Questions about range results...

[Richard]

I have questions in my mind which I cannot answer?
The NC weather has been getting quite hot lately. Yesterday at 7:00 a.m. it started out 70* and by the time Herman, Bill and myself left the range it was 82* in the shade. There are a number of shooters on this forum who are kind of "wishy/washy" about using the cool rod For me, and quite a few others, it is a way of shooting all year long particularly in hot weather.
Group #1 (which is not pictured) was a three shot-er to "condition" the bore. The first shot as usual from a clean dry bore was the highest in velocity and printed out of the group but was still 1.2" Shots 2&3 were touching. NO cool rod was used!
From here on out, the cool rod was used after almost every shot.

Next up is a load I tweaked from last week. I kept the booster at 10 gr. (SR4759) and upped the main charge from 60 to 62 gr. of H-322. I used the smooth blue Harvester sabot and the Nosler 200 gr. HP and shot a 100 yard group. Note the average velocity of this load...........2748 fps with a low 14 fps ES. And yet, the group was not a five shot ONE holer?
Moving out to 300 yards...........same load but using the 200 gr. SST. (re-adjusted to scope to put the bullet about 2"+ at 100 and moved the windage an inch to the left.)
Here the velocity was in the same range and except for one shot, the ES would have been single didgit. This group was more what I am interested in...........on a regular basis.
Wanting to prove it out, I proceded to shoot a second group with the exact same combination. Maybe five minutes later? The point I want to make is group three may have been one or two degrees cooler than #4.
#4 Note the increase of velocity by around 25 fps average from say 2750 to 2775 but the ES at only 10 fps..................! I would have figured this group to be as small at the preceding one but NOT!! Yes, three of the five did go in the same area but not three in a row? and why #2 and #5 out of the group by that much? All shots felt good, no wind, the crosshair staying on the dot when the shot broke
On to the last group which turned out to be no group at all Same charge but used the 195 Barnes. First shot..........Elevation the same but out a couple of inches to the left............Reasonable that a different bullet prints a little different; velocity 2772 which is good. Second shot............An odd sounding muffled bang, a look at the chronograph: 2470 ............No impact on the target and a conclusion that it was a blown sabot?
All shots were equally cooled and no problem occurred with the SST's or Noslers. The Barnes? And I would not consider this a "hot" load.
I cannot for the life of me figure out why the 25 fps difference in targets 3 and 4? Did the sun shifting cause it? And why with such low ES's did two go out of the group when the previous group had a shot 25 fps slower and it went in the group?
As Herman and Bill always say: d**n muzzle loaders ;D
Richard

[Savage Shooter]

Gotta second Herman and Bill .......dang muzzleloaders!! ;D

[dennis31]

Now, if we could figure that out we wouldnt be shootin groups like that . Nice shooting on targets 2&3 though ;D.

[handy458]

As far as the 25fps between 3 & 4, my suspect would be an electronic scale in and out of the sun which might soften the sensor enough to read a .3gr off. If you have a beam/magnetic scale or a calibration weight you could rule that in or out.
I'm assuming you are using a 18-20x scope so correct me if not, but mirage the last few days has been really boiling (next door here in TN) which might account for some of your verticle.
Nice report.

[Deleted]

Thermals lifted your group from 3 to 4 with the heat on the increase, humid air evaporating probably neglible at 100yds but at 300 and farther could be a factor. My best educated guess,take it or leave it.
Blown sabot on last group , inferior sabots .I'm so sick and tired of reading about sabot failure that it is driving me nuts that no one has been able to beat that beast.
Whats really bad is that we spend big bucks building these awesome mls only to be at the mercy of how a little piece of plastic holds up under pressure and heat.
You can build the best bullet in the world but if its in a sabot you'll never know its real potential.
The sabot companies don't give a sh** about making something that works in our smokeless guns because of such a small group that we are and they have been making money on their inferior products for so long that why fix it when it only is a problem for the very few . DISGUSTING thats why I have been really interested in the sabotless shooting that the pioneers here have been developing.
The sabot makers need to step up to the plate and invest some in RandD to come up with something that works, if they can make something that will hold up to smokeless don't you think the sub guys would feel better using it also,duh.
Pissed Off!!!!!
Greenhorn
DANG INFERIOR SABOTS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[deadon]

Richard, great report as always. I have read your post reverently for over a year but I am old and tired so I do not remember if this has been ask of you nor do I remember if you responded. When you find a boring almost one hole load, Have you shot it ten or fifteen more times to test for consistency? Please don't answer with a "Rusty &&&&&&&&&&&&&&&&&&&" If that is a dig,I did not understand it so it did not stop whatever you were trying to stop. Thanks again for the great bedding job, Rusty

[edge]

Bent Recoil Lug!
;D ;D ;D

You knew it was commin'! Hey I didn't say you should move your front rest back to be under that bent recoil lug...but it would have added to the laugh factor

IMO, variances in sabot thickness or loading.
It is very hard to load a bullet perfectly straight, heck it is hard to align things in general!

Ever use a lathe? ( rhetorical)
You can load the same part 30 times and rarely will they be on the same centerline but a few times. That is the reason most precision parts are cut in one setup!

If I cut a shaft all in one setup the diameters are almost always near perfect. If I add a human and send that part to a secondary machine then there is almost always some error...actually 99.99995 there is some error!
I can use a sub spindle machine and the error will be much more consistent but still there.

IMO, my mushroom shape full bore or the Swinglock design are hard to beat if you are willing to not use a sabot.

IMO, a sabot that you can bend in your fingers and actually measure a difference in petal thickness is not really meant for extreme range...much over 300 yards with a pistol bullet IS extreme range...IMO .

edge.

[Richard]

Handy.............These powder vials are all loaded at home by the same method. No rhyme or reason why one group of five give one set of velocities and the next, another? The scope is a Leupold 6.5 x 20 with a varmint hunter reticle AND a 3X Davis converter lens which brings my X count up to around 30 X. The rifle is in a custom stock (see stocks by Richard in the "hints and tips") It has an added 3" wide benchrest type forend and sits in a modified lead sled with corresponding bag. The sled rides on a base which allows it recoil just like a benchrest heavy gun. An added 16 lb. leather bag with lead shot keeps recoil very comfortable. The gun actually moves rearward about one inch each shot.
dougsmessageboards.proboards.com/index.cgi?board=gear&action=display&thread=2257
The mirage was manageable............nothing like what we experience at 600 and 1,000 yd. benchrest matches.
Rusty...........If you have followed my weekly reports you would see that I have shot some loads a number of times but not most. Some times I just tweak a load the following week if I think it has potential. Sometimes I go back thru my loose leaf folder and review what has shot good in the past, then re shoot them. Sometimes they do not shoot quite as good as the first time, sometimes they do. I look for loads with low ES's in the velocity range I want and the size of the groups. Here again, the results the second time are not always the same? Last week I shot 10/60.......4759/H-322 and it was fairly good........this week I shot 10/62...............the velocity only went up slightly (20 fps) but it gave me low ES's. Yet the group with the lowest ES was not the best? Go figure?
Edge.........I was seriously thinking about that d**n recoil lug and was going to throw it in but thought I would let sleep in GOATS lie ;D
I get your point and agree. When I chamber a rifle, I ALWAYS use a reamer that has everything included.........body, shoulder, neck and leade. And, will never remove the barrel from the lathe until completed. The entire threads, shoulder, any fitting of bolt face to breech and chambering are done with the barrel as originally indicated. There are some smiths that will use a body/shoulder reamer and then play with different neck and leade reamers. I guess its cheaper to taylor a chamber to a customers needs (provided he is not a benchrest shooter)
Its funny too, I spend a lot of time making fixtures for the muzzle to align the bullet with my short seater and Herman would not use the guide I made for him? He starts his bullet with the factory plastic one ;D...........And he shoots great groups? Go figure?
Still curious as to why that Barnes blew the sabot? Not a particularly fast load!
Richard

[deadon]

Richard, Thank you for you response and all you do, Rusty

[jeremylong]

Even with a cool rod, I just dont think your going to be able to shoot saboted loads at those velocities when its 80F and above outside. Well that is unless your shooting bunk has A/C too!?!

[dans]

Did you have your components in a cooler or some where they would not be subjected to the rising temperature? This could be a factor.

[edge]

Richard, you know I'm just bustin' on ya

If you merasure sabot petals they are almost always tapered from the base forward.
This is just the way things are molded. The last thing a manufacturer wants are parts sticking in molds. If they are tapered when at extraction/ejection temperature then they will cycle. The base has lots of mass and if the petals stick the base will surely get distorted because it is barely solidified when extracted/ejected.
The base of the sabot petal is probably 0.001 or more thicker than the muzzle end.
IMO, the bullet is stuck in the sabot and it sits in the bore at a random angle. Now 0.001 does not seem like much,and let's average it to 0.00005 but over a bearing length of say 3/4 inch ( which is longer then most bullet bearing surfaces or sabot petal lengths ) this amounts to a huge aiming error.

1MOA is about a Tangent of 0.0003
The theoretical error in the bullet misalignment is about 0.04 or ten MOA!!
Now the bullet will absolutely revolve around its center of mass at some distance after it exits the bore.
How much it stays misaligned in the bore,
How much it "squirms" in the bore as it accelerates to 3k fps is something for the physicists to debate
Heck it may almost come out square to the bore due to forces, but if it does it probably is not centered.
This would lead to another theory

The theory of bullets going to sleep

Lets say that a bullet will rotate around its CoG unless acted on by outside forces.
We must accept that a bullet is almost never exactly in the center of the bore in a sabot.
As it is fired it follows an elliptical path down the bore. FACT!
When it exits the bore it is thrown a distance "x" in the direction that it was offset.
IMO, this can't be disputed in physics! IF YOU WANT TO PLEASE START A NEW THREAD.
So, you have a bullet/projectile moving at "x" fps at "y" rpm it WILL "JUMP" "z" amount as it exits the muzzle.

Since your exit velocity is known you ( in theory ) should be able to calculate how far a PERFECT bullet was off center in the bore.

This obviously would need to have a perfect bullet that was perfectly centered to verify this ;D

So SWAG would be how I would do it ;D ;D
It is what it is, unless you know that the bullet is loaded in the "CENTER" of the bore, this is NOT the same as square to the bore!
SQUARE can be done with a false muzzle, centered is another matter and without some scientific devises it probably can't be measured!
edge.

[Jon]

Richard and Edge very interesting and informative post.
Jon

[wilmsmeyer]

Edge,

In response to your comments in Reply #11...all I can say is.....holy crap.....it's amazing all our shots even hit a 55 gallon drum at 100 yds. A gun shot is the ultimate example of controlled chaos.

[bigmoose]

Edge,

What did you say....I'm lost. I just load, pull the trigger, and what do you know sometimes I even hit the target, If I understood what you folks were saying, I'd take up knitting [ the very biggest smile]

[deadon]

Jun 4, 2011 15:23:32 GMT -5 bigmoose said:

Edge,

What did you say....I'm lost. I just load, pull the trigger, and what do you know sometimes I even hit the target, If I understood what you folks were saying, I'd take up knitting [ the very biggest smile]

+1 Bigmoose

[edge]

-2

A perfect bullet fired from a perfectly centered barrel will theoretically put bullet after bullet through the same hole. I hope we can agree there!

Now, fire a bullet with a defect ( say a void in the jacket) at ( 9 o'clock) as it exits the bore. You would not expect it to hit the same hole since it weighs less due to the void and the center of gravity will certainly move it to the left ( 9 o'clock for those not paying attention )

Now lets's take the same exact bullet and have it exit with the void at 3 o'clock, you guessed it it will hit to the right.

Now instead of a bullet defect we load a bullet offset in the bore... lets take a 45 caliber bullet in a 50 caliber barrel and offset it by 0.050
Yep it is hugging the bore on one side.
It will leave the bore and "jump" to the side but still fly true but not on the same line as the bore...but nearly parallel to it assuming it does not tumble.
How much it jumps will depend on a lot of variables like how far it was offset, the twist rate, velocity, etc.

edge.

[bigmoose]

Edge,
Your explanation show why you are one of the "wisemen" It very nice have someone think for you, it lets a dummy like me, just load and shoot
final score

:)782

and ask question ;D

[bigmoose]

I forgot the plus sign next to 782, proving my dummy status once and for all time

[boarhog]

I have got to agree with a lot of what Greenhorn said. The plastic sabot is the weak link. I am anxious to see how consistent the sabotless groups are with the new bullet being tested. I have also wondered how well aligned to bore hand knurled bullets will be? Perhaps the same inconsistency as with a sabot?
Boarhog

[Richard]

Borhog............the new bullet Rangeball is testing is .40 cal and being shot with a sabot.......Not sabot less! So, no matter how good a bullet, it still the same old story........THE SABOT and keeping the bullet aligned inside the sabot/barrel.
Richard

[deadon]

Jun 11, 2011 18:35:22 GMT -5 Richard said:

Borhog............the new bullet Rangeball is testing is .40 cal and being shot with a sabot.......Not sabot less! So, no matter how good a bullet, it still the same old story........THE SABOT and keeping the bullet aligned inside the sabot/barrel.
Richard

IIRC Deadeye is testing it sabotless.

[Richard]

Curious how he can test a .40 cal bullet sabot less in a .45 barrel?
Richard

[Jon]

Richard. If I'm not mistaken he has just recently built a 40cal which seems to shoot well? If I'm not mistaken you commented on his first post you were tempted to go .400?

Jon

[Deleted]

He used a dime to cover up his group.

[boarhog]

Guess I misread something somewhere. I had the idea that this new bullet was for sabotless shooting. I have been so busy lately, that I have had to try reading posts in spurts. Temps here have been over 95* for almost a month straight, and I've had roofers dragging out a 1 week job into 3 months. It's hard to think about shooting right now. There will be a good test when I do get a chance to shoot. I have 3 rifles still loaded from the last day of deer season. Kind of anxious to see where those shots hit.
Boarhog

[Richard]

OK, so he is shooting this .40 cal bullet in .40 cal. barrel
The original testing was being done saboted in a .45 right? And not going well? CRS!
Richard