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10MM Ammo Confusion. Any care to clear it up?

Discussion in 'Caliber Corner' started by Ya_Huckleberry, Aug 15, 2012.

  1. So I keep seeing threads where people say the 10MM ammo you can buy in most places is just a .40 S&W round. IT is not the original 10MM round that had all the nuts when first developed for the FBI. I guess I dont understand what separates them. Some people say the some of the ammo you can get online is the real 10MM ammo but the grain count (175 for example) is the same as the stuff they call weak. I know I am missing something, please advise on what it is.
  2. JW1178


    Jul 17, 2009
    Underwood, Double Tap, Buffalo Bore are a few. Georgia Arms isn't bad stuff either, and you can get the 500rd case for a decent price. Most get into reloading to reach full potential and keep cost down. Considering you reuse your brass, 10mm is as cheap to reload as .40S&W.

  3. I appreciate the response JW. I am still confused as to why people say the Double tap is a real 10MM round and stuff you can buy at say Bass Pro Shop from remmington that is the same grain count is not as potent as is more like a .40 S@W round that the original 10MM.
  4. GlockWheeler


    Apr 14, 2005
    Velocity. Plain and simple. Most ammo manufacturers load 10mm to near or just barely over what 40 S&W loads are pushing. Double Tap, Buffalo Bore and Underwood offer 10mm loaded to typically higher velocities regardless of bullet weight.
  5. English


    Dec 24, 2005
    You will have to learn that most things said about the 10mm are false.

    The original loading was something like 1200fps with a 200gn bullet. The first commercial loading was by Norma, I think, and was hot but erratic.

    The FBI tests that ended with the selection of the 10mm were done with handloaded rounds loaded down to what is now S&W .40 ballistics with 185 gn bullets. This was because part of the original test criteria was that no round must have more than the recoil of the normal 230gn ball .45ACP and so it ended up at 185gn and about 1176fps, again if I remember correctly. In the tests the 10mm came out just a little ahead of the .45ACP but the test agregate score was weighted heavily towards effective performance after penetrating automobile doors and glass. This is important to the FBI and in many police engagements but is less important for the civilian user. It is important to understand that no tests against animals were conducted as part of the evaluation of effectivness. Terminal ballistics were tested against ballistic gelatine and assessments were made using what I believe to be a flawed model.

    After the 10mm was selected a contract was placed with S&W to produce a run of their series 3 pistol in 10mm. This pistol actually weighed more than the 1911 and so with the same bullet momentum as the .45ACP the felt recoil was less than that of the 1911. The stories that were later put around about it being too big for female hands and having too much recoil for agents to manage were just attractive rumours with no relationship to reaity but they served the purpose of some within the FBI. The S&W pistols were single stack and the length overall of the 10mm was almost precisely the same as the .45ACP so the grip size was no more of a problem than that of the 1911. The complaint that agents did make was that the pistol was too heavy.

    After the pistol started to be brought into service a turf war broke out within the FBI and it was in the interests of some to denigrate the agent who had led the selection team. Part of this strategy was to appoint a non gunsmith to check every pistol as it came in from S&W and return it if any fault was found. A loose sight was good enough for the pistol to be returned. The normal process in virtually all government agencies was that new pistols would be checked by their own gunsmith who would fix minor faults and return only serious ones. This cost S&W so much that they were ready to let the FBI get out of the contract and the rumours of unmanageable power provided the FBI with a public excuse to drop the pistol and the round.

    Because the FBI had put the stamp of approval on an underloaded 10mm, most of the large manufacturers produced it in that form. Full performance was available from Norma or by handloading. Winchester's Siver Tip was between the two. More recently, perhaps the last 5 to 10 years, a number of boutique ammo companies have been producing 10mm in the power it was designed for.

    Back in the day, Elmer Keith knew from shooting many animals that .45ACP ball ammunition was ineffective and that 9mm was much the same. He did not have expanding bullets of course, but this does point up the inadequacy of the belief that the .45 is a proven and superior man stopper.

    Handgun hunters generally prefer revolvers but those who use auto loaders know from experience that the 10mm is generally superior to the .45ACP when both are loaded at the hot end of their range. As a defensive round the particular benefit of the 10mm is that more rounds can be packed into the same volume of magazine than with the .45ACP. The 9mm can pack in more than either, but both 10mm and .45ACP can be considerably more powerful and the 10mm always is able to pack in more rounds than the .45 and has equal or better power per shot. In a rational market place the .45 ACP would have become a niche product and the 10mm would have taken over the majority of sales in the role of optimum performance in a service pistol size.

    Before the FBI abandoned the 10mm an engineer at S&W realised that the same performance could be obtained in a round of the same diameter but with the overall length of the 9mm. The Directors liked his proposition and that became the .40S&W. The FBI did not ask S&W to do this and it was some time before the FBI used the round. I have already explained why the felt recoil of the FBI's 10mm pistol did not sprain wrists or dislocate shoulders but the .40S&W fits into a pistol the same size as a 9mm and is lighter than one intended for 10mm. This led to accuracy problems and got the .40S&W an undeserved reputation for inaccuracy. Fired from the S&W 610 revolver it is renowned for its accuracy, but its felt recoil from most pistols made for it is heavier than ordinary 10mm loadings from an equivalent 10mm pistol. Fully charged the 10mm has heavier felt recoil than the equivalent (same manufacturer) .40S&W but it is well below even a hot .357 Magnum in the same weight of revolver.

    I hope this answers your questions.

    Last edited: Aug 15, 2012
  6. DRJ1911


    Jun 30, 2011
    The grain you are talking about is the bullet weight. The difference is how much and what kind of powder the case contained. Sort of more powder=more power but not quite that simple.

  7. pisc1024

    pisc1024 AASG

    Oct 9, 2005
    Something else to keep in mind is that there is really only two bullets designed to be pushed to 10mm velocities on the market right now. They are the Winchester silver tip in 175gr and the Hornady XTP in 200gr. While other bullets are loaded to 10mm velocities by companies such as double tap, they are merely bullets designed to be pushed to .40cal velocities. This may cause unintended performance issues due to the increased stress on the bullet. An example of this would be the Speer Gold Dot 180 gr. This round is designed by Speer for a .40 s&w load of around 950 to 1000 FPS. The 10mm is capable of much higher velocities. When you see testing on this round you will notice much larger expansion of that round with the 10mm vs the .40cal. This may affect things such as penetration through intermediate barriers and bare targets. Just some food for thought...
  8. _The_Shadow

    _The_Shadow Ret. Fireman

    Jul 23, 2007
    Southeast, LoUiSiAna
    Lets see if this answers any questions as to what performance levels are considered from mild to wild! :wow:


    With careful powder selection and loading and guns set up for the performance these wild loadings can be achieved, although some guns will not atain the upper most performance.
  9. fredj338


    Dec 22, 2004
    The original 10mm ammo was quite a bit hotter than most made today. It was made by Norma & would throw a 200gr bullet @ close to 1200fps, a 170grJHP @ 1250fps. This I verifed chronographed from my 1st gen Delta & a BRen10. The problem was the Delta was cracking frames & many of the FBI couldn't handle the sharp recoil & larger weapon in the 1076. Of the larger manuf, Winchester 175grSTHP & the Hornady 180gr XTP are pretty close to the original Norma stuff IMO.
    Last edited: Aug 15, 2012
  10. cowboy1964


    Sep 4, 2009
    I hear good things about the Silvertip if one wants a fairly full power 10mm.
  11. Man, everyone provided me with a lot of good information. I definitely appreciate it. Thinking back, I dont not remember a measurement on the ammunition boxes for the amount of powder in the round. I do not believe that is provided correct? So basically, I have to go off of their FPS speed and ftlbs rating to know I am getting a more powerful round then a standard .40 S&W?
  12. countrygun


    Mar 9, 2012

    A measure of the powder charge on the box would be useless since their are dozens of different powders possible and comparing the weight of a powder charge with different powders is complicated.

    To make it simple and without even naming the powders, in a .44 mag nine grains of one brand of powder gives me about the same velocity as seventeen and a half grains of another powder.
  13. GlockWheeler


    Apr 14, 2005
    More or less, yes, you are correct. It appears that you have a G29, yes? I will say the the Winchester 175 grain Silvertip is a very accurate and controllable round for the G29 and seems to be a warm load as well. Nice combination for carry.
  14. fredj338


    Dec 22, 2004
    No, maybe you are thinking of shotgun ammo. Rifle & pistol ammo just have a bulet wt & maybe some will have a test vel printed, but not all.
  15. rkwjunior


    Aug 13, 2012
    I use cheap PPU 10mm out of a G20c and it has substantialy more recoil and noise compared to my buddies .40 "short & weak" Ruger sr40

    Why doesn't someone open up a couple rounds of the major brands a weight the powder charge???? This should answer some of the age old questions, NO?
  16. agtman

    agtman 10mm Spartiate

    Feb 28, 2001
    Truth trailer sez ...

    English had most of it right ...

    Currently, look to Buffalo Bore, DT, Underwood, for:


    Old School Days for this cartridge (circa 1986):

  17. Merkavaboy

    Merkavaboy Code-7A KUZ769

    No, it wouldn't.

    The powder being used in your Prvi Partizan ammo is going to be totally different than from what Winchester, Remington, Federal or even Fiocchi uses. Different powders burn at different rates. And powders come in different styles; spherical, flake, granular, tubular etc. There's also different brands and different manufacturing styles too. The powders can also be in the form of a "blend" of two or more brands.

    Powders can be (and often are) different amongst same calibers from the same company. The powder in Winchester's economy USA brand ammo is going to be different from what they use in their L.E. grade Ranger line, especially when the ammo is using "low flash" suppressed powders.