Neck Tension and seating depth
- Thread starter akinswi
- Start date
I say you should continue to seat your bullets at the same die setting you have been using, and see if there is any difference in the COL measurement. I would be suspicious that the increased tension would cause an increase in resistance to seating, producing a slightly longer bullet, and changing the distance to the lands.
isnt that called neck tension?
I don't see where that would matter. Seating depth depends on "fixed" constants that you set, and consistency of the bullets contacting the seating stem at the same point of their length.
Squeezing the neck a little tighter means the force needed to seat the bullet will increase slightly, but that doesn't change the distance of full ram travel, though if it increases enough to where the seating stem is actually digging into the bullet, you've gone too far.
Often it is, but the correct term is from SAAMI's glossary...
BULLET PULL
The force required to extract a bullet from the case into which it was loaded.
Military ammo has specs for it. 60 or more pounds for 30 caliber service ammo, at least 20 pounds for match ammo. For each pound of force needed for these,13 psi in the case is required. Bullet cross section area is about 1/13th square inch.
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stagpanther
New member
I prefer the way Quickload refers to it as start pressure--makes more sense in terms of intuitively indicating an additive relationship to the pressure rating of the charge.
This is the simple answer .
Typically seating depth and neck tension are independant .
Some folks like to complicate things ... but it realy isn't necessary .
Remember ... D.O.I. ... (Don't Overthink It)
Overthink is the correct way to spell it ... trust me !
Gary
60lbs vs 20lbs is quite a difference, Im assuming it has to do more with service ammunition is crimped into place, vs match ammo is not.
44AMP, do you really get each and every cartridge exactly the same COL, as measured by a collimator attached to a caliper, (not OAL from cartridge case base to bullet tip) with each stroke of your press?
MAYBE if you use the same manufacturer's new brass, but my experience has been, reloading multiple brass firings, particularly from multiple manufacturers, usually results in perhaps minute changes in the final OAL, which might be traceable to changes in resized neck/mouth thickness, which offers resistance to seating that can be perceived if one is paying attention at that point in the process. One variable might be the insufficient depth of primer insertion, elongating the OAL, while another can be a subtle difference in the position of the ogive on each bullet in a group of the same lot, depending on the quality of manufacturer or intent of use as target, hunting or match.
MAYBE if you use the same manufacturer's new brass, but my experience has been, reloading multiple brass firings, particularly from multiple manufacturers, usually results in perhaps minute changes in the final OAL, which might be traceable to changes in resized neck/mouth thickness, which offers resistance to seating that can be perceived if one is paying attention at that point in the process. One variable might be the insufficient depth of primer insertion, elongating the OAL, while another can be a subtle difference in the position of the ogive on each bullet in a group of the same lot, depending on the quality of manufacturer or intent of use as target, hunting or match.
No, and I'm not trying to. and, just out of curiosity, where the hell did that come from??
The only collimator I own is a cheapie intended for scope boresighting and I haven't used it in years. And I do measure CARTRIDGE OVER ALL LENGTH from case base to bullet tip. How do YOU measure it??My calipers measure in thousandths, and one can "eyeball" half way between marks, which means a +/- of a bit less than 0.0005" and that's more than adequate for me, since I'm only concerned with measuring to the nearest 0.001" anyway.
For me, tiny variations in over all length, (due to tiny variations in actual bullet tip length) are essentially irrelevant.
I've never heard of such a thing. All the collimators I've seen are used to measure optical things.
https://www.google.com/search?q=col...droid-samsung&sourceid=chrome-mobile&ie=UTF-8
jetinteriorguy
New member
I’m interpreting the question like this. If increasing neck tension should I seat a bullet out further. I.E. having less of a bullets bearing surface seated in the neck to compensate for the increased hold on the bullet, thus allowing it to release with the same pressure but allowing you the option of seating a bullet out further to either chase the lands or increase powder capacity. Not sure if this makes sense, but just my interpretation of the OP’s original question.
I'm still wondering just how he measures cartridge over all length if not from the case base to the bullet tip.
I mean, how else would one do it??
As to seating the bullet out a little more, to make up for the change in bullet pull, I guess you could, but it would require quite a bit of calculation.
And I have no clue how to determine some of the factors you'd need to know, but my guess would be that, first, you'd need to know the force needed for what you currently load, then figure out some way to include the surface area in that force.
Then you'd have to do the same for what the force of the increased pull is, over the same area, and then adjust the area of bullet & case contact to return the force/area amount to what it was in your original load.
Which I guess is do-able if you know how, but I have to wonder, WHY?? I mean, why bother??
And, particularly why not shoot the ammo with the "adjusted" neck tension and see what it does, before making any other changes?
I mean, how else would one do it??
As to seating the bullet out a little more, to make up for the change in bullet pull, I guess you could, but it would require quite a bit of calculation.
And I have no clue how to determine some of the factors you'd need to know, but my guess would be that, first, you'd need to know the force needed for what you currently load, then figure out some way to include the surface area in that force.
Then you'd have to do the same for what the force of the increased pull is, over the same area, and then adjust the area of bullet & case contact to return the force/area amount to what it was in your original load.
Which I guess is do-able if you know how, but I have to wonder, WHY?? I mean, why bother??
And, particularly why not shoot the ammo with the "adjusted" neck tension and see what it does, before making any other changes?
44amp,
I typically measure from base to ogive. I rarely measure from overall length from base to tip of the bullet since my 168SMKs are not pointed and they vary quite a bit . But the ogives which I sort by in 1 thousandths increments are usually spot on.
When I seat them almost all my loaded ammo from base to ogive come within 1 thousandths of eachother, which with the handheld instruments I have is the best that I can do.
The reason for my question is that since the cartridge Im loading for 30-06 isnt loaded to max , was wondering if more neck tension would lower my SD/ES since its holding onto the bullet for longer period time and inturn provide better ignition thus lowering my SD/ES
I typically measure from base to ogive. I rarely measure from overall length from base to tip of the bullet since my 168SMKs are not pointed and they vary quite a bit . But the ogives which I sort by in 1 thousandths increments are usually spot on.
When I seat them almost all my loaded ammo from base to ogive come within 1 thousandths of eachother, which with the handheld instruments I have is the best that I can do.
The reason for my question is that since the cartridge Im loading for 30-06 isnt loaded to max , was wondering if more neck tension would lower my SD/ES since its holding onto the bullet for longer period time and inturn provide better ignition thus lowering my SD/ES
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Loading using base to a point on the ogive that you choose, works for your specific situation ,means nothing to any other situation. And its not the standard definition for measuring cartridge over all length.
Works for you and give you uniform results, its not wrong.
I think the thing you should do is load and shoot a test batch with no change but the increased neck tension and see what the actual results are.
Theory says lots of things but real world performance is what matters.
Sometimes, little changes don't show measurable differences. Sometimes they do. and sometimes the change actually affect performance in some way.
ONLY testing in your gun with your ammo will tell you what does, and doesn't happen.
That's what theory says, but the real world results may not be a linear change. And small changes might not create a measurable result amongst all the other factors involved.
I'm sure you've noticed performance "plateaus" in handloading, where making a small change doesn't seem to have any result, and certain points where it does. These are the same in principle, but the exact point (and amount) of the change is specific to your gun and your ammo combination.
Load and shoot some with the (slightly) increased neck tension. If there's no (safety) issues shoot enough for a reasonable size sample, and see if you need to do something more, or if you just want to,...
Nothing wrong with just wanting to, if you're seeking something, you have to look to find it (experiment, test shooting etc) until you either find it, or find you're not going to get it.
Good Luck!
Works for you and give you uniform results, its not wrong.
I think the thing you should do is load and shoot a test batch with no change but the increased neck tension and see what the actual results are.
Theory says lots of things but real world performance is what matters.
Sometimes, little changes don't show measurable differences. Sometimes they do. and sometimes the change actually affect performance in some way.
ONLY testing in your gun with your ammo will tell you what does, and doesn't happen.
That's what theory says, but the real world results may not be a linear change. And small changes might not create a measurable result amongst all the other factors involved.
I'm sure you've noticed performance "plateaus" in handloading, where making a small change doesn't seem to have any result, and certain points where it does. These are the same in principle, but the exact point (and amount) of the change is specific to your gun and your ammo combination.
Load and shoot some with the (slightly) increased neck tension. If there's no (safety) issues shoot enough for a reasonable size sample, and see if you need to do something more, or if you just want to,...
Nothing wrong with just wanting to, if you're seeking something, you have to look to find it (experiment, test shooting etc) until you either find it, or find you're not going to get it.
Good Luck!
The SAAMI glossary is available to check a term's definition. I think we would be safely within Fair Use Doctrine limitations to put up a few lines here:
SAAMI said: