Are my powder charges too inconsistent?

[WayneConrad]

Hi experts. Since you all got me through my troubles reloading for 9mm Luger, I've gotten into reloading for rifle, and I need your experience again.

I've been shooting IMR 4064 though my K31 (7.5 swiss). It seems to shoot great, but it sure doesn't meter great. Using my RCBS Uniflow to throw charges of IMR 4064, I get a spead of 0.75 grains and a standard deviation of 0.16.

I don't know if that large a spread would be a problem for accuracy, so I've been putting each throw on the scale and trickling it up to weight instead of just using what the measure puts out. It's a little bit of a pain.

I am not a bench rest shooter: If I shoot a 2 minute group I'm very happy with myself. The charge I am throwing is 1.9 grains below what Sierra 1978 lists as max.

My questions are:

• Does a spread of 0.75 grains indicate a problem with my equipment or technique, or is it what I can expect with this powder?
  
• Is a spread of 0.75 grains excessive for the kind of accuracy I need, or is it nothing to worry about? How much of a difference in point of impact is +-0.325 grains going to make at 100 yards?
  
• Will IMR 3031 or IMR 4895 meter any better than IMR 4064?
  
• I'm not throwing max charges, but I'm curious how it's done. Do those of you who throw max charges not worry about the variance in your throws putting you a bit over maximum, or do you feel the need to trickle your charges to avoid going over max?
  

 

[Jim Watson]

Answers:

1. That is about what I get with the same setup, 4064 in a Uniflo.

2. I doubt it will make any difference at only 100 yards. But you have the powder and you have the rifle. Shoot it and see. Compare with weighed charges.

3. 3031 has as long or longer granules and will meter no better, maybe worse. 4895 is a short-grain powder and will meter closer than 4064.

4. At maximum I weigh all charges.

Comment: For casual shooting I load ball process powder and don't have much variation to worry about nor the teeth-on-edge feeling of granules shearing in the measure. But for serious target shooting, I get better accuracy in most rifles with extruded powder so I measure short and trickle to weight.

 

[Steve in PA]

I use IMR-4350, 4064 and 4895 for various loads in my M1 Garand, K-31, K98 Mauser, etc.

I set my Uniflow to throw just short of the powder weight I want. I then trickle in powder until I get the weight I want.

I weigh all my rifle charges, even when using a ball powder like H-414 in my hunting .30/06 loads.

 

[milanuk]

Wayne,

As you aren't running hot loads, and I'm guessing shooting iron sights at relatively short range, I'd say keep on throwing. Might want to consider one of the cheapy Lee Perfect Powder measures for 4064 and other nasty stick powders. Somewhat more accurate w/ the big stick stuff, and even when it isn't, you don't get that nasty catching and hanging up you do w/ the 'better' powder measures. For under $20, it works like a champ w/ stick powders.

Steve... you're trickling up ball powders in a hunting rifle? Wow. Ever actually notice any meaningful difference down range, either on target or on the chrono, btwn weighed and thrown charges of ball powder? I guess it's one of those things that if it makes you feel good and doesn't hurt anything, by all means, keep it up. Seems like a minor waste of time to me, but my measure throws ball powder +/- 0.1gr easily.

Monte

 

[Deavis]

WayneConrad: What sort of setup are you using to measure your powder throws? I'm asking because it is important to look at your measurement setup just as closely as your powder dispensor. Since you don't mention the type of scale, it might be helpful to make sure your scale is capable of repeating precise measurements and is capable of the accuracy you are looking for. Maybe that 0.75 is actually lower than that but a stray breeze or a little residue in your pan could be throwing you off. Just thought I would throw that out there as another thing to be certain of.

 

[Steve in PA]

No, for my hunting loads I said I weigh the charge for each round. I only trickle if necessary, which is very rare since the Uniflow throws very consistant charges of H-414.

And as for the reason I do it, its because I want to make the most accurate load I can. I'm not a perfectionist. I don't weigh each case, bullet but with the exact same powder in every bullet I keep my groups easily under 1" @ 100yds, more often than not they come in around 3/4".

 

[milanuk]

Well, if it makes you more confident in your load and that helps you hit what you are aiming at, then go for it. Personally I feel weighing charges on a ball powder that meters like sugar and throws pretty dang close to dead on is beating a dead horse, but then again, for small quantities of .30-06 hunting ammo it's probably no big deal. I've been going thru 300-400rds a week the last couple weeks of .308 and I for one am getting *dang* tired of weighing charges of Varget. As soon as I get a chance to play around w/ the chrono @ the 600yd line again, I hope to test how much difference I see btwn thrown and weighed charges in velocitiy (ES/SD) and accuracy. I've got better things to do w/ my time, like practice dryfiring (yuck!). Long range for 8/9/1000 I might be stuck weighing, but I rarely get a chance to shoot that far anyway.

Monte

 

[halvey]

Does a spread of 0.75 grains indicate a problem with my equipment or technique, or is it what I can expect with this powder?

That seems awfully high to me. Try the technique first. Practice about 20 or 30 throws, then start to weigh. My hunch its a technique problem first. But yeah, the measure will be off a bit.

I shoot max loads, and I weigh and trickle (if necessary) every charge. It wook a bit of practice, but I can throw +/- .1.

 

[Dave P]

Does a spread of 0.75 grains indicate a problem with my equipment or technique, or is it what I can expect with this powder?


The large grains of powder will do this. Prove your technique and equipment with 4895.

 

[WayneConrad]

I just got off the phone with a tech at Hodgdon who will email me load data for 7.5 swiss, including loads for H380 and H414, both ball powders. With that in hand, I'll be able to switch to a ball powder for my "casual plinking" as Jim Watson and others have suggested.

Deavis, I'm using a 10-10 scale that Ohaus repaired and refurbished ealier this year. The scale routinely measures within 0.1 grains of my RCBS check weights, so I'm happy with its accuracy. However, I haven't formally tested the scale for repeatability and precision. I'll try to come up with a protocol for those tests.

Milanuk, Thanks for the suggestion of a Lee powder measure. I'll consider that.

Looks like the load data is already in my email inbox. Thanks, Hodgdon! Maybe I'll pick up some H414 on the way home.

 

[Steve in PA]

If you plan on using H-414, I suggest starting somewhere around the 45-46gr level. I worked up a load and was getting a slight delay in the lower grain weights. I think they were around 42-43. I don't have the loads in front of me right now. But I would get a "click", "bang" until the loads got to the 45-46. Once I got to thm they groupings were great and so was the ignition.

 

[Rockstar]

Note to those who think that .75gr. is larger than .1 grain, think some more!

 

[WayneConrad]

Note to those who think that .75gr. is larger than .1 grain, think some more!

Rockstar, I'm thinking and thinking, and what I think is that my head is gonna explode . Maybe I'm being confused by that "new math" they tried to teach me, but did you mean to say "smaller" rather than "larger?"

 

[halvey]

Math 101

Note to those who think that .75gr. is larger than .1 grain, think some more!

Using old math:
0.75 grains is greater than 0.10 grains.

-OR-

3/4 is greater than 1/10

-OR-

75/100 is greater than 10/100.

 

[30Cal]

I doubt you'll be able to see the effect of +/- 0.3grs on paper at 300yds or less, especially if you're shooting with iron sights. For competition, I weight individual charges for 600yds and adjust them as necessary to get +/- 0.1grs. For 200&300yds, I don't bother--I use what drops out of the powder measure. My service rifle and ammo will win the match if the shooter does his part.

Many powder measures throw more consistanly if you operate it more consistantly. My Dillon measure works best if I tap the body before dropping the charge.

Ty

 

[Rockstar]

Well, it was a misread on my part. I was thinking .075, as I was keyboarding .75. .75gr. would be way over my consistency standards. .1-.2gr. won't make a lot of difference.

 

[Deavis]

WayneConrad: Sounds like you've taken the necessary steps to insure that the scale has been serviced. Repeatability is easily tested by taking a weight (known or unknown) and simply weighing it multiple times from scratch in whatever order you normally use. If it lands on the same weight say, 90% of the time, then you might consider your equipment as being capable of repeatability. Precision is making sure that the check weights weigh what they should, and it sounds like your scale does that as well.

Don't get discouraged and remember that your rhythm is really important. I was teaching a buddy how to use the press this weekend and his charges were varying somewhat (using a ball powder helped him) until he started being smoother with the sequence. Of course he wasn't seating the primers all the either but we fixed that too

If your consistency doesn't drop to the +/- .1gr level with practice, consider cleaning your powder measure just in case. I was reading an article in the Blue Press where some rifle team actually coats the sliding portions with brush on graphite to insure their loads are super consistent. If you are hitting +/- .1gr, then you are doing about as well as most scales we purchase can accurately measure.

Good Luck!

 

[Vern Humphrey]

How do your loads shoot? If you're getting an acceptable level of accuracy, don't fix what isn't broken.

You can improve the accuracy of a powder measure by fabricating a solid mount (say of 3/8" steel plate or better) to prevent flexing as you throw the measure.

 

[wanderinwalker]

I agree with the suggestion that if it works well, don't fix it! BTDT with my .223 loads in my AR-15 and decided it wasn't worth the effort.

For competition, I do as 30Cal describes and just take what the thrower gives me. I use Varget and a Lee Perfect Powder measure, and my untrickled, +/- .1-.2gr ammo will clean the targets and win matches, provided I was (un)able to do so. Even out to 600 I don't fret over fine-tuning the ammo, as practice is more important until a shooter gets really good.

As far as 4064 is concerned, I've always been told metering it is a pain, so I have avoided it. Short-grained stick powders like 4895 and Varget have always metered fine for me, and ball powder drops so consistently it is a waste of time to weigh each charge from the powder measure IMO. But I haven't shot ball in a while, as it caused me many headaches in temperature swings and cost me an AR firing pin.

 

[RugerOldArmy]

I think the powder being IMR 4064 has a lot to do with it. The grains are huge. I've gone to the meter-shy-and-weigh-trickle approach for it to. IMR 4895 meters pretty well, and Varget meters better than IMR 4064.

Anybody use Win 748? (Meter well?) Or RL-15? (want to try).

Personally, I think I'd like 4064 a lot better if it metered well. Now I'm choosing Varget over it for heavier .308 and IMR 4895 for .308 Varmint loads.

 

[cracked butt]

If you use a baffle, kep the powder hopper at least 1/2 full, use a consistant technique, and discard 2 charges after every 'cut grain', replenishing the hopper, or bad throw stroke, you can do better than a .75 gr spread with 4064.
I have no problem keeping charges within +/- .2gr of the setpoint, a spread of which will make no difference in accuracy in a case that roughly has the capacity of a 30-06.

The measure has to be mounted solidly to throw consistantly. The Uniflow comes with a strip of metal with 2 holes in it, throw this thing out, its too springy to mount the measure solidly with. I simply screw the measure directly into a single stage press. For throwing technique, I lift the lever smartly up, pause for a 1/2 second, then slap it smartly downward. I probably get a cut grain every 10th charge or so, usually the charge with a cut grain will be good, but the next one will almost always be off.