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Post by timbers on Feb 18, 2016 16:42:53 GMT -5
I've already done some load development with the hornady 285 grain hpbt in the past and had a decent load worked up and the last time I shot I had a six shot group at 1 3/4" c/c @ 400 yds. I was trying to reload a bunch of these today and I kept coming up with different c.o.a.l every 7 or 8 rounds. The best I can tell is the ogive on these bullets are not the same. I did have two different batches of bullets with different lot numbers and I have kept them separate but there doesn't seem to be any real consistency with either batch. Some can be off a few thousands to as much as 30 thousands! I've reloaded for .223 and .308 in the past and never had this problem. This can't be normal can it?
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Post by timbers on Feb 18, 2016 16:45:38 GMT -5
Forgot to add that this is for a 338 lapua with lapua brass.
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Post by Deleted on Feb 18, 2016 17:22:10 GMT -5
Inconsistent tips are pretty normal but 30 thou would be a lot in my opinion. That's enough to possibly cause issues with magazine feed rifles. A lot of top notch guys measure everything to the ogive and don't care much about OAL consistency after desired length is established. Do you have an ogive comparator? I would bet your ogive are doing pretty good, if not you have some malformity with your seating die IMO.
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Post by timbers on Feb 18, 2016 18:14:19 GMT -5
I do not have a comporator guess it's time to buy one. I've just been using brass fired from my gun and slightly size the neck and seat the bullet in my chamber and check them this way. Maybe this isn't the best way to do it but I am noticing the same pattern with the same bullets that are giving me problems doing it this way. I didn't mention I'm marking the bullets and brass with the dimensions then pulling them to recheck. I hadn't really thought about the die I guess, I've used it before without problems but it wouldn't hurt to check it out. Maybe it got some trash in it. I really appreciate all the help.
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Post by Deleted on Feb 18, 2016 22:46:10 GMT -5
Not sure I completely follow. You are chambering the reloads and having issues with some?
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Post by 7mmfreak on Feb 19, 2016 7:36:46 GMT -5
I think I am to understand that he uses a partially sized case to determine base to ogive when jammed. It works but you won't get a true length to the leade like you can with a Lock'n'Load tool. You will always get a jammed length that can be jammed up to .030" based on having measured both ways; I used his method when I was a kid although I used a hack saw to split the neck like a collet to give less neck tension.
I don't worry about differences in base to tip; it will always be large enough to concern you until you realize it doesn't matter too much. I worry about base to ogive because it is the measurement that matters in regard to variance. Depending on the quality of your bullet and die quality BTO should be .010 or less. Good bullets and dies will usually be .003" or less. That variance is why you will often see a recommendation to either shoot jammed (specific purposes ) or a minimum of .010" jump.
Find your base to ogive length when kissing the lead then measure your overall length and make sure it fits your magazine. If it doesn't back it up until it does then measure your BTO and work from there.
If you are getting unexplained fliers my first question is do you adjust your seating die to make the overall length the same for each cartidge? If you are you are changing your jump every time you do. If this is a new problem have you cleaned your dies regularly? How many firings do you have on your brass?
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Post by timbers on Feb 19, 2016 8:56:48 GMT -5
Thanks for explaining it better for me 7mmfreak! I had seen variances in bullets and aol before when reloading but never this extreme so it had me frustratd. This is only my second loading on this particular brass and I'm using rcbs dies. I'm going to clean my dies today and I also ordered a comporator online last nite. I really appreciate all the help guys!
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Post by esshup on Feb 19, 2016 22:37:14 GMT -5
I'm with 7mmfreak. I experiment with the base to ogive dimension when searching for group size after the powder charge has been determined and don't care about COAL unless it's too long to fit in the magazine. I can't even tell you what the COAL is for my different rifles.
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Post by 7mmfreak on Feb 20, 2016 7:23:16 GMT -5
I only know my COAL for gas guns.
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