Hi All,
Hmm I have heard this nonsense about being 0.005" off the lands too
.
Have you ever seriously checked through a box of bullets?
The position of the actual ogive can and often will vary by as much as 0.25"
so how can you seat to only 0.005"?
Also if you load for enough differetn rifles you will find the errors in the statement
I found this out whilst loading some Hornady 139 grn 7mm bullets for a hunting trip. I brought a box of their 139 Flat pointed bullets and their Spire points. Using the same load i.e powder charge, case and primer and seating both bullets out a little from the cannulure to reduce the jump to teh thraot as the "experts" recommend I found the the flat ppinted bullets shot nice tight groups but the spire points produced a spread of about 1 3/4"
The problem with the flat point bullets is that thet hang up on the left side of the chamber mouth when trying to feed from the mag which is no good
so I was left with only a few weeks in which to sort to spire point load out
Tried varying the seating depth out more, reducing the charge, increasing the charge and nothing I tried grouped anywaer near like the FP bullets and none smaller than about 1 3/8" groups size. It was then that I tried seating the bullets base level with the juncture os the neck. the group tighten up some. Finally I ended up with the bullet seated about 1/16" out from the cannulure and a slightly increased powder charge from the FP bullet load. This combination shout right on 1 MOA but the bullet had losts of jump to reach the leade.
In my 6.5x55 spoerterised Swedish Mauser it likes Speer 120 grn falt based bullets, the jump on these is more like 1/4" and if I do my part groups of 1/2"-5/8" are fairly normal. I also have a bolt action rifle chambered in 30-30 win which loves 125-130 Grn spiters, again lots of jump to the leade and as of yet I have not ben able to get such good groups using 150 grn RN bullets which have less jump.
My personel experieince has been that there is NO hard and fast rule about jump distance, every rifle is different and what the benchrest crowd is different because their rifles are totally different wiht minimum chambers and tight necks whihc require carefully matched cases with turned necks to minimum clearances.
A guy at the gun club is trying to improve his groups in his pest control rifle, it's a .223 chambered rifle and he has finnaly gotten around to turning the necks nd his groups hae opened up a little
some one has told him the barrel is shot out for some reason he asked me what I thought was wrong
so after getting him to describe his relaoding process which it seems has maily been adopted from what he has read on the benchrest way. I asked about his rifle, it has a normal factory barrel and chamber
so by turning the necks he has increased the clearence and made the cartridge alignment in the chamber worse .......... not better. he then tried loading a few cases that had not been turned and his group size improved again
It was hard work explaining to him that if he wanted to use all the bench rest techniques then he would have to have a tight neck chamber and also get a benchrest seating die or micrometer match seating die to keep the jump exactly the same for each round which would need to be checked with a guage which measures on the ogive and not the point to elimnate any varibles from the manufacturing proccess of the bullets.
Sometime we get blinded by it all