Accurate metering powders for M1A


September 7, 2003, 07:30 PM
Word is that IMR4895 doesn't meter very well on account of those long grains, so the hunt is on for another powder for the M1A - desired characteristics: consistent metering and correct pressure curve for the gas gun.

I do not want to hand weigh each charge if I don't have to - would prefer to use the Dillon 550B in progressive mode if possible.

Speer was nice enough to show 'gas-gun approved' powders in their manual, and for their 168 grain HP-Match bullet they recommend:

IMR 4064
IMR 4320
IMR 4895
IMR 3031

My question: are any of the powders listed above more accurate-metering than IMR4895? The press in question is a Dillon 550.

Thanks in advance,


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September 7, 2003, 11:55 PM
It's not the press, it's the powder measure. You can get an adapter from Dillon I think to use adapt almost any measure, or at least use theirs in conjuction with some Rube Goldberg'd Ace Hardware adapter sleeve with some imagination, and install a better measure than Dillon provides. Forster-Bonanza, Lyman's 55, Hornady, all make killer powder measures. My favorite is probably the Forster, but it ain't cheap, retailing at around $130 or $150 if I recall. I didn't know that when I stumbled onto mine at a garage sale for $5. They're so 'unheard of'; I missed one about 2 weeks ago (EBay? LR that sold for $15 because that seller also didn't know what he had. Even the touted Harrell's and Neil Jones' won't guarantee that 4064 throws better than +- .1gr (if I recall my phone research correctly), so you KNOW the Dillon's not gonna set any worlds on fire.

I do not want to hand weigh each charge if I don't have to - would prefer to use the Dillon 550B in progressive mode if possible.

I'll bet money I'm lazier than you are, and more easily frustrated, but there ain't no way around diligence if you want accuracy. Of course, there's accuracy, and then there's accuracy. How tight do you want it? 2MOA? 1MOA? .5 ? The smaller you want, the more you'll have to work.

I'll bet with a Hornady or Lyman55 you could get =- .2gr (a swing of .4 gr) from an 'unregulated, progressive' drop. Most folks I know can't shoot the difference of two loads .3gr apart and call it. I certainly can't.

I don't use Varget in an M1A, I've read several sources that say that powder is too slow. Do I believe it? Not necessarily, but I see no point in trying it when RL-15 does fine by me. I use IMR 4064, too, and it's physically a pain to meter, but I've got a system down where I can get a regulated and weighed drop +-.15gr w/ about 80% dead on at =-.05 (by my RCBS 5-0-5). You've read my input before on my PACT dispenser, scale and Lyman55 setup, so I won't rehash it. I've timed my reloads. 100 rounds "progressive" vs. 100 rounds weighed separately each and every one, results in a difference of 1 1/2 minutes per 100, so I don't sweat the "lost time" weighing each charge.

Paul "Fitz" Jones
September 8, 2003, 02:08 AM
Sven,The most accurate powder measure I have ever seen and used is the Cast Iron California Saeco measure with the closest tolerances ever. I am still asked for them even though I sold my last one for pistol with a extra rifle barrel in the spring of 2002 to a employee of a an Alaskan army base.

I have a complete spec and operation sheet on them if you want me to mail it to you. And it is accurate with any powder.

However I feel that spherical powders meter more accurately as the measure would precisely cut off a 4895 stick if necessary.

I competed in our State championships with my National Guard issued Garand and issue armor piercing ammo with 4895 powder. I pulled the bullets and metered the powder more accurately with a hand made powder measure made by my high school welding and gunsmithing instructor.

No matter what you are using now keep your eyes and search function of your computer on the the auctions set for Saeco Powder Measure and the best one is Black Cast Iron, not Redding Saeco Green or any other color. I saw two of them at auction last winter.

Steve Smith
September 8, 2003, 09:59 AM
I started using IMR 4895 in M1As when I began loading for an M1A. I had good accuracy from the gun. I also started loading for my ARs with IMR 4895. I would still use the powder for the M1A without accuracy concerns. Here's why:

#1 I don't believe that any mechanical powder measure on the market measures long grain powder properly. The electronic ones do a much better jb, but are too slow to keep up with a progressive. The only one that would really work is a Prometheus, as D. Tubb uses on his Dillon, but that's $1K in powder measure alone. The Redding may do a better job for long stick than the Dillon, and it can be fitted to the Dillon system. I think either could be adequate, provided you do some testing.

#2 I accept a variation of roughly +- .1 grains in my loading, even for 600 yard loads. I know they will tear the x ring to pieces if I do my job. Consider the percentage of variation of the load (24.3 grain load) (about .45% variation) and then consider a .308 load that is double in volume. I'll bet you can stay in the same realm of percentage of variation. This is why I won't use 4895 in a small caliber, but I will in a large one.

#3 The old timers will tell you that 4895 pressures and accuracy follow volumetric differences, rather than weight differences, to a large degree. IOW, if you have a +-.2 grain differential, it may not mean anything if the volume is the same. Remember, all of the "match" factory ammo is measured volumetrically, too.

Ball powders are too temperature sensitive for Highpower shooters.

September 8, 2003, 10:12 AM
I have to agree with the others it’s the power measure. One thing to keep in mind is that IMR4895 is an extruded powder and when you cycle the handle it can and will cut the powder. 4895 isn’t as long as some extruded powders so it’s a little easier but the extuded powders don't meter well. I use ball powders in most of my rifle reloads including loads for my M1A Super Match. Ball powders meter very accurate. Ball Powder gives accuracy better than I can hold. The Super Match is boring to shoot from the bench with a scope as it puts the bullet where aimed.

Concerning different Powder Measures, over the past 30 years of reloading I’ve used three different manufactures measures and highly recommend Redding’s go to their web site and check them out . The Redding Match-Grade Model 3BR is the most accurate and consistent I’ve ever used but it still won't meter extuded powders as well as Ball powders.

Give the Ball powders a chance.

Have a good day and remember to pray for our troops.


September 8, 2003, 11:45 AM
I think I disagree with a couple points, but not in a contentious way, more like an exchange of ideas.

Turk favors the ball powders because they meter well. I don't disagree with that opinion at all, but I asked a very well-recognized powder supplier to recommend a powder that would meter well and allow me to drive a 175SMK at 2700fps and offer consistent accuracy capable of .5MOA groups with an M1A, if all else was up to the task. His reply was
I would recommend either IMR4895 or CMR100. You will find that the single based propellants ('stick') are much more stable and consistent than the double based (ball) types.
I won't mention his name because I don't want to start an argument, but several Expert shooters recommended him as a knowledgeable source with regard to reloading, so I followed his advice without experimenting with ball loads for the M1A. (I never followed up, so I don't know what he meant by "more stable and consistent".) I know that’s not much of a reason to favor extruded powder, but I decided to follow his advice on the faith in his experience and expertise.

The electronic ones do a much better jb, but are too slow to keep up with a progressive. As usual, I agree with Steve as he's expressed this opinion, but I rigged an electronic measuring system that I almost cannot keep up with on a semi-progressive Dillon 450 (and as I understand it, a 550 is semi-progressive also). I've never seen a Dillon 650 in action, but my impression is that it is fully ‘automatic’--that is to say, one can crank the handle without any other physical actions required, and each crank produces a finished bullet. If that's the case, I would guess that time spent waiting for the electronic dispenser with my system when using a Dillon 650 would be about 4-6 seconds (maximum) per cycle. I've timed my reloading (for 100 rounds) when using a semi-progressive like a 450; a round made with a 'press-dropped' powder charge is about 1-2 seconds faster than a 'hand-measured' powder drop (it took less than 2 minutes more for 100 hand-measured loads). The minimal lost time is because the time used “waiting” for the dispenser to finish is used to insert a new bullet and rotate the shellplate. By the time those two physical actions are done, the newly dispensed charge is usually already waiting.)

I'm sorry this is so long-winded and the following, so detailed, but once it's set up, it's proven to be a speedy and accurate system for me.

I have the PACT 110V electronic dispenser and scale. I set them up according to directions, but the dispenser is mounted 1/2" above the tabletop (shimmed with a couple blank CD cases that are taped to the tabletop). I replaced the OEM plastic scale pan with a toy pot (2" tall, about 2 1/2" diameter, from Walmart's kitchen section). Behind the scale I bolted a powder measure stand and installed a threaded drop tube so I can screw in a Lyman55 (and switch Lymans for different loads; used Lymans are extremely accurate and fairly cheap, costing ~$40on EBay). I made the powder measure stand out of an L-brace, a piece of metal pipe that I had threaded, and 2 water hose clamps, which are used to hold the pipe to the L-brace. I attached a tiny hand-made funnel to the end of the drop tube (my threaded pipe). The funnel has a 90 degree bend at the end of it; the funnel forces the powder to drop out of the measure, curve, and then dispense into the pot horizontally (because when powder is dropped from any height vertically into any container, it bounces, like tiny BB's, and spews out everywhere). This horizontally-oriented nozzle at the end of the funnel allows me to touch the inside wall of the pot to the funnel and 'cushion' the drop so none of the powder is lost, as the powder swirls around in the pot like a whirlpool and settles. I drop a charge within .3gr of my desired load with the Lyman55, put the pot on the PACT scale, and press the actuator button on the PACT dispenser and it functions as a trickler, and takes about 3-4 seconds to finish up the load. (using this regimen, the only time I've lost is the time it takes to drop the powder into the pot, hit the actuator button on the dispenser, retrieve the pot later, and drop the charge into a funnel on the reloading press. It took longer to type this than do it.) 80% of the time the charge is dead on, and the rest of the time, I'm +- .15gr. I didn't know one could measure to .01 gr margin of error without a beam scale. Steve, did you mean .01, or do you measure each charge with a beam scale? I haven't seen a PACT nor RCBS electronic scale (reasonably priced) that can measure in hundredths.

Thanks for your patience, and I hope this helps.

Steve Smith
September 8, 2003, 11:59 AM
Edited my post to remove that zero. I meant .1 grain.

September 8, 2003, 12:01 PM
dammit. I thought I was onto something...

September 8, 2003, 03:18 PM
I agree with what Steve said 100%.

My experience with 4895 revolves around 223 with a 40gr bullet going almost 4000fps. In that case, the .5gr high/low fluctuation in powder charge was the difference between a .25" group and a .75" group @ 100yds.

We're not dealing with a quarter-MOA gun in the M1A and I'm not convinced this relatively minor variation in powder charge will lead to accuracy problems with a 168gr bullet at <2500fps. My gut is saying, as long as the dropped charges stay short of max, the accuracy will be well beyond the limits of the gun.

But I need to test it to be certain, like the Mayor in Blazing Saddles said, "work work work work..." :D

Saddle up Sven, we got powder to burn!

September 8, 2003, 03:57 PM
Just ordered 500 count of the IMI "Match" brass from Wideners... Krieger and McMillan are working their tails off for me (I'm sure), just a matter of time now...

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