Powder Tendencies?

[wolfe28]

I've been reloading for a while, and I noticed something with Lil-Gun, and I was wondering if it happened with other powders.  When I use Lil-Gun in my 357 Magnum, 357 Remington Maximum, 22 Hornet, etc., I get the best accuracy when I get close to the maximum loads (using Hodgon's data). 

Have you all noticed anything similar with other powders (at a certain percentage of manufacture listed max, you get the best accuracy)?  Specifically, I'm interested in this info for Varget (its what I use in my 308), but I think this info would be helpful for any powder.

D

[necchi]

I use varget in 308, 708 and 223 when the bullet weight works with the powder.
 
 I've found in the 308 I usually get 2 accuracy nodes, one about 2 grns under max and another up near max.
 It's tuff to say for any given gun what or where the charge should be. It has alot to do with what your going to use the round for, short range target is nice to have the light load, with hunting loads I want something that hit's harder so I opt for the higher charge.

[wolfe28]

The accuracy nodes are exactly what I was wondering about.  Obviously, it has a lot to do with barrel harmonics, the weight of the bullet, and so on.  Knowing the tendencies of the powder, or where the nodes likely are helps to give a starting point for load development. 

Thanks, and keep the input coming.

D

[SHOOTALL]

The faster the bullet travles up the bbl. the less time the bbl. has to affect it .

[Old Syko]

The faster the bullet travles up the bbl. the less time the bbl. has to affect it .

Although this is true that effect can be for the better OR worse.  Just depends on the variables.

[SHOOTALL]

True . Conventional wisdon says a 26 inch bull bbl bedded in a composite stock with alum bedding block should be the best shooter in most cal. And they do some extream shooting with such. Yet some of the most accurate guns I have shot were XP-100's off the shelf. 15 in pencil thin bbls , one ragged hole at 100 yards is pretty normal. Just an observation on bbl length .

[the jigger]

In most of my rifles I am finding the accuracy node about .5gr under max. The one exception is IMR4831 in my 25/06's. Both like the load 1.5gr below max. Who knows why? they are completely dissimilar. One is a Weatherby Vanguard sporter weight; the other is a Savage 110fp varmint weight. They shoot the same load, one with 100gr Partitions and the other with 100gr Match Kings to the same POI. None of my other rifles in duplicate calibers come close to this. Generally speaking each rifle has its own preferences. One must search for that accuracy node by starting low and working up.
GOOD LUCK and GOOD SHOOTING!!!

[Skeezix]

I've noticed that tendency also with H110 and W296 in pistol calibers for which that powder is suitable.  They shoot best at or very close to the max load.  And yes, I've also noticed this with Varget in my .308 with 150 gr bullets, with H4831SC and H414 in my .250 Savage with 100 to 120gr bullets, with RL 19 in several cartridges with certain bullets, and with IMR 4831 in my .300 Win Mag with 180 and 190 gr bullets.  And I've seen that tendency also with RL 22.  But I've noticed that with IMR 4064, IMR 4895, and some other powders, the most accurate loads are always several grains below the max. 

You just have to find that right combination. 

[Larry Gibson]

Wolfe28
 
Doesn't have anything to do with "barrel nodes".  Every powder has a certain minimal pressure range where it begins to burn efficiently giving lessor extreme spread velocities and psi's.  Lil'Gun is a slow burning powder for the cartridges you mentioned and it isn't burning efficiently until close to maximum capacity loads are reached. 
 
Larry Gibson

[necchi]

Doesn't have anything to do with "barrel nodes".

Whaaa? 
 
 

Every powder has a certain minimal pressure range where it begins to burn efficiently giving lessor extreme spread velocities and psi's.

True, but several other variables can effect that "pressure" beyond the volume of the powder in the case.

[cwlongshot]

Different powders act differently sometimes for the same reasons sometimes totally different...
Powders like #9, 296, H110 and LIL GUN do seem to work best at max or near max loadings. the twins 296/H110 specify NOT to reduce loadings...
Bulkier rifle powders, also do work best near max, but not so much for pressure as for densities. You will find the mosty accurate loadings are always at or over 100% density.
 
CW

[wolfe28]

Good morning all, and thanks for the responses.

Every powder has a certain minimal pressure range where it begins to burn efficiently giving lessor extreme spread velocities and psi's.

 

This is what I'm trying to figure out.  It would seem to follow that powders with a lower pressure range would have an accuracy node that is lower or further away from the max load, where as those with higher pressure ranges work best at close to max levels.  Does this make sense, or am I on the wrong track?

D

[Larry Gibson]

"Nodes" are generally referred to in conjuction with barrel vibrations.  I think the the "nodes" you are referring to are generally called "sweet spots" by most shooters.
Most faster burning powders are easier to ignite and therefore will burn efficiently at a lower pressure rate.  This is easily seen by looking at the ES and SDs of chronographed loads.  I also measure pressures of numerous cartridges using a lot of reduced loads with both jacketed and cast bullets and the burning efficiency between powders of different burning rates is easily seen by the ES and SD of the pressure measurement and by the pressure trace.  Also as you suspect many of the faster burning powders have a much larger "sweet spot" for powder burning efficiency in many cartridges than do medium and slow burning powders.
 
Larry Gibson

[necchi]

OK, I'm not gonna get hung up on a word, sweet spot if you like,
 But a node of harmonic balance has alot more going on than barrel vibration. And barrel vibration doesn't mean something is vibrating.
The term sweet spot I guess can be understood by anyone.
 The way I use powder burn rate data is for different size cases, and for different bullet weights for those cases, a fast, medium or slow powder does not work for me across the board even with the same case. Beit a 223, 308 or 30-06.
 
Here's some good reading,,
http://www.varmintal.net/amode.htm

[/color]http://www.varmintal.net/arelo.htm

[mudcreek]

when you refer to maximum loads, whose max are you referring to?  It seems different manuals sometimes note different max loads, as do different websites.

[wolfe28]

when you refer to maximum loads, whose max are you referring to?  It seems different manuals sometimes note different max loads, as do different websites.

To keep things simple and consistent, I was thinking of the max as listed by the powder's manufacture.  That is what I was using with my Lil-Gun reference.

D

[SHOOTALL]

max load data n most cases is a guide. It was the experince of one batach of powder with one case , primer and bullet at a certiant temp. , elevation and elevation. This was driven home to me once while shooting loads developed to max or a tad more in december at 25 deg.then shooting in aug, at 105 degrees . It is best to use data for the componets being used. Speer books from the 80's offer hotter load data than today. It may be the way pressure was read or it may be powder lots used . Things like chamber deminsions , brass  etc all effect finial ballistics . A hot load offers - a quicker and good case to chamber seal. Less time to the peaks in pressure and faster time for bullet exiting bbl. all would contribute to less effect on bullet from a time stand point and should aid accuracy if other factors are right for accuracy.

[williamlayton]

Do batches of powder cause this effect/affect?
I know they are all made the same way with the same formula's----buttttttt.
I have never reloaded for accuracy---looking for the best--just for shooting, so i don't know.
Blessings

[SHOOTALL]

Yes and no , I shot alot of H322 . At first it was new production then Govt. surplus H322 came on the market . Same container but marked Military surplus. It was $6.00 a pound where reg was about $8.00 a pound. They were different shades in color . The MS always grouped tighter . After the MS powder was gone it seemed the H322 would group better or worst from lot to lot. We started to buy in 8 lb kegs if we could find the good lot numbers. With IMR 4831 which I have loaded for 20+ years never saw a difference.

[williamlayton]

HUMMMMM!
Blessings

[223fan]

I have also noticed this with W296/H110 in my handguns & with H4831,H4198,& BLC2 in my rifles.I have not noticed a decrease in accuracy with light loads vs full loads of Unique in my handguns.