Post by Richard on Feb 4, 2016 12:18:09 GMT -5
How group size can be affected……………..
Just some thoughts that have been revolving around in my head and I thought I might throw out for discussion. This will entail bullet quality along with the integrity of the rifle and shooter.
Looking at the bullet first: Cheap or as I like to call them “generic!” Do you get what you pay for? Sometimes yes and sometimes no? For purposes of this discussion I will use Hornady, Sierra, Speer, Nosler, Barnes to name a few as generic. Other than the Barnes, the other common ones are called cup and core---------copper cup (jacket) and lead core along with possibly a polymer or machined tip inserted into the nose. Should any of these three components be out of balance or inserted crooked, the bullet, spinning at well of 50,000 rpms, will more than likely not print in the exact same spot on the target. IMO, the core, which represents the largest portion of weight, would be the biggest culprit. An inclusion/air pocket in the lead (whether it is a poured core and extruded one from lead wire) , this will throw the bullet out of balance. Next the jacket: These have to be drawn form a copper/nickel (or whatever) plug and formed into what looks like a “lipstick tube?” Any variation in the wall thickness will manifest itself as an out of balance bullet. The tip, being in the center is probably the one component that will least affect balance since it is light and causes less of a disturbance rotationally being more centered but none the less a factor. Most all custom bench rest bullets do not include a tip. Sometimes a little less BC trumps a precision bullet.
Next, we have to look at the stability factor. This entails bullet weight, bearing surface, bullet form, rifle twist rate and powder charge. The longer the bullet, generally speaking, the faster the twist rate for bullets of the same weight. This can be seen with copper bullets and bullets with a very long pointed profile. Speed is another factor that can influence stability. A bullet that might be marginally stable at say……..2900 fps might benefit by be driven 2950 fps. Weather temperature can also be a factor on marginally stable bullets. In warm weather, say down to 40* a 6.5mm 140 gr. bullet might stabilize in a 1-9 twist barrel but at 37* it might not (seen this happen). It is best to over spin then under spin a bullet. So now lets add in the fit of the bullet in the bore of our muzzle loaders (some of this is applicable also in CF rifles but I am leaning more towards our SML’s for this discussion).
If a smooth sized bullet does not swell up for the powder charge, it may not grab the rifling enough to start spinning it as it comes off the powder. In effect, it may be slip/sliding down the bore and exit the muzzle not properly or unstabalized? This will definitely affect the accuracy on the target.
So lets look at your actual grouping on the target. You shot a five shot group at 100 yards with your .45 SML with “X” bullet and it measures say………..2” but 3 of the five bullets are clustered in a nice .750 group? Shot #4 is out low and left and shot #1 is high and right. But 2, 3 & 5 are nice and tight? WTF? Been there and done that many times.
You know your hold was good the trigger broke when you were on the target with your high dollar NF scope so way the large group?
Did you ever put a small drill bit (usually happens with small bits) in your drill or drill press and not get it centered when you tightened it up? You will see the end of the bit wandering around in a large circle . If you tried running it thru a piece of paper you would get a much larger hole than if it was properly centered right? So now picture your bullet coming out the muzzle and wobbling out of balance/stabilization (however little) and traveling down range; when it hits your target, it might impact at 3:00, 5:00 or who knows where? The shot could be faster or slower than those three that grouped. Speed is irrelevant as to POI. It could be high and still be the slowest one of the bunch? Obviously, the further away from the muzzle, the wider the dispersion will be.
So now lets take a box of these bullets that have some inconsistencies and you can see where groups can get big and yet you think you are doing everything correct. Different “lots” of bullets can vary in their quality control. You would expect custom bullets to have far less variation than generic bullets. Kyle takes a lot of pride in the way his bullets are produced which will help with your group size………………………….BUT, if it does not stabilize from your particular barrel, powder charge, ignition system it will not group well. I mention this because it happened to me while I was testing Kyle’s bullets. I had no doubt that his bullets were put together with close tolerances and great QC however in my barrel/ignition system they were exhibiting an accuracy problem…….two of three in a bug hole but why the one out? STABALIZATION! I believe the single powder charge of 78 gr. IMR-4198, was not stabilizing the bullet consistently…………NOT swelling or OBTURATING the bullet consistently to grab the rifling and hence the flyer! When I switched to my duplex?.................BAM! NO flyers!
Yet, when I used the same 78 Gr. IMR-4198 with the 275 Ballistic Extreme……….which has approximately .100” more bearing surface and a thinner jacket? They grouped.
I have come to the conclusion that unless you have a proven system (which I believe Hank has) and stick with just those components, you will have to do y our homework with other loads and components. Many of these other bullets and load combinations can be made to shoot more than adequate for MOST hunting needs. However if you want to stretch your range beyond what the genaric’s can provide, then you need consistent and quality components.
I hope this will generate some meaningful discussion!
Richard
Just some thoughts that have been revolving around in my head and I thought I might throw out for discussion. This will entail bullet quality along with the integrity of the rifle and shooter.
Looking at the bullet first: Cheap or as I like to call them “generic!” Do you get what you pay for? Sometimes yes and sometimes no? For purposes of this discussion I will use Hornady, Sierra, Speer, Nosler, Barnes to name a few as generic. Other than the Barnes, the other common ones are called cup and core---------copper cup (jacket) and lead core along with possibly a polymer or machined tip inserted into the nose. Should any of these three components be out of balance or inserted crooked, the bullet, spinning at well of 50,000 rpms, will more than likely not print in the exact same spot on the target. IMO, the core, which represents the largest portion of weight, would be the biggest culprit. An inclusion/air pocket in the lead (whether it is a poured core and extruded one from lead wire) , this will throw the bullet out of balance. Next the jacket: These have to be drawn form a copper/nickel (or whatever) plug and formed into what looks like a “lipstick tube?” Any variation in the wall thickness will manifest itself as an out of balance bullet. The tip, being in the center is probably the one component that will least affect balance since it is light and causes less of a disturbance rotationally being more centered but none the less a factor. Most all custom bench rest bullets do not include a tip. Sometimes a little less BC trumps a precision bullet.
Next, we have to look at the stability factor. This entails bullet weight, bearing surface, bullet form, rifle twist rate and powder charge. The longer the bullet, generally speaking, the faster the twist rate for bullets of the same weight. This can be seen with copper bullets and bullets with a very long pointed profile. Speed is another factor that can influence stability. A bullet that might be marginally stable at say……..2900 fps might benefit by be driven 2950 fps. Weather temperature can also be a factor on marginally stable bullets. In warm weather, say down to 40* a 6.5mm 140 gr. bullet might stabilize in a 1-9 twist barrel but at 37* it might not (seen this happen). It is best to over spin then under spin a bullet. So now lets add in the fit of the bullet in the bore of our muzzle loaders (some of this is applicable also in CF rifles but I am leaning more towards our SML’s for this discussion).
If a smooth sized bullet does not swell up for the powder charge, it may not grab the rifling enough to start spinning it as it comes off the powder. In effect, it may be slip/sliding down the bore and exit the muzzle not properly or unstabalized? This will definitely affect the accuracy on the target.
So lets look at your actual grouping on the target. You shot a five shot group at 100 yards with your .45 SML with “X” bullet and it measures say………..2” but 3 of the five bullets are clustered in a nice .750 group? Shot #4 is out low and left and shot #1 is high and right. But 2, 3 & 5 are nice and tight? WTF? Been there and done that many times.
You know your hold was good the trigger broke when you were on the target with your high dollar NF scope so way the large group?
Did you ever put a small drill bit (usually happens with small bits) in your drill or drill press and not get it centered when you tightened it up? You will see the end of the bit wandering around in a large circle . If you tried running it thru a piece of paper you would get a much larger hole than if it was properly centered right? So now picture your bullet coming out the muzzle and wobbling out of balance/stabilization (however little) and traveling down range; when it hits your target, it might impact at 3:00, 5:00 or who knows where? The shot could be faster or slower than those three that grouped. Speed is irrelevant as to POI. It could be high and still be the slowest one of the bunch? Obviously, the further away from the muzzle, the wider the dispersion will be.
So now lets take a box of these bullets that have some inconsistencies and you can see where groups can get big and yet you think you are doing everything correct. Different “lots” of bullets can vary in their quality control. You would expect custom bullets to have far less variation than generic bullets. Kyle takes a lot of pride in the way his bullets are produced which will help with your group size………………………….BUT, if it does not stabilize from your particular barrel, powder charge, ignition system it will not group well. I mention this because it happened to me while I was testing Kyle’s bullets. I had no doubt that his bullets were put together with close tolerances and great QC however in my barrel/ignition system they were exhibiting an accuracy problem…….two of three in a bug hole but why the one out? STABALIZATION! I believe the single powder charge of 78 gr. IMR-4198, was not stabilizing the bullet consistently…………NOT swelling or OBTURATING the bullet consistently to grab the rifling and hence the flyer! When I switched to my duplex?.................BAM! NO flyers!
Yet, when I used the same 78 Gr. IMR-4198 with the 275 Ballistic Extreme……….which has approximately .100” more bearing surface and a thinner jacket? They grouped.
I have come to the conclusion that unless you have a proven system (which I believe Hank has) and stick with just those components, you will have to do y our homework with other loads and components. Many of these other bullets and load combinations can be made to shoot more than adequate for MOST hunting needs. However if you want to stretch your range beyond what the genaric’s can provide, then you need consistent and quality components.
I hope this will generate some meaningful discussion!
Richard
