Powder settling/compression methods

[BurnOut]

In my quest for speed, I have found myself running compressed loads on one of the cartridges that I reload (338 WM), and have been playing with various powder settling/compression methods. After reading an article (http://www.65guys.com/tips-techniques-bullet-seating/), I have been using my (vibratory) case tumbler to settle the powder in my cases when I need to, but even still, I often find myself hearing that crunching sound as I (slowly) seat the projectiles. It is my understanding (and I can see how it would be true) that compressing the powder charge with the projectile can increase (loaded projectile) runout.

I have been thinking of buying/building a big drop tube to replicate the results in the article, but have been kicking around an idea for a different method for actually compressing the powder... what about using an expander mandrel? The shape of the tip of it mimics the shape of a boat tail on a projectile, and by pre-compressing the load before the projectile is introduced, we're looking at mitigating/minimizing any (loaded projectile) runout resulting from running a compressed load (or so the theory goes).

So... what do y'all think? Is this likely to be a viable approach, or one of those mental masturbation things? It's possible, I suppose, that the powder would have some degree of "spring back" once the expander mandrel is withdrawn from the case, but even so, it would be that much less compression of the load that the projectile would have to do...

 

[diverdon]

It sounds like it could not hurt. In order to find out how much good it would do you would have to try it.

 

[spife7980]

Sure you could do that but what would keep the powder from falling back in the cavity? The only compressed loads Ive ever messed with were ball powders so maybe it doesnt work the same and the rods would pack a bit better. While I never checked for runout I did find that compressed loads made for uneven seating depths.

 

[BurnOut]

Sure you could do that but what would keep the powder from falling back in the cavity? The only compressed loads Ive ever messed with were ball powders so maybe it doesnt work the same and the rods would pack a bit better. While I never checked for runout I did find that compressed loads made for uneven seating depths.

I thought about that, and my solution would be to cycle it several times... so, compress the load once, lower the case away from the mandrel to allow for kernels that were pushed out of the way to fall into the cavity, then compress again.

The powders that I have been using in these situations have been H4831SC and RL19; but you're right... the ball powders that I've played with (mostly a couple flavors of Ramshot) tend to have a much higher bulk density, so they take up less room in the case for a given charge weight.

 

[MtnCreek]

It seems to me the goal would be to get the powder to consolidate in the case without compressing or crushing it. A long droptube funnel will help with that. Also, just tapping a normal funnel with the powder pan helps. JMHO.

 

[Dutch260]

I've had decent results using an electric toothbrush and just touching the neck of the brush against the side of the case and then rotating the case. During some load development I had on my 260 I had a lot of compressed loads using RL26 and this seemed to really help settle the powder.

 

[mcfred]

First, I try not to have ‘compressed’ loads. Chances are that there’s a more appropriate powder that frees-up some space. Besides that, I either use a long drop tube or tap the case head on the hard surface with my finger tip over the case mouth before I put it in the shell holder to seat the bullet. It often settles visibly .060”-.100” depending on the powder.

I’ve also had a loading tray with 50 cases all filled with powder and I hold the tray and lightly tap it on the bottom with a small mallet (RCBS bullet puller or whatever’s at hand). That can help settle powder in the case while you’re looking for uneven charges as part of QA/QC.

I’ve found powder kernels to be quite hard. They do not deform easily. If you’re crunching powder I can guarantee you it’s affecting runout.

 

[PatMiles]

Long drop tube, SLOW pour.

 

[Milo 2.5]

Long drop tube, SLOW pour.

View attachment 6882407

Holy crap, you really want to shoot a compressed load, lol

 

[mcfred]

Haha! That's awesome, Pat.

 

[PatMiles]

Holy crap, you really want to shoot a compressed load, lol

Yeah, the BC on the funnel kinda sucks but it sure gets everybody's attention when I light it off!

 

[Wingnut00]

This is what I use to get powder to settle in a little better. Call it my double funnel mother fucker.

 

[PatMiles]

I'd have to agree with the name. Does it double as a still?

 

[Wingnut00]

It might but hadn't thought about that. I am now though. Great, my drinkin problem is already good enough.

 

[BurnOut]

Well, as a method for assembling compressed loads, the expander mandrel method is a success. I'd pour my powder (RL19) into the (.338 WM) case, and the charge (77.5gr) would come probably half way up the neck. Using my vibratory tumbler, I was able to get the powder to settle such that it was perhaps half way up the shoulder. Having assembled this load previously, this is when I'd normally seat the projectile... and would feel/hear the projectile compressing the powder further.

This go 'round, after settling the powder, I'd put in the expander die/mandrel, and start working it down into the powder. I likely could have forced things on the first pull of the handle, but chose instead to raise, lower, raise, lower the ram several times, compressing the load a bit further with each pull of the handle. By the time it was all said and done, the load was (slightly) below the bottom of the shoulder, and I was able to seat my projectile without any of the typical compressed load feeling/noise. Good stuff.

I haven't gotten to the range with those loads yet (I only assembled them yesterday), but so far, things look encouraging.

 

[Fig]

I'm gona be the contrarian. I think if you've long dropped or used a vibratory method to settle the powder in the case there is NOTHING wrong with a compressed load within SAAMI specs. In fact, I think it is actually MORE uniform and consistent to have a little compression (little being the operative word) in the case than to have any powder rattling around. If it's actually unseating your bullets or causing concentricity issues it's WAY too compressed, but for there to be a slight crunch at the end of the stroke, and a case with no space when you shake it I've had nothing but excellent results, and never had any sort of problem.

Choosing a powder that will give me 100%+ of case volume, along with looking at burn rate, is often where I start load testing precisely because I've had such good and consistent results with compressed loads for decades. To me a "C" load desirable situation rather than one I'm trying to avoid.