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Thread: 45 ACP Bullet Seating Depth in a 1911 questions

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  1. #1

    45 ACP Bullet Seating Depth in a 1911 questions

    I am trying to seat the bullet at the correct depth for MY gun, a Rock Island Armory Tactical Model 1911 in 45 ACP.

    I am currently loading Berry's 185 grain round nose bullet above a charge of 4.7 grains of Clay's with a OAL of 1.2-1.22". I'm reasonably happy with that load. However, in the spirit of constant improvement that is inherent to handloading, I'd like to see if I can make it better.

    I did some internet reseach and read that if you seat the bullet such that the rim of the case is level with the hood on the barrel, you are seating THAT bullet at the correct/optimum depth for THAT gun. So I tried this. It turns out that even with the bullet ridiculously long (1.3"), the bullet still isn't level with the hood. So then I tried an empty, sized case, and the case fits at the same spot.

    Is this what they refer to has "headspacing on the case mouth"? If all this is correct, perhaps the method that I read about with regard to the barrel hood is incorrect?

    What are others doing to get the bullet seating optimal, besides trial and error loading?

    Thanks in advance, Chris

  2. #2
    Join Date
    17th January 2005
    Location
    Rhode Island, USA
    Posts
    347
    Quote Originally Posted by chbrow10
    I am trying to seat the bullet at the correct depth for MY gun, a Rock Island Armory Tactical Model 1911 in 45 ACP.

    I am currently loading Berry's 185 grain round nose bullet above a charge of 4.7 grains of Clay's with a OAL of 1.2-1.22". I'm reasonably happy with that load. However, in the spirit of constant improvement that is inherent to handloading, I'd like to see if I can make it better.

    I did some internet reseach and read that if you seat the bullet such that the rim of the case is level with the hood on the barrel, you are seating THAT bullet at the correct/optimum depth for THAT gun. So I tried this. It turns out that even with the bullet ridiculously long (1.3"), the bullet still isn't level with the hood. So then I tried an empty, sized case, and the case fits at the same spot.

    Is this what they refer to has "headspacing on the case mouth"? If all this is correct, perhaps the method that I read about with regard to the barrel hood is incorrect?

    What are others doing to get the bullet seating optimal, besides trial and error loading?

    Thanks in advance, Chris
    Here's my $0.02 worth-

    a. "...in the spirit of constant improvement that is inherent to handloading, I'd like to see if I can make it better. What is better? For a Bullseye/NRA Conventional Pistol shooter, that usually means optimizing accuracy and reliability.

    b. "I did some internet reseach and read that if you seat the bullet such that the rim of the case is level with the hood on the barrel, you are seating THAT bullet at the correct/optimum depth for THAT gun." Don't believe everything you read on the internet It ain't necessarily so.

    c. "Is this what they refer to has "headspacing on the case mouth"? " Yes

    d. "What are others doing to get the bullet seating optimal, besides trial and error loading?" Not much. The parameters are not that flexible to begin with (or that critical), and if your pistol is shooting 2.5 inch groups at 50 yards, you're better off training than playing with seating depth.

    If you aren't getting good groups, and you are using a well established load, seating depth isn't likely to be the problem, and changing it won't help much, either.
    Richard
    Last edited by govtmodel; 19th July 2008 at 09:11.


  3. #3
    govtmodel,

    So I take it that you don't think that bullet seating depth is all that important...?

  4. #4
    Join Date
    30th November 2006
    Location
    Pine Grove, PA
    Posts
    688
    If you REALLY want to know how changing your load, seating depth, or crimp, affects your guns grouping.

    I would suggest purchasing a Ransom rest.(I have the Caldwell Hammer)

    http://www.midwayusa.com/esearch.exe...gin+Search.y=0

    Load in ten round increments, varying what you wish, go to the range and find out what effect your changes make.


    P.S.
    Seating out far enough for the bullet to rest on the lead of the rifling can seriously raise pressures. As can seating too deaply.

  5. #5
    Join Date
    17th January 2005
    Location
    Rhode Island, USA
    Posts
    347
    Quote Originally Posted by chbrow10
    govtmodel,

    So I take it that you don't think that bullet seating depth is all that important...?
    That's right. Reliable feeding is far more important.

    High Power rifle shooters spend a lot of time with seating depth for 600 yard loads, but not pistol shooters.
    Richard

  6. #6
    Join Date
    6th April 2008
    Location
    Charleston, SC
    Posts
    69
    Quote Originally Posted by chbrow10
    So I take it that you don't think that bullet seating depth is all that important...?
    In a .45ACP it is important, but not to accuracy. Adjusting OAL will affect reliable feeding, and it will alter chamber pressures, probably for the worse.

    In a match rifle, tuning seat depth is a regular practice and may help accuracy greatly. Of course, in a match rifle "greatly" may only mean improving accuracy .1" at 100 yards.

  7. #7
    I have read about this idea of getting your COL so that the case rim is flush to the barrel hood and it is not possible. The brass head spaces on the case mouth and making the COL only means the bullet will be closer to the lands and grooves.

    The only way to make the round flush to the barrel hood is to set the bullet so far out once it contacts the lands it pushes the round out closer to the hood, not a good idea.

    The other way is to either have longer brass or ct your hood but the point is that there is no way to make the round flush to the hood. I sat at my bench a few hours and looked at all this and am not sure where this info ever came from. Perhaps barrels are different but to achieve this rim flush to the hood it depends on how your barrel is cut, not how you create your reload.

    Simply decide on a COL that is reliable in your gun and in consistent with your chosen powder charge. Do note that up to a certain point the longer your COL the better accuracy you achieve. I recently tried 1.255 COL on 45 230grn and am now back to my 1.265-1.270 COL because I think it is better.

    PS think about a round that is flush with the barrel of the hood as being less supported by the barrel which weakens brass and is a bad thing. Be happy your rounds are like mine and in a quality barrel are not flush to the hood meaning more of the round is supported by the chamber.
    Last edited by Brian1979; 19th July 2008 at 12:08.


  8. #8
    Join Date
    25th September 2006
    Location
    South of Lake Superior
    Posts
    13,112
    Quote Originally Posted by Brian1979
    Be happy your rounds are like mine and in a quality barrel are not flush to the hood meaning more of the round is supported by the chamber.
    How far in from the hood the case head is when the round is fully forward in the chamber may have nothing to to with how much of the case is not supported by the chamber.

    The only time case support by the chamber is important is when the cartridge is fired. And, when the cartridge is fired in the assembled gun the case head finds itself forced against the breech face by the pressure of the burning powder gasses.

    If your hood is snug against the breech face when the barrel is fully forward in the slide then judging unsupported case length by hood-case head distance does have some meaning.

    If, however, there's a gap between your hood and breech face when the barrel is fully forward in the slide, the case head (when fired) will back out aftward by the amount of that same gap.

    Another way of visualizing it is that a 45GAP and 45ACP cartridge will have the exact same amount of unsupported case length when fired in the same gun - even though the shorter 45GAP cartridge can go a lot farther into the chamber.

  9. #9
    "The only way to make the round flush to the barrel hood is to set the bullet so far out once it contacts the lands it pushes the round out closer to the hood, not a good idea."

    Brian, quite correct with many bullets, especially jacketed, except that you'll find that many 200 and 185 SWC's, when seated with 20-30 thou of bullet shoulder out of the case (proper procedure), the bullet may indeed headspace on the rifling origin.

    In many cases this results in a OAL length of 1.245-1.250" with a H&G pattern 200 LSWC. Since seating deeper to avoid rifling contact may reduce the lead shoulder protrusion out of the case and approach flush seating of the bullet shoulder with the case mouth (not good) in these cases headspacing the bullet on the shoulder of the SWC is in fact proper procedure.

    Many handloaders have been getting away with it for many years, and tolerances prevent them from doing anything different. It works just fine.
    Last edited by 1944Colt; 19th July 2008 at 16:57.


  10. #10
    This is good stuff folks, thanks.
    Last edited by chbrow10; 19th July 2008 at 16:59.


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