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Thread: Powder up/down questions

  1. #1
    Boolit Buddy
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    Smile Powder up/down questions

    Dumb question(s) time....again! I have been looking at M.D. Smith's reloading pages, and the differences in velocity using .38 Special brass and Unique. Iirc, he experienced about a 150 fps difference when the powder was against the bullet, as compared to when the powder was against the primer.
    Shortly afterward, I read an article where another scribe advocated deep seating the boolit, with a corresponding powder weight adjustment, which he claimed eliminated the "problem".
    His idea was to seat the boolit, crimping over the front driving band, instead of in the crimping groove, or crimping the boolit over the ogive, shortening the overall length of the cartridge.
    My general loads use the "medium" powders..Unique, and Universal for velocity 900-1000 fps .My favorite loads are 5.5 gr Unique, and 5.2 gr. Universal. Will increasing either load by 1/2 grain change anything except velocity or reduce the "powder up, powder down effect? I am thinking of trying True Blue, or AA#5 in 357 magnum brass. About the same bulk? It's hard to find information about that. I'm thinking of using Trail Boss or HP 38 exclusively for my wadcutter loads.

    My questions are:
    1. Is powder position a real-world problem? I'm thinking of 2.4 gr. of Bullseye in .38 Special cases. Lots of air space, and the combination has won more matches than anyone can remember. Position sensitive? Unless competitors raised the muzzles of their guns before each shot, that would seem to be self-defeating, particularly during rapid fire.
    If a person just HAS to do this, instead of going to all the trouble to recalculate (WAG ) powder charges, etc. Why not just deep-seat boolits in 357 brass, and use a starting .38 special load, working up as necessary?

    2. Find a bulkier powder? Trail Boss comes to mind, but here desired performance may be a bit lacking.

    3. Buy or cast a Keith-style SWC with the two crimping grooves, seat it to the front groove, and let COL go where it will?

    4. My favorite loads are 5.5 gr Unique, and 5.2 gr. Universal. Will increasing either load by 1/2 grain affect the "powder up, powder down 'problem'"or change much except velocity?

    Are any of the many extremely knowledgeable reloaders on the forum able to offer any direction? With so much information, it is a temptation to go back 40 years or so, look in the manuals, go by the TLAR (That Looks About Right) method, pick a load that's about mid-range... about .38 Spl. +P or slightly better...and load 'em up?
    Thanx!

  2. #2
    Boolit Master Walks's Avatar
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    Geez,
    Hasn't this question been beaten to death too many times already.

    Powder against the primer. Nuff Said
    Happiness is a Warm GUN & more ammo to shoot in it.

  3. #3
    Boolit Buddy
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    I load Hp- 38 .in all my 38spl. Works great 125gr up to 158gr. I shoot a lot of 148gr wad cutters I use a light crimp on top of the bullet.

    Sent from my SCH-I435 using Tapatalk

  4. #4
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    Shaner...I'm going to have to buy a can of H-38, and give it a try. Thanks.
    Last edited by sniper; 11-22-2018 at 09:30 PM. Reason: Contentious!

  5. #5
    Boolit Master RU shooter's Avatar
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    I don't know the real scientific answer for it but I've never had issues with light charges of Bullseye in handgun or rifle ctgs 30-06 which are way way bigger than a 38 spl . Think about it unless your aiming at a severe up hill or down hill angle the powder is gonna be laying horizontal in the case for the most part . I know in the30-06 I use 6 gr of Bullseye and a normal weight bullet there's a ton of empty space and I've never attempt to position the powder just work the bolt aim and fire and at 100 yds these are as accurate as just about any other load I've shot. With other powders that take up a lot more space or if I would use a tuft of Dacron .i also load 2400 , W231,Red dot and unique the same way with light loads .
    If you find yourself in a fair fight, your tactics suck!

  6. #6
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    Many powders are not position sensitive but some are like 4895 that works better with dacron on lighter loads.

    I also would be interested in seeing/having a list if one exists.

  7. #7
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    Quote Originally Posted by sniper View Post
    Well, Walks, that was certainly unhelpful, but not unexpected. Can you give me specific examples of where the effect had been so fully discussed?

    After attempting to research the problem, and finding precious little information addressing my particular questions, I hoped that some of the supremely knowledgeable and helpful members on the forum would have some knowledge of the effect, and might respond. Hopefully, they may yet.

    Shaner...I'm going to have to buy a can of H-38, and give it a try. Thanks.
    Start by searching for the "Use of Fillers" in the "Favorite Reduced Loads" section ,(if I recall). Larry Gibson has posted a ton of good info regarding reduced loads/position-sensitive powders.
    Warning: I know Judo. If you force me to prove it I'll shoot you.

  8. #8
    Boolit Grand Master tazman's Avatar
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    Quote Originally Posted by sniper View Post
    Shaner...I'm going to have to buy a can of H-38, and give it a try. Thanks.
    I assume you are going to be using this in handgun cartridges judging by your original post. Most handgun powders are position sensitive to one degree or another. Some more, some less.
    About a year ago, a member did some tests on that very thing and posted them on this site. Sorry, but I am currently having trouble remembering his name.
    The thing to remember is, unless you are a master class shot and shooting at distance, it is unlikely you will be able to notice any difference. A 50-75 foot per second spread isn't going to matter much out to 25 yards for most people. Many loads have that much extreme spread built into them without worrying about how the powder is oriented.
    If you are talking about rifle cases and small powder charges, you need someone else to help you. I haven't experimented with those yet.

  9. #9
    Boolit Master Walks's Avatar
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    sniper,

    This was discussed in an article back in the late 1970's in either SHOOTING TIMES or GUNS and AMMO.

    The article delt with "flash detonation" where the primer ignites all the powder at once. And "powder position" were the powder is either back against the primer or forward up against the bullet.

    I tried this at the Pistol Range using .38spl loaded with HORNADY 148gr HBWC over 2.8grs of BULLSEYE. At 25yrds I fired 20 successive 5 shot groups. Using a S&W M14-6" bbl Revolver. I fired the 1st 10 groups starting with the gun raised muzzle up at 90degrees, I slowly lowered the muzzle to horizontal and slow-fired single action, repeating this 5 times for each group.

    For the 2nd set of 5 shot groups, I lowered the muzzle to 45degrees taping it on the front edge of the bench. I then raised it to horizontal and slow-fired single action the 2nd set of 5 shot groups.

    The 1st set of 5 shot groups averaged 1 1/2" - 1 3/4".
    The 2nd set of 5 shot groups averaged 2" - 2 1/2".

    It was decided "detonation" was caused by double charges. And that both accuracy and velocity was affected by "position" . Powder to the rear up against the primer increased both accuracy and velocity, powder to the rear made a difference.

    I tried this again with standard RIFLE loads at the range myself, in the early 1980's when My DAD bought a Chronograph. Raising a rifle muzzle up before firing put the powder up against the primer. It increased consistency in both.
    Happiness is a Warm GUN & more ammo to shoot in it.

  10. #10
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    JSnover...thank you for the guidance, and others, for the responses.
    I found the referenced sites, and reading the posts was instructive, to say the least! I don't do Unique or 2400 in rifle cartridges any more, and am not a match competitor by any stretch of the imagination.

    My usual use with my .22 or 357 is walkabout, carry in holster, draw, and shoot at targets of opportunity, or enjoying a day at the range, where myself and other olde pfarts are satisfied to keep our boolits in an 8" target at 25 yards. As long as the load doesn't fly back and shoot my hat off, I'm good to go!

    Under those conditions, powder position would seem to be a very minor concern. Sometimes, I get these attacks and start overthinking stuff. (At least, that's what my wife says.) I think my best bet would be to use bulkier powders, and my go to powder...Unique seems like a good fit here...and just enjoy the journey, shooting "Hot .38/Mild Magnum" loads with complete satisfaction. I might even try the 173 gr. Keith boolit just for grins. AND...some of the newer powders do look very interesting...

  11. #11
    Boolit Buddy
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    For many loads powder position will cause surprising velocity variations.

    I ran a 38 special test in an LCRX and found I got 20% - 25% more velocity with the powder to the rear. Results were essentially the same using a "high bulk" powder, Red Dot and a powder promoted as not position sensitive Tightgroup.

    The weird thing is that the LCRX shoots fine with these loads. No detectable change in point of impact.

    Now with a 30-30 load with lots of free space in a 14" Contender, I got big swings in both velocity and in impact location.

    The big take away is that the velocity variations may or may not really affect how a load shoots.

    Take your load, get some form of rest, fire 5 at one target with powder forward, fire 5 at another with powder to the rear. Good chance there will be not enough difference to matter. If there is, then consider changes.
    Last edited by P Flados; 11-23-2018 at 08:30 PM.

  12. #12
    Boolit Buddy Petander's Avatar
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    FWIW many of my most accurate loads are slightly compressed w/ heavy for caliber bullets. 9mm (VV 3N37), 45-70 (VV N135), 300WM (VV N165).

  13. #13
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    I've never put Dacron or a filler in anything I've ever loaded, and I can't say that I've had problems. Even fairly light loads for fire forming my A.I. rifles do well. I will say that True Blue is the best metering powder I've ever bought, and a decent charge of it is lively...
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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check