yards or less. Has anyone shot pellets and loose powder in the same rifle and noticed any differences?

 

[Ginormous]

The muzzle velocity/energy for 150Gr of pellets is 2249/2696. For 150Gr loose powder it is 1879/1882.

Is this correct Havicman? It strikes me that the opposite would be true. I always assumed that loose powder was a better propellant than the compressed and glued together pelletized version. A few shots over a chronograph with both would render some interesting results.

 

[arcticap]

Pyrodex pellets produce slightly higher velocity than loose Pyrodex because it's a propellant that likes compression.
But 777 pellets can sometimes produce slightly lower velocity than 777 loose.
There was recently a report about how a load of 777 ffg produced higher velocity than the same load of 777 fffg in a particular caliber rifle with a specific bullet. IIRC it was a .45 inline shooting a .40 caliber bullet.
Even if true that doesn't make it a rule, but rather a single occurance that illustrates that anything is possible depending on the circumstances.
Which powders, granulations, primers or barrel lengths are being compared with the velocity figures above aren't known or being revealed.

 

[Havicman]

Is this correct Havicman? It strikes me that the opposite would be true.

It is correct, and I would agree.

Which powders, granulations, primers or barrel lengths are being compared with the velocity figures above aren't known or being revealed.

T.C. only differentiates pellets or FFG black powder in the manual. The rest should be the same since the manual is specificaly for the TC Omega.

For a 240Gr Mag Express Sabot, the TC Omega manual states:

2 pellets=1889FPS/1902FtLbs
3 pellets=2249FPS/2696FtLbs (Max Load)

100Gr FFG=1672FPS/1490FtLbs
150Gr FFG=1879FPS/1882FtLbs (Max Load)

150Gr is the max load with either the pellets or the black powder. Even if it is true that the pellets burn better than loose, there must be a reson why the loose charge can't be increased to match the performance (FPS/FtLbs) of the pellets. It seems that there is something else besides which one burns more efficient. Since the max load with pellets will push the 240Gr sabot at 2249FPS but the max load of loose will only push the same bullet at 1879FPS. My current setup is two 50Gr pellets. According to the manual I would need 150Gr FFG to get close to what 100Gr in pellets can do. I would think that the loose would be better, but not according to the manual. I'm wondering if the pressures increase at a quicker rate with the loose than with the pellets. The manual doesn't differentiate between the different types of loose black powder or pellets. Since my set up does what it needs to do with the 2 pellets, this is more of a curiosity questions.

 

[jim147]

Maybe the hole in the center of the pellets makes a huge difference.

I can't answer for sure but this does seem a bit backwards to me also.

jim

 

[fyrfyter43]

Just like with any BP gun, you will need to spend some time at the range working up a load.

The MV/ME with even the 100gr. of FFg is more than adequate for deer out past 100 yards. I've never chrono'ed it, but 85 gr. of FFFg behind a .530 PRB easily gets it done in my GPR. Many folks use even lighter loads.