The accurate scale dilemma

[coyotemaster]

I read with some amusement the post concerning the pros and cons of different scales, beam vs digital etc. While I agree that being as consistent as possible with all reloading sequences is important I think being concerned with the gr. weight to the n'th degree is not as important as some think. If we are discussing pure accuracy then we need to consider barrel harmonics. It is known that the vibration travels from chamber to muzzle and back again repeatedly after the bullet is started down the bore. The most accurate loads will always have the bullet leaving the muzzle as the harmonic is at the chamber in it's cycle. In my rifles the groups are the same size and location if the charge is within .5-.7 of a grain. As an example my load in the .220 Swift is 39.7 IMR 4064 but it will shoot just the same at 39.3 and 40.0 gr. The harmonic as far as I can tell is right around the 39.7 gr. but either way a bit is not enough to change impact as the harmonic has not influenced the muzzle yet.

This is not new science and you can avail yourself of the theory at Newberrys OCW website.

[fortune]

Yes:-

I fell into problems with harmonics when I fitter a PES silencer onto my win70 /223. I have reduced this by bedding the barrel. The weapon will shoot the same batch of ammo to one point without the silencer and to a different point about 8 inches different with the silencer fitted. what it means in practical terms is that if zeroed on with silencer fitted then I have to use it with the silencer.

[dicehorn]

I read with some amusement the post concerning the pros and cons of different scales, beam vs digital etc. While I agree that being as consistent as possible with all reloading sequences is important I think being concerned with the gr. weight to the n'th degree is not as important as some think. If we are discussing pure accuracy then we need to consider barrel harmonics. It is known that the vibration travels from chamber to muzzle and back again repeatedly after the bullet is started down the bore. The most accurate loads will always have the bullet leaving the muzzle as the harmonic is at the chamber in it's cycle. In my rifles the groups are the same size and location if the charge is within .5-.7 of a grain. As an example my load in the .220 Swift is 39.7 IMR 4064 but it will shoot just the same at 39.3 and 40.0 gr. The harmonic as far as I can tell is right around the 39.7 gr. but either way a bit is not enough to change impact as the harmonic has not influenced the muzzle yet.

This is not new science and you can avail yourself of the theory at Newberrys OCW website.

 

Yes to a point...................... in cases with a capacity over 35 grs but try your .5 to .7 variation in a Hornet or .17 at your own peril.

 

In my book - whether you use beam or electric scales, without consistent powder weight, it somewhat negates your careful case preping

[coyotemaster]

Yes to a point...................... in cases with a capacity over 35 grs but try your .5 to .7 variation in a Hornet or .17 at your own peril.

 

In my book - whether you use beam or electric scales, without consistent powder weight, it somewhat negates your careful case preping

 

I do shoot a .17 Remington and a .17 Predator and while it is true that with a smaller case small changes in charge can have huge consequences I still find that I can be within .1 or .2 and it still shoots the same IF I am on the node. I use a Redding measure and do weigh every 8th or 10th charge to make sure I am still where I need to be. You are entirely correct about consistent weight as well as consistent bullet seating depths, neck tensions etc. to give most accurate reloads---it is a package deal. I use a beam scale RCBS 505 and don't fret if I see a small variation +/- .1gr.

[kent]

I do believe harmonics effect accuraccy, i do not believe its the be all and end all though. The right bullet to suit your barrel, well preped quality brass, a well constructed staight round and a very consistant push giving the lowest possible SD over the chrono etc. all take president.

 

Anyone who has attended practice sessions among serious bench rest shooters will have seen visibly different loads thrown (unweighed) and shot into bug hole groups at 100yds. its realy then only SD that will let such a load down as range increases. Short, stiff barrels flatten harmonics and long limber skinny ones make it more apparent, so there will always be differences though i am saying it aint a hill of beans compared to more important matters. To develop a load based on the theory you have found the best harmonics for that barrel at 100yds is just laughable though. Indeed if all test ammo was mixed up (could only be done if all were proven safe) and the shooter was unaware of it i bet most guns would show a marked performance peak in harmonics

 

If anyone wants to rubbish my statement, just convince me why a load with the so called "best harmonics" ie flatest could beat one with the lowest SD at extended ranges. The two as far as i am aware cannot be said to occur simultaniously without a goodly dose of pure luck.

 

 

The most important tool in load development remains the chronograph IMO

[kent]

Yes to a point...................... in cases with a capacity over 35 grs but try your .5 to .7 variation in a Hornet or .17 at your own peril.

 

In my book - whether you use beam or electric scales, without consistent powder weight, it somewhat negates your careful case preping

 

 

Interestingly, the Hornet produced very similar max velocities when i tested it with Lil gun. There was some marked differences in SD as loads increased. 10.8 grn - 12.2 grn. Case in point i actually recorded a single shot of 2933 at the start load mentioned (the SD was 80.75 though)

[1066]

 

In my book - whether you use beam or electric scales, without consistent powder weight, it somewhat negates your careful case preping

While I agree that if your load is in the middle of a wide node, a little powder either way may not make a lot of difference. Many shooters are quite happy just throwing charges straight from a measure, it depends what you are looking for in a load. We are often told that benchrest shooter throw charges and it works for them but I don't think you will find many 600yd bench or 1000yd F-Class shooters happy to just throw charges.

 

If I'm going on a day out for a long range shoot it's a ninety mile drive each way and I may fire 50 rounds at about 85p a bang. I prep my cases carefully, Sized, flash holes, primer pockets, necks, length, annealed, etc. etc. Bullets are sorted and seated to my satisfaction. - Why would I guess how much powder to put in the case when it takes so little extra effort to weigh each load as exactly as you can even if it dosn't make a measurable difference.

 

Of course loading rounds for my .357 gallery rifle is a different story all together.

 

Consistency is the key - It doesn't matter so much what the weight is as long as they are all the same. A good beam scale will easily show a difference of 1/20th grain and never drifts with low batteries or interference from strip lights.

[coyotemaster]

I do believe harmonics effect accuraccy, i do not believe its the be all and end all though. The right bullet to suit your barrel, well preped quality brass, a well constructed staight round and a very consistant push giving the lowest possible SD over the chrono etc. all take president.

 

Anyone who has attended practice sessions among serious bench rest shooters will have seen visibly different loads thrown (unweighed) and shot into bug hole groups at 100yds. its realy then only SD that will let such a load down as range increases. Short, stiff barrels flatten harmonics and long limber skinny ones make it more apparent, so there will always be differences though i am saying it aint a hill of beans compared to more important matters. To develop a load based on the theory you have found the best harmonics for that barrel at 100yds is just laughable though. Indeed if all test ammo was mixed up (could only be done if all were proven safe) and the shooter was unaware of it i bet most guns would show a marked performance peak in harmonics

 

 

 

If anyone wants to rubbish my statement, just convince me why a load with the so called "best harmonics" ie flatest could beat one with the lowest SD at extended ranges. The two as far as i am aware cannot be said to occur simultaniously without a goodly dose of pure luck.

 

Kent I don't know why you would think one would want to rubbish your statement, you are certainly entitled to your opinions and I personally think highly of them. I do believe S.D. is important and as I stated in the post above yours that there are many variables that enter into accuracy. My thought and reason for posting is that charge weight alone is not the end all nor is harmonics nor is S.D., annealing, case prep etc it is a PACKAGE DEAL. I chrono after I find the load that shoots the best-most accurate- and usually find the S.D. is quite low, but it is not what I am chasing. I need to know load speed for drop calculations at extreme range.

 

 

The most important tool in load development remains the chronograph IMO

[kent]

I don't think anyone would care to rubbish it, they would struggle to i think. I do actuall weigh every charge into every case after throwing it, for every gun. I don't find it an issue to record SD at the same time as shooting the groups. a few 3 or 5 shot groups at a charge weight show little or nothing IMO. I tend to work a load up chronoing each, find what i think the best ones potentially are then load around 30-50 of that type to parrellel test with others.

I think many pick thier best load from one flukey group, what i look for is solid repeatability personally. As for complete package i totally agree 110% Whats sometimes missing is sometimes one extra process might actually be counter productive to a load, though precise weighing can never be such so i always do it (mentally it gives me a confidence boost :yes: ) thats a big factor! I know at 100yds it wont matter a jot though

[Graham M]

Barrel harmonics are absolutely key to accuracy, but must be linked to consistent ammo.

I changed a batch of Tenex a few years ago and although it shot well in my mates Anschutz, it was not as good in mine as my previous batch. Simply tightening up the bedding bolts from 5NM to 6NM made all the difference, with the harmonics coming into line with that particular velocity of ammo.

 

I have seen people putting elastic bands around the front end of their match rifles, over the barrel and fore-end, and sliding them back and forth to alter harmonics until they got smaller groups sizes.

 

Is it worth it for shooting in the field...........nah!!!!!

 

 

 

G.M.

[coyotemaster]

Barrel harmonics are absolutely key to accuracy, but must be linked to consistent ammo.

I changed a batch of Tenex a few years ago and although it shot well in my mates Anschutz, it was not as good in mine as my previous batch. Simply tightening up the bedding bolts from 5NM to 6NM made all the difference, with the harmonics coming into line with that particular velocity of ammo.

 

I have seen people putting elastic bands around the front end of their match rifles, over the barrel and fore-end, and sliding them back and forth to alter harmonics until they got smaller groups sizes.

 

Is it worth it for shooting in the field...........nah!!!!!

 

 

Agreed Graham! I wouldn't think out messing with rubber bands etc. in the field. When I develop a load I stick with it and if it shoots .5 I am plenty confident that if/when I miss it is my fault not the gun. I am more confident shooting a .5 or .25 rifle afield as it is a confidence builder to know you could shoot them in the eye.

 

Kent Points taken! I have learned a great deal from you and like to think that we can sometimes disagree in order to learn from each other.

 

G.M.

[kent]

Don't get this wrong Harmonics are relivent, just if your shooting MOA at 100yds you will never find the sweet spot anyhow. Match .22 rifles are a different matter, 50yds win or loose prone can be decided on so little barrel tuning is relient, you cannot tune your load into it though as your shooting factory produced ammo