Confused on a few things

Confused on a few things

This is a discussion on Confused on a few things within the Reloading forums, part of the Defensive Ammunition & Ballistics category; I have Lyman's 49th edition manual, a Lee 4 turret press, using barry's 115 gr FMJ RN, and Unique powder. For the 9mm, it shows ...

Results 1 to 8 of 8
Like Tree6Likes
  • 4 Post By gasmitty
  • 1 Post By Archie
  • 1 Post By aus71383

Thread: Confused on a few things

  1. #1
    Member Array bundy845's Avatar
    Join Date
    Nov 2011
    Location
    Toledo, OH
    Posts
    28

    Confused on a few things

    I have Lyman's 49th edition manual, a Lee 4 turret press, using barry's 115 gr FMJ RN, and Unique powder. For the 9mm, it shows the trim-to length to be .751". On the same page, there is a diagram that shows the case length as .754". I thought the .751" was to be the max? Why the discrepancy?

    The Lyman is the only manual I have and the only 115 gr "recipe" they have is for Jacked HP. Does the grains or OAL change significantly between FMJ and JHP?

    For the 147 recipe they list that as TMJ. The appendix says this is Totally Metal Jacket (Speer). Is this just speer's version of a FMJ? Would using a non speer bullet use the same specs?

    I am looking for another manual to have as cross reference but not sure which to add.

    Sorry if I jumped around, I thought I had a handle on this stuff but rereading things gave me pause.

    Thanks in advance!


  2. #2
    Moderator
    Array gasmitty's Avatar
    Join Date
    Jun 2007
    Location
    Gilbert, AZ
    Posts
    11,244
    The 9mm design case length maximum is 0.754". Trim-to-length dimension is a different story; Lyman specs 0.751" and Hornady specs 0.749" - hardly enough to natter about. Most auto-pistol cartridges "headspace" on the case mouth, which means that the cartridge moves forward in the chamber until the bullet end of the case reaches a 'step' in the chamber. That provides a repeatable locating point; revolvers typically use the rim of the case to provide a locating reverence. Typically, brass cartridge cases expand when fired, and over time (and for other reasons) the case will stretch. If it stretches beyond the design length, the case will protrude further from the chamber than it's supposed to, which may cause function and firing problems. The "trim to length" number given is a dimension that allows for a reasonable amount of case stretch with repeated firing or reloaded cases. Just as a data point, I've reloaded about 10,000 .45 ACP rounds since I began to reload, and random case measurements have never revealed one over max length. The 9mm operates at a higher pressure so it's more likely to stretch, but my point is that you need not be overly concerned with case length. I don't know anyone who trims handgun brass for anything below .44 magnum power-level.

    What is of greater concern to the handgun reloader is the OAL (overall length) of the loaded cartridge. For a given charge weight of powder and bullet design, a shorter OAL means the bullet is seated more deeply and the resultant case pressures and bullet velocities will be higher than for a longer OAL. You really do have to pay attention to bullet seating depth, especially with high-pressure cartridges like 9mm and .40 S&W. The old .38 Spl and .45 ACP operate at much lower pressures and bullet seating depth, while important, is less critical. Autoloading pistols also are fussier about OAL - too short or too long won't feed or won't chamber completely. You'll just have to find the sweet spot for your gun and your load.

    In addition to your Lyman manual I highly recommend either the Hornady or the Lee, or preferably both. No one manual shows the recipes for all the combinations of bullets and powders, and by God, there's a lot of 'em out there. I would start by picking a bullet weight and style you want to use, then look at the recipes and study them for differences in velocity, and see if overall length is a contributor to those variations. A few thousandths of an inch are meaningless, but OALs varying by more than 0.020" or so are something to pay attention to.

    The Lyman is the only manual I have and the only 115 gr "recipe" they have is for Jacked HP. Does the grains or OAL change significantly between FMJ and JHP?
    Lots of bullet makers offer 115 gr FMJ, but Lyman just doesn't show recipes for them. The JHP data isn't vastly different than the FMJ rounds, so you can use the JHP data for your FMJs... just don't start at the "Max Load" charge weight. There's a bigger difference between lead and jacketed then between FMJ and JHP.

    For the 147 recipe they list that as TMJ. The appendix says this is Totally Metal Jacket (Speer). Is this just speer's version of a FMJ? Would using a non speer bullet use the same specs?
    I think the "TMJ" (total metal jacket") designation is just Speer's. Another maker's 147 grain jacketed bullet should be very close to the Lyman data published for the 147 TMJ.

    Hope this helps.
    Smitty
    NRA Endowment Member
    NROI Chief Range Officer

  3. #3
    Member Array Archie's Avatar
    Join Date
    Aug 2005
    Location
    Hastings, Nebrasksa - the Heartland!
    Posts
    318

    It is confusing.

    Maximum length is the longest a case should be in order to fit in the chamber. Trim to length is the shortest. Anywhere in between is acceptable. Most handgun cartridges don't really stretch. (Bottle neck rifle cartridges do, however.)

    Yes, the 'Total Metal Jacket' projectiles are essentially the same as 'Full Metal Jacket' bullets. However, they can be a bit different; they should be okay at starting loads, but don't substitute one for the other at higher pressure levels.

    Lyman's Manual is great; I think it the one best manual. I also like the Speer manual, the Hornady manual as well. Then, any others. Any of the major powder producers are good. Hodgdon, Winchester, Alliant and so forth. But make sure and read the introduction part; that has the valuable information.
    bmcgilvray likes this.
    Anyone Worth Shooting Is Worth Shooting Well
    Please take a look at my Blog: http://oldmanmontgomery.wordpress.com/

  4. #4
    VIP Member Array BigJon10125's Avatar
    Join Date
    Apr 2011
    Location
    California
    Posts
    3,245
    Right there with you Bundy! I have much of what I need but plates and dies are backordered seemingly everywhere! Did not know that pistol cases stretch less, if much at all so thanks Smitty. Currently reading Lyman's 49th edition while I wait for my backordered items. Seems like divine intervention Always looking for these unique tidbits that come from the pros and many times aren't covered in a book. Can't wait to start actually reloading and shooting em. Going to be more nervous than a long tailed cat in a room full of rocking chairs on that first trigger pull!
    BigJon


    "Better to keep your mouth shut and be thought a fool than to open it and remove all doubt" ~ Mark Twain

  5. #5
    Member Array bundy845's Avatar
    Join Date
    Nov 2011
    Location
    Toledo, OH
    Posts
    28

    Confused on a few things

    Gasmitty thank you for the very detailed reply. It was very helpful. Archie you as well. I now know how to proceed.

    Bigjohn good luck when you get your equipment.

  6. #6
    VIP Member Array aus71383's Avatar
    Join Date
    Jan 2007
    Location
    WA
    Posts
    2,543
    Very good info above.

    Also it's important to know that your Barry's bullets are not FMJ - they are plated lead. They are much softer than a true FMJ, and you can in most cases use the loading data for a 115 gr LRN interchangeably with the plated bullets. The real FMJ 115s will create a much higher chamber pressure than the plated lead.

    Austin
    TX expat likes this.

  7. #7
    Distinguished Member Array dangerranger's Avatar
    Join Date
    Sep 2012
    Location
    Exact center of CA
    Posts
    1,996
    Quote Originally Posted by aus71383 View Post
    Very good info above.

    Also it's important to know that your Barry's bullets are not FMJ - they are plated lead. They are much softer than a true FMJ, and you can in most cases use the loading data for a 115 gr LRN interchangeably with the plated bullets. The real FMJ 115s will create a much higher chamber pressure than the plated lead.

    Austin
    This, And TMJ is also a plated bullet that shares its data more closely with lead bullets. DR

  8. #8
    Distinguished Member Array dangerranger's Avatar
    Join Date
    Sep 2012
    Location
    Exact center of CA
    Posts
    1,996
    Quote Originally Posted by aus71383 View Post
    Very good info above.

    Also it's important to know that your Barry's bullets are not FMJ - they are plated lead. They are much softer than a true FMJ, and you can in most cases use the loading data for a 115 gr LRN interchangeably with the plated bullets. The real FMJ 115s will create a much higher chamber pressure than the plated lead.

    Austin
    This, And TMJ is also a plated bullet that shares its data more closely with lead bullets. DR

Sponsored Links

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Search tags for this page

9mm case stretch

,

alliant recipes can equal weight bullets be substituted

,

overall length for 147 grain speer tmj bullets

,

reload specs barry 115 fmj oal

,

reloading data for the speer tmj fn 147 gr

,

speer tmj 115gr with unique recipe

,

speer tmj 147 gr length

,

speer tmj 9mm bullet seating depth

,

speer tmj fn reload data

,

why does hornady list 9mm max trim length at .749 but others list it as .744?

,

winchester 115 grain fmj rn with unique recipe

Click on a term to search for related topics.