WEIGHING BULLETS TO REDUCE VELOCITY VARIATION AND IMPROVE ACCURACY

  • 2.2K Views
  • Last Post 02 February 2018
joeb33050 posted this 10 January 2018

 

 

WEIGHING BULLETS TO REDUCE VELOCITY VARIATION AND IMPROVE ACCURACY

 

223, 5.5 gr Titegroup, 40 gr bullet, 2063 fps, 53 gr bullet, 1784 fps, delta fps/gr, 21.5

 

223, 8.5 gr Titegroup, 40 gr bullet, 2678 fps, 53 gr bullet, 2374 fps, delta fps/gr, 23.4

 

22-250, 5.5 gr Titegroup, 40 gr bullet, 1857 fps, 53 gr bullet, 1622 fps, delta fps/gr, 18.1

 

22-250, 8.5 gr Titegroup, 40 gr bullet, 2418 fps, 53 gr bullet, 2137 fps, delta fps/gr, 21.6

 

The largest delta fps/gr of bullet weight is 23.4; a bullet weighing 1 grain more than another would go 23.4 fps slower.

 

Weighing, segregating, loading and shooting bullets into .1 grain classes reduces delta fps to 2.34 fps.

 

In .5 gr classes, delta fps is 14.0 fps.

 

Weighing bullets and segregating them into small classes won’t improve accuracy.

 

joe b.

 

 

Attached Files

Order By: Standard | Newest | Votes
Larry Gibson posted this 02 February 2018

Ken

I've never been able to see any affect weight sorting has on velocity variation.  I earlier posted, in this thread, the average velocity, the SD and the ES of the test of weight sorting (also posted earlier).  I could find no correlation or affect and joeb's analysis apparently didn't either.

LMG

Concealment is not cover.........

Attached Files

frnkeore posted this 01 February 2018

These stand out and we even recognize them with screamer patches. What we notice less are the 6s, 7s, and 8s, that these same shooters, including Mel, sometimes produce at the next match.

The above fits in with my number 5 & 6

5. All match shooters have their up's and down's. What they shoot on any one day, can differ from their best. There are no exceptions to that!

6. There are things about cast bullets that no ONE person can explain.Cast bullets don't "play by the rules" and don't seem to abide by the laws of  physic's! We all do our best to improve and most improve by attention to detail.

Frank

Attached Files

John Alexander posted this 01 February 2018

Frank,

I think that if you can make any argument for some improvement in the art, Mell Harris is your best bet. In spite of his health problems he continues to shoot small groups better than ever. Joe's numbers from the nationals might even show a tad of hope if Mel and the other two shooters shooting Mel's old rifles had attended the last few years.

Yes, a fair number of groups in the 3's and 4's and even an occasional 1 or 2, are produced in the classes you mention as well as by PBB shooters.  These stand out and we even recognize them with screamer patches. What we notice less are the 6s, 7s, and 8s, that these same shooters, including Mel, sometimes produce at the next match. These we tend to forget.  I think this is human nature. I know I don't like to dwell on the days when things just didn't seem to work. I remember the ones where everything went right and I will bend your ear about them if you don't run.

My point is that if we aren't quoting averages of consecutive performances with no exceptions over some period of time, we are not talking about the REAL level of performance but are kidding ourselves. 

I would define real performance as the level that can be achieved 50% of the time by that rifle/shooter at all the matches he enters with that rifle/load.

John

 

Attached Files

Scearcy posted this 01 February 2018

I maintain a spread sheet that contains the best groups and scores for each rifle class, including military, shot at the nationals each year. Without digging around in the archives too much the first year included in this data, as I recall, is either 2002 or 2003. I trend this data as well as track 5 year moving averages of each number. As you can imagine some years and indeed some venues are tougher than others.

While it is true that all of the best CBA shooters are not in attendance at the Nationals, it is also true that the 90-100 shooters (remember military is in here also) in attendance likely includes a representative sample of the best shooters in each class. The point of this is that the scores at the Nationals, over time, fairly represent the the progress or lack there of achieved by the CBAs competitive shooters. 

These scores can not represent the efforts of those members who test their ideas in private so I cannot speak to their progress. What I can tell you is that the numbers thus collected from the Nationals show no evidence of consistent improvement in our group sizes and/or scores over the last 15 years. In some classes it actually appears that we may be regressing slightly.

My last observation is that these competitive shooters certainly include individuals who are practicing most if not all of the refinements we discuss and debate on this forum. Indexing, weighing, sorting with magnification, changing alloys, throating, bumping etc are all being tested and employed by someone every year. High velocity with a slow twist barrel and recently powder coating are now beginning to be explored. And yes, many of these techniques are being tested and employed by shooters/rifles consistently capable of 1/2 MOA in sanctioned competition. Still there is very little measurable progress being made.

I wonder if we have reached the point where a rapidly aging pool of shooters is offsetting any small improvements available to us by refining  practices.

Attached Files

frnkeore posted this 01 February 2018

John,

If you consider UNR, UNP and Heavy as one overall class, since the records over lap in those classes, you'll note that Mel, either holds them or is very close to all those records, since 2013, a 4 year span. I think that shows some improvement, since many of them are very old records.

Many of the "Screamers" I spoke of are groups and scores that are close to records also, they happen every year. There are a couple of other, Roseburg/Springfield shooters that either better Mel or come close to him, in the monthly matches.

Frank

Attached Files

John Alexander posted this 01 February 2018

Additional thoughts about Franks eight food for thought post:

Frank wrote:

 4. The best CBA, GC target rifles, have improved over the last several years, as witnessed by new records set. Mel Harris owns many of them. Granted, records don't come that often but, they are shot with some regularity, as well as "screamers".

I respectfully disagree.  Joe’s analysis of the actual scores fired since 2000 at our nationals clearly show no significant improvement. Anybody can look at his results and judge for themselves.

There are two difficulties in trying to judge progress by records.  The most important is that the longer a group of shooters shoot (even if they don’t actually improve) records will be broken just by sheer weight of trying again and again and again.  Distribution of scores will keep on producing records but at an ever diminishing rate. In long established classes records are few and far between (unless there is real improvement.) In production class there has only been one in the last 9 years and in heavy class only 1 in the last eight years in spite of heavy competition in both of these classes. This argues that improvement has been near zero in these two classes.

The second difficulty is that in the first few years of a new class a bunch of new records are set as the first and second crop will be weak records so it is natural that records will be rapidly broken multiple times.  Mel is arguably the best active CBA shooter but the big flurry of records he has set in the last few years are almost all in our relative new UNP class.  A lot of records have also been broken over and over in our other relative new class (Hunting Rifle).

Looking to records to assess the level of accuracy we have reached is an exercise in self-deception.

Attached Files

Ken Campbell Iowa posted this 01 February 2018

hey !! ... i just now read the title to this thread and it says "".... to reduce velocity variation "" ...

my bad... i thought we were weighing bullets to find internal voids that would ... might .... cause the bullets to fly off the desired path  ... wrong thread .....

so since we are allowed ( by custom ) to fantasize, i predict that if you had two quality mold cavities... say 30 cal 170 gr.  ... and one was 5-10 grains  longer at the back ...( 178 gr. ? ) ...  with the same charge and same oal .... all the bullets would go into the same group at 100 ... probably 200 yards .....   and of course each shot and especially  any outliars would have their velocity recorded to prove i was right ...

just wandering, ken

Attached Files

Larry Gibson posted this 01 February 2018

"Saying a rifle is capable of xx shouldn’t mean that it will do it once every 10 or 20 tries.  That borders on the dishonest. After all we all shoot a 3/8" group once in a while.  Most shooters know that means next to nothing in itself. "

That is exactly right John.  It's why when I quote HV accuracy capability of my 30x60 XCB rifle I usually state 1 moa to 1 1/2 moa with 10 shot groups.  That's because that's what it normally did.  However, since I started casting the better bullets I may have to change that to 3/4 to 1 1/4 moa because that's the range it does now with the weight sorted bullets. Occasionally I shoot a smaller group, especially if a 5 shot group but those are seldom done.  Conversely I also will shoot a larger group occasionally (some days are diamonds, some days are stones). 

The same can be said for my other serious competition rifles (the M39 MN and the M70 Match),  They both have their level of "normal accuracy range.  Occasionally a smaller group sis shot and occasionally a larger group is shot.  More to do with the shooter than the rifles or loads.

LMG

Concealment is not cover.........

Attached Files

John Alexander posted this 01 February 2018

45.2.1 wrote:

Here on the home page this is written under #4 mid page: In the last three decades, experimentation with cast bullets, the lubricant and alloys is producing accuracy at velocities up to 2700 fps. This rivals the speeds of jacketed bullets for hunting and target applications. And what's more amazing, with these modern techniques and lubricants, the loads can shoot groups less than one-half minute of angle (1/2 inch) with no lead fouling in the barrel!!

 Note the 2700 fps with groups less than 1/2 MOA (that's how most people would read that).... that outdoes what I said and I would like to see some documentation. 

=================

I agree. Sounds like someone got a bit carried away with our brags.  The 2700 fps can be done of course but I know of nobody that has shot four consecutive groups under .5 MOA at 2700 fps -- and then can come back the next day and do it again and that is what is implied.  I am embarrassed and  will ask to have that changed to something I know has been documented.  I apologize to all for a misstatement on our website.

=================

As far as 3/8 MOA five shot groups at 100 yards out of a production rifle, the National Records on this site show Mike Mohler shooting a 0.245" smallest five shot group with an aggregate of 0.422" at 100 yd in Production class. It seems to me that I'm not the only one doing what I've talked about. Looking at the other classes at 100 yard smallest groups, they range from 0.111" to 0.425". It would seem that there is no shortage of people capable of shooting less than 1/2" at 100 yards and some doing considerably better than what I said.

========================

 I am surprised that you would quote records as indicating the honest accuracy of a rifle and load. I believe we all understand that a record is usually the best out of many tries that the shooter has made over time. Often a record will be the best the shooter has done in a lifetime.  A record by definition is a rare event, that exceptional group or aggregate that happens but isn't an honest measure of what that rifle/load can average. 

The late Mike Mohler was an honest gentleman and a great shooter.  I'm sure he would spin in his grave if he knew someone was quoting his records as proving his 243 would average under .5 MOA.  On the day he shot those groups he told me “That rifle has never shot nearly that well.” He seemed as amazed as the rest of us.

 Saying a rifle is capable of xx shouldn’t mean that it will do it once every 10 or 20 tries.  That borders on the dishonest. After all we all shoot a 3/8" group once in a while.  Most shooters know that means next to nothing in itself.

Please read the post I recently wrote to Frank about using records to prove how well a rifle will shoot.

 

John

 

 

 

Attached Files

OU812 posted this 01 February 2018

I have shot 3/8" groups @ 100 yards using a production Remington, but can I do it consistently?...not yet. And that was without weight sorting.

Sorry if I sound superior sometimes. Words are just too easy.

Attached Files

45 2.1 posted this 01 February 2018

Larry says: 

“What I hear 45 2.1 saying is exactly what I've been saying in this thread; if we continue to do what we've always done that moa+ average will never get any smaller.  If we simply emulate what the top shooters have been doing for the however many years can we really expect to do better?  No we can't.  To do better we must think "outside the box".  We must find the reasons we aren't doing any better and correct them.  That's what I hear 45 2.1 saying and, again, I agree 100%."

 If that’s what he is saying, I agree 100% as well. 

 However, if that is what 45.2.1 is saying it is obscured by his constant claims of superiority and a complete lack of any helpful information. 

John

Larry did indeed hit on the meaning. As to claims of superiority... just where did you surmise that? Lets take some examples from this forum. Here on the home page this is written under #4 mid page: In the last three decades, experimentation with cast bullets, the lubricant and alloys is producing accuracy at velocities up to 2700 fps. This rivals the speeds of jacketed bullets for hunting and target applications. And what's more amazing, with these modern techniques and lubricants, the loads can shoot groups less than one-half minute of angle (1/2 inch) with no lead fouling in the barrel!!

Note the 2700 fps with groups less than 1/2 MOA (that's how most people would read that).... that outdoes what I said and I would like to see some documentation. As far as 3/8 MOA five shot groups at 100 yards out of a production rifle, the National Records on this site show Mike Mohler shooting a 0.245" smallest five shot group with an aggregate of 0.422" at 100 yd in Production class. It seems to me that I'm not the only one doing what I've talked about. Looking at the other classes at 100 yard smallest groups, they range from 0.111" to 0.425". It would seem that there is no shortage of people capable of shooting less than 1/2" at 100 yards and some doing considerably better than what I said.

 

 

Attached Files

John Alexander posted this 31 January 2018

Frank has posted some food for thought.  I will add some more.

4. The best CBA, GC target rifles, have improved over the last several years, as witnessed by new records set. Mel Harris owns many of them. Granted, records don't come that often but, they are shot with some regularity, as well as "screamers".

I respectfully disagree.  Joe’s analysis of the actual groups fired since 2000 at our nationals clearly show no significant improvement. Anybody can look at his results and judge for themselves.

There are two difficulties in trying to judge progress by records.  The most important is that the longer a group of shooters shoot (even if they don’t actually improve) records will be broken just by sheer weight of trying again and again and again.  The natural distribution of scores will keep on producing records but at an ever diminishing rate.

In long established classes new records are few and far between (unless there is real improvement.) In production class there has only been one in the last 9 years and in heavy class only 1 in the last eight years in spite of heavy competition in both of these classes. This argues that improvement has been near zero in these two classes.

The second difficulty is that in the first few years of a new class a bunch of new records are set but the first and second crop will be weak records so it is natural that records will be rapidly broken multiple times.  Mel is arguably the best active CBA shooter but the huge flurry of records he has set in the last few years are almost all in our relative new UNP class.  A lot of records have also been broken over and over in our other relative new class (Hunting Rifle).

John

Attached Files

Larry Gibson posted this 31 January 2018

A quick check last years National CBA match results;

If we look at last years Nationals we see there were 12 shooters in Production, Heavy Rifle and Unrestricted Rifle that had 100 yard 5 shot agg's under moa.

Of those 12 only one used other than .30 caliber; a 6mm.  Of those who shot less than MOA agg's there is an obvious trend toward slower twists with higher velocities; in Pro Class there was one 10" twist and one 11" twist.  In HvyR class there was one 10" twist, one 11" twist, one 12" twist, one 14" twist and one gain twist.  In UnR rifle there were two 11" twists, one 12" twist, one 13" twist and one 14" twist. 

Eleven of the 12 with less than MOA agg's had velocities of 1750 to 2400 fps.  Only one below at 1550 fps.  Of those that shot in those classes there were 8 (38%) with estimated velocities. 

Might be beneficial in the long run to add a column on the Technical Data sheet  asking if they weight sorted their bullets?

LMG

 

Concealment is not cover.........

Attached Files

John Alexander posted this 31 January 2018

Larry,

A lot of things when sorted by some attribute do not produce a normal (bell shaped) curve, so your theory about bullets is plausible.  As noted earlier, i will try to replicate your curve although if I fail it may only mean that I cast poor bullets. We will see.

John

Attached Files

frnkeore posted this 31 January 2018

Some food for thought:

1. One MOA, will not get you anything in target classes

2. Velocity won't get you anywhere, if you use a low BC bullet. They will counter act, against each other.

3. Well cast bullets will get you more consistent results. In ASSRA matches, most of the top shooter DON'T weigh their bullets and only visually inspect. They consistently shoot a 10 shot average of around .75 MOA @ 200 yards, with a velocity of <1500 fps.

4. The best CBA, GC target rifles, have improved over the last several years, as witnessed by new records set. Mel Harris owns many of them. Granted, records don't come that often but, they are shot with some regularity, as well as "screamers".

5. All match shooters have their up's and down's. What they shoot on any one day, can differ from their best. There are no exceptions to that!

6. There are things about cast bullets that no ONE person can explain.Cast bullets don't "play by the rules" and don't seem to abide by the laws of  physic's! We all do our best to improve and most improve by attention to detail.

7. Loading density, seems to help but, in my sport, you can not prove that. Many of our records are held by the, very old 32/40's with ~15.0 gr of dense powder in a 3+ cc case. Loading density make make up for some attention to detail? I don't know!

8. Based on the role that powders play, regarding accuracy, internal ballistics play a part. But, something that no ones addressed here, barrel harmonics, do too, especially lighter barrels, such as the production types. Internal ballistics are what causes barrel harmonics.

9. There are more things but, no one thing is the answer. My opinion is that you need every thing to come together, or at least as many as you think you can control, to improve your accuracy!

Frank

Attached Files

  • Liked by
  • RicinYakima
Larry Gibson posted this 31 January 2018

John

"However, if that is what 45.2.1 is saying it is obscured by his constant claims of superiority and a complete lack of any helpful information. I have been waiting a couple of years for some small contribution from him that might help other CB shooters. He claims to routinely shoot under 0.5 moa averages with commercial rifles and I am willing to believe that he has a lot to contribute."

Yes, I have had more than one discussion with him about all that also.  But when he is correct I do have to agree with him......just have to get around and ignore the other is all. 

The biggest thing I've learned, as I've said before, the last 8 - 10 years is how to cast much better bullets.  That long ago I cast what I thought were excellent bullets and like most being able to shoot moa to moa and a half with them was what I thought .....pretty darn good.  We all thought that and there were/are a myriad of theories as to why better accuracy just wasn't to be consistently had with cast bullets.  Once I started pushing the HV/RPM window is when I found (no claim there to be the only one) that my bullets were only "good" bullets.  I learned then to cast much better if not truly excellent bullets.  In this context "excellent" means not simply the same weight w/o defect but bullets that are as consistently balanced as possible.  That requires complete fillout with minimal shrinkage in the mould. 

With .30 caliber bullets in the 150 - 200 +/- gr weight the key to finding success is through weight sorting.  If your weight sortment has a "bell curve" to it then you are not casting the best bullets possible. The reason could be your casting technique or the alloy.  The sortment curve must curve up somewhat sharply and then plateau with the majority (50 to 60+ %) of bullets in that plateau segment.....usually a +/- .1 to .2 gr for those bullets in the plateau range of bullets.  The plateau should then drop off very suddenly to almost no other bullets heavier than .1 gr of those bullets in the plateau.  It is those bullets in the plateau weights that will give the finest consistent accuracy and which are capable of leas than consistent moa accuracy in a rifle capable of that accuracy level.    

LMG

 

Concealment is not cover.........

Attached Files

John Alexander posted this 31 January 2018

Larry says: 

“What I hear 45 2.1 saying is exactly what I've been saying in this thread; if we continue to do what we've always done that moa+ average will never get any smaller.  If we simply emulate what the top shooters have been doing for the however many years can we really expect to do better?  No we can't.  To do better we must think "outside the box".  We must find the reasons we aren't doing any better and correct them.  That's what I hear 45 2.1 saying and, again, I agree 100%."

 

If that’s what he is saying, I agree 100% as well. We need to find and sort out the fundamentals of CB shooting we are still missing if we are ever to improve -- what works and what doesn't. I have presented evidence and argued long and hard that several of the things we do faithfully don’t work. I also agree that some CB shooters don't want to do the kind of research we need and instead want a recipe to follow.  I have been frustrated with that attitude and have written about it long before I knew either you or 45.2.1.

 

However, if that is what 45.2.1 is saying it is obscured by his constant claims of superiority and a complete lack of any helpful information. I have been waiting a couple of years for some small contribution from him that might help other CB shooters. He claims to routinely shoot under 0.5 moa averages with commercial rifles and I am willing to believe that he has a lot to contribute.  I am still waiting and hoping he will respond positively instead of just providing more criticism of others.

 

I have nothing helpful to say about your differences with Joe except I plan to experiment when the weather is warmer and hope to replicate and support one position or another. I urge all the readers of this thread to do the same, maybe we can learn something useful.

 

John

 

Attached Files

Larry Gibson posted this 30 January 2018

Managed to slip off to the range for a bit today.  Wanted to test the recently developed load with the 30 XCB in the M70.  I used the 157.8 +/- .1 gr bullets.  Loaded up enough for 4 five shot groups at 100 yards and maybe 2 ten shot groups at 200 yards plus a fouler/sighter.  Was a pleasant enough day except for the wind and mirage.....what else!  Here is the M70 as shot today.

Since the CBA matches I shoot at most often just shoot for score that is what I wanted to test and confirm zeroes for.  The first target (top left) includes the foulers.  Top right target I was over holding/compensating for the wind to the right and that's where the two shots to the right shots went.  With the bottom targets I finally got the wind/mirage figures out and was pleased with them.   Agg for the first two targets was 94, agg for the second two targets was 98 with a total agg of 192.  I'll include the group sizes here even though I was shooting for score.  The average group size was 1.0475", almost exactly moa.  That was a better score by several points that I was able to manage with the previous load I used. 

I had 2 CBA targets left and 21 rounds.  I had not shot this load at 200 yards before so I took a swag and moved the scope elevation up 4 moa.  The first 4 shots formed a group low so I adjusted the scope up 1 moa and promptly shot the next 4 shots high.....oops.  Went back down 2 clicks (1/2 moa) and put 3 shots "in there".  Shifted to the last target as I had 10 rounds left.  Shot the bottom target for a score of 99.  I was pleased. 

Not trying to prove anything here.  I'm just reporting on what I did with the weight sorted bullets.  It appears I've improved with higher potential scores at 100 and 200 yards.  Will have to get in a couple more practices before the next match.

LMG

 

Concealment is not cover.........

Attached Files

Paul Pollard posted this 30 January 2018

My limited statistics experience was my place of work. We made heavy truck wheels. The wheels consisted of a disc which bolted to the axle of the truck and a rim which held the tire. These two pieces were pressed together and welded. Each part was checked for runout throughout the day. The assembly was 100% checked on a runout machine. The Quality Control Department people constantly told us there was no direct correlation of the runout of each part to the total runout of the assembly. The operators asked why we bothered to check the runout of each part if that was the case.

 

One day a newly hired person was given yet another “What’s causing the runout” project. He gathered samples from each of the lines, then pressed them together, welded them and ran them across the runout machine. He took all his information and ran it through a statical program call MiniTab. His information showed that there WAS a direct one-to-one correlation of the runout of each part to the runout of the assembly.

 

 

What was the difference, and why did he find the relationship? He didn’t know any better and used in-tolerance parts and also dug some parts out of the scarp bins. With the really high runout of the parts, the software detected the relationship of the wheel assembly. The Quality Control people only sampled in-tolerance parts. The variation was not large enough to detect on the QC Department samples.

 

Attached Files

Ken Campbell Iowa posted this 30 January 2018

when i wuz another ornery little bas... er... youth ... me and my friends would seek out and irritate bumble bee nests ...the idea was to swat with a paddle the attacking bees and the fun was that a bee would sting a buddy, not yourself .....

the lifetime lesson i took from that ..... was that it is the bee that you don't see that will sting you ...

larry points out that we may have a few unseen bees flitting around our best efforts at the casting accuracy game.  occasionally you can hear a buzz, but not see it clearly ...

ken

 

Attached Files

Show More Posts
Categories
Search
Popular Tags
This Weeks High Earners
Hot Topics
Close