Which Scale Check Weights?

[normmatzen]

My lab balance is 200g full scale so I bought two identical 100g masses and used fine emery paper the polish the base of the heaviest one till they were identical on my balance. I use them for setting full scale (both masses together) and one mass for the linearity test. I don't really don't care how accurate they are (within reason) as I measure loads from 30gr to 60 gr on that balance and I have a set of weights from 1gr to 20 gr and use them to insure something is awry when my total 33gr weights don't measure 33 gr! The accuracy of the 1-20 gr weights is way better than the variations I can load to (1 granule) so I
am a happy camper!

 

[JimSC]

the thread got me curious so I gathered up all the check weights I have accumulated with various inexpensive scales over the years and I have 2 - 10 gr, 1 -20 gr, 1-30 gr, 1- 50 gr, and 1 -100 gr. I calibrated my fancy $225 dollar Tree 123 with the 30 gr and came up with the following measurements. Looking at the cumulative results I think the problem is the scale weighs low. The 100 gram looks to be the farthest off. Bear in mind that .1 grains is .0064 grams

 

[varget204]

Not if your in the middle of a node. It's all about tune and not velocity differences. Matt

You must not be shooting at 1000 yards,because if you were you would Know 50 fps difference shell to shell makes a BIG Difference,thats why some people get Large Vertical Groups.If you don't Believe it ,GO shoot at 1000 yards.I shoot thousands of rounds at long distance.You want ES and SD in the Single Digits if you can

 

[dkhunt14]

You must not be shooting at 1000 yards,because if you were you would Know 50 fps difference shell to shell makes a BIG Difference,thats why some people get Large Vertical Groups.If you don't Believe it ,GO shoot at 1000 yards.I shoot thousands of rounds at long distance.You want ES and SD in the Single Digits if you can

I have shot over 30,000 rounds at 1000 yards in testing and matches. Many times the load with lowest ES is not the best load. As an example, I had a Dasher that would shoot in the zeros and low ones at 100 yards and the ES was 2 and three. The best that gun and load ever did in competition was a big 13 inch at 1000, all vertical. Another load in that gun had ES of 10 to 12 and that load would shoot 4 inches when conditions allowed. This is why they shoot ladders at distance. I saw this happen with many guns over the last 18 years of competition.

Here is an example of a load for my 338 Lapau IMP. This gun has a 1.450 diameter barrel and is 36 inches long. It is glued into a block and built just like my competition guns. The bullet was 300 grain Berger Elites and the loads were 102 grains of RE33 and averaged 2932, 103 grains averaged 2993 and 104 grains averaged 3042 and I shot them just like a match. I ran them as fast as I could to beat conditions. The rounds were 4 shots each and I colored the bullets so I could tell which load hit where. The total group was 6.5 inches for 12 shots and 11 of them was in 4.25 inches. Barrel compensation and where the bullet leaves the barrel is important. While the load varied almost 50 FPS average with a grain of powder, they shot to almost the same exact point of aim at 1000 yards.

It is sometimes, all about being in the middle of a node. That way temperature or changes in atmospheric conditions keeps the load shooting good. This is why scale check weights dont need to be exact. As long as your using the same weight to check the scale. You work up the load to find the accuracy node. Matt

 

[Bart B.]

Barrel compensation and where the bullet leaves the barrel is important.

Exactly.

Both small and large velocity spreads can be positively compensated for if the slower bullets leave at a higher angle than faster ones at the right place.

Different powder types can change that even if they produce the same muzzle velocity. Barrel time can be different and bullets leave at the wrong angles to the LOS. .

 

[Ron Gorski]

Hi Alan. I had a customer

se

Hi Alan. A customer of mine a few years back dropped off his Redding scale and a set of RCBS check weights. I finished his scale and proceeded to test the check weights. The two 20 grain check weights were .2 grains apart from each other.

Scott

Did you check it on the scale you just repaired? That won't work!!!

 

[Ron Gorski]

the thread got me curious so I gathered up all the check weights I have accumulated with various inexpensive scales over the years and I have 2 - 10 gr, 1 -20 gr, 1-30 gr, 1- 50 gr, and 1 -100 gr. I calibrated my fancy $225 dollar Tree 123 with the 30 gr and came up with the following measurements. Looking at the cumulative results I think the problem is the scale weighs low. The 100 gram looks to be the farthest off. Bear in mind that .1 grains is .0064 grams

View attachment 1088154

What class weight is your 30 gr weight? I have a A&D FX120I. They sent me a ANSI Class 7 weight to calibrate with. Not good enough. I bought a class 1.

 

[sparker]

Did you check it on the scale you just repaired? That won't work!!!

Did you check it on the scale you just repaired? That won't work!!!

Are you being serious?

 

[JimSC]

What class weight is your 30 gr weight? I have a A&D FX120I. They sent me a ANSI Class & weight to calibrate with. Not good enough. I bought a class 1.

I have no clue, it came with a less than $100 scale, the RCBS 750 that I destroyed hauling to the range in the back of my Jeep I think. Like I said in my first post I am not compounding pharmaceuticals or buying platinum with these scales and plus or minus a couple of milligrams is fine for their accuracy. I am more concerned if the pulled .22LR bullet I pulled weighs 39.96 grains plus or minus .02 grains than the 30 gram checkweight would weigh 30.000 grams or 29.998 grams if I asked my local pharmacist to weigh it on his $5000 lab balance . I weighed the 30 gram checkweight this morning and it weighed 30.000 gns on the same scale that said it was 29.998 grams yesterday. In a few minutes I will be weighing out some 24.5 gn charges of Varget for some 300 yard .223 rounds. Will that .002 grains one way or the other make a rats butt worth of difference on target? I seriously doubt it. I like to put my shooting money onto barrels, triggers, and practice. In other words things that will make more of a difference on paper than plus or minus a single kernel of powder. But that is just the way I think, each to their own when it comes to what they think is important. This morning I just spent more on a good pair of waterproof snake boots than you probably paid for that class 1 checkweight. If they keep my feet dry or that copperhead from getting my leg they are well worth what I paid. Knowing that my scale could be used to buy and sell gold is not on my priority list

 

[Webster]

DUH,if your trying to weigh your 45.25 grains,how do you know your scale is Reading Correctly;With Out Checking the Accuracy of your scale w/ precision scale weights ?? If your shooting at 1000 yards or farther,it makes a Difference,If your trying to hit 55 gallon drum at 100 feet it Doen't.

It doesn't matter if it's actually 45.25 grains. All that matters is repeatability. If you get repeatability with your standard and the scale reads 45.22 and it's really 45.3 you are always getting the same powder charge that gave you good groups.

 

[Dusty Stevens]

I have shot over 30,000 rounds at 1000 yards in testing and matches. Many times the load with lowest ES is not the best load. As an example, I had a Dasher that would shoot in the zeros and low ones at 100 yards and the ES was 2 and three. The best that gun and load ever did in competition was a big 13 inch at 1000, all vertical. Another load in that gun had ES of 10 to 12 and that load would shoot 4 inches when conditions allowed. This is why they shoot ladders at distance. I saw this happen with many guns over the last 18 years of competition.

Here is an example of a load for my 338 Lapau IMP. This gun has a 1.450 diameter barrel and is 36 inches long. It is glued into a block and built just like my competition guns. The bullet was 300 grain Berger Elites and the loads were 102 grains of RE33 and averaged 2932, 103 grains averaged 2993 and 104 grains averaged 3042 and I shot them just like a match. I ran them as fast as I could to beat conditions. The rounds were 4 shots each and I colored the bullets so I could tell which load hit where. The total group was 6.5 inches for 12 shots and 11 of them was in 4.25 inches. Barrel compensation and where the bullet leaves the barrel is important. While the load varied almost 50 FPS average with a grain of powder, they shot to almost the same exact point of aim at 1000 yards.

It is sometimes, all about being in the middle of a node. That way temperature or changes in atmospheric conditions keeps the load shooting good. This is why scale check weights dont need to be exact. As long as your using the same weight to check the scale. You work up the load to find the accuracy node. Matt

You Just CANT be an actual real life 1000yd shooter though. You should try it sometime.

 

[Fotheringill]

Sorry, I wasn’t clear. There were two twenty grain check weights in his set. They were .2 grains apart from each other.

I have seen that in a set of weights. Perfect on either end of the spectrum but off by .2 grains in the middle ones.

 

[Ron Gorski]

Are you being serious?

As a heart attack. Worked in aerospace metrology for 37 years and have seen engineers do some dumb stuff with test equipment. If they even knew how to use it.

 

[sparker]

As a heart attack. Worked in aerospace metrology for 37 years and have seen engineers do some dumb stuff with test equipment.

Fair enough. I’m very familiar with the concept of pathway dependency when it comes to scientific/technical data. Having a known, verified reference is an assumed operating practice with me.

 

[Milo 2.0]

You must not be shooting at 1000 yards,because if you were you would Know 50 fps difference shell to shell makes a BIG Difference,thats why some people get Large Vertical Groups.If you don't Believe it ,GO shoot at 1000 yards.I shoot thousands of rounds at long distance.You want ES and SD in the Single Digits if you can

You threw that one at the wrong guy. I'm not accusing here, but your train of thought has sold a ton of fx 120i's in the last 2 yrs. It pays to listen when some of these guys talk.
I shot 5 shots @500 yards, ES of 1, it grouped 11", all vertical. Single digits bite at times.

 

[Dusty Stevens]

You threw that one at the wrong guy. I'm not accusing here, but your train of thought has sold a ton of fx 120i's in the last 2 yrs. It pays to listen when some of these guys talk.
I shot 5 shots @500 yards, ES of 1, it grouped 11", all vertical. Single digits bite at times.

Ive seen 20 and even 30 shoot better than single digits. Guess its the real world again. And yes that was funny talking to my 1000yd hero like that.

 

[varget204]

I did not say some loads that verried, could not shoot good groups, Lower ES and SD will usually give you the Best Groups.If you run Data on Billistic Calculator [example] at 2900,2950.3000 fps you will get different amounts of Drop.If your groups were 11" at 500 yds you should be changing bullets,my 204 ruger will shoot 1/3 moa or better at 500 yards.When you shoot at 1000 yards or more just about Every thing makes a difference

 

[Dusty Stevens]

I did not say some loads that verried, could not shoot good groups, Lower ES and SD will usually give you the Best Groups.If you run Data on Billistic Calculator [example] at 2900,2950.3000 fps you will get different amounts of Drop.

correct in theory. not so much on the actual range. Never been to a ballistic calculator or chronograph match though. What happened to check weights? My bullet still weighs the same surprisingly.

 

[Milo 2.0]

I did not say some loads that verried, could not shoot good groups, Lower ES and SD will usually give you the Best Groups.If you run Data on Billistic Calculator [example] at 2900,2950.3000 fps you will get different amounts of Drop.If your groups were 11" at 500 yds you should be changing bullets,my 204 ruger will shoot 1/3 moa or better at 500 yards.When you shoot at 1000 yards or more just about Every thing makes a difference

I know how to develop loads. A chrono is a tool used, not the sole source. The target is my deciding factor.
But yes, usually numbers tighten up in accordance with group size, there is a reason for that too. Can you tell us why?

 

[Campbell]

This has got to be one of DUMBEST POSTS i have seen,bullets vary in weight,JOIN the NIT CLUB

I beg to differ. Within reason the exact weight of the charge does not matter a jot. What does, is the consistency of the charge weights.

One gradually develops a load, starting low and then working to a higher weight. If the optimum weight is established, then all one is concerned with is the repeatability of subsequent throw weights.

Just to be clear, I reiterate the "within reason". If the recommended start weight was, say, 44 gr but one's scales threw 54 gr then need I say more?