flytie 1 Posted March 13, 2010 Author Report Share Posted March 13, 2010 it all depends on the rifle mate, some rifles like a jump back from the lands, and others like to be seated touching the lands, most reloading books quote that for hunting rifles the SWEET SPOT is in around 20 to 40 thou of the lands, with most of the bullets i shoot i have found this to be true.. Snap. Snap, I totally agree. You have to bear in mind that with the SST (being only 129gn) there is no way on earth that I am going to get it seated anywhere near to the lands. I have just increased, very gradually, my COAL untill I found a sweet spot, just as you suggest. Now I am going to play with powder weights and see if this affects the sweet spot at all. ft Quote Link to post
SNAP SHOT 194 Posted March 13, 2010 Report Share Posted March 13, 2010 i tend to move the col back 5 thou at a time, but gererally now just stick to 20 thou as it seems to be spot on every time... i just test 105g a-max in the .243, and its shooting into .3 of an inch on first trials....!!!!!!! so i think my testing finished already....lol Snap. Quote Link to post
dicehorn 38 Posted March 13, 2010 Report Share Posted March 13, 2010 Peter, I tried to get the longest COAL because; I quote from Modern Reloading by Richard Lee, "Most rifle ammunition produces best accuracy with the bullet seated so it almost touches the rifling. Few people know the reason this works so well. It provides a uniform start pressure." Similar info in my other reloading books. ft I would not argue with Richard Lee and his knowledge of reloading - well hell yes I would argue with that statement - if he was referring to bench rest custom rifles - then I am on his side. I reload for a friends 6mm x 284 weighing in at a respectable 19 lbs and that likes the bullet head rammed into the lands before it will shoot. If Mr Lee was just referring to bog standard hunting rifles then his statement is misleading. Consider this - If you were loading just on or within 10 thou of the lands in a hunting rifle, only perhaps 15% of these rifles will accept these long bullets into the mag - so.....if they shoot best around the lands - why did'nt the rifle manufacturers take this into account when designing the magazine? Have a look at this piccy - a friend's 6.5 in Sako that I developed loads for. You will see I set out for a five shot group then altered the scope down for the final two shots - please note the distance from the lands http://i438.photobucket.com/albums/qq101/wyndog/Graham1.jpg Two other friends I reload for both with 6.5 using Styers group sub .5 - one is 205thou and the other 215 thou back - sorry no pics My 6.5 shoots well even from a cleaned bore - bullet is 220 thou from the lands http://i438.photobucket.com/albums/qq101/wyndog/hpqscan0001.jpg And whilst nothing to do with 6.5, my 22.250 pics - only to reinforce my arguement! At 200 yards - lands distance 222 thou http://i438.photobucket.com/albums/qq101/wyndog/R93Varmint204yds.jpg and at 100 yds http://i438.photobucket.com/albums/qq101/wyndog/100yardR9322250.jpg FT I think what is not talked about with the seating depth is this - if you keep the bullet long, you have a situation whereby it creates a lot of air space at the top of the powder in the case ie the longer the bullet the more air space - fine if you wanted to shoot up in the air - the powder is all packed against the primer flash hole and will give an even burn rate. However we all shoot just about on the horizonal, so with the long seated bullet the powder lies also on the horizontal in the case, perhaps almost exposing the flash hole, so you are potentially not going to get an even burn rate. Conversely, if you seat the bullet well into the case, you natuarally take up the air space and so get an even burn rate. FT I am not suggesting for one moment that you start seating the bullet at a different distance from where you are at the moment- it could be that your extra 2 grains you use over mine takes up some of that all important air space in the case - the above was just my attempt to query the experts who say nearer to the lands = more accuracy Peter Quote Link to post
flytie 1 Posted March 13, 2010 Author Report Share Posted March 13, 2010 Peter, I tried to get the longest COAL because; I quote from Modern Reloading by Richard Lee, "Most rifle ammunition produces best accuracy with the bullet seated so it almost touches the rifling. Few people know the reason this works so well. It provides a uniform start pressure." Similar info in my other reloading books. ft I would not argue with Richard Lee and his knowledge of reloading - well hell yes I would argue with that statement - FT I think what is not talked about with the seating depth is this - if you keep the bullet long, you have a situation whereby it creates a lot of air space at the top of the powder in the case ie the longer the bullet the more air space - fine if you wanted to shoot up in the air - the powder is all packed against the primer flash hole and will give an even burn rate. However we all shoot just about on the horizonal, so with the long seated bullet the powder lies also on the horizontal in the case, perhaps almost exposing the flash hole, so you are potentially not going to get an even burn rate. Conversely, if you seat the bullet well into the case, you natuarally take up the air space and so get an even burn rate. FT I am not suggesting for one moment that you start seating the bullet at a different distance from where you are at the moment- it could be that your extra 2 grains you use over mine takes up some of that all important air space in the case - the above was just my attempt to query the experts who say nearer to the lands = more accuracy Peter Peter, again I will say that with 129gn SST's the term "nearer to the lands" is a relative term as with this length of bullet, when pressed into a correctly trimmed case there is no way it will reach the lands. I started out using the Hornady recommended length, 2.905" and 40gn of N160, which is towards the top end of the powder weights they give for N160. I have slowly increased both the COAL and the powder weight untill I found a load which seems to work in my rifle. I am still going to play with powder weights. Using my Stoney Point guage my length to the lands (bullet tapped to seat into the lands, the rod locked off, guage taken out, bullet tapped out of the barrel, reseated into the dummy case and measured) is 3.225". Given that I am seating at 3.080 there is plenty of space to the lands. Forgive me if I try and model my reloading on what proven experts in their field have published, but it seems to work. Seating nearer (as per the experts) the lands improved my accuracy, as did using a load that filled my case nearer to the maximum. I have gone from a rifle that with Federal Powershoks would do 3/4", to 1 1/2" with RWS and now to .442" with homeloads, not too shabby from a Finnlight and an old crock driving it. I still have lots to learn, and it will be fun finding out what works in my rifle. ft Quote Link to post
dicehorn 38 Posted March 13, 2010 Report Share Posted March 13, 2010 (edited) Using my Stoney Point guage my length to the lands (bullet tapped to seat into the lands, the rod locked off, guage taken out, bullet tapped out of the barrel, reseated into the dummy case and measured) is 3.225". Given that I am seating at 3.080 there is plenty of space to the lands. ft If my maths is correct FT your bullets are seated 145 thou back from the lands and (hopefully) proves my point over the people who say you must be 0 to 50 thou back FT - do get yourself a comparator - they do give a more accurate reading than tip to headstamp- measuring from the ogive gives a more precise measurement Peter Edited March 13, 2010 by dicehorn Quote Link to post
flytie 1 Posted March 13, 2010 Author Report Share Posted March 13, 2010 If my maths is correct FT your bullets are seated 145 thou back from the lands and (hopefully) proves my point over the people who say you must be 0 to 50 thou back FT - do get yourself a comparator - they do give a more accurate reading than tip to headstamp- measuring from the ogive gives a more precise measurement Peter Peter, those awfully nice people at Reloading Solutions should have already posted me one, hopefully it wil arrive early next week. ft Quote Link to post
dicehorn 38 Posted March 13, 2010 Report Share Posted March 13, 2010 If my maths is correct FT your bullets are seated 145 thou back from the lands and (hopefully) proves my point over the people who say you must be 0 to 50 thou back FT - do get yourself a comparator - they do give a more accurate reading than tip to headstamp- measuring from the ogive gives a more precise measurement Peter Peter, those awfully nice people at Reloading Solutions should have already posted me one, hopefully it wil arrive early next week. ft Well done FT - that will be one item of your reloading kit you will never get rid of. Quote Link to post
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