I've gone all out on by reloading process with my new 300 rum, but my first batch wasn't really impressive as far as SD of 21fps over 10rds.
All I was really working on was 10 rounds to zero my scope before I put a ladder together, but sent them over the chrono anyway.

Here's my loads- rem brass, yes cheaper than the nosler but I trimmed, deburred flash holes, cleaned pockets, neck turned, and weight sorted within less than 1%. So I assume brass is pretty consistent.
I full length sized the first time, so maybe fire formed and neck sized only may help my SD the 2nd go round(???)

Berger 210s I didn't weigh them but surely these are top end bullets and no need to weigh them?

.003 tension, and loaded to just touching lands.

Seated with forester bench dies, the kind with the sliding sleeve, I don't have a concentricity guage, but I assume this die is gonna get them pretty dang straight? If not I don't know how I could get them straighter.

Powder trickled and weighed individually absolutely no variation in charge.

Primers WLRM (couldn't find any fed215's) with the lee handheld, I may could pay more attention to seating my primers, but I think I was pretty consistent there.

Action is a stiller 700, 30" hart all custom built.

So, 21fps SD?? what could I do better? Can some charges be better than others, or seating depths? I was under the impression round consistency was the key to SD more so than trying different load variables. Group size about 1" not near what I want, but I attribute that entirely to my shooting- really learning the prone position right now for the first time, need lots of practice. I know my groups will get smaller after a while I'm not concerned at the moment.

Just getting started on this gun but I need to now how to improve my SD to get the most out of it.

I always ask this question.  It may the most important question of all.  What are your goals?  Write them down.  

What type of shooting are these loads for; hunting, plinking, competitive benchrest shooting, somewhere in between?  What distance(s) do you shoot at?

Why are you so concerned with and measuring all sorts of cartridge dimensions?  How do those characteristics track back to and support your goals (quantitatively)?  How uniform does concentricity (or weight, or OAL, or...) have to be to meet your goals?  How does that support your goals?  

Why are you so concerned with low deviation in muzzle velocity as measured over your chronograph?  How low is low enough?  How does low SD characteristic support your goals?

Most reloaders are primarily shooters.  Most are concerned with accuracy on target, whether hunting paper or animals.  


My advice to you -  

Work on improving your prone position shooting rather than improving your reloads any further.  I am absolutely certain, given your description above, that your reloads are not limiting your accuracy.  

Spend the time at home dry firing rather than reloading.  The benefits will be evident next time you go to the range.

An SD of 21 ft/s on what velocity?

3099avg

This is going to be a range toy out to 1000yd. Maybe an occasional hunting situation.

Yes I know improving shooting skill is important, but I have fun reloading as a past time and getting better at that is something I'm really starting to enjoy, and hopefully can eventually see the effects at longer ranges.

What kind of chronograph do you have?  Bryan Litz did extensive testing of various chronographs for his book "Modern Advancements in Long Range Shooting".  One problem he noted was that many chronographs are simply too flimsy.  Mine, a CED Millennium, was said to be one of those.  For years, I've struggled with Standard Deviations that seemed high, and now I know why - my chronograph is flexing too much.  Perhaps that is your problem?

SAB

Can't help much but will add this.

Anything under 20SD and I am pleased.

That's with mixed brass and a progressive press.

Chronographs play a big part in this game.

I watch 3hrs of David Tubbs YouTube video that shows you exactly what you are looking to do and how.

He is not happy with anything over 10SD and painfully shows how to get there step by step.

http://youtu.be/NUnrYp0NH38

IMHO... I do not put to much merit in SD.

21 SD is fantastic... yet it is also proof of how little it CAN mean... again IMHO.

I have fired and chrono'ed tons of OEM ammo and reloads over the decades, and there is little proof that the lowest SD =  the smallest group.

I have fired tons of high SD ammo with tiny groups.

It is a mathematical equation... and unfortunately all ammo has way to many variables for the SD to mean much.

It is a good way to predict how well that specific powder and primer combo is working.

Think about what it is actually measuring v. what variables it is not taking into account.

( with that said real high SD shows your powder charge , primer, neck tension combo to be erratic.... that makes SD helpful to me )

The only thing it is accounting for is how uniform your loads velocity is.... not the slight breeze on shot 3.. not you moving your stance.. not the one bullet that is slightly "off"... etc.

You sound like you  have a great grasp of reloading... so I suggest you buy a copy of this... and see how much difference the components make in accuracy v. sd.

Title of the article is..."Developing the Most Accurate .308 Winchester Load"

The article really put a perspective on how many variables there is in reloading.... again 21 SD is in my opinion, fantastic... and rather then you chase a smaller SD, maybe you should try a different component.

They only have it on CD, "Handloader" magazine... it is "516-257C Handloader Issue 2008 #257 December
Discount Price: $5.95"

https://www.riflemagazine.com/catalog/detail.cfm?page=251&Productid=1556&subcategoryid=225


I understand that you are looking for a smaller SD, but truly believe the way to a smaller group is through a different variable.

Yes, but run the numbers.  What is the maximum velocity variation you can tolerate (right now) at the distances you shoot (right now)??  In other words, how much velocity variation would be required to see X% increase in group size?  Let's say 10%, just for kicks?  

How much does your point of impact change due to the 20 fps change in muzzle velocity?

If you are shooting at 800 yards (the "easy" long range target), and you misjudge the wind speed by X mph, how far off the point of aim are you?  Let's say 2 mph for now, because seeing and appropriately responding to a 2 mph change can be difficult for a newbie.  

Compare the magnitude of the errors in point of impact from the wind shift to that of a 20 fps change in muzzle velocity.

I was just going to say am SD of 21fps is not bad.

I pay the most attention to extreme spread.

If it is high pay more attention to weighing your powder charges.

If it is still high, try more neck tension and/or closer to the lands.

We`ve had SDs` of 2. A few zeroes on 5 round lots. All done with a magneetospeed.

This is with a VERY accomplished shooter that knows anything over an SD of 10 and he is at a disadvantage to some of his competitors.

The fact that you ( if your chrony is accurate) are reporting SDs` in the twenty range tells me you have the patience to get even better results. I think you`ll find that using "once fired" brass will lower your SD. At my last count there were over three hundred variables that one could go nuts trying to deal with. My shooter now uses only new Lapua brass and only 5 steps in his loading routine. He uses another three steps in the QC process.

Remember that the real measurement that you should be concerned with in loaded rounds is the charge weight. Next in importance is concentricity. Next would be ogive to base # repeatability. Next would be to add some steps to the basic five.

What scale are you using?

Thanks for the replies.

ACE I'm hoping the once fired brass will improve it some, right now that's all that's going to change, like ya'll were saying improving my shooting and reading wind will probably be more significant.

I'm using a pro chrono, which is a cheap one but I've read some good stuff about it, could very well be a POS though.  Using a dillon terminator scale.

I feel a little better with everyone saying 21 ft/s sd is pretty good. Guess I'm being a little anal over it. Just like to find input on how to make things better.

So is ladder testing still a good idea to figure out my charge?

Standard deviation (SD) without a sampling of at least 1000 rounds is pretty useless information. Extreme spread is more informative as it will effect elevation impact at long range. Like stated, it depends on what your goals are for usage. Accuracy goals at 100yds (may) require different loads at 1000 yards. A 100 yard super accurate load my be really bad at 1000 yds. and vice versa.

Knowing what various statistical values mean is really more important than the data they generate.  If you don't "get" what these values tell you, it's just numbers.  For example, Standard Deviation expresses the "variance from the mean" for your sample.  The smaller the SD is, particularly in relation to the values of the mean, max, and min, the more consistent the data (velocity) among the samples is.  Just on its face, a Standard Deviation of 21fps with a velocity of over 3000fps is great.  It indicates that the "bell curve" distribution of your loads' velocities is really, really skinny, which is a Good Thing statistically.  But you didn't include other data that would help interpret the number better, and your sample of only 10 rounds isn't a whole lot to base interpretation on.

What were the raw velocity numbers?  You posted your average velocity, but your max and min would be helpful data as well.    What were the conditions under which you did your shooting?  Did you fire slowly or quickly?  Did you leave the action open for long enough for the barrel to cool a bit between rounds?  Did the ambient temperature change while you were shooting?

For a thoroughly tested load with a mean velocity over 3000fps, an SD of only 21 is pretty darn good.  For a new load you're just developing, it's an indication that, under the conditions you tested the rounds, the load is quite consistent.  The more important question to ask, here and in any load development, is "did these rounds print close together on the paper?"  There are a lot of factors involved in accuracy, and velocity consistency is only one of them.  You might find that a different load with a slightly higher SD tends to print closer together - those rounds are more accurate despite having more variation in velocity.

Your scale is holding you back. I`m sure it is a good scale but if you aren`t using tweezers you won`t ever get to where you want to go. Our scale is good to 0.005 grains. That means, in the real application, we are EXACTLY at , say, 42.65 grains +/- 0.005 grains. You can chase only so many rabbit holes in this game. Choose carefully or you`ll find yourself reloading and not shooting. I personally think weight sorting projectiles is not a great expenditure of my time for example. Bullet tipping? Yep. Turning necks? Maybe,,if you have a way to determine the neck tension other than an estimation. Meplat trimming? Sure,,and it`s easy to do,,,BUT,,you then will be FORCED to weight sort your projectiles. Being anal is a great thing,,,if you have unlimited time and budget.

20sd is pretty bad for all that work.

I get 8-13 using LC surplus brass loading for speed on my LNL-AP weighing nothing.

I would suggest though, at least 2 firings through the gun before looking for real good numbers. Another thing I have found that Berger bullet suck for base to ogive length consistancy. I hate paying $0.52/bullet and having to measure each one love the BC though.

I would try just throwing the powder so you are going by volume rather than weight if possible. I use ball powder because it meters.


Also don't check SD on a cold clean bore.


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pop tell me how you measure your bergers, I have the hornady gadget that clamps in my calipers to measure base to ogive of my loaded rounds, I assume you could sort your bullets by using that to measure your bullet only? I never even imagined they would have much variation.

That also is something I haven't thought of with powder volume vs weight, I may load a few without weighing just for the fun of it and see what happens! My RCBS measure dumps the weights nearly exact every time already though without even trickling much so who knows. May also switch scales.

Sorry I meant to throw in- my ES was 60ish, without having the numbers in front of me. Maybe 61 or so.
Some of your replies really have made me aware of how little the numbers are compared to shooting skill. Ya 21ft/s SD is .7% of 3099, and 60 ft/s ES is 2%, so probably fractional difference of what a flinch or bad shooting technique produces.
But again, why try to load custom ammo if its not as bad ass as possible, and give me a chance to get out of the house and dick around in the shop instead of watching american idol with the wife!

I have two Hornady comparitors and a set of different inserts. I pick the insert that goes to the same point(pretty close) on the ogive as my seater stem does. Then I usually mount another on the other jaw of the caliper the comes just behind bearing surface on the boattail. Or you can just put the base on the open jaw of the caliper. I like to use an insert on each jaw because it is faster than trying to assure the base is flat on the caliper jaw.


I have not had the length problems with the 210 or 230gr Bergers that I did the 185s.

The fact that you are loading 300rum I assume you will be shooting long distances and 20SD and 60ES will make a huge problem trying to hit things.

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Ya if you plug in 3070 at 1000 is a 205" drop, 3130 is 196.5, so 9" difference. So around 5" from avg velocity.
One day I dream that my shooting ability improves enough for that to be a big deal!

What happens to your drop if the bullet weight varies, or the BC varies?  I mention these two as examples of things that are out of your control and cannot be remedied.  

If you study these variations and their effects on point of impact, you will find the shooter's aiming error and inaccurate doping of the wind are the dominant effects.  You will find that some of the variations counter-act others.  They don't just stack up to negatively affect POI.

Yeah not a big deal if you are shooting a huge target like a 100% IPSC silhouette but smaller stuff.... Why not eliminate the variables that you can? Atmospherics are bad enough to deal with. It should be easy to get SDs below 15 and ESs below 40.

Give the brass a couple firings and check with a warm, copper/carbon fouled bore.

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Bullets "just touching " can cause velocity variations due to bullet ogive variations. Some will just touch, some not at all and some hard into the lands. Try seating them well into the lands or not at all. I never seat into the lands anymore unless fire forming. Extracting an unfired round can allow a bullet to stick and dump powder into the action and if not carefully worked up, excessive pressure issues with otherwise safe loads. Primers can vary lot to lot and some primer/powder combinations are better than others.