Do I need a Chronograph?

[W.R.Buchanan]

Well,,, yesterday marked the 4th time I have shot Silhoutte with my Ruger Gunsite Scout!

This round was fired with my newest batch of reloads using 45 gr of IMR 4895 and my first run with the new recycled bullets I got from HI-Tech. All the charges were weighed as I couldn't get my powder measure to repeat, and were 45 gr +/-.1

After shooting the match I set up the Chrony to see what was actually going on with my loads, and was surprised to find something I had not expected.

When I picked the 45 gr charge I had done so by consulting all of my reloading manuals, and extrapolating where I wanted to be based on what was purported to be the Federal Factory loads speed of 2800 fps from a 24"barrel. IE I was seeking a charge that duplicated that Federal generic load. This is the most common factory .308 ammo out there running $10.95 per box at gun shows, and is likely the only Factory ammo I will ever use in this gun.

Allowing 25 fps per inch loss in velocity the 16.5" barrel should have been yeilding @2600 fps. And this is what I based my Ballistic Calculator charts on. The results so far in the matches have validated the elevation settings yeilded on the charts for the 4 distances, So I had considered the velocity to be in the 2600fps range.

First shot over the Chrony was a surprise!,,, 2792 fps! Second shot was 2786 and so on right in that area for 5 shots. I had had some primers that were a little flat, but not that flat, and others that weren't flattened at all. Since they were Remington 9 1/2's which are noted for having soft cups and since all of them were not flattened. I dismissed it as near the top but not into any danger zone at all. I had fired 150 of these same loads with no outward signs of pressure like hard bolt opening or damaged cases. Etc.

Then the eye opener came. I fired 5 Federal factory rounds and they all were in the 2710-20 fps range. I guess I was a little hotter than I thought, and definately more than I wanted.

But It still managed to put 5 into a 7/8" group at one hundred yards and exactly 2" high and on center!

I will be reducing the powder charge, and now that I have a complete scientific set up working I can go about working up the load in a more empirical manner starting at about 42gr and going up to about 44 tops.

Several things were learned by this experiment

First: shorter barrels are not bleeding off as much velocity as formerly anticipated. If the Federal factory ammo in fact does yeild 2800 fps from a 24" barrel then this gun is only losing about 12 fps per inch.

Second: Anyone who claims these guns are not accurate is not doing something right! Asking more than 1 MOA accuracy from a generic gun is asking alot. And at 7/8" on the front end of of the load development, I see potential for even better groups from this gun. The factory ammo yeilded a 1.5" group and it was shot into a Caldwell target that I couldn't index properly. Also I will get better shooting this gun off the bench, something I haven't done much of in years.

Third: this gun is completely suitable for long range silhoutte. I am competing with much more experienced shooters many of which have dedicated guns built specifically for this sport and I am starting to beat them, and rather than beat my own drum, I am suggesting that this gun is largely responsible. Highest score yesterday was 14. Which is about average for our group of about 20-25 shooters.

Any of you who were holding back because any of the internet BS you have read about poor accuracy of this rifle need look no further, Just go buy one. I promise you I'm not getting a kick back from Ruger!

One last point,,, If you don't have a Chronograph of some type, and you are trying to work up loads, you are shooting in the dark. I had no idea I was above factory velocities, and would have carried on blissfully until ? The $79.95 I spent on this tool gives me a very accurate assessment of my progress and I urge any of you who are serious about the reloading hobby to spend the money. I put it off for many years and I would be much farther up the food chain had I aquired one earlier. It is a must have tool for reloading. It tells you exactly what you've got, so you don't have to speculate.

Refer to above paragraphs for results of my speculations.

I hope this motivates some of you.

Randy

[1hole]

There is a lot of BS written about reloading and ballistics. The effect of barrel lengths vs. velocity is one of them. The variations depend on a lot of things beside barrel length, bullet weight and the cartridge's expansion ratio being perhaps the most important.

[lbaize3]

yep! I like my Ruger Gunsite Scout, too!

[Idaho Sharpshooter]

You only need a chrono for two reasons:

1. you want exact MV to calculate drop at yardages past 300yds.
2. you want to compare loads.

Rich

[W.R.Buchanan]

Rich: did you notice I found out my loads were a little hottter than I "thought" they were?

100 fps hotter than factory ammo is kind of a big deal. I got that load from Lyman 49!

And it turned out to be completely different than what the book said it would be.

I know,, I did it the other way for 25 years, and only in the last couple of years have I found out just how far off I was from where I "thought" I was.

I have learned being a machinist for the last 30 years that you just gotta check everything.


Randy

[Dan Cash]

Rich: did you notice I found out my loads were a little hottter than I "thought" they were?

100 fps hotter than factory ammo is kind of a big deal. I got that load from Lyman 49!

And it turned out to be completely different than what the book said it would be.

I know,, I did it the other way for 25 years, and only in the last couple of years have I found out just how far off I was from where I "thought" I was.

I have learned being a machinist for the last 30 years that you just gotta check everything.


Randy

So? Were your loads doing what you wanted? Seems like they were. There are many things that affect MV and you have addressed but a few. Your ammo in another rifle could produce much lower velocity or, perhaps excessive pressure. I think you could relax a bit and enjoy what you're doing more.

[August]

You only need a chrono for two reasons:

1. you want exact MV to calculate drop at yardages past 300yds.
2. you want to compare loads.

Rich

3. you need to assure yourself of the power factor of a load for competition.

[Morgan Astorbilt]

Randy, I find a major benefit of chronographing loads missing from this thread. I don't know which unit you were using, and how many functions it has, but I find with my Oehler 35P, after the actual velocities, the SD's (standard deviations) are the most useful data. Lower SD's = smaller groups. High SD's are a sign of poor quality reloads, and/ or perhaps poor primer ignition due to a weak mainspring, etc.

Morgan

[pdawg_shooter]

When I bought my Pact, I used it on every load I made. Now it only gets used when I change powder lots. Bout once a year or so.

[W.R.Buchanan]

Morgan: I agree with what you said, but SD is kind of a thing that is not really understood by many. Most people can grasp extreme spread. and they certainly do recognize the velocity, but the SD numbers are much harder to grasp.

I mean what they actually mean, not what people think they mean.

I have an Alpha Master Chrony, and it does report Standard Deviation, but I really haven't gotten to the point where those numbers mean more than the size of the groups I'm shooting. Eventually I will, but for now I can visually extrapolate the consistancy of 5-10 numbers at a time with out having to include the added burden of the understanding of Standard Deviation.

I am an appraiser as well as a machinist, and I do have a cursory understanding of standard deviation, however I donot have a working understanding of the term. In other words I can't use the information effectively. As I increase my usage of this tool I will eventually absorb it into my vocabulary, and it will be come part of the trip to the range.

Here's a slightly related tid bit I just got off the "View" this morning while writing this. Herman Cain early on was a Ballistic Statistician for the Navy. Be a good thing to have a shooter in the WH!

I'm starting to like this guy alot. Have a look, he's pretty smart, and since he is not a politician, he could be exactly what this country needs.

Randy

[Boolseye]

Although W.R.'s initial question was strictly rhetorical, I will answer it anyway. Speaking for myself, no, I really don't consider a chronograph a necessity. Thus far, I have dialed in all my most accurate loads without one. I just like them. Don't forget the fun factor! I's cool to know how fast those little pills are going. I have an old copy of The American Rifleman where it shows you how to make a chronograph using a magneto off of a model T, aluminum foil and a few other items. You calculate the bullet speed by counting the number of burn marks on the foil, plugging them into some formula....we've come a long way.

BTW, there's a great deal on chronys at Wally World

[Wally]

The Std Deviation (SD) merely means that whatever the SD is for a sample--68% of the shots would fall within one SD of the mean---99.7% of the shots would fall within three times the the mean... Low SDs are nice, but IMHO small groups are even nicer.

[Morgan Astorbilt]

Wally, You can't have small groups without low SD's. If the rotational speed is not within the bullets' "sleep" rotational window, the bullet will be corkscrewing it's way to the target, and the rotational point at which it impacts the target, will be governed by the velocity, and the group size will be a result of the variations in velocity.

Paul

[Crusty Deary Ol'Coot]

"Hotter" Well being "HOT" is really relative when we are talking 1000s of units of pressure.

It has been my finding in the years since having a chronograph, that there are three basic groups of rifles as per velocity.

And as long as a person is following good and safe guide lines and remaining within well tested and published data, I think the "hotter" factor is, in most cases NOT a safety factor as far as pressure is concerned.

One of the fun things about having a chronograph is, seeing the reaction of friends when they find out that their favorite rifle, shooting a real barn burner velocity according to the reloading manual is 100 - 200fps off the pace of the published data.

The three groups of rifles I have found as per velocity, are #1 and the largest of the groups, those who are "slow" according to published data.

The 2nd and smaller group being rifles which closely meet the published data.

While the 3rd and smallest group are rifles which exceed published velocity data.

Bear in mind that the above is happening all while within the confines of the published data, and all while shooting nothing which presents any indications of excessive pressures.

On top of that, I have seen changes in velocity in the 100fps +/- range just with the change from one powder lot number to another.

So, providing you are following good and safe reloading practices, and not trying to push the limits, be happy if your rifle is one of the few but fast ones, but relax if instead your rifle is in the first group.

You do your job, that critter will be just as dead as if you had started the bullet 200fps faster. History and our every day/year hunting experience proves it.

Just like the car that is for some reason faster then your friends, while everything is as close to the same as possible as to make/model/engine, trans. etc., you just happen to be driving one of those cars where everything came together just right. It happens.

I have seen published data which gave some velocities to be dreamed of, if that is your thing, but in the real world, few if any rifles would shoot within 200 FPS of that level.

Now considering this info is published in a well respected loading manuel from a company that has been in the business for many years, I truely believe there was no miss print or intent to miss-lead us, the reloading public, by slipping in some greatly excessive pressure levels.

I do believe however, that everything came together just right during their tests, bullet, powder, primers, cases AND!!!! their rifle or pressure barrel so that they did, in fact, arrive at the published velocities and did so at safe pressure levels. This also happens.

Do I need a chronograph, no, I developed very good loads for years before I had one. But -------- I do enjoy this added factor and the facts it provides.

Keep em coming!

Crusty Deary Ol'Coot

[Sonnypie]

Do I need a chronograph?
No.
But I have one... somewhere in the USPS System's clutches...
Because for some dumb reason, UPS decided to hand it off to the Postal Service for delivery....
And today, as with almost every day, there is a UPS truck in the neighborhood making deliveries. It is due today...

Never mind... (Note the time)
It is on the porch... finally. The mailman was here early this afternoon.
Good. The Grandson and I will put it to good use at the range Friday.
I have a lot of loads to test.
Tomorrow, the pellet guns for starters. Because I can get away with them in the back yard.

Because Inquiring minds want to know.

No I don't need a chronograph.
Mine finally got here.
Miracles never cease!

But that is #2 for this hand off baloney. Midway is going to hear from me, this time.

[W.R.Buchanan]

Sonny: we get the same thing here in Ojai EXCEPT my Postal idiot woman won't deliver packages to my house because I asked her not to drive so fast down my driveway three years ago!

The service is called "UPS Basic" and Midway uses it unless you specifically demand other wise. Potterfield makes big money on his shipping in case you haven't noticed, and he's not changing his policy anytime soon. This service cost him about $1.50 per package less, and over a million orders shipped, that's worth doing.

I complianed to Midway and they flagged my account NOT to ship with this service again

I got my UPS people to get into a pretty good fight with the Ojai Post office over this. I pay for UPS service, they farm delivery out to the post office, and the Post office doesn't deliver.... that's on UPS!!!

You have to make them perform and they will buck it. You have to be insistant. You paid for something and they aren't delivering? ***? You hold all the cards.

Randy

[Larry Gibson]

Is the chronograph necessary? No it isn't. But groups at 100 yards won't necessarily tell you if they will be as accurate at 500 meters (as in shooting the rams) or at 600 yards (as in HP matches) or at 1000 yards (as in prone or Palma matches) or at 472 yards as in varmint shooting. Using a chronograph in conjunction with shooting those 100 yards groups will. As mentioned many better chronographs show the SD (Standard Deviation) and the ES (Extreme Spread). I've learned over the years (been using Oehler chronographs since '75) to pay attention to both SD and ES. I prefer the SD to fall within 20-45% of the ES. If that occurs and the group is good then the load is good.

Too many times I have had loads give a low SD and an overly large ES (10 shot test strings BTW) with what appeared to be a good group also. Paying attention to just the SD and the group would have said it was a good load. However, subsequent testing proved those were not accurate loads. Just as a flyer (not a called shot) out of the group tells you something, too wide a variance between the SD and the ES is also telling you something.

I've also learned that small groups at 100 yards with large SDs and proportionately large ES's are quite common. When tested at longer ranges verticle stringing due to the large ES becoms readily apparent.

Nope, you sure don't "need" a chronograph but if you are serious about developing quality loads that will shoot accurately across a broad spectrum of ranges without extensive testing at those ranges then the chronograph is a must. Loads that shoot small groups at 100 yards, have small SD and a proportionately small ES will shoot well out to long ranges. Loads that don't have all 3 of those won't. Without a chronograph just shooting groups at 100 yards will only tell you how accurate that load is at 100 yards.

Larry Gibson

[G. Blessing]

Do I need one?

Yes.

Do I use it for all loading?

No.

Its easier and a lot of fun to do it the math way, from the book, etc.. for light and mid range loads, if its accurate, thats all that matters.

But for top end loads, or ones that exceed published data, I use it. I like to know by how far i am exceeding known speed, and somewhat know on pressure, from that speed.

But, my main use is when I am creating loads that there is no published data for at all.

Like my heavy 30-30 hunting load. I used a powder that i could find no data for in that cartridge, regaurdless of speed or bullet weight, let alone what i was trying for. I converted data from another cartridge that sent the weight i wanted at the speed I wanted(replicating a third cartridges ballistics), then worked up from alooooong ways down loaded.... without the chrony I'd never have known what i was actually getting at any point.

G.

[Crusty Deary Ol'Coot]

INteresting Larry G.

Thanks.

CDOC

[Maven]

"But, my main use is when I am creating loads that there is no published data for at all."

G. Blessing's comment (above) says it all. Given that we cast bulleteers are thrifty, we are attracted to all sorts of lower cost options to feed our hobby. Ergo, we purchase lower priced milsurp powders (Well, they used to be downright cheap!), whose lots vary significantly and which sometimes come with little [reloading] data. IMR 7383 is a case in point. You cannot safely work up loads with such a propellant without a chronograph. With one, you can safely do so and turn an oddball bargain into something useful.