Thread: Acceptable variation in powder charge

I've been reloading for my t3 7rm for awhile now, using the now out of production IMR 8133 with good results but i find it doesn't run through my powder measure very smoothly and gets hung up in the tube.
But if i pull the handle down and give it a couple of taps then a couple more taps with a large bolt (LOL) it comes out with pretty consistent charges. I check the charges on my scales every 4 or 5 cases and it varies by about 1/10th sometimes 2/10th of a grain so is that variation enough to cause accuracy issues.
I tried under loading with the powder measure then topping it up on my scales with my trickler(a teaspoon) LOL but that is very tedious and prone to spilages. cheers

Greetings,
Powder measures and stick powders are not the best of friends as you have discovered and trickling up to the exact charge is the usual fix. This is made easier with a proper powder trickler although I have used a Lee dipper and carefully adding the powder with that after dipping most of the charge. As far as how much difference this makes you would need to test in your rifle at long range and chronograph to see how much your velocity varies in your rifle.
GPM.

I remember reading an article quite a few years ago written by someone in the benchrest fraternity. It was about variations in ammunition which can happen during the reloading process and what affect on accuracy those variations might have. they covered things like concentricity, primer pocket uniformity, Neck turning, bullet seating, powder charge variations, etc. the finding from this was that small variations in powder charge was one of the lesser factors to affect accuracy. No surprise that the bench rest guys generally use powder throwers and do not weigh their charges. Admittedly they do use some quite fancy powder throwers. So I would say that if you are getting down around 1/10 to 2/10ths of a grain variation in charge you are doing well and this should be just fine, particularly in a large case and large powder charge in a 7mm RM

when throwing charges try this
throw into a cup..then add into case...if you get a hangup/crunch...chuck it back in hopper and throw again....I am pedantic and throw into cup,then weigh on scales and trickle up if needed for the big rifle....

Originally Posted by Micky Duck

when throwing charges try this
throw into a cup..then add into case...if you get a hangup/crunch...chuck it back in hopper and throw again....I am pedantic and throw into cup,then weigh on scales and trickle up if needed for the big rifle....

I do same. An old 35mm film cannister would be ideal, I use a pill bottle.

How much difference in a 7mm mag? SFA

In a 22Hornet? Yep, it will matter.

Originally Posted by Oldbloke

How much difference in a 7mm mag? SFA

In a 22Hornet? Yep, it will matter.

Thats what i have found. Larger the case the less sensitive they seem to be

Originally Posted by blip

Thats what i have found. Larger the case the less sensitive they seem to be

Of course. It's just common sense.

0.2gr is 2/5ths of SFA if it's a 50gr load. It's double if it's a 25gr load.

I use electronic scales to weigh EVERY charge of powder

No variation is acceptable


I have never ever used a powder thrower, and never will

Originally Posted by 7mmsaum

I use electronic scales to weigh EVERY charge of powder

No variation is acceptable


I have never ever used a powder thrower, and never will

Attachment 249128

Unless you are rocking an Autotrickler or Prometheus, a good volumetric measure is still more reliable.

The top of the line Lee one is very good, but let down by the small reservoir.

Harrels measure is on my list.

Originally Posted by caberslash

Unless you are rocking an Autotrickler or Prometheus, a good volumetric measure is still more reliable....
Harrels measure is on my list.

I load on a 120i / V4 Autotrickler system which as we know is accurate to the kernel. I also have a Harrells thrower and with stick powders like H4350 / AR2209, you can't be certain to keep within 2/10gr. That's not good enough for me with small cases.

Originally Posted by 7mmsaum

I use electronic scales to weigh EVERY charge of powder

No variation is acceptable


I have never ever used a powder thrower, and never will

Attachment 249128

Sorry to burst your bubble Andy!
Read secrets of the Houston warehouse.
Your theory about exact powder charges is not your main worry.
Neck tension is a bigger problem.
Ring me when your ready to order your Amp annealer and will hook you up.
That goes for anybody on here to be fair!

Sent from my SM-A226B using Tapatalk

Originally Posted by andyanimal31

Sorry to burst your bubble Andy!
Read secrets of the Houston warehouse.
Your theory about exact powder charges is not your main worry.
Neck tension is a bigger problem.
Ring me when your ready to order your Amp annealer and will hook you up.
That goes for anybody on here to be fair!

Sent from my SM-A226B using Tapatalk

What a salesman!

Surprised you didn't work a Nightforce sale into it too!

Just buy better brass (ADG or Alpha), no case prep required apart from resizing.

Originally Posted by caberslash

What a salesman!

Surprised you didn't work a Nightforce sale into it too!

Just buy better brass (ADG or Alpha), no case prep required apart from resizing.

Baby steps!
If I can help people out I will as I have had a lot of good things happen on here and seen alot of paying forward and great deals.
Cheers Andy

Sent from my SM-A226B using Tapatalk

I have powder thrower that came with my press I used it a couple of times but couldn't get the hang of it so use beam scales and teaspoon until recently when I picked up cheap a RCBS trickler, so now its teaspoon and trickler to finish.