Velocity, Accuracy and different powders

[JohnH]

Played a bit today with my 38-55 and XMR5744. Found that 17 grains under Lee's 379-250-RF shoots better than I do. Makes circa 1300 fps. Shot 7" high to point of aim for the rifle being sighted for a 850-900 fps load. Backing off to 11.5 grains, I was hitting point of aim but the groups had opened up and were very like the groups I get from 7.2 grains of #107.....7 in 7/8" or so and 3 opening the group to 1 3/4"-2" No rhyme or reason to the fliers as usual. I've not yet tried uping the charge of #107 to get 1300fps to see if the rifle is liking the velocity or the powder, but it was nice to stumble on this combination.

[BOOM BOOM]

HI,
I have come to believe that there is a difinate relationship, in a rifle (maybe a pistol too) to how it groups and the vel. of a certin bullet. If a bullet in a centin rifle gruops well at say 1300'/s w/ say 700X, a load at that vel. w/ green dot or unique often groups well w/ the same bullet.
I BELIEVE THIS HAS TO DO W/ BARREL HARMONICS.
I also believe these harmonic nodes of a barrel/bullet combo can & do occur at several velocities at set increments simular to harmonic vibrations in organs & other musical insterments.

[JohnH]

Boom Boom, glad you figured out what I was trying to say. I knew what I wanted to say but just couldn't quite get it out clearly. I'm hoping you're right and that a warmer load of #107 will shoot as well.

[felix]

If your boolits are certified good, then you have multiple pressure peaks causing the fliers. ... felix

[BOOM BOOM]

HIAGAIN,
Let us know what you fined out. As what I said is just my observations, I don't know if others have observed simular vel. corralations.

[felix]

The same velocity with two different powder burn speeds seldom will give the same accuracy. Tweaking closely related powder speeds will, though. Velocity has nothing to do with barrel whip, only accelleration does. ... felix

[waksupi]

John ,do you suppose it could be lube purging, or barrel heating?

[felix]

Yes, it very well could be lube purging, but usually shows up as one flier out of a group of say, seven shots. ... felix

[Bass Ackward]

No rhyme or reason to the fliers as usual.

John,

95% of my fliers with a straight sided case are from differing ignition or leading. If it ain't one, .......

Since you prefer the faster powders, I would try a tuft of dacron with the 5744 just to see what happens even if you have to cut the charge a 1/2 grain. Then think what else can you do to improve ignition. (seating depth, crimp, ets.)

[Buckshot]

...........I got a Savage M112 in 223 back in 1992. I put a Tasco 6-24x44 scope on it. Without a doubt the most accurate rifle I own. Let me hasten to add that the scope and tweaked trigger has some to do with it, plus piller bedding (my own), and bbl bedding. I do have to credit a fine barrel/firearm from Savage too.

When I got the rifle I immediately began a steady program hunting for a very accurate load combo for it. There were many weeks when I was at the range twice a week. I had a great supply of LC83 once fired brass, totally prepped. I had several batches of 20 rnds that weighed exactly the same, and several 50 round batches that weighted within .1gr of each other.

I found it very interesting doing this reloading project. My targets for the most part were Leupold types with a 2" black square with a 1" diam white circle, 4 to a target paper. At 100 yards the crosshairs would divide that 1" white dot into 4 equal pieces, for a good consistant picture.

The course was using loads out of the Sierra and Speer books and generally of .5gr charge increases to book max. Charges were always done on a Hornady balance beam scale. Loads showing promise were then reloaded with .2gr increases. After several months of shooting, the best were loaded in .1gr incremental increases. During these tests, all groups fired were 5 rounds.

What was new to me as I'd never seen it before (never had a rifle this accurate, or with such a scope either) was the fact that groups would open and close as the charges increased. This was long before the threaded "barrel tuners" were around. I've wondered if some of these excellent groups could have been made even better with one?

As expected the groups also printed higher on the target and marched off to the right like a spring uncoiling. I have to suppose it was all barrel harmonics.

What did I eventually pick as all round best load? That would be 28.5grs of Win748 and a 53gr Sierra HP.

Another good load I found several years later and had just loaded up for fun was the (can't remember if it was Sierra or Speer) 63gr SMP, SP over a casefull of surp WC852. Top velocity was just barely at 3K, but the accuracy for what is basicly a hunting bullet was phenominal. I figured if I ever went after coyotes, this would have been a superb combination.

.............Buckshot

[Pop_No_Kick]

John ,do you suppose it could be lube purging, or barrel heating?

Lube Purging ???

Chuck

[Bass Ackward]

What was new to me as I'd never seen it before (never had a rifle this accurate, or with such a scope either) was the fact that groups would open and close as the charges increased. This was long before the threaded "barrel tuners" were around. I've wondered if some of these excellent groups could have been made even better with one?
.............Buckshot

Richard,

Absolutely. Harmonics create a velocity "zone". The more friction under acceleration the higher the frequency and the closer the zones are together. Kinda like running your finger around the top of a wine glass. That's what Hornady did when they came out with their youth loads was just to back them down to their next harmonic range from there regular listed loads.

The old standard for cast bullets say they are the most accuracte in the 1500-1800 fps range. If you include 45 caliber the range widens to 1100-1800. This is the easiest band to obtain because you don't have to worry about pressure to operate in this range.

But all the benchresters run in the next band up which is in the 2000-2450 fps range. This band is not really all that hard to achieve if you have some case capacity to avoid maximum pressures. The next band above that seems to be 2600-3000 always with the smaller calibers running the top of the range and larger calibers below that. Here case capacity is your friend. This range can really be a toughy and I can only attain it in warm weather above 80 degrees.

Of coarse you can operate in .... or out of these areas by adding, changing or eliminating bedding pressure in order to change the vibration pattern depending on how your particular barrel responds. Or changing bullet hardness too. But the larger the bore, the tougher it is to tune the range from my experience.

[waksupi]

Chuck, lube purging is what occurs when there is a surplus lube build up in the bore. When this happens, it will push out of the bore ahead of the next bullet, creating a flyer. As Felix stated, this is usually after 7-8 shots. And it doesn't always happen. I believe it is more common with the good lubes we now have, than some of the less efficient types. The easiest way to control it, is to not over lube a bullet, in my way of thinking.
My thinking was, possibly a lube such a Felix' was made, with additional castor oil added. To me, this may create a condition of such a slick bore, as to take more than one shot to clear the bore, and get it back to prime condition.
I may be full of poop, and Felix can straighten me out if my assumption is wrong on this. I've had little experience with the condition, so much of it is speculation on my part.

[felix]

Yes, Waksupi, what you've said is correct. Chances are you will never see a lube purge when shooting offhand, and most likely only when shooting small bores off of the bench. Slick lubes typically do not build up enough to worry about, but can cause accuracy problems that are easily noticed by the third shot. You know, slipping and sliding in the bore. However, some lube materials can and will get hard after a short time of "hot" shooting. In particular, castor oil and lanolin are culprits because they are easily oxidized with circa 40K CUP pressures. In these situations, and when the rifle is put down for 30 minutes or so before the second group is shot, the bore has become plastically constricted. Very noticable with shallow grooves. The solution is to shoot more rounds like you say before positive results return. But, I would not call this lube purging, but lube hardening. ... felix

[sundog]

http://www.castpics.net/RandD/lube_star/lubestar.html

Just thought I'd throw this in for grins.... Mrs. Felix is a dandy photographer! sundog

[Buckshot]

..........When the Oldfeller 6.5 slug came out, it was found pretty quickly that it wasn't a good thing to fill all four LG's.

............Buckshot

[felix]

That lube star in Sundog's post is just about ideal for 150 shots, and should remain that way for another 150 or more. If I am not mistaken, this lube version he made up uses mineral oil for the solvent. If using peanut oil, the black won't be as black and it would be harder to tell what a good lube star would look like. The lube star should start being seen after about 7 or 8 shots when using mineral oil and/or paraffin. If the star is seen before then, then the amount of lube should be cut back, like not filling the top boolit groove. If the lube cannot be cut back in amount, then the lube should be made slightly harder, or the melting point of the lube raised some. Look at the stickies for this process, and if not there, then say so here. ... felix

[JohnH]

Thanks for all the response guys, lots to chew on for sure. I'm currently only filling one of two lube grooves. In past I posted on my "Goofy Lube", and I am currently using that mixed 1 to 1 with a batch of Felix lube I tried my hand at. The lube is soft, soft enough that it will squeeze out of the lubrisizer at room temp if I don't take the pressure off the screw. (betcha can guess how I discovered that one :)) Lube seems to work quite well though. The Lee 379-250-RF is a plain bevel base design, I'm shooting WW+1.6% tin. No leading even at 1600 fps, 23 grains of 5744 gave me two 5 shot groups of 1.5". Nothing out of the ordinary there. The rifle will shoot as tight as the 17 grain 5744 load with 24.5 and 28 grians of WC680 or 25 grains of 4198, all three of those loads are 1700-1900 fps.

Jacketed was more forgiving, but nearly as interesting.

[Pop_No_Kick]

Chuck, lube purging is what occurs when there is a surplus lube build up in the bore. When this happens, it will push out of the bore ahead of the next bullet, creating a flyer. As Felix stated, this is usually after 7-8 shots. And it doesn't always happen. I believe it is more common with the good lubes we now have, than some of the less efficient types. The easiest way to control it, is to not over lube a bullet, in my way of thinking.
My thinking was, possibly a lube such a Felix' was made, with additional castor oil added. To me, this may create a condition of such a slick bore, as to take more than one shot to clear the bore, and get it back to prime condition.
I may be full of poop, and Felix can straighten me out if my assumption is wrong on this. I've had little experience with the condition, so much of it is speculation on my part.

Thanx's for the Primer on the lube purging..
Ya'll Explain things WELL !!

I don't need to be smart, Just keep Smart Peaple around Me!

[Rrusse11]

http://www.castpics.net/RandD/lube_star/lubestar.html

Just thought I'd throw this in for grins.... Mrs. Felix is a dandy photographer! sundog

Sundog,
32-40? Well I should joining the club shortly. Picked up a Marlin barrel and half a reciever at an auction over the weekend for the princely sum of $15. It appeared to have been fire damaged, and was VERY ratty looking, I was after the forend cap and tenon and the magazine tube end and stud. The bore was still shiny however, and after some Kroil and wire wheel and files and stones,,,,, low and behold it looks like I've got myself a lovely old 26" octagon barrel in 32-40 from a 1893, the markings have surfaced thru the murk. Need to plug it into a 336 action, and wind her up. Brass is a coming! as well as dies and I've got the Lee C324-175-1R mould, should be interesting. {:o)
Cheers,
R*2
Ps. My buddy bought the Marlin 1893DL TD in 32-40, half octagon barrel,, for a LOT more money, lol. He also got a Win 1886TD in 33WCF,,,,, another interesting cartridge, Lee dies and a mould are in the same order.