I think I need a better scale....

notsorichguy

notsorichguy

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I am finding a few problems (inconsistancies) with my velocity lately.

I have been using this RCBS scale for the last 18 months or so after my Ohaus scale bit the dust when I moved (I guess I didn't pack it well enough)

I 'feel' (I used feel as it is more of a feeling than an actual fact) that my scale is more than accurate enough for the handloading I do for my 'larger' calibers (read hunting rifles), but I recently got a .223, and I find the velocity readings a bit inconsistant. (35 to 50 fps is fine in my 30-06 but in my .223 it's hurting my groups)

I am thinking if I am going to buy a new scale it's got GOT to be better than +.1 gr. I was thinking something in a +.04gr would be ideal....

Any info on where I can get something like this? Cost? How much more to get to +.01gr? I've tried all the big reloading web sites (Hornady, RCBS &LEE) but I can't seem to find any info on anything 'more accurate' than +.1gr.

Thanks
 
I use an RCBS 5-10 to double check my Chargemaster for my match loads and have no issues whatsoever.

Maybe it's your component choices that are causing the velocity variations.

The tightest SD and ES loads do NOT always mean tighter groups, some of my best shooting groups have had ES's in the 30-40fps mark.

Your RCBS is made by Ohaus so you are using one of the best available as far as loading beam scales are concerned, You will have to spend many more times what the RCBS scales are to get anything less than +/- .1gr accuracy.

Tell us what you are using for your loads, powder, bullet, primer, case, dies, etc...maybe your powder choice is wrong for the bullet you are using, etc.
 
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I am using a Remmy model 700 SPS Tactaicl in .223. I have already bedded the action and properly floated the barrel.

Benchmark Powder
50gr Nosler BT
Federal Match primers
Federal brass, 1xf (from this firearm)

I double measured all my test loads. I first measure out all my loads at the required measurement. When all that is done, before I seat the bullet, I then re-measure the loads to be sure I have the powder EXACTLY where I want it.... (yes I can be a bit anal sometimes)

I am getting some decent groups with one group but not the next. I have some groups that are .634" at 200y but then the next group will have one 'flyer' about an inch away.
My Nosler manual states that Benchmark Powder was the most accurate powder tested and that 25.5gr of powder was the most accurate load tested. I loaded up a few of them (before bedding) and was impressed with the results (under an inch at 100y). After bedding I loaded up 3-5 shot groups with this same load (to try before & after load testing) My best group was .634" and my worst was 1.141" (with one flyer) @ 200y. Velocity was measured at the same time and the differances in Velocity was consistant with the group size.

I was doing some load development earlier today. wind was at my 1'oclock to my 7'oclock at 7 to 3 Kph so I don't think wind was really a factor.

I was trying a new way of 'building a load' (authored by Jerry at Mystic Percision)

http://www.longrangehunting.com/articles/reloading-load-tuning-1.php

The process seems to be factually sound but in my test groups consistancy (in my mind)just wasn't there. I found that Velocity was jumping a little bit, in some of my test groups there was as little as 10fps and as much as 86fps differeance in test loads.

In the groups with a larger range of velocity differeances there was a direct corelation to the group size. The smaller groups were all closer in FPS and all of the larger groups were farther apart in FPS......

Makes me think I need to get a more consistant scale......
 
Scale is fine, powder and primer are fine.....brass and bullets could be better.

Lapua brass....bit more money but more consistant brass from case to case.
If you are shooting less then 300 yards max then go to a flat based 53 grain match bullet. If you plan on shooting farther then that then got to a 69 grain match bullet.

What distance are you loading the bullet off the lands. start with your best group at 10 thou off the lands and try it again 5 thou off and then touching, 5 though jam then 10 thou jam. things will settle in.

Since you admit to be anal....start weighing your cases and sort them by weight.

real anal? weigh your bullets

Its easy to make a larger caliber heavy bullet fly straight...small light bullets will cause hair loss as stated in most quality reloading manuals.
 
Well - Theres another phenomenon to deal with. Powders display varying degrees of combustion stability for a given load. This can be checked with a pressure trace, although a chrony can be indicative.
I tend to work at minimum load, and I find that some powders consistently work at min load, better than others. I attribute this to their ability to work at these lower pressures, and possibly higher case voids.
 
I currently have the bullets seated at 10 thou off the lands. Usually when I finally get a load figgured I start to play with the OAL, just to see if groups tighten up.

The problem as I see it is the 80(ish) fps differeances in the same 2 or 3 shot group. 30-40 fps is about what I would expect from a +.1 gr..... 80 fps seems to be more like +.3 gr.......

You see what I am trying to say.....

Or do you all still think my problem is 'something else'

Cheers!
 
If the groups fine in your other cartridges than Id say its not the scale.

I would start by loosing the federal brass and working with better brass, trying another bullet wouldnt' hurt either. As mentioned Velocity spread could be inconsistency in other factors / components.
 
FM69 - I never crimp my rifle loads...... I never have, can't see me starting now.

I ensure that I have about 2-3 thou of neck tension (these are 'hunting' rounds after all)

PF - The other rifles I reload for are a lot more forgiving if you are out .1 or .2 gr.

This .223 is a bit pickier (seems to me anyway) than the larger calibers I shoot.

Maybe I'll just go back to the start and triple check every variable this time.

Cheers!
 
You can get a 50 gr bullet out far enough to be .010" off the lands and not fall out of the case? Is your brass weight sorted? I agree with Pathfinder, dump the Federal brass.
 
OAL of 2.284 puts me 10 thou off the lands. ther bullets I am using avg out at .789 which leaves me with .265 in the neck of the case.

Fed brass is what I got, I have never had a problem with Fed brass in all the years I have been reloading...... Whats the problem with Fed brass? I've alwyas had good results with them before.... 243, 270 & 30-06. I guess I should source some other brass just to see if it makes a differance.

I sorted out enough caes to get 100 cases with-in 10% based on volume. I then further sorted the cases to get each 'group' in cases that were as close to the same volume as I could get.

Federal Match primers, Brand spanking new powder, Solid bench rest, Bedded action and barrel....... What other variables could there be that cause the velocity differeances I am seeing?
 
My best load with 50grn bullets in my .223 was using H4895. I have no idea what ES was as it was shooting ragged holes at 100m so I didn't care how fast it was going or how large the velocity spread was. It also made gophers blow up real good.

Don't get yourself hung up on the velocities/spreads too much unless you are going to be shooting it out past 500-600m.

If it shoots with a given load then stick with it and be happy.
 
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Everyone can spend their time doing what they believe is important.
I personally would not worry about your scale, or the accuracy of of your powder charges. With a 50 grain bullet you are not shooting at long ranges (400 yards plus), I suspect, so velocity variation is unlikely to cause accuracy issues.
 
notsorichguy said:
I double measured all my test loads. I first measure out all my loads at the required measurement. When all that is done, before I seat the bullet, I then re-measure the loads to be sure I have the powder EXACTLY where I want it.... (yes I can be a bit anal sometimes)
Click to expand...

Nsrg, please explain this. Are you dumping powder into your case then dumping it from the case back into your scale pan? When (if) you do this how often are you finding you are adding a tough more powder? Are you taking any out?

I have no idea why you would do this, you already weighed it once, why would you weigh it again? As another poster alluded, could neck tension be a variable? What is the load density of the load you are using? If it is less then 85-90%, maybe try a powder that gives you a higher density?
 
notsorichguy said:
I am finding a few problems (inconsistancies) with my velocity lately.
[...]
(35 to 50 fps is fine in my 30-06 but in my .223 it's hurting my groups)
Click to expand...

Velocity variances aren't the biggest issue up to about 300 yards. Having said that, my standard deviation is about 14fps (standard deviation is a better measure than extreme spread).

Assuming you're using the scale correctly (away from air currents, for example), and you still want to lower your stdev, have a look here:
http://www.snipersparadise.com/tsmag/sept03/sept03_1.htm
 
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