Compressed loads - pressure question

[turbo54]

Here's an oddball question...

Say you are loading a cartridge that likes H4831 or H4831sc, known "bulky" powders. In my case, the cartridge is 284 Win.

My rifle really likes 54gr H4831sc and a 175smk.

If I charge the case using a standard funnel, this is a compressed charge, though not a heavily compressed one. If I charge the case using a 6" drop tube, it is not compressed, and I can hear powder shaking inside the case.

Think there is a pressure difference between two cartridges; one charged with a funnel, one charged with a drop tube...assuming equal charge weights of course!

 

[woodland-ghost]

Re: Compressed loads - pressure question

Using the standard funnel, if you shake it after seating the bullet is it still compressed or loosens up? Same charge is same charge though, should be the same pressure considering all other things equal like seating depth

 

[milo 2.0]

Re: Compressed loads - pressure question

Interesting topic Turbo,
I have no way of checking, but I'm with the guy above.

Myself, I'll take a compressed load over non-compressed any day.

 

[turbo54]

Re: Compressed loads - pressure question

I don't have anything against a compressed charge either, but because I load on a Dillon 650, I've found that with 54gr H4831sc, I've got to be super careful when lifting/lowering the ram or else I'll bounce some powder out of the case.

When testing with higher chargeweights, I needed the droptube or I'd get inconsistent seating...

...So I've kept using the droptube even though I don't *need* to.

I don't really see why it would make a pressure difference either - but still wondered a bit. I also have no means of testing this, as primer flatness, casehead expansion, bolt lift have WAY too little resolution to discern this.

Ultimately though, the amount of "boiler room", and the mass of fuel is the same regardless, so I wouldn't think it would have much difference.

Still wonder though - a compressed charge adds some force on the base of the bullet, so you'd think it would release slightly easier than a non compressed charge...so you'd think that would ease pressure slightly. I'd expect the flame propagation through the powder to occur a little better/faster through a compressed medium though, which would add pressure.

Mouse farts worth of difference, I'd guess.