Bullet seating tolerances

Discussion in 'Ammunition & Reloading' started by JWagner, Apr 17, 2012.

  1. JWagner

    JWagner New Member

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    I have just started reloading .45auto and have a bit of variation in the seating depth. The spec's call for 1.275 overall length and some are coming up short. I would think that being .005 inch short would not be a real problem, but how short is too short? The reloads are .45 auto, 230gr fmj bullet and 5 gr of Bullseye. It will be used in a 1911 pistol. Would the problems be with gas pressure or unreliable feeding?
     
  2. beaglesam

    beaglesam Active Member

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    Measure a factory load, the Remington's measure 1.265 to 1.27. Mine measure 1.268 and shoot great.
     

  3. JWagner

    JWagner New Member

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    That sounds good. I sorted mine by length and decided arbitrarily that I could use all of them from 1.270 to 1.277 length. Additionally more were sorted in a group of 1.265 to 1.269 length. The shorter ones will be dealt with later with a bullet puller. Thanks for the input.
     
  4. JonM

    JonM Moderator

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    seating dies generally work off the ogive not the very tip of the bullet. in the case of things like flat nose bullets they work off the tip. but for conical round nose or spitzer type its the ogive. thats why you see a slight variation. when setting a seating die you can pick a bullet with a median length or just pick one and set the die.

    some dies come with two seating stems. a flat and round. the round ones use the ogive for seating and flat the nose of the bullet.

    the slight variation wont matter unless your being super anal grognardish about it.

    if you use a bullet comparator and chamber gage you can seat more accuratly when getting an exact seating depth to match a gun's headspace. you want to be a little off the lands. this is really only important for making super accurate target rifle ammo.
     
    Last edited: Apr 17, 2012
  5. Model70

    Model70 New Member

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    LMAO! Love it!
     
  6. ryguy00

    ryguy00 New Member

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    seating just off the lands or just touching the lands is what you're looking for with rifles. For pistols, you will be limited to the longest length that will fit in your magazine. The 1.275 OAL is for Max length. If you seat to max length, they will probably still fit in the mags for a 1911. If I remember correctly, mine did but a few were very close to hanging up. The problem is trying to unload an unfired round from the chamber. If your bullets are seated to the max oal, they are not coming through the ejection port without a fight. Trust me, it's not something you wanna be fussing with at the range. If you set your seat depth to 1.250, you will find that they will cycle and unload (unfired) smoothly. If you want to go longer for whatever reason, make a few dummy rounds first at the lengths you are aiming for and then test them in the gun at your reloading bench to make sure they cycle. Having a loaded round that doesn't wanna eject at the range when it needs to wouldn't make me feel very warm and fuzzy.
     
  7. JonM

    JonM Moderator

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    lol you dont know the true meaning till you run into a bench rest shooter that shoots one hole groups at 4 miles heh. those guys know how to build ammo to very exacting standards.

    i used to be pretty anal about sorting weighing measuring but it just gets old and takes the fun out for me. but i dont begrudge the folks that enjoy that level of precision. there is enough range space for everyone
     
  8. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    The .45 ACP is a very forgiving cartridge. A couple of thousandths of an inch do matter a hill of beans. Save the Anal Retentive OCD stuff for precision rifles.
     
  9. JWagner

    JWagner New Member

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    Thanks for the advice. I am really new to this , so I will have more than a few questions to ask.
     
  10. BlueTurf

    BlueTurf New Member

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    The different manufacturers list the cartridge overall length(C.O.A.L.) for the bullets they tested with powder charges. There is often quite a variance with the C.O.A.L. in the different manuals for bullets of the same weight and design type. I have listed some different C.O.A.L. measurements for the .45acp 230-grain RN from a few manuals I have. I use this bullet weight for my .45acp loads and I usually just stick with the C.O.A.L. listed in the manual for the brand of bullet I am using at the time. Good luck with your reloading.

    Sierra - 1.270"
    Hornady - 1.230"
    Speer - 1.260"
    Lyman - 1.275"
     
  11. 1hole

    1hole New Member

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    Book OAL isn't a rule nor even a 'suggestion'; it's just what the team that produced the book used when developing their data and it's often just what put the bullet's crimping cannalure at the case mouth. And, it isn't the nose of the bullet that matters anyway, it's the base and how its position changes the internal case volume at ignition. Fact is, there is little effect to changing an OAL from book length UNLESS we're loadng MAX book loads for one of the few smallish high pressure, high velocity autoloader cases such as the 9mm and .40 cals.

    The excellant old .45 ACP is quite tolerant of what ever length it takes to make it feed and chamber correctly, it will never notice a change of 5 thou so give your bullet puller a rest.
     
    Last edited: Apr 18, 2012
  12. BlueTurf

    BlueTurf New Member

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    This is true. I only mentioned the C.O.A.L. measurements listed in the books as a general reference that someone with limited reloading experience could use. These measurements and loads have been tested. This information is very useful for a new reloader. It takes time to learn the ins and outs or reloading and not everyone has been at it for a long time. Someone with limited experience could seat their bullets too deep or too shallow to the point where a problem occurred. I know that some types of semi-auto .45s are more tolerant of different bullet types than others, and some are more sensitive to the overall length of the cartridge. I fed ammo through my Colt 1911 that jammed my friends Sig.
     
  13. 1hole

    1hole New Member

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    "I fed ammo through my Colt 1911 that jammed my friends Sig. "

    Well, they ARE different pistols so surely that's no surprise and it doesn't require decades of experience to understand. Fact is, no book or factory ammo OAL can assure proper feeding and chambering in every auto weapon ever made so why should a handload? But I was addressing JWagner's concern about the safety of 5 thou of difference in OAL in his own handgun's ammo, not your feeding problems.
     
    Last edited: Apr 18, 2012
  14. BlueTurf

    BlueTurf New Member

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    I wasn't trying to address feeding problems. I was trying to simply say the information listed in manuals can be helpful to loaders with limited experience. The reloading manuals are not the absolute rule when it comes to this science, but the information contained within them was derived from tests done with firearms and ammunition under controlled conditions. This is information loaders can use for their own tests. You offered your thoughts on this and I offered mine, so isn't that good enough for this post?