If ballistics is a science ....

Get or give advice on equipment, reloading and other technical issues.

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AlanF
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Re: If ballistics is a science ....

#16 Postby AlanF » Fri Mar 08, 2019 5:49 pm

My view is that while advanced scientific analysis could dramatically improve the performance of our equipment, there are simply not enough people in our sport with the skills and resources to fully investigate the multitude of aspects with potential for development. Despite that, as an amateur sport, we do pretty well. For example in my experience, on those occasions when we compete against miltary and police snipers at long range, we usually give them an unpleasant surprise. That is despite their substantial training, research and development budgets, particularly of the military. I believe this is because we have a good mix of scientific theory, experimentation, engineering precision, and common sense across our membership, plus (more so in recent times) a readiness to share good advice.

bruce moulds
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Re: If ballistics is a science ....

#17 Postby bruce moulds » Fri Mar 08, 2019 6:53 pm

and we don't have to do 10 pushups before shooting a string like some disciplines.
bruce.
"SUCH IS LIFE" Edward Kelly 11 nov 1880
http://youtu.be/YRaRCCZjdTM

RJNEILSEN
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Re: If ballistics is a science ....

#18 Postby RJNEILSEN » Fri Mar 08, 2019 7:18 pm

Nor do we ski cross country in Lycra prior to first shot.

Trevor Rhodes
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Re: If ballistics is a science ....

#19 Postby Trevor Rhodes » Fri Mar 08, 2019 7:56 pm

What bugs me is l put a lot of time in case prep, bullet prep, barrel prep and load development. Go to prize meetings and at the end of the day if beaten l ask the winner of their prep work and usually are told l just throw the loads and pick the bullets out the box as l go. That makes me think l am wasting hours and hours for nothing but l still persist and live in hope.

RJNEILSEN
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Re: If ballistics is a science ....

#20 Postby RJNEILSEN » Fri Mar 08, 2019 8:14 pm

Trevor, firstly don't believe all that you are told. But if true this reinforces my plan of focusing on what matters with the time you have free to spend on this sport.

RDavies
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Re: If ballistics is a science ....

#21 Postby RDavies » Sat Mar 09, 2019 7:21 am

Trevor Rhodes wrote:What bugs me is l put a lot of time in case prep, bullet prep, barrel prep and load development. Go to prize meetings and at the end of the day if beaten l ask the winner of their prep work and usually are told l just throw the loads and pick the bullets out the box as l go. That makes me think l am wasting hours and hours for nothing but l still persist and live in hope.

Maybe at 600yds you can get away with that sort of thing, especially if it is pretty tricky conditions where it is not just an X count competition, but not once you get back to 900 or 1000yds. At 500-600yds which is where most OPMs are in Australia, in my area anyway, you can get by with an ES of 25 or so and not see much effect on target, but once you go back to 1000yds, you would be lucky to keep them in the 6 ring in calm conditions, so this is where all the extra work on your reloading bench comes into play. Having prepped and batched bullets with identical BC does not really matter at 600 yds, and wont hurt too much at 800yds, but at 1000yds would start seeing you use a bit more of the target.
So, for short range club shoots, concentrate more on shooting than reloading, but for long range and big shoots, you only concentrate on everything.

pjifl
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Re: If ballistics is a science ....

#22 Postby pjifl » Sat Mar 09, 2019 9:14 am

It is easy to become blinkered wrt to one or two 'rituals' during loading and forget that many factors influence the final accuracy.
Assessing all and ranking them in importance is the secret. Do not waste time on the less important things. They may become important but only if you have successfully addressed the more important ones will you see more gains.

No one has mentioned the Gunsmithing. You need a good concentric chamber. Many commercial rifles fail in this regard before you even start. It is not hard but it takes more time to guarantee a top chambering/threading job.

As mentioned by others, long range shows up your loading deficiencies. Case prep is definitely very important.

This thread started by questioning the importance of consistent neck tension which has since been ignored.

I do not neck turn as long as the cases are of good quality. Nor do I anneal cases. I am not against annealing but have watched others doing it with no apparent gain.

But I do two things that help with consistent neck tension.

1/ Batches of Cases are always reloaded the same number of times.

2/ Some lube is applied inside the necks before bullet seating. Some people use Graphite here but I use a slight wipe of grease on a wire brush in a drill. Then each inside neck is wiped 'dry' with cotton buds. In the end, what is left is only a slight smear. This must be done so no powder sticks on the inside of the neck. The projectile then slides into the neck with a far more consistent grip. The feel when seating a projectile is very noticeable. It also achieves a few other things. A grease stops corrosion between the bullet and neck if the rounds are kept for a while before firing. It reduces any damage to a projectile as does careful deburring.

BTW, I do not clean the cases down to bare metal by tumbling or ultrasonic or chemical action. I believe that spotless brass neck insides against spotless jackets may produce a cold weld and more variable neck tension which gets worse if they age before firing. I once saw serious corrosion between bullet and neck in some commercial rounds that I pulled and I think this helps to minimize this. At one time, many top shooters were deliberately hand seating loaded rounds as supplied on the mound a few thou deeper before firing to break any cold weld. Ancient cupro nickel jackets were definitely susceptible to cold welding thus increasing pressures.

I find it hard to definitively place the importance of lubing the neck inside but in my opinion it is ahead of measuring up projectiles. It is definitely worth a visual inspection of projectiles but if they are from a reliable batch of bullets I think there are other more important things to do. OK, I have measured projectiles for some special long range shoots.

Peter Smith.

Trevor Rhodes
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Re: If ballistics is a science ....

#23 Postby Trevor Rhodes » Sat Mar 09, 2019 9:29 am

pjifl wrote:It is easy to become blinkered wrt to one or two 'rituals' during loading and forget that many factors influence the final accuracy.
Assessing all and ranking them in importance is the secret. Do not waste time on the less important things. They may become important but only if you have successfully addressed the more important ones will you see more gains.

No one has mentioned the Gunsmithing. You need a good concentric chamber. Many commercial rifles fail in this regard before you even start. It is not hard but it takes more time to guarantee a top chambering/threading job.

As mentioned by others, long range shows up your loading deficiencies. Case prep is definitely very important.

This thread started by questioning the importance of consistent neck tension which has since been ignored.

I do not neck turn as long as the cases are of good quality. Nor do I anneal cases. I am not against annealing but have watched others doing it with no apparent gain.

But I do two things that help with consistent neck tension.

1/ Batches of Cases are always reloaded the same number of times.

2/ Some lube is applied inside the necks before bullet seating. Some people use Graphite here but I use a slight wipe of grease on a wire brush in a drill. Then each inside neck is wiped 'dry' with cotton buds. In the end, what is left is only a slight smear. This must be done so no powder sticks on the inside of the neck. The projectile then slides into the neck with a far more consistent grip. The feel when seating a projectile is very noticeable. It also achieves a few other things. A grease stops corrosion between the bullet and neck if the rounds are kept for a while before firing. It reduces any damage to a projectile as does careful deburring.

BTW, I do not clean the cases down to bare metal by tumbling or ultrasonic or chemical action. I believe that spotless brass neck insides against spotless jackets may produce a cold weld and more variable neck tension which gets worse if they age before firing. I once saw serious corrosion between bullet and neck in some commercial rounds that I pulled and I think this helps to minimize this. At one time, many top shooters were deliberately hand seating loaded rounds as supplied on the mound a few thou deeper before firing to break any cold weld. Ancient cupro nickel jackets were definitely susceptible to cold welding thus increasing pressures.

I find it hard to definitively place the importance of lubing the neck inside but in my opinion it is ahead of measuring up projectiles. It is definitely worth a visual inspection of projectiles but if they are from a reliable batch of bullets I think there are other more important things to do. OK, I have measured projectiles for some special long range shoots.

Peter Smith.

Running the risk of lightly greasing the inside of the necks and having powder sticking to it, wouldn't it be easier to lube the projectile?
Cheers Trevor

pjifl
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Re: If ballistics is a science ....

#24 Postby pjifl » Sat Mar 09, 2019 9:41 am

Trevor wrote

Running the risk of lightly greasing the inside of the necks and having powder sticking to it, wouldn't it be easier to lube the projectile?


I don't think it would be as easy to get consistency and one would need to guarantee no grease was on the rest of the body of the projectile but it is a thought. It is easy to wipe out the necks with cotton buds. One cotton bud end does about 5 necks then throw away. Although one is left with hardly any discernible grease - just a shiny layer - the different feel when seating is very noticeable.

Peter Smith.

Barry Davies
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Re: If ballistics is a science ....

#25 Postby Barry Davies » Sat Mar 09, 2019 10:45 am

If you must lubricate the inside of case necks, ( I never do ) use a 308 mop impregnated with graphite powder. Leaves a light coating of graphite and powder will not adhere to it. You will probably wipe most of it away when you seat the projectile anyway but it does stop welding of projectile to case during prolonged standing after reloading.

Gyro
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Re: If ballistics is a science ....

#26 Postby Gyro » Sat Mar 09, 2019 1:07 pm

I lubricate the nk inside with a mix of isopropyl alchohol and fine graphite, with a cotton bud. Just paint it on. It dries in no time. BUT I went to a weekend comp last season and didn't bother with that step and the gun shot lights out ( 60.6 90.12 90.7 60.4 60.7 90.10 ) all at 600 yards except the first group. Why ? I suggest it was because I had the gun set up in a particular way that weekend with a particular media in the bags.

Litz has proven that annealing has negligable effect on accuracy.

I would suggest many shooters need to look at thier stock design and the whole system set up. This to me has huge implications for what the "system" does during the bullets approximately 2 milliseconds of barrel time.

I reckon a lot of the case and bullet prep and sort stuff is not nearly as important as having the system behave properly during recoil. Have yall noticed how much more widely accepted today is the discussion around the importance of limiting stock flex ??? This one aspect has huge implications for how the gun behaves during recoil.

A classic example is to try shooting the big bullets in FTR with a shite stock and you will see what I mean. Some manage ok in easy conditions when theres time to focus seriously on the gun-handling but when it blows they are nowhere.

Who said I was myopic ! Regards Rob Kerridge.

wsftr
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Re: If ballistics is a science ....

#27 Postby wsftr » Sat Mar 09, 2019 2:23 pm

this is well worth a read. In particular the conclusion.
https://blog.ammolytics.com/2018-12-12/ ... ocity.html
I found it fascinating that he measured a forward motion before recoil that he attributed to the firing pin.

Conclusions
When shooting a precision rifle, preloading your bipod is an incredibly effective technique for managing recoil and getting your sights back on target to watch for impact or prepare for your next shot. However, if you expect it to have an effect on your muzzle velocity, you're going to be disappointed.

Here's what I learned and observed based on the experiment I described above:

I measured no change in muzzle velocity with either technique.
Due to huge differences in mass, the bullet has left the barrel before the rifle moves under recoil.
Chamber pressure readings verified that some of the rounds shot with a preloaded bipod were slower by coincidence, not correlated to or caused by recoil technique.
The median velocity is more robust than the mean (average) and is better suited for ballistic calculators.
My reloading practices need improvement, likely around bullet sorting.

bruce moulds
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Re: If ballistics is a science ....

#28 Postby bruce moulds » Sat Mar 09, 2019 4:43 pm

maybe litz can't partially anneal anneal consistently.
he certainly is not the god his marketing machine would have us believe.
annealing will make cases last longer if nothing else, so is worth learning to do in such a way that you don't make things worse.
no amount of trying to improve in flight consistency, e.g. bullet pointing, is of value if you cannot start all bullets the same.
starting bullets the same is step1.
neck tension might be a less correct term than neck grip on the bullet.
what makes bullets start the same?
bruce.
"SUCH IS LIFE" Edward Kelly 11 nov 1880

http://youtu.be/YRaRCCZjdTM

pjifl
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Re: If ballistics is a science ....

#29 Postby pjifl » Sat Mar 09, 2019 5:27 pm

I believe that a thin coating of grease is more likely to minimize corrosion between bullet and neck than Graphite. I used to use Graphite but have changed.
I understand how people are afraid to use grease because one must wipe out all excess and leave only a tiny thin film behind. It is not the problem some expect and I will continue with it as the best solution.

Have you ever seen the corrosion that results from using Graphite Packing on Trawler Prop Shafts ?? The metals are Stainless and Bronze. Graphite is a no - no.

In any case, it is well worth thinking about the problem and coming up with a solution that you are happy with.

Annealing when using a fairly large neck/projectile gap will definitely prolong case life. Thus a minimum gap is desirable with the occasional annealing but I just do not see any gains in accuracy. This is from watching people using fairly sophisticated annealing gear. A collet die also helps over working the brass as does a good light bushing die.


Peter Smith.

Gyro
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Re: If ballistics is a science ....

#30 Postby Gyro » Sun Mar 10, 2019 5:04 am

wsftr wrote:this is well worth a read. In particular the conclusion.
https://blog.ammolytics.com/2018-12-12/ ... ocity.html
I found it fascinating that he measured a forward motion before recoil that he attributed to the firing pin.

Conclusions
When shooting a precision rifle, preloading your bipod is an incredibly effective technique for managing recoil and getting your sights back on target to watch for impact or prepare for your next shot. However, if you expect it to have an effect on your muzzle velocity, you're going to be disappointed.

Here's what I learned and observed based on the experiment I described above:

I measured no change in muzzle velocity with either technique.
Due to huge differences in mass, the bullet has left the barrel before the rifle moves under recoil.
Chamber pressure readings verified that some of the rounds shot with a preloaded bipod were slower by coincidence, not correlated to or caused by recoil technique.
The median velocity is more robust than the mean (average) and is better suited for ballistic calculators.
My reloading practices need improvement, likely around bullet sorting.


The real problem for me here that's not mentioned in the conclusion is that as many of us know : if you release shots at a target with the rifle not on its NPOA then the bullets will go everywhere. This is a fundamental to accurate shooting and plays out in all kinds of ways across all shooting classes. For an F Class rifle, of either class, the guns relatively higher inertia value compared to say a carry-around sporting rifle may perhaps lessen this dynamic, but believe me if you handle an F Class gun incorrectly/inconsistently you will not shoot well. And I suggest if you are shooting a cartridge/bullet combo that generates a relatively higher "gun upset" during recoil then the problem just get worse.

Whether the velocity is affected or not I have no idea ( despite many saying it is ) but I would presume it would be, just from basic physics theory.


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