Hi all,
I've not been reloading for that long, less than a year to be exact, but have loaded a decent amount of rounds in that time.
Most of my loads have been for deer/vermin/other game but I have loaded a few for 'target' or practise use in the .308.
Whilst researching, I came upon a strange phenomenon around the topic of seating depth.
Reloading books and manuals offer pretty much the same advice, seat the bullet to a depth that produces a cartridge overall length (COAL) that is recommended by the bullet manufacturer. This usually gives a length that will fit nicely into the magazine of any sporting rifle, feeding well and not causing any safety concerns.
Unless satisfactory results (usually 1 MOA or less on a sporting rifle) cannot be attained by adjusting the powder charge, then you should adjust seating depth.
Now, I've loaded for two chamberings (.308 and .270, but will soon tackle the .243 and .223) and during this time have tried about half a dozen types of bullets. At no point have I had to alter seating depth outside of manufacturer recommendations, let alone extend COAL to the point that single feeding or modification of the magazine was necessary. In fact, most of the loads I have tried in my rifles have performed so well that I deemed further development pointless as I would be unable to detect any improvements with my current level of shooting ability.
I realise that the average hunting bullet and older match bullets were of tangent ogive design, which has the advantage of seating depth tolerance but the disadvantage of a reduced ballistic coefficient when compared to secant ogive designs. I appreciate that bullet designs have evolved over the years, with companies such as Berger producing 'Hybrid' designs that claim to offer the best of both worlds.
To put it bluntly, manufacturers are moving away from designs that are sensitive to seating depths and require tweaking to produce good loads.
Yet, many a post on the reloading section of this forum seems to fixate on this issue, as it is something that gives the greatest appreciable visual difference when comparing loaded rounds.
Whilst such discussions should not be dismissed out of hand, adjusting seating depths on secant ogive bullets to deliver the nth degree of accuracy and precision would be more at home on a benchrest or F-class forum.
To see questions being asked about extended seating depths on hunting bullets which were designed to be loaded to a certain depth in the neck and not extended further makes me wonder why bullet manufacturers should even bother with load data when the consumer evidently knows more about cartridges, reloading, bullet design along with internal and external ballistics than the experts employed by the manufacturers.
'Jamming the lands' is a practise which even the highest echelons of competition shooters have been moving away from, listen to Bryan Litz and his thoughts on the matter:
Whilst measuring the distance to lands is not bad practise by any means, the idea that this is necessary for the purpose of tuning seating depth in hunting rounds strikes me as being highly unnecessary but I'm happy to be corrected by an authority on this matter.
Maybe we should worry less about whether people choose to call bullets 'heads' and more about how they are being used.
Cheers.
I've not been reloading for that long, less than a year to be exact, but have loaded a decent amount of rounds in that time.
Most of my loads have been for deer/vermin/other game but I have loaded a few for 'target' or practise use in the .308.
Whilst researching, I came upon a strange phenomenon around the topic of seating depth.
Reloading books and manuals offer pretty much the same advice, seat the bullet to a depth that produces a cartridge overall length (COAL) that is recommended by the bullet manufacturer. This usually gives a length that will fit nicely into the magazine of any sporting rifle, feeding well and not causing any safety concerns.
Unless satisfactory results (usually 1 MOA or less on a sporting rifle) cannot be attained by adjusting the powder charge, then you should adjust seating depth.
Now, I've loaded for two chamberings (.308 and .270, but will soon tackle the .243 and .223) and during this time have tried about half a dozen types of bullets. At no point have I had to alter seating depth outside of manufacturer recommendations, let alone extend COAL to the point that single feeding or modification of the magazine was necessary. In fact, most of the loads I have tried in my rifles have performed so well that I deemed further development pointless as I would be unable to detect any improvements with my current level of shooting ability.
I realise that the average hunting bullet and older match bullets were of tangent ogive design, which has the advantage of seating depth tolerance but the disadvantage of a reduced ballistic coefficient when compared to secant ogive designs. I appreciate that bullet designs have evolved over the years, with companies such as Berger producing 'Hybrid' designs that claim to offer the best of both worlds.
To put it bluntly, manufacturers are moving away from designs that are sensitive to seating depths and require tweaking to produce good loads.
Yet, many a post on the reloading section of this forum seems to fixate on this issue, as it is something that gives the greatest appreciable visual difference when comparing loaded rounds.
Whilst such discussions should not be dismissed out of hand, adjusting seating depths on secant ogive bullets to deliver the nth degree of accuracy and precision would be more at home on a benchrest or F-class forum.
To see questions being asked about extended seating depths on hunting bullets which were designed to be loaded to a certain depth in the neck and not extended further makes me wonder why bullet manufacturers should even bother with load data when the consumer evidently knows more about cartridges, reloading, bullet design along with internal and external ballistics than the experts employed by the manufacturers.
'Jamming the lands' is a practise which even the highest echelons of competition shooters have been moving away from, listen to Bryan Litz and his thoughts on the matter:
Whilst measuring the distance to lands is not bad practise by any means, the idea that this is necessary for the purpose of tuning seating depth in hunting rounds strikes me as being highly unnecessary but I'm happy to be corrected by an authority on this matter.
Maybe we should worry less about whether people choose to call bullets 'heads' and more about how they are being used.
Cheers.
Anyhow, all shots were called good. It is a well fitted and familiar rifle that was shot under controlled conditions on my belly using a bipod. Conditions were calm. Many people would accept all those group sizes as acceptable for a working field rifle but it is still abundantly obvious at what point the ammunition produces its best and it coincides with the advice given by manufacturers. Tis why when I work up loads, I simply load them all up approx 30thou back and shoot a quick OCW Satterlee test over the chrono which takes about 10 rounds, pick my lower accuracy node from the velocity data, load up another 5 at that charge weight and almost everytime it results in a stellar load and that is my load complete in sometimes less than 15 rounds.
