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Thread: Techniques for compressed loads...

  1. #1
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    Question Techniques for compressed loads...

    I'm always learning with this handloading stuff, and I've just come to realize that in the years that I have been doing this, I have never really worked a significantly compressed load. Honestly, it just hasn't come up until now. How do you guys compress the charge? Is it just a simple process of slow and progressive advancement when seating the bullet? I would imagine that the technique varies if using spherical VS protruded powders...but I'm guessing? How about bullet creep after seating (i.e., do you need to crimp as you seat?). Thanks in advance!

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    It will help from the start if you drop the powder through a long drop tube. Six to ten inches. This is especially helpful for extruded powder. The extra fall distance helps to compact the kernels and saves space. Extruded powder has the compressability of gravel. It is very hard and doesn't really crunch much, but that is the term as the pressure just crunches the powder. I suppose it does break the kernels, too and I don't know of any other way and I don't know of a problem with the "broken" kernels. Lacking a drop tube, tapping the case as powder is poured in will serve the same purpose. I suppose the correct term is settles the powder.

    Ball powder is more compressable but it will push a bullet back up and change your overall length. That could be a problem. If the bullets don't push up over night without a crimp they are good to go. I don't suppose I have a good reason for this but I think that if I need to crimp to keep the bullet down, I have too much compression. The problem is that it usually creeps up before you can crimp it. I have a Frankford Arsenal drop tube with a funnel attached and this works for those times when I have a full case. Dropping the powder in a funnel over the case and tapping the side of the case works pretty good.

    Honestly the best way to handle this is to change to a one step faster burning powder that will give good results with less powder. Or the short cut seems to be denser than the long cut extruded powders.

    Maybe the bullets are too long.
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    Default Thanks Professor Murphy...

    ...lot's of good information. I probably should have given more details about my current application.

    I'm going to be working some 357 SIG loads using AA#9. I've successfully loaded a dozen or so experimental rounds in the past with this combination. The charge I used is within spec's for this little powerhouse, but it takes up alot of case space. On one hand I like the idea of packing the case (within spec's) with this spherical powder because it provides resistance against bullet pushback during feeding with this high pressure cartridge (at least that's my thoughts on it). However, it is a compressed load, and I did get some bullet creep after seating, which I corrected with a light crimp. At this point I want to load up a few hundred rounds, and I was wondering if I could improve the situation with a compression technique so I don't have to crimp.

    I value your opinion Professor, and it sounds like you're not a fan of compressed loads. Your "test" of an over-compressed load (if I'm following you) is to seat the bullet without a crimp, then measure OAL the next day for bullet creep...and if there is any creep, then drop down in charge or change to a faster powder? If I'm on track with what you're saying, then I'll probably decrease the AA#9 until I don't have overnite bullet creep, as opposed to going to the faster AA#7 and gaining some unwanted empty case space.

    I was hoping to learn some trick way to compress the load, but it doesn't sound like it with this spherical powder...as opposed to EXtruded powders. Nonetheless, you gave me a simple solution, thank you sir.

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    Default Just a thought...

    Possibly sitting your loading block of charged cases on a surface next to your vibratory case cleaner....for a while...

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    Quote Originally Posted by Doc View Post
    I'm always learning with this handloading stuff, and I've just come to realize that in the years that I have been doing this, I have never really worked a significantly compressed load. Honestly, it just hasn't come up until now. How do you guys compress the charge? Is it just a simple process of slow and progressive advancement when seating the bullet? I would imagine that the technique varies if using spherical VS protruded powders...but I'm guessing? How about bullet creep after seating (i.e., do you need to crimp as you seat?). Thanks in advance!
    I always crimp after seating if I crimp at all.

    Over compressed loads can push the bullet back out.

    My personal approach to handloading is if I cant get the bullet to seat easily over the powder then I will pick a different powder. I always use the load that will give the highest velocity with the least powder. I have not once yet picked one that was compressed enough to use a drop tube. I think if a drop tube is needed then that powder really isnt suited to that cartridge. I feel I have in no way handicapped myself with this approach. The only cartridge I used very many compressed loads in was the 338 win mag and 250 grain bullets.
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    Default Thanks guys

    Thanks Snowshooze for responding and offering a different idea...interesting.

    I'm with you Miller regarding compressed loads and never really needing to consider them in all the years that I've been reloading many different rifle and a few pistol calibers. I guess this little 357 SIG cartridge is pushing me a bit...perhaps needlessly...but I'm a little nervous about bullet pushback during feeding and pressure spiking in this already high pressure round, so I'm trying to fill that case (within specs) as much as I can. On the other hand, I may be over thinking this project and overly cautious...both of which I tend to do! Anyho, I've got some ideas of where to go with this project, and thanks for the response.

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    What Snowshooze said. With the rifle cartridges, I hold them by the neck and tap them with index and middle finger against the side of the press for a couple seconds. Really settles the powder.
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    I was thinking on the lines of rifle and not handgun loads. The AA#9 is some pretty dense fine grained spherical, it will respond better to the shaking or settling than bullet compression. Also, is the crimp for that a tapered crimp or roll crimp. I've never loaded for the 357 SiG but I think it technically headspaces on the case mouth so would have a taper crimp. If overly compressed it still may stretch after a while. #9 is a little slow for that one and I guess #7 is a little fast for the full case load. But in any case, settling is always better than crunching.

    In general with any rifle caliber it is always better loading to fill the case and set the bullet on the powder. It would be more economical to use a faster powder but the space of the case is there for a reason. The most efficient way to load is with a powder that reaches optimum loading with a full case. I use drop tubes to settle powder and seat the bullet on the powder. If that were not the most efficient loading and only a partially filled case with faster powder was better the 308 could equal the '06, which it can't. It will with the same powder that is optimum for the 308 but the '06 will only reach its potential with a case full of slower burning powder. For what reason would we use a bigger case with the same bore size? And for those who don't know a drop tube is not compression, it is used to avoid compression. But then looking back over all my posts, Miller has disagreed with everything I've ever posted here so I should expect that.
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    My most recent load I have discovered for the 30-06 is a 160 grain GS custom with a compressed load of H4350. I get 2950 with it and I really like that speed as it by far my fastest load for a medium weight bullet.

    I was just loading them today. Right before seating the bullet I put the bullet on the case to keep the powder from flying out. I had my 18 volt cordless drill on the table and would turn the drill on and rub the rim of the case on the chuck. That technique quickly settled the powder down.
    Attached Thumbnails Attached Thumbnails S5030149.JPG  
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  10. #10

    Default Rmiller

    Wow,
    Gotta give you credit, but take a look how lazy I can get!
    Poor mans' power case trimmer. works great. $25.00 to me for our guys here and I will do yours too.
    Mark
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  11. #11

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    Being new to reloading myself I am always trying to find the rules to use. I believe that a charge weight that completely fills the case will provide a more consistent burn and (hopefully) more repeatable POI. I am not sure how a compacted charge fits into this though. I haven't had to cross that bridge yet.
    Please feal free to correct me though as I am trying to learn reloading.

  12. #12

    Default Exactly

    Quote Originally Posted by Murphy View Post
    In general with any rifle caliber it is always better loading to fill the case and set the bullet on the powder. It would be more economical to use a faster powder but the space of the case is there for a reason. The most efficient way to load is with a powder that reaches optimum loading with a full case. I use drop tubes to settle powder and seat the bullet on the powder. If that were not the most efficient loading and only a partially filled case with faster powder was better the 308 could equal the '06, which it can't. It will with the same powder that is optimum for the 308 but the '06 will only reach its potential with a case full of slower burning powder. For what reason would we use a bigger case with the same bore size? And for those who don't know a drop tube is not compression, it is used to avoid compression. But then looking back over all my posts, Miller has disagreed with everything I've ever posted here so I should expect that.
    You hit that nail on the head. Additionally it prevents bullet setback in the magazine on cartridges with heavy recoil. I normally find the most consistent loads with a full case.
    This will also prevent an accidental double or even triple charge. Many people say it can't happen to me but there are too many blown up guns out there, just like traffic accidents, nobody's perfect.

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    Thumbs up

    Thanks again to all for sharing your ideas and suggestions. This forum is a fine resource, which I value greatly.

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    That is how the Lee case trimmer works too. The shell holder chucks into a drill. I can trim, deburr and bevel the case mouths with each case on the drill.
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  15. #15

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    Some brands of cases hold a tad more powder than do others. I use IMR 4831 in 30-06, 6mm Rem and 243 and all of these are compressed loads. I like Remington cases as they seem to have just a little more capacity.

    Seating depth and bullet shape (boat tail as opposed to flat base) will also reduce compression. I know this doesn't apply to the 357 sig but thought I'd throw it out there anyway!

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