Author Topic: Why a Drop Tube? (Read 2011 times)

whitfang · « **on:** August 13, 2004, 04:05:32 AM »

This has been bothering me for a while. In reading about reloading CAS brass with blackpowder, I keep noticing this thing called a 'Drop Tube'. It's just a brass funnel, but it's always about 2 FEET long! :shock:

My question is "Why 2 feet?" :?:

Wouldn't a 2 INCH funnel do the same thing, namely get the powder inside of the brass? :?

Redhawk1 · « **Reply #1 on:** August 13, 2004, 08:13:39 AM »

I have seen some drop tubes as long as 30 inches. What the long drop tube does is it let's the powder settle and it is somewhat compressed together. If you poured you powder from a 2 inch tube and then poured the same charge from a 24 inch tube the 24 inch tube would be lower in the case. Try it, then take a caliper and take measurements and you will see the difference. I have a Lyman black powder measure with a 20 inch tube on it. I also have a drop tube I made that is 30 inches long. I reload for my 45-70 Shiloh Sharps. There is a noticeable difference between a 20 inch and a 30 inch drop tube when the same charge is dropped through them. Also how slow you pour the powder affects the amount the powder settles.

Hope this helped.

whitfang · « **Reply #2 on:** August 13, 2004, 02:32:19 PM »

OK, Thanks.

I was pretty sure that gravity was the reason, I guess I just didn't believe that dropping 2 feet would cause the powder to compress noticeably.

Thanks again.

Redhawk1 · « **Reply #3 on:** August 13, 2004, 03:45:16 PM »

No problem. If you get into black powder reloading it is a little different than smokeless. But still a lot of fun.

JBMauser · « **Reply #4 on:** August 14, 2004, 06:59:42 PM »

I will jump in to add a point. The long drop tube does not compress the powder. The long drop tube allows the grains of powder to seperate and loose any forced pattern. They become random and settle into the case more evenly like snow on the ground. (Yankees understand this) They settle evenly without any voids or light spots. Compression is applied after the settled collum of powder is attained. Compression is exerted and since the powder settled evenly, the compression should be even throughout the collumn of powder yielding a better burn. JB

Cuts Crooked · « **Reply #5 on:** August 14, 2004, 09:17:34 PM »

..and one more comment, regardless of how off topic :oops: . The use of a drop tube makes sense when yer loadin fer BPCR competition, but fer most CAS shootin', revolvers, scattergunz, 'n pistol caliber main match rifles, the use of a drop tube is purdy much a useless frill. Not needed fer the smaller cartridges 'n scatterguns at all!

Redhawk1 · « **Reply #6 on:** August 15, 2004, 02:10:05 AM »

Quote from: JBMauser

I will jump in to add a point. The long drop tube does not compress the powder. The long drop tube allows the grains of powder to seperate and loose any forced pattern. They become random and settle into the case more evenly like snow on the ground. (Yankees understand this) They settle evenly without any voids or light spots. Compression is applied after the settled collum of powder is attained. Compression is exerted and since the powder settled evenly, the compression should be even throughout the collumn of powder yielding a better burn. JB

You are 100% correct.

Thanks

The Shrink · « **Reply #7 on:** August 15, 2004, 02:26:59 AM »

And it is useful with any cartridge case where you compress the load. I'm compressing my 44WCF loads and consequently drop tubing them. As JB said, it provides a more even burn.

Wayne the Shrink

There is no 'right' that requires me to work for you or you to work for me!

Lead pot · « **Reply #8 on:** August 17, 2004, 12:38:48 PM »

I use a 36" drop tube for both black and the slow burning smokeless powder. With that slow burning smokeless you can get a full load in a case with out excessively crushing the powder.

Kurt

m-g Willy · « **Reply #9 on:** September 11, 2004, 08:03:15 PM »

Would vibrating the case have the same effect? I notice that you can settle the powder quite abit by just tapping the side of the case.--Willy

The Shrink · « **Reply #10 on:** September 13, 2004, 01:43:48 AM »

Willy

Yes, and I use two taps after the drop tube to get the powder below the top of the case. The problem is getting enough vibration consistently. I remember someone on the old Shooters.com who rigged up an old electric shaver motor to get the effect, and timed how long he applied it to the loading block. Again, this just settles what's in the case, it doesn't put more in the case initally. If you want more, you have to have a way to add just that amount after settling, settle again, etc. Drop tubes are more practical. They settle the powder from the bottom up and continue to fill to your measured amount. Then you compress to make room for the bullet.

Wayne the Shrink

There is no 'right' that requires me to work for you or you to work for me!

Goatlips · « **Reply #11 on:** November 16, 2004, 07:11:56 PM »

Hay pards,

I load my cowboy cartridges with BP and vibrate the cases forty at a time while still in the loading block (I dip). I tried drop tubes (too slow and awkward), aquariam pumps, electric toothbrush and :oops: similar devices.

Fastest way I've found is to poke a vibrating engraver in the side of the RCBS block and watch the powder level recede in all the cases at the same time. Takes six seconds and gets more powder in my loads!

Does anyone else do this?

Goatlips

Duck of Death · « **Reply #12 on:** November 22, 2004, 09:38:52 AM »

Goatlips

Yep, I filled one case with a 30" drop tube and another using a vibrating pencil, the results were the same. Only the agrivation changed, it was much easier with the vp.