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Thread: Help with overall length back offs

  1. #1

    Help with overall length back offs

    As I am new to reloading, and as the chap who was going to mentor me has passed away I wonder if some of the seasoned reloaders on here could offer me some words of wisdom relating to the following.

    I am currently loading 85gr .243 bullets and have been using the C.O.L 2.625" as shown in the manual below:



    Groupings are better than factory reloads but I would like to improve on them further.

    I recently spoke with my gunsmith who used one of these modified hornady bullet gadgets in the rifle and said that the head of the bullet would touch the barrel if the length was 2.732" which is 0.107" longer than currently used by me.

    As I have spent all the money on reloading equipment I would like to get things as accurate as possible. This being the case, how do i decide how much to lengthen.shorten the overall length to?

    Hope this makes some sort of sense

    cheers

    david

  2. #2
    Have you found what you think is the optimum powder charge? & are you using all same brand stuff in the loads you make up?.
    (The Unspeakable In Pursuit Of The Uneatable.) " If I can help, I will help!." Former S.A.C.S. member!

  3. #3
    I'm keeping everything consistent throughout.

    Using N160 powder (always same load),
    cci primers
    same cases (trimmed, cleaned etc)

  4. #4
    Backing off from the lands / leade, is just a case of moving the bullet back into the case by degrees until you find that your desired point of impact / grouping has degraded or improved, you will probably find that there may be an alternate powder, and or bullet / primer combination that will improve or degrade the results. have you any paper targets with some results on?
    (The Unspeakable In Pursuit Of The Uneatable.) " If I can help, I will help!." Former S.A.C.S. member!

  5. #5
    No but I am hoping to go out tomorrow, weather permitting to try the back off lengths to see how that looks.

    If the max size is the 2.732" figure, what should I start at and what increments should I work back on?

    Cheers

  6. #6
    A lot of NON competition reloaders will tend to start at a minimum seating depth of one calibre, & go from there in set increments of your choice, I usually move stuff around a couple of thou', don't make up loads of stuff, you just want a couple of FIVE round groups for starters.
    (The Unspeakable In Pursuit Of The Uneatable.) " If I can help, I will help!." Former S.A.C.S. member!

  7. #7
    So a thousandth being 0.001 I could start at 2.730 then work back to 2.728, 2.726 etc?

  8. #8
    Yup!, or any combo you like yourself., just as long as you stay within the min/max dimensions, & your rounds cycle through your mag / action..... an invaluable thing to do is make written notations of all your adjustments, It can be very frustrating to find a great load, & find your records have been mislaid!.
    (The Unspeakable In Pursuit Of The Uneatable.) " If I can help, I will help!." Former S.A.C.S. member!

  9. #9
    Thanks ill give it a go and keep my notes and if I remember take some photos.

    It's funny all this length stuff as the factory loads i used to use were 2.553

  10. #10
    david if you are decreasing the seating distances, ie. oal from 2.553" to 2.730" start off with minimum safe powder charge as having the bullet that close to the rifling will greatly increase the pressure within the chamber, personally I would start 030" from the rifling, then 015", then 010" then reduce in 002" increments if neccessary, 2.732"-2.553"=.179", almost 3/16" or 4.5mm is a helluva jump in one go, with small increments you'll be safe not sorry...callie

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