shooting charley Posted August 25, 2012 Report Share Posted August 25, 2012 Hi all just a quick question i am getting vertical stringing on a load i am developing what would you say is the main cause of this is. Shootingcharley. Quote Link to comment Share on other sites More sharing options...
Bewsher500 Posted August 25, 2012 Report Share Posted August 25, 2012 it would imply slightly different MV deviation could be as simple as clight charge difference, more complex issues would come from neck tension causing pressure differences and then MV variation how much are we talking, over what range and what load? Quote Link to comment Share on other sites More sharing options...
shooting charley Posted August 25, 2012 Author Report Share Posted August 25, 2012 We are looking at sub 1” at 125 yards the load is 26.5 grn of N133 neck tension is .224 bullet wt 40grns set 20 tho off the lands this is for a .204 Ruger. shootingcharley. Quote Link to comment Share on other sites More sharing options...
kent Posted August 25, 2012 Report Share Posted August 25, 2012 it strings vertically yet within 1" at 125 yds? try it further, is it much worse? Chrongraphs are you friend on load development especially if limited to such shorter ranges. if no issue with consistant speed then look at bedding, action screw tentions, mounts then scope and the hold you use try hard hold / soft hold and free recoil etc. Quote Link to comment Share on other sites More sharing options...
shooting charley Posted August 25, 2012 Author Report Share Posted August 25, 2012 I have put the load over a chronograph and got less than 15 fps variance over 12 shots which i don’t think is bad, at 200 yards it is about 1 ½ “ which would kill any fox but i would just like to get it right. shootingcharley. Quote Link to comment Share on other sites More sharing options...
kent Posted August 25, 2012 Report Share Posted August 25, 2012 I have put the load over a chronograph and got less than 15 fps variance over 12 shots which i don’t think is bad, at 200 yards it is about 1 ½ “ which would kill any fox but i would just like to get it right. shootingcharley. 15 fps will not effect 125 yds groups, the load is not yet sorted or its another issue. no point having a .20 cal if it wont do better than that IMO i can and do get better at 200 with the Hornet, not bragging just illustrating you aint getting the best out of it. Back to the loading room i think as i have no idea how good the gun is or shooter for that matter, it might need a different bullet or something difficult to say. But if you going for a tecnically superiour calibre to the run of the mill .22 CF's then there aint much point if it dont shoot better however "accurate enough" for 200yds foxes it might well be at that stated std. A note take the total added of velocities recorded then divide by the number recorded and you have the true Standard deviation or SD 15fps is good enough for any hunting purpose calculated as above it will not give you any real issues to much more distant ranges Quote Link to comment Share on other sites More sharing options...
Graham M Posted August 25, 2012 Report Share Posted August 25, 2012 Is the headspace OK.? G.M. Quote Link to comment Share on other sites More sharing options...
wymberley Posted August 26, 2012 Report Share Posted August 26, 2012 A note take the total added of velocities recorded then divide by the number recorded and you have the true Standard deviation or SD 15fps is good enough for any hunting purpose calculated as above it will not give you any real issues to much more distant ranges It's probably me, but try as hard as I can I can't undrestand that and it looks like a useful bit of info. Could you kindly reword that a little for the benefit of this thicky? Many thanks. Quote Link to comment Share on other sites More sharing options...
coyotemaster Posted August 26, 2012 Report Share Posted August 26, 2012 How is the barrel stock clearance? Vertical stringing is also caused by barrel/stock contact as the barrel warms. Quote Link to comment Share on other sites More sharing options...
shooting charley Posted August 26, 2012 Author Report Share Posted August 26, 2012 For toughs of you who are interested i have now got this load right it was as simple as adding 2 thou to the neck tension, Shootingcharley. Quote Link to comment Share on other sites More sharing options...
MiLisCer Posted August 26, 2012 Report Share Posted August 26, 2012 Your barrel is getting hot - unless you have a heavy barrel - if it is a sporter or lightweight barrel - then that will be the cause. Mike Quote Link to comment Share on other sites More sharing options...
coyotemaster Posted August 26, 2012 Report Share Posted August 26, 2012 I have never had a load string due to neck tension, although at present I anneal with regularity. I am not saying it is not possible just outside the realm of anything I had heard of. Quote Link to comment Share on other sites More sharing options...
kent Posted August 26, 2012 Report Share Posted August 26, 2012 It's probably me, but try as hard as I can I can't undrestand that and it looks like a useful bit of info. Could you kindly reword that a little for the benefit of this thicky? Many thanks. You add total velocities up then divide by number taken, thats the average velocity, to get the SD is then the individual velocity differences from the average previously calculated divided by the number of readings. sorry must have got sidetracked. OR buy a chrono that does it for you Quote Link to comment Share on other sites More sharing options...
kent Posted August 26, 2012 Report Share Posted August 26, 2012 I have never had a load string due to neck tension, although at present I anneal with regularity. I am not saying it is not possible just outside the realm of anything I had heard of. i dont aneal but i seriously doubt the load was sorted purely by adding 2 tho extra tention to the neck, although it might well have produced better at a subsequent testing. Even neck tention will have an effect but adding 2 tho more i seriously doubt that gave the improvement Quote Link to comment Share on other sites More sharing options...
dicehorn Posted August 27, 2012 Report Share Posted August 27, 2012 i dont aneal but i seriously doubt the load was sorted purely by adding 2 tho extra tention to the neck, although it might well have produced better at a subsequent testing. Even neck tention will have an effect but adding 2 tho more i seriously doubt that gave the improvement I think when ShootingCharley said adding 2 thou more neck tension he meant he reduced his bushing by 2 thou not the length of the neck by sizing it 2 thou more into the die. Quote Link to comment Share on other sites More sharing options...
kent Posted August 27, 2012 Report Share Posted August 27, 2012 I think when ShootingCharley said adding 2 thou more neck tension he meant he reduced his bushing by 2 thou not the length of the neck by sizing it 2 thou more into the die. Yes i am aware of that, it dont make much difference in terms of accuraccy unless his previous brass was springing back. If it were springing back then the bullets could be pushed into the case or pulled by hand. two tho' or four tho' of grip wont change a load significantly. This springing back sometimes occurs quite a while after the round is produced and is the only reason i know why extra tention of .002" would help Quote Link to comment Share on other sites More sharing options...
dicehorn Posted August 27, 2012 Report Share Posted August 27, 2012 Kent - I can assure you that on the very small cases 2 thou can be quite significant in closing up groups. I see you do not anneal, so I suppose it follows that your theory once again is that " it dont make much difference in terms of accuraccy". Apart from extending brass life it does also to a certain degree assist with the prevention of excess spring back. Can I assume you use Redding bushings on your various calibres? Quote Link to comment Share on other sites More sharing options...
kent Posted August 27, 2012 Report Share Posted August 27, 2012 Kent - I can assure you that on the very small cases 2 thou can be quite significant in closing up groups. I see you do not anneal, so I suppose it follows that your theory once again is that " it dont make much difference in terms of accuraccy". Apart from extending brass life it does also to a certain degree assist with the prevention of excess spring back. Can I assume you use Redding bushings on your various calibres? No i am not having it coz after testing i never found a jot of difference, i have had spring back giving issues- but 2 tho' or 4 tho' nope! grip is grip. when you consider the bullet re-expands it anyway on seating another .002" is nothing provided the first is good (which it might not be). Even necks are the key not tighter ones, pull a bullet from a std one size fits all neck die and one from a bushing they should be quite similar due to the fact that the bullet re-expands them i use LE Wilson gear generally and buy one size smaller bushing at the same time as the so called correct one as you dont know how much spring back will occur. i don't anneal and can get many,many reloads before i get cracked necks. Correct anealing will extend life bad anealing wont, there are some cartridges that need anealing as the brass is overworked in fire-forming etc. but i don't care to own such guns personally. Quote Link to comment Share on other sites More sharing options...
wymberley Posted August 27, 2012 Report Share Posted August 27, 2012 You add total velocities up then divide by number taken, thats the average velocity, to get the SD is then the individual velocity differences from the average previously calculated divided by the number of readings. sorry must have got sidetracked. OR buy a chrono that does it for you Many thanks, I'm with it now. That makes 4 methods that I've looked at and they give 4 different answers (I like yours as it's the lowest figure). I was only looking at it half out of boredom and half to see what factory loads produce so I could compare my homeloads. However, just read Denton Bramwell (whoever he is, but he makes perfect sense) and I think I'll just aim to continue to keep my spread to below 50 (which it would seem is about 60% of across the board factory loads). Quote Link to comment Share on other sites More sharing options...
dicehorn Posted August 27, 2012 Report Share Posted August 27, 2012 Even necks are the key not tighter ones, pull a bullet from a std one size fits all neck die and one from a bushing they should be quite similar due to the fact that the bullet re-expands them Similar as in English Springer Spaniel and Welsh Springer Spaniel? LOL. OK I will just have to accept your opinion - not something that would be shared with by most benchrest shooters. I assume you also shoot something in the .17 to 20 calibre range to have come to these conclusions? Quote Link to comment Share on other sites More sharing options...
Catweazle Posted August 27, 2012 Report Share Posted August 27, 2012 A note take the total added of velocities recorded then divide by the number recorded and you have the true Standard deviation or SD 15fps is good enough for any hunting purpose calculated as above it will not give you any real issues to much more distant ranges That's not Standard Deviation. Here is a short explanation on why there is a difference between your "average of the difference to average" and SD. http://www.mathsisfun.com/data/standard-deviation.html#WhySquare Quote Link to comment Share on other sites More sharing options...
Redgum Posted August 27, 2012 Report Share Posted August 27, 2012 I say its odds on being barrel heating up, bad stock fit or driver error if its stringing. Neck tension, not quite right load or OAL will open up groups but not vertical stringing. Quote Link to comment Share on other sites More sharing options...
kent Posted August 28, 2012 Report Share Posted August 28, 2012 That's not Standard Deviation. Here is a short explanation on why there is a difference between your "average of the difference to average" and SD. http://www.mathsisfu....html#WhySquare I know i lost the end of the paragraph somehow, check the latter post Quote Link to comment Share on other sites More sharing options...
kent Posted August 28, 2012 Report Share Posted August 28, 2012 Similar as in English Springer Spaniel and Welsh Springer Spaniel? LOL. OK I will just have to accept your opinion - not something that would be shared with by most benchrest shooters. I assume you also shoot something in the .17 to 20 calibre range to have come to these conclusions? No i dont but my conclusion is based on real testing and simple common knoledge that the bullet pushes the brass out adding .002" if the present setting gives correct grip will not add any appriciable amount of grip as its re-expanded via the bullet. I have had past issues with grip relaxing and needing to move it more in the first place but if you doubt me try this; load one round with a factory non bushing die on the neck and one with your favoured bushing. Now pull both bullets with a kinetic hammer and re-insert the bullets in both with a hand die in an arbour press or between your knees. Both will feel the same, simply the brass moves back from the bullet just like using an expander mandrel. Quote Link to comment Share on other sites More sharing options...
Catweazle Posted August 28, 2012 Report Share Posted August 28, 2012 I know i lost the end of the paragraph somehow, check the latter post That's wrong too. Have a look at the link I posted, right at the bottom of the page it explains the importance of square and square root in the equation - to take account of numbers well outside the normal. In our terms they would be "fliers". Perhaps we have a mathematician here who can explain it better than me, it's not something I would ever use in reality. Quote Link to comment Share on other sites More sharing options...
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