8x57/4759/powder position/primer test

[Depreacher]

Well, I finally got it done. Please bear with me as I can't figure out how to arrange results with the cursor???? My grandkids can, I can't. Powder throughout test is 4759. Boolit is Lee .324-175. 170 gr 3 to 1, WW to lino mix. .3235 x .3149 nose. 5 shot groups. Rifle is K98 sporter W/ Simmons 3x9x40. Test #1 19gr. rear of case, CCI 200, group 2", avg vel 1668. Next, 19 gr., powder toward front (I loaded rather rapidly), CCI 200, group 2 3/4", avg vel 1603, POI was 8" high in relation to first group. TEST #2: 19gr., powder at rear, CCI 250 Mag., group 2 1/8", avg vel. 1700. Next: 19 gr. Powder at front, CCI 250, group 1 9/16", avg vel. 1610 (that's 90 fps difference folks!!!), POI was 6" high. TEST #3: 19.5 gr., powder at rear, CCI 200, group 2 7/16", avg vel. 1677. Next: 19.5 gr., powder at front, CCI 200, group 3" (bad), avg vel 1635, POI 5 1/2" high. Lastly TEST #4: 19.5 gr., powder at rear, CCI 250 mag., Group 3 7/8" ( go ahead and laugh, at least I admitted it, and nobody likes a lying preacher), avg vel. 1733. Next: 19.5 gr., powder at front, CCI 250, group 2 3/16, avg vel 1633 (what a diff, 100 fps wow), POI was 6" high from c-c to c-c. All this has probably bored you to death, but one exciting thing did occur during the tests. As I was trying to jer- uh- squeeze off a shot on test #3, something flashed across the center of my scope field. I looked up in time to see a whitetail deer disappear into the pine thicket that borders both sides of our range. If I had squeezed off the shot 1/2 sec. sooner, or he had got out of bed 1/2 sec. later that morning, I would have "made meat". You would think the ten or twelve previous shots would have scared him away. I guess not. After all this, I will probably go to mag. primers, and load in a level position. Will try to use the same speed of snick-snack when forwadring and lowering the bolt handle. 19 or 19.5gr? Hmmm.

[Buckshot]

............Good stuff. An old friend and a knowlegeable cast boolit shooter (now passed on) once told me that SR4759 was an excellent cast boolit powder. That is, if your rifle liked it :D It just shows that NO powder is insensative to position, it's just that some are less so then others.

Let me add this. I did this a few weeks ago with the initial firing of 100 new cases. Ie: Fireforming. I was shooting my Swiss K-31. Of these 100 cases, 20 had dacron in them. All new WW 284 brass, a Ly 311291 with WLRP to ignite 18.0grs of 2400.

10 rnds, fired as stripped from the magazine:

High: 1726.3
Low: 1687.0
SD..: 10.8
ES..: 39.3
Avrg: 1700.8

10 rnds, fired with the powder oriented to the rear (load & tip up muzzle).

High: 1856.1
Low: 1745.2
SD..: 47.8
ES..: 110.9
AVRG: 1781.7

10 rnds, fired with Dacron

High: 1732.7
Low: 1686.3
SD..: 13.3
ES..: 46.4
Avrg: 1703.4

Naturally as a big user of dacron, I would have liked to have seen the dacron stats lower. Possibly for the next group (if there'd been one) things might have been different. Yet what happened is presented. Actually my major concern is 'Why' is there such a large velocity jump with the oriented powder? Again, possibly just an anomoly for that group?

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

[Frank46]

Castboolitpreacher, your deer tale brings to mind a similar occurance. Our range had a small trail at the far end of the 200yd berm. One day we were shooting (two of us) and my buddy starts yelling stop shooting. Behind one of the 200yd target was a rather scrawny cow. The only reason you could see it was cause of the four legs. Ok down to the 200yd targets to chase them away.Would not move. So had to get a switch and whack em on the butt to make them move. You'd think that with all that noise that they'd move at the first shot. Deaf cows??. Frank

[swheeler]

Preacher; not trying to one up ya , but about 20 years ago the wife and I were shooting at the Whitefish rifle range, there were a half dozen other people there, and they had a BBQ going. There had been steady shootin' for several hours, opened the bolt to eject an empty, and lo and behold, a black bear came running out of the trees and across the range. Guess he figured he'd sneak in and have some bbq!

[Depreacher]

Hi Buckshot, Thanks for reading my test. Sorry about my groups. Sometimes 3 or 4 would go into a 3/4" or 1" group, then the inevitable 2 1/2" flyer ruins the group. Your results verify mine with powder positioning. Was really surprised at the velocity for the dacron load. Figured it would be more. Here's a country boys theory. With powder at front, the primer only ignites the sloping side facing it. The boolit holding the powder in position most likely. With powder at rear (no filler), the primer blows the powder forward, with the flame penetrating and igniting more granules at once, maybe launching the boolit with higher initial pressure in the case, such pressure making the powder burn hotter initally and peaking earlier in the boolits travel down the bore???? Get a bowl of cornstarch. Try to light it. Nutin! But get your mother-in-law to throw the cornstarch high in the air, and flick her Bic in the middle of the cloud as it descends (just kidding). Light a glass full of gasoline. It burns. You are only lighting one side of it, so it burns slowly to the bottom. But throw it up in the air, partially atomizing it. KA-WHOOF. Yeah, quite a difference. Bet I'll be roundly scolded for this theory, but its all I can come up with. Now my test has to be run with a reamed out primer pocket vent. A good test would be to start with a slightly reamed vent, and gradually increase the drill size until SD stabilizes at minimum, then go slightly beyond just to make sure. Of course you also have to experiment with different powders, different charges, diferrent primers, boolit seating depths, boolit weights, boolit design, case capacity, neck tension, and so on. Should have it done in a couple hundred years or so. Maybe some geek will come up with a computer program to do it for us. HA!

[44man]

Preacher, what you describe will happen with any powder that has a lot of airspace above it. I have 3 powders I use for almost everything from 7R, 7BR, 7-08, 6.5X55, 45-70 revolver, .44, .45 and .475. Those are Varget, 4759 and 296. I get some of the most fantastic accuracy from these that I never change anymore. I use dacron in the 45-70.
I think you have something about the primers. Most of my loads need a very mild ignition. I stick with Fed standard primers in everything except the .475. For some reason it likes the Fed 155.
Even with the 45-70 BPCR I use LP 150 primers and paper wads over the primer before dumping in the powder. Too hot of ignition has never worked for me except in the 300 WBY and up.

[NVcurmudgeon]

The Chabot Gun Club range, near Castro Valley, CA is located in a regional park miles from town. I was a once a week shooter there, and on at leastb half of the occasions I was there, we had to cease fire and wait for or chase away one to three or four blacktail deer on the range. In a place that deer cnsider safe, noise doesn't seem to bother them at all.

[Urny]

From late '76 until early '82 it was my young boys chasing those deer, most Saturday mornings. They were born in '70 and '72 and were the perfect age for running down the range while us adults watched and laughed. Wish I had known Curmudgeon then.
We used to arrive at the range as early as they would allow the shooting to commence, and there were frequently small bunches of does and fawns out there.

Ta, ta, off to the Big Reno Gun Show.

[9.3X62AL]

I've seen the same sort of deer interference at Angeles Shooting Club a couple times--muleys doing counter-surveillance, most likely. These are the herd members who draw the short straw, no doubt about it.

Straying back to CBP's original thrust.......I started using Dacron about a year ago in loads that left a lot of space in the case--anything up to about 50% empty. I had done some good work with "small-percentage" loads of 2400 in several rifle calibers, and still believe it to be relatively insensitive to positioning in a case.

Still, facts are what they are--and using Dacron has accurized many of these loads. Not all of them, and none have degraded......but there it is there. It only makes common sense that elimination of of a fairly large variable would result in improved performance via resulting consistency. So, position consistency via the filler has improved my results overall.