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Ok.. Just dying to ask this 10mm question

Discussion in 'Reloading' started by RYT 2BER, Oct 14, 2012.

  1. Many of you know I just started reloading and for now I'm focused solely on .40 (and I'm fine with that)..

    However I am a reader and I've been snooping around on the net and one thing that confuses me..

    I've got my g20 loaded with underwood 155gr bonded hollow point, and I've been doing some underwood stocking when funds are loose.. I find these underwood loads to be awesome at he range, and as hot as blazes..

    There has been much underwood testing by folks on line and although I don't have a chrony I'm reasonably comfortable that the advertised fps is on the money...

    So here is my question... In my Internet snooping I've yet to see loads that recreate the kinds of performance I've seen from underwood.... So it begs the question... What do companies like underwood do to goose so much out of their ammo :dunno:
  2. sellersm

    sellersm disciplinare

    May 28, 2009

  3. Angry Fist

    Angry Fist Dehumanizer® Lifetime Member

    Dec 30, 2009
    Hellbilly Hill
    I'm pretty sure UA loads have been broken down. These power levels are older than you are.
  4. F106 Fan

    F106 Fan

    Oct 19, 2011
    Underwood says their 155 gr 10mm flies at 1500 fps.

    The Hornady manual lists a Blue Dot load that will do 1450 fps.

  5. shotgunred

    shotgunred local trouble maker

    Mar 1, 2008
    Washington (the state)

    1. Other than self defense loads there is absolutely no reason to push bullets that hard. Paper doesn't know the difference. You guns and your wrist will know the difference and will show it with premature wear.

    2. It is all about powder choice. You want a slower powder that will pack the cartridge 3/4 or more and burn to the end of the barrel.

    A quick google check shows he is loading hot enough to cause flat primers and Glock chamber smiles.


    Last edited: Oct 14, 2012
  6. more powder
  7. fredj338


    Dec 22, 2004
    I feel ammo manuf always tweek their vel levels to sell ammo. If you can find one test gun that gets the stated vel level, you say that's what it is. Forget that it might be 100fps off in another test platform. You can find a lot of data that get's you 1400fps+ w/ a 155gr bullet in the 10mm & w/othe guppy creating affects. If your brass looks like that above, you are way over pressure for your bbl.
    Last edited: Oct 15, 2012
  8. freakshow10mm

    freakshow10mm 10mm Advocate

    I've seen it happen with almost every 10mm manufacturer out there. They see a niche in full power 10mm ammo and they run with it. People like the high velocity and word spreads. The customers buy and buy. The manufacturer starts making money hand over fist and can't get enough of these velocity crazed shooters willing to spend money to shoot fast 10mm.

    Two things happen: 1) they start to "cook" the numbers and the velocities aren't as advertised or 2) they try to push loads farther and end up compromising the safety of their customers. It's happened with many boutique ammo companies over the short few years I've been in this industry.

    I just keep plugging along loading and selling 180gr ammo at a solid 1200fps. I have loads in my database that will push the SAAMI limits to the single digits of standard deviation in SD of pressure but I won't load them for customers. People need to get a grip and get off the high velocity bandwagon.
  9. countrygun


    Mar 9, 2012
    This is good advice. there are a lot of people that don't understand the law of diminishing returns.

    I am happy hunting deer with a .41 mag 210-220 gn bullet at 1,200 fps. It works very well out to as far as I am comfortable trying. A 200gn 10mm bullet at 1,050- 1,200 is too close to split hairs about. A 180gn will do. In a G-20 that is 15 rnd of a deer hunting load on tap per mag. That is all I rationally expect from a handgun.
  10. I realize you are a very experienced guy and I have seen your posts for years so I know you know what you're talking about. However I don't really understand your post. 180 gr moving at 1200 fps is running about 575 ft lbs of energy. That's not altogether different from some hot .40. At that level why even bother with 10mm? As far as I'm concerned (or believed) the value of 10mm is to be able to get into the 600-700+ ft lb neighborhood. If not what's the point

    And as far as getting off the high velocity bandwagon... Isn't the whole point of the large case of 10mm a velocity issue? That's like saying people should just shoot 38 instead of 357. :dunno:
    Last edited: Oct 16, 2012
  11. F106 Fan

    F106 Fan

    Oct 19, 2011
    The problem for reloaders of hot 10mm (or any other hot load) is that we have no way to measure pressure. Or, more importantly, the consistency of pressure. As with all statistics, there is a high value in the extreme spread and that's where guns blow up.

    Bullet and powder manufacturers aren't going to publish really hot loads because they can't control the reloading process. Even if they knew how to make that super fast fire breathing 10mm, they aren't going to tell.

    There are outliers in every hobby. Scuba divers who want to dive deeper and stay longer, skydivers who want to jump higher, open lower and do it in a crowd and reloaders who want to write their own book on hot loads.

    I tend to reload on the boring end of the curve. All I want is middle-of-the-road loads that won't destroy a gun even if my powder measurement is off a tenth or so. Boring...

    For the outliers, I wish them good luck! Because luck is the only thing keeping them from having a really bad day!

    Last edited: Oct 16, 2012
  12. Yeah... that's what I do. :cool:
  13. Well I think there are two issues here..

    From a reloading perspective I have no interest in getting anywhere near this uber hot stuff.

    But from an experienced loader with perhaps 10s of thousands of rounds fired (like underwood) I'm perfectly happy shooting his nuclear stuff.
  14. Colorado4Wheel


    Nov 2, 2006
    His "experience" does nothing to make his over pressure loads safer. Laws of science apply equally to the smart, dumb, rich and stupid.
  15. freakshow10mm

    freakshow10mm 10mm Advocate

    The two original loads for the 10mm Auto from Norma who developed the cartridge and loads are a 200gr at 1200fps and 170gr at 1300fps. Unless you're shooting cast bullets, I'm not aware of a jacketed bullet in the 170gr weight that's readily available, so we generally substitute 180gr. Could I push a 180gr bullet to 1300fps safely and be accurate? Of course. Why don't I? Reduced recoil with the 180/1200 load means the shooter can be more accurate and shoot longer because they aren't getting beat around with heavy recoiling loads. I'd rather the shooter be able to handle the weapon's recoil and be accurate than fighting the recoil and not enjoying the shooting session. Business perspective I'm going to sell more ammunition to shooters that enjoy shooting than don't enjoy shooting.

    The whole intent of the 10mm was not to be a hunting cartridge, but it was to replace the 45 ACP as a service cartridge. Kinetic energy in ballistics is overemphasized and there is too much focus there. People try to quantify that into penetration and expansion, but it's nearly impossible to calculate the resistance of the human body. We do an OK job using 10% gelatin, but it mimics tissue, not blood, fluids, fat, skin, difference in tissue with different organs, etc.

    People see value of the same object in different ways. If a shooter wants to have the perceived value of a 600+ ft lb kinetic energy, that's fine with me. The value I see in the 10mm is a cartridge that is more versatile than any other service cartridge. I can load it light and slow for small game, heavy and slow for target shooting, or heavy and moderately fast for self defense and big game hunting. There is something that is intrinsic in American culture where we want the dials all turned up to 11. There is diminishing returns when that happens. As a general practice, I don't exceed the velocity standards set by Norma nor pressure standards set by SAAMI.

    My 180/1200 load has killed deer out to 100y and if I started the bullet out 100fps faster, I don't think I would have improved terminal performance in any of those situations. The bullet struck the deer in the heart and the deer expired within 50y of being shot. I've killed 14 deer with my 10mm pistols inside 100y.

    There is a difference between the necessity for higher velocity to achieve a goal and just turning the dials to 11. The latter is what I'm referring to. You can push the envelope so much before one of the two aforementioned things in my previous post happen. People obsess too much about velocity and energy and not enough about shootability and accuracy. Very few are satisfied with the excellent performing Norma velocity loads and they just want more, more, more.
    Last edited: Oct 16, 2012
  16. Zombie Steve

    Zombie Steve Decap Pin Killa

    May 31, 2007
    Old Colorado City

    The .40 might be able to approach 1,000-1,100 with a 180, but that .40 is maxed out, redlined and running the ragged edge. The 10mm will putt along with that load forever at lower pressures. Easier on the gun, the brass, et cetera...

    If you really have the itch for horsepower, get a .44 mag. Even loads in the upper mid-range will leave 10mm in the dust, and again, it will do it at lower pressures.
  17. Colorado4Wheel


    Nov 2, 2006
    I keep my 10mm for Bear Protection so I need a really HOT load.

  18. countrygun


    Mar 9, 2012
    You have the order of things backwards completely.

    The idea of the 10mm, which came first, was to (as was said) to push a 200gn bullet at 1,200. just that simple. Basically the recoil was too much and the grips to big for some and so the FBI suggested a reduction in case length and velocity and bullet weight, hence the .40S&W.

    The 10mm did, in original loadings, what it was intended to. Light for caliber bullets at high speeds weren't the intent.

    No, the .357 magnum was well known ot the time and competing with it, via velocity, was not a concern. The ultra-ligh bullet path is a side track followed velocity devotees and is an aside to the designers intent.
  19. Thanks for the info and input guys.. Good information here..