Ball vs extruded powders for 6.5x55

[mtnbkr]

This year, I started loading for the 6.5x55 in a Winchester Featherweight. On the results and recommendations of others, I started with IMR-4350. I've gotten good results, but the only way I can get even loads is to use my powder measure for a gross measurement and a trickler for fine tuning each charge. Otherwise, I get .25 gr variation or more. The stuff just won't meter well for me.

That got me looking at ball powders. However, I rarely see powders such as H414 (close to 4350 in burning speed, from what I read) and accuracy in the same sentence. Why is that? Is there something about extruded powders that make more accurate loads? I know it varies from gun to gun, but I'd like to avoid a half dozen range trips and several hours of work to find out that ball powders won't work.

Are there any extruded powders that do meter well?

Thanks,
Chris

 

[Mike Irwin]

Try an experiment, Chris.

Try loading volumetrically, and only weighing to see if you have a charge that is too heavy by a factor of a half grain.

Don't trickle up to an exact charge weight.

You might be VERY surprised at the results.

Some of the most accurate National Match ammo ever loaded, the 1957 batch from Lake City, was loaded volumnetrically.

Quite frankly, a quarter grain variation in a 44-grain loading is NOTHING..

When I loaded for my .243 regularly my pet load was an 80-gr. bullet and about 38.5 gr. of IMR-4064.

I set my RCBS Uniflow so that it would throw about 38.5 grains with a well prepped measure, and then just threw the charges. After getting the measure set, I only randomly checked my charge weights.

If I had the rifle properly supported, it would shoot sub 1/2" groups at 100 yards all day.

 

[mtnbkr]

Try loading volumetrically

I think I know what this means, but what would you say it means? I wanna make sure we're on the same page here.

So a quarter grain variance is no big deal? That's good news to me. It was driving me crazy to set my powder measure (Lee Perfect Powder Measure) to a given charge and see it drop .25gr on either side of what I set. :banghead:

I'm getting better though. When I first started loading (for handguns), I worked up loads in 1/10th grain increments.

Chris

 

[Mike Irwin]

The Lee measure is, like the RCBS Uniflow, volumetric. In otherwords, the powder falls into a container that's been preset to a specific volume. The essential idea is that X amount of space will be occupied by approximately Y amount of powder. Obviously air space between the grains, or how they pack into the measuring chamber, will change the amout. That's why you take pains to prepare your measure and why consistency in operation is important.

There are electronic combination measures/scales that meter the powder by weight by dropping it into a pan. Some of them are pretty slick, but they're expensive.

A quarter grain variation in a 44 grain load is what, 1/2 of 1% of the total volume? That's probably not even going to register if you were shooting across a chronograph.

As for handgun loads, working in 1/10 grain increments isn't a bad idea when you're near the maximum.

In rifle reloading, you normally work in 1/2 grain increments and when a particular load shows promise, then you can finess it in 10ths to see if you've hit something good.

 

[mtnbkr]

Yup, we were on the same page.


Chris

 

[Mike Irwin]

The 1957 National Match ammo?

Supposedly it had variation range of upwards 1.5 grains -- 3/4 of a grain below the intended setting to 3/4 of a grain above.

 

[cracked butt]

Mike,

I have a question about loading volumetrically. It seems like kind of a voodoo subject to me and makes me really nervous for this reason: I use alot of IMR 4064, I've tried my RCBS powder thrower and seem to get within a few tenths of a grain in accuracy. The thing that really makes me wonder is that when I dump a shot of powder on my scale, and then pour it through a funnel into a case, it occupies alot less space in the case than if I threw the powder in from the powder charger. Have you seen the same circumstance and does it make any significant diference in how the cartridge performs? I've never had the time time to test the difference between loading by weight and by throwing the charges.

 

[Mike Irwin]

"Have you seen the same circumstance...."

Yes. Many times while using 4064 to load .30-06, .300 Savage, and .243, among others.


"does it make any significant diference in how the cartridge performs?"

In a word, no. It may make a tiny difference, but it would probably take hundreds of shots and measurements fed through a statistics package to really find out.

Essentially what is happening is that when you throw a load into a powder pan, and then pour it through a funnel, you're making the powder granules line up a LOT more efficiently. That's one of the reasons why you see people refer to the use of drop tubes when loading heavy charges of slow burning powders.

Even though you've made the powder granules line up and pack more efficiently, you've still got the same X grains you had when you threw the charge into the pan in the first place.

Getting those powder grains to pack efficiently in the powder measure when its being filled prior to a loading session is one of the keys to getting consistent throw weights.

I know people who fill their powder measure with a drop tube. Others tap on the side of the measure while filling it, and after they've filled it, to get the powder granules to settle down.

I even know one guy who puts his measure on top of his vibratory case cleaner for a few minutes to shake the granules into orientation.

Does this answer your question fully?

 

[cracked butt]

Actually, yes.
Thanks.