Berger seating depth test results - what do you think?

Discussion in 'Reloading' started by bookworm, Sep 11, 2009.

  1. bookworm

    bookworm Well-Known Member

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    I loaded up some 190gr Bergers for my Remington 700 300 win mag with H1000 powder. Per the recommendations in an article on this site I loaded 4 different seating depths ranging from 0.010" to 0.130" and shot two groups of three of each depth. The article said that one depth would group better than the others. What I found instead is one depth grouped poorly and the other three were somewhat close. I shot in round robin fashion and here are the results:

    Depth 0.010"
    Group1 = 0.79"
    Group2 = 1.51"
    Ave = 1.15"

    Depth 0.050"
    Group1 = 0.98"
    Group2 = 0.99"
    Ave = 0.99"

    Depth 0.090"
    Group1 = 0.68"
    Group2 = 1.20"
    Ave = 0.94"

    Depth 0.130"
    Group 1 = 2.12"
    Group 2 = 1.60"
    Ave = 1.86"

    There was some inconsistency between my first and second rounds, as you can see (could have been barrel heat, or me?). It appears that the 2nd and 3rd depths were close on average, but one turned in a better group and the other was more consistent (or I was more consistent).

    Given this data, what would your next move be? Would you duplicate the 2nd and 3rd depths again and another one or two in between and give it another go? Or would you pick one of the above and run with it.

    Part of my dilema is the fact that I'm running out of time between now and hunting season. I still need to tweak powder charge, as these were loaded near the min loads.

    Looking for recommendations to get me to a reasonably optimized load in the most efficient manner possible.

    Thanks.
     
  2. trebark

    trebark Well-Known Member

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    All four of your tests yielded 1moa or more. My recommendation would be work up loads using increasing powder charges. Find the load that will give you .5moa, then start tweaking the seating depth to fine tune the load.
     

  3. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Good test, but I wuld say your results are inconclusive. From what I've read here, Bergers like to be seeated to the lands or slightly jammed or slightly off. So I would recommend trying some seated to the lands. Also, you just might not be hitting your rifle's sweet spot for this bullet and powder combo. It's the old which came first, the chicken or the egg?

    I'm going to be doing some load development on the Bergers and my approach will be to seat them to the lands based on what I've read and find the best powder charge for accuracy starting with max and working down. Then I'll try fooling with the depth.

    Hope you get it worked out... those groups are plenty good for 400 yd shots :)

    You might also try anther powder and/or bullet....

    one more thing.... I found loading 210 Bergers to the lands in my Sako 300 WSM gave them only 2/3rds contact with the neck. I dont think I could have loaded the 190's to the lands with much contact at all.
     
    Last edited: Sep 11, 2009
  4. shootinfool

    shootinfool Well-Known Member

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    I would say take the one that yeilded the best, consistant groups and tweek it up or down. If you can use that one this year for your hunts then use it now and work on getting better in the spring or after the hunt, depending on weather. Did you run them over a crono? if so which has the most consistant velocity with the smallest deviations? You can also try retumbo powder, alot of guys get good results with this powder. I personally use 7828ssc and get very good SD and ES and very good accuracy with it.
     
  5. bookworm

    bookworm Well-Known Member

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    I did run them over a chrony. They were all pretty similar on average. I have some of the 3 shot groups pretty tight with ES around 10, and I have some that are more up around 30. There does not seem to be a correlation between group size and velocity ES.

    What kind of ES should I be looking for as being reasonable for what I'm trying to do?

    I'm wondering if I should fire a few more with the Bergers touching the lands? I have heard that they like to be touching or in the lands, but I followed the process outlined by the fella that posted an article that works for Berger.

    Or, would you go ahead and work on the powder load with one of these seating depths and then tweak seating depth once I find powder charge.

    I'd like to keep shooting until I find something that gets me to 0.5moa, but I don't think I have the time and frankly I'm not sure this particular rifle is capable. And while I don't want to think this...perhaps it is me that is not capable of shooting .5 moa consistently.
     
  6. shootinfool

    shootinfool Well-Known Member

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    I only mentioned the ES and the SD for long range purposes. You might have a load that is producing 3/4 moa at 100 with a very high SD that will throw you problems down range due to the differing starting velocities. An ES of 10 is very good. This also rules out the possibility of the loading process causing you problems. If you have found a load that has a low SD and ES then that is a good place to start. You are right about the bergers liking to be jammed. I too have read the thread about getting the best accuracy out of the bergers and after reading it, i wondered what my rifle would see. I currently see on average .5 moa out of this gun. The best accuracy that i have ever gotten out of my setup is .217 @100 on paper. I have recorded some .3moa groups on steel down range but that is not the norm, it usually stays around .5moa when i do my part. I jam mine .005 and they shoot very well. when i went back and tried the steps that were mentioned mine only got worse. the best accuracy out of them was when i jammed them. I will say that i got no bad groups, the largest was around 1.2 inches or so at 100. If they will fit in the mag well while jamming the bullet, then give it a try if you are not worried about it. Like i said before, if you dont have the time and resources then go ahead and pick the one you like the best and test it at ranges that you will shoot to make sure it will work for you, and use it. work on getting the .5 moa at a later point in time where you have the time to work with it. It can be a frustrating process but in the end it is all one big learning experience that will only help you on the next one. Good luck and let us know how it goes!
     
  7. cdn shooter

    cdn shooter Active Member

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    I tried the seating depth test with two different rifles and I did in fact find that in both there was a spot that was considerably better than everwhere else. But it was almost exactly where I've found other bullets shoot their best if measuring from head to ogive. Maybe it was a fluke in my case.
     
  8. jmason

    jmason Well-Known Member

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    I would use this depth because of the depths you tested it is clearly producing the most consistent results.
    Depth 0.050"
    Group1 = 0.98"
    Group2 = 0.99"
    Ave = 0.99"

    Like .280 fan said I would now work on your powder charge. If the intention is long range I wouldn't fret too much about 100 yard groups. Get a powder charge that yields a consistent (low) ES/SD and send them down range further to see what you get. Your powder charge stands to make the most change in your results.
     
  9. MontanaRifleman

    MontanaRifleman Well-Known Member

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  10. Varmint Hunter

    Varmint Hunter Well-Known Member

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    For a hunting rifle you really don't want a load where the bullets are into the rifling if an acceptable load can be developed with the bullet off the rifling or even at magazine length.

    In my 300RUM, the 210VLD shoots better @ .020" off the rifling than it does loaded into the rifling. Loading at magazine length didn't work in this rifle so I will be using the .020" off length.

    In a custom .308 I tried loading an Accubond to the magazine length just to see how it would shoot. At magazine length, the bullet ogive is .122" off the rifling. Believe it or not, this proved to be a more accurate oal than any other that I tried and regularely shoots under .5".

    I agree with the author, Berger VLD's will often shoot quite well with a jump to the rifling. You just have to find the correct amount of jump for your rifle/load combination. There is often more than one "sweet spot" so a little experimentation is always a good idea. Contrary to what is often posted on the web, bullets don't always shoot best when close to (or into) the rifling.
     
  11. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Varmit Hunter,

    In case there might be a misunderstanding, I am in no way implying that bullets *always* shoot better when seated to or just off the lands. I am implying that from what I have read in these forums and others, I am under the impression that *most* (not all) of the reports I read say the Bergers shoot best when seated to the lands. My impression made be wrong and I didn't see anyone mentioning that to the OP so I just though I would offer it. The best results I've seen from any bullets fired from MY 300 WSM are the Bergers seated to the lands.

    I think we all agree that different rilfes and different powders and bullets produce different results. Some might like the Bergers or what ever bullet seated .100 off and some might like them in the lands, but I think that in most cases, Bergers like very little jump, if any jump at all, and this is why I sugested to the OP to find the sweet powder charge and then fien tune the seating. He may be using a charge that his rifle just doesn't like and in my past experiences, the powder charge seems to affect accuracy more than seating depth... just my experience.
     
    Last edited: Sep 13, 2009
  12. bookworm

    bookworm Well-Known Member

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    Thanks for everyone's input and help. Here are answers to a few questions by MontanaRifleman:

    Yes, very often there are two of the three shots very close (often 1/2" range) with one that flies out by an inch or more. In fact, as I sit and look at my targets right now, I see that of the 6 groups that were similar (1 - 1.5 moa), every one of them followed that pattern. Two shots will be 0.25" to 0.5" and then the 3rd is out by an inch or so.

    My rifle is a standard Remington 700 SPS dropped in an HS Precision stock and trigger adjusted down to 3#. I saw no improvement in accuracy with the HS stock, so I just returned it. I'm going to go with a laminate stock and will pillar and glass bed...which is next weekend's project.

    I clean after every trip to the range, which is 20 to 40 shots. I usually shoot 3 fouling shots.

    No, I have not shot MOA consistently before. I've been shooting casually for a lot of years but am a newbie to the higher accuracy and long range stuff. I'd like to get my hands on a proven rifle and see if part of the problem is me. I'm shooting off of a solid concrete table with a stable rest on the front and a nice leather rabbit ear bag in the rear. My shots are breaking clean and everything seems to be very steady.

    Also, I've tried a couple different scopes to rule out a bad scope as a contributing factor.

    Keep the suggestions coming - I appreciate the input.
     
  13. Varmint Hunter

    Varmint Hunter Well-Known Member

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    MontanaRifleman,

    My comment was not in reference to anything that you or any other individual has posted. After reading thousands of posts, over several years, one could interpret that most bullets shoot best at, or into, the lands. I'm not sure if that is true or not but there are certainly many fine shooting rifles that use ammo loaded with bullets that are well away from the rifling. I doubt that any factory match ammo has bullets that will be close to the rifling but it still shoots competitively in many different firearms. Some of my A-Max loads shoot very tight groups when seated deeply in the cases. I'm not convinced that "close" is inherently more accurate.

    My point was simply that for hunting purposes, I'd rather look for an accurate load with bullets loaded well off the rifling than to get hung up looking for a load that should be accurate because the bullets are close to, or into, the rifling.

    I also think that it would be beneficial to work up his powder charge until he is in the range of where his final load will be, then try tuning for oal. As pressure changes so do other related factors such as the best seating depth. At least that has been my observation.

    Charlie

     
    Last edited: Sep 13, 2009
  14. MontanaRifleman

    MontanaRifleman Well-Known Member

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