Testing required bullet seating force before bullet seating

You may have seen some allusion to this over where I was talking about my new Criterion Barrel under Aftermarket Barrels.

I consider bullet seating force one of the most overlooked factors in achieving consistent muzzle velocity (low ES and SD figures).

I'm currently working on a way to test required bullet seating force... before bullet seating. I can't go into detail because I do not yet have all the materials to perform the testing (I should have it all this week), but if it works out in that testing I'll pass along all information. I will also say, if it works, it's considerably cheaper than a K & M Arbor Press w/ Force Measurement and a Wilson seating die.

Whether this method works or not, I'm convinced there has to be some way to do this preliminary testing and I'm going to find it.

You might ask, if you prepare all your brass identically, won't the bullet seating force be the same? I think guys using the K & M Arbor with Force Measurement can answer this. I've seen other forum posts with K & M readings and from what I've seen they vary widely... and sometimes wildly. I believe this has to do with variances in the molecular makeup of the brass. One table I saw had reading ranging from under 20 lbs to over 30 lbs. The author indicated he had prepared all the brass identically.

You might might also ask, why would you want to test for seating force before actual bullet seating? Efficiency mainly. Here's my reasoning:

Say you have 300 cases that you’ve prepared. You need 100 cases for an upcoming match. You start seating bullets using a system like K & M offers for measuring seating force. What if you don’t come up with 100 the same out of the 300? You’re going to have 1) prepare more cases/rounds and 2) have a bunch of odd lot rounds lying around.

With my method, provided it proves itself in testing, if you have 100 cases that all force weight test the same prior to bullet seating, then you've got 100 cases for your match… and no leftovers. Also, on future preparations, you can stop when any category reaches the number of rounds you need for a match. Say I had 300 cases and I’ve got the following spread (note, my method will likely require less force than actual bullet seating, but it should be proportional):

60 @ 6lbs
80 @ 7lbs
92 @ 8lbs
68 @ 9lbs

I would only have to keep preparing cases until any of those weight categories reaches the 100 mark. Then I could make 100 rounds with NO leftovers. Say I hit 100 of the 8 lbs sort group first and had the following distribution:

66 @ 6lbs
90 @ 7lbs
100 @ 8lbs
78 @ 9lbs

I make complete rounds out of all the 8 lb sort group and am left with

66 @ 6lbs
90 @ 7lbs
0 @ 8lbs
78 @ 9lbs

Another match comes up and I start prepping cases until the next category hits 100. Maybe something like…

88 @ 6lbs
100 @ 7lbs
35 @ 8lbs
90 @ 9lbs

I use the 100 @ 7lbs for the next match.

Never do I have whole rounds sitting around waiting for mates. Will I have to change my sight settings when using 6 lbs instead of 8 lbs? A click or two possibly. But you won’t be using stray odd lot rounds for those spotter/foulers. With my method, you can use the same quality rounds you’ll be shooting in the competition.

And what if you come up with another crucial step in your reloading process? You might be able to rework the prepared empty cases. If you have entire rounds laying around, your only choice is to shoot them all as spotters or foulers or pull their bullets (risking scaring them in the process), dump the powder and hope you don’t have to waste perfectly good primers also?

Stay tuned. As I said, I should have results toward the end of the week.

Sounds interesting...

Why would you just accept results though? What's the point of knowing what the seating force if you can't do anything about it? There are also some variables in seating force that will not have an effect on actual neck tension. Neck tension is the goal, specifically release force, correct? It is easily possible to have 20 cases that have exactly the same release force but have different seating forces because of small things like bullet alignment as the bullet starts into the case. I would think a way to test release force and actual neck tension would be a more telling project.

The good news is that you CAN change neck tension and you can standardize some things to get everyting as close as possible. Steps would include, size, trim, neck turn and anneal. Cases should be consistent as possible after that.

Looking forward to hearing your results.

As with the others, awaiting some concrete results - like demonstrably better vertical on target at distance, not just abstract numbers (and that includes chrono results - consumer chronographs are not always the most accurate devices).

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Originally Posted by memilanuk

As with the others, awaiting some concrete results - like demonstrably better vertical on target at distance, not just abstract numbers (and that includes chrono results - consumer chronographs are not always the most accurate devices).

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I couldn't agree more. If it doesn't translate into less vertical it's of no use.

I can say with my rifle, if the MV is the same (SD under 5), the vertical is the same. That's one part of the equation I'm not terribly worried about.

Tracking# for both items say today is the day. When I can test with chrony, I can't say. Maybe not until the 26th.

Doug,

I didn't mean to come across as busting your chops on that last post... I am honestly interested in anything that can minimize the variables at the loading bench - I have enough headaches with the variables on the firing line!

That said, bear in mind where I (and possibly others) am coming from. I've read time and again of people who claim single digit ES is the one true path to glory and fame and itty-bitty groups at distance. As far as I can tell, my loading techniques are pretty solid - yet after numerous chrono sessions over the years, I've yet to get single digit ES. I tend to put more weight on longer strings, as in matches I shoot ~2 sighters and 15-20 record shots in any given string. I'll work up loads in shorter strings, but my final 'acid test' strings over the chrono are minimum 20 rds. Given that length of string... if I get under 30fps ES, I'm satisfied. Under 20, I'm really happy, and under 15 I'm dancing on top of the shooting bench... Given that I can (generally) under good conditions hold sub half-minute (or dang close to it) vertical @ 1k... that works out about right for a 20fps ES (roughly 5" vertical).

Normally... the wind causes enough problems that shrinking my vertical much more might be considered a matter of chasing diminishing returns. Up drafts, down drafts, weird swirly stuff caused by terrain and vegetation, etc. But there are those days when the conditions just lay down and die off, or when the wind may be blowing pretty good but is steady and/or readable enough to be able to just punch the center out of the target. Those are the days I'm wanting less ES/SD for...

I've got one of the K&M arbor presses w/ the dial indicator... but like a lot of people, I have yet to really be able to find a correlation between seating force and results on target. It sounds good in theory, but there are enough other confounding variables in play that mask the results.

Monte

Quote:

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Originally Posted by memilanuk

I've got one of the K&M arbor presses w/ the dial indicator... but like a lot of people, I have yet to really be able to find a correlation between seating force and results on target. It sounds good in theory, but there are enough other confounding variables in play that mask the results.

Monte

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Yep. I've been all over the web and seen quite a few tables where K & M has been tested. I thought I was really onto something on one of them. His four 29 lb rounds had a low ES and single-digit SD. Then I looked a lot closer. He had 19 lb MVs higher than 30 lb MVs and vice-versa.

When I tested before (shown under Aftermarket Barrels) I had my last 12 rounds in a row under 6. 6 of those were under 3. I went to shoot the next weekend and my last 10 rounds were SD 20... and where they hit on the target correlated. I will say the first weekend I was using new Lapua brass and the second weekend I was using 1x fired Lapua for one group and 1x fired Winchester for another group. Also, the first time I was using Varget and the second weekend I was using Reloder 17 in the Lapua and Reloder 15 in the Winchester. How much difference that made I really can't say. I have heard good things from a lot of shooters about the Alliant powders.

I use a D. I. MXX-123 scale and feel my procedures with it ensure that the powder measurement is very precise.

To the touch, all the seating seemed about the same with only 2 "hard ones" out of 73 rounds fired. Go figure.

What hits me is I don't really expect my measurement to be any more accurate than the K & M... merely more efficient in terms of round preparation.

We'll just have to wait and see.

Well any news yet on this new method?

Still no information?

Any luck?

Guess not.....................

So what about this new method ?
It has been over two months, since this topic has been started, how about an update?

Well it is almost the middle of June, so what did you find out?

I'm not holding my breath any longer. :o

Nope, looks like the issue/results died.

Question: Why would you want to know this UNLESS you are going to use these cases for bench rest competition, for hunting not needed for cross course shooting maybe for mid course (600 yrds) , F class certainty at 1000 yrds. sounds like a lot of extra work and equipment for ME weighing cases is a lot of work.