Question about groupings?

Discussion in 'The Ammo & Reloading Forum' started by dsv424, Sep 14, 2009.

  1. dsv424

    dsv424 New Member

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    Not sure how to even phrase this question with out coming off as an idiot. But here goes. I'm kinda of a newbie and have been reloading for about a year now and would like to understand how groupings work and how to adjust for it. Mainly with loading .308 for my Saiga .308 16 inch. I mostly load with recipes between low and mid-range and most of the time I can group with my scope set within about 1 inch all around the bulls-eye from 100 yards. So here is my question: On some of my reloading recipes the grouping is 3 to 4 inches above the bullseye. It is still a nice group just not around and in the bullseye. Here comes the dumb question: Do you compensate for this by adjusting the scope for this load or is it something in the recipe that I can do to move the grouping down into the bullseye area? This has only occurred in 2 or 3 different weight bullets. The last one was with the Sierra 155 grain HPBT Palma MatchKing which grouped about 4 inches above the bullseye. Thanks for any wisdom someone may be able to impart on a newbie.:eek:
  2. woolleyworm

    woolleyworm Active Member

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    Oh Lord, please don't do that, we're already a saturated bunch as it is!! :D:D

    Your question makes perfectly good sense, here's my .02 :

    Once you have a load that groups well, don't change the load, you're liable to throw things all out of whack. Scope adjustments are exactly the thing you should do; document the load and the adjustment and you'll be all set. Typically, once i narrow down what my guns favorite load is, I don't tamper with the load at all. Usually no more than one load per bullet weight in a particular gun. I have yet to find that i'll load several recipes with the same bullet ( for a particular gun ). The gun will have a single favorite in most cases. For plinking and hunting, you may end up with different loads.

    My question of you would be this, have you worked up your loads extensively, across the whole spectrum of data? Just seemed to me that you have tried recipes here and there, maybe a little more load development will help you find that sweet spot and you won't have so many adjustment. There's so many options out there for the 308, its one of those kid in the candy store calibers for reloaders!

    Hope this helps, if not, LD will be along shortly and he can probably sum it up neater than I.

    Semper Fi,

    Woolley
    Last edited: Sep 14, 2009
  3. LDBennett

    LDBennett Well-Known Member

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    dsv424:

    A lot of things affect the point where you are aiming and where the bullet goes. It can be everything in the recipe: bullet weight, powder charge, primer, seating depth of the bullet, exact bullet selected.

    People searching out the best accuracy try varying all these parameters and still others to get to a group size they find acceptable. If you count all the possible variation that could be tried it would be hundreds and you would soon tire of the pursuit. I try a few variations: different powders, different bullets, different load levels and maybe even different bullet seating depths. Once I get an acceptable group size (anything close to an inch at 100 yds for the average of five 5 shot groups shot with the gun rested on the bench). For a hunting gun five three shot groups averaged is probably a more realistic measuring stick with acceptable group sizes perhaps twice that of a bolt operated varmint gun. Semi-auto guns like yours would be doing good to get under about 5 inches for five shot groups averaged at 100 yds.

    But it is all about what is acceptable to you. Once you got the magic load then adjust the sights to match the point of impact regardless of the indicated range on the sights. You should not adjust the recipe to change the point where the bullet hits if the best possible accuracy is required. Find the load you like and change the sights to accommodate your good load.

    But if your sights have pre-marked sighting ranges like 100,200 300 meters then you may want to adjust the load to get it to match the ranges marked on the sights but that may not give you the best accuracy. For this case you pick a bullet close to the "standard" for that particular caliber, vary the powder charge until you get the bullet to land in the center of the bull. You may have to try several different bullets and/or several different powders along with different powder levels. You may find a combination that only aligns with the sights at one range and not the others. And you may have to change everything again to find a load that has more acceptable accuracy and still hits the center of the bull.

    What's important... the sights matching the range or the best possible accuracy?

    Want more info on how to find the magic load either way? PM me.

    LDBennett
  4. olehippy

    olehippy New Member

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    Well said, Wooleyworm! dvs424, if your shooting tight groups your loading techniques and measurements are pretty precision and on target.

    I’m a little embarrassed to offer any advise here, there’s many, many experts online that can offer much better, but. . . each bullet weight, type of bullet, on and on behave differently. For tight groups, consistent bullets characteristics , powder charge, even consistent OAL’s and crimps have more effect than commonly recognized.

    I would recommend your first select a bullet/powder charge you like, I don’t shoot 308 but in the rifle calibers I do shoot, and as a mostly open range hunter, I mostly look for a round that behaves predictability at different distances – but whatever fits your shooting style.

    Then, perfect your load and THEN sight your scope in for that load. The next step in the game is to try different OAL’s ect ect for even tighter groups.

    I only change bullets is when the game I’m hunting changes (shooting varmints and mule deer lend to different rounds, as does those paper tigers at the end of the range), but when I do its time to sight in my weapon for that load.

    Hope a little lay (lame?) rambling helps you.

    Miles
  5. LDBennett

    LDBennett Well-Known Member

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    OPPS!

    Missed that there is a scope on the gun. In that case develop the best accuracy load and adjust the scope to the point of impact as I stated. Making the load match the sights is for open sighted guns, not scopes.

    LDBennett
  6. dsv424

    dsv424 New Member

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    Thx for everyones wisdom and advise. It appears I'll be dong more load adjustments, which is the most fun about this whole hobby. Back to the drawing board I guess, although I will probably have to start making a log on ideal scope settings for particular recipes that I like. One thing that I have never done before is to change the OAL from what is stated in the reloading book. This seems to be a dangerous practice for a novice like myself. I think I'll do a bit of reading on adjusting the OAL and pressure changes that will incure when this is done. I have sooooo much more to learn! It just seems as soon as I understand one thing another question pops up.:confused: Thx again.
  7. woolleyworm

    woolleyworm Active Member

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    There are a few well written threads on the subject matter of bullet seating and loading for a specific chamber. It's not nearly as complex as it may seem, just requires a few measurements and a little time.

    I have a leather bound log book for my reloading data and I assign each load a sequencial number. Any notes or data to go along with it are kept in one spot. I do have an excel file with load data also, but most notes are kept in the log book. Each time i fill out a sticker for my reloads, the load number is included, making it easy to check notes before heading to the range.
  8. cycloneman

    cycloneman Well-Known Member

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    Groupies are women who,,,,,,,, oh groupings. I like crown royal and coke. hehehehehehe
  9. Appliancedude

    Appliancedude Well-Known Member

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    I still drink like a kid. Vodka and OJ for me.
  10. LDBennett

    LDBennett Well-Known Member

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    Changing the overall length (bullet seating depth) to minimize group sizes is the opposite direction of changes that would increase pressure. That is, you make the OAL LONGER. The idea is you make it so that the bullet ends up closer to the start of the rifling when cartridge is in the chamber. There are limits, so you must read up on them.... you do not ever want the bullet to be forced into the lands of the barrel. You can try various seating depths from that point (but not so much that the OAL is less than what the recipe suggests). Variations in OAL of 0.005 inches can make a difference in some guns. That means more combinations to test!

    By measurement you find the OAL that allows the bullet to just touch the rifling. Then you back off a couple of thousandths. Try that load then move the bullet into the case by 0.005 inches and try that load. Then another 5 or 10 thousands, and so on but never make the OAL less than that called out in the manual.

    LDBennett
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