The Accurate Reloading Forums THE ACCURATE RELOADING.COM FORUMS Guns, Politics, Gunsmithing & Reloading Reloading My chrony must be wrongGo | New | Find | Notify | Tools | Reply | |
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| one of us |
As I look at the various posts on this board I have come to realize that my chronigraph must be off by 200 to 300 fps! I am getting much info about loads that tell me that there is no other possible answer. I load and load and chronigraph each of them and I still come up short on velocity. It doesn't seem to matter which rifle or barrel length I use. Rugers, Winchesters, Brownings, Mausers and Remingtons all seem to lack speed. Maybe I live in an area that has extra dense air mass or something? Perhaps my powder scale is wrong? What am I missing here? | ||
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| <OTTO> |
I have noticed the same problem here too. | ||
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| one of us |
Knew a guy several years ago, he always got higher velocities with his chrono than anyone else. One day I drove out to the range, guess who was shooting. Glanced at the screens and something looked funny. He had made up a shorter rail that pulled the screens closer together!! Mystery solved. Now he forever has the nick name: "Short Rail". | |||
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| one of us |
If your screen spacing is off by even a tiny ammount, it can affect the readings. Get somebody with a caliper or other measuring device capable of the spacing reqiured, to confirm it's right on. | |||
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| one of us |
Yeah, we sure seem to have a lot of .30-06 Springfield Magnums around here! -Bob F. ![[Big Grin]](images/icons/grin.gif){kind=icon} | |||
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| one of us |
Savage 99 What model Pact do you have? You probably already know this but, if you have the Pact Professional with ballistics calculator, the default distance setting in the software for the screens is 2 feet apart. It can be manually changed if they are closer together or further apart. The sensor mount Pact sells eliminates any guessing at distances since the sensors permanently mount 2 feet apart. [ 12-05-2003, 19:38: Message edited by: DennisF ] | |||
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| one of us |
You can "proof" your chrony by using match grade .22 ammo. I find that it is very close to the box velocity. Can you shoot some of your ammo over someone else's chrony? If you are not getting the velocity and have no pressure signs, you could go out of the book in small increments. When your velocity gains flatten out, you are at the operating max for that rifle. That is not a suggestion, merely an observation and if you go that route, you do so at your own peril. | |||
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| one of us |
Beemanbeme: I only have a shooting Chrony, not the most sophisticated but it gives me the info I need. I've noticed the same thing that you note. Now, when working up a load, I load 3 cartridges with a powder charge then usually increase the charge by 1/2 gr. & load 3 more. I shoot these over the chrony & note the impact on the target. When the velocity curve begins to flatten, I may shoot another 1 or 2 groups of 3 at increased powder charges, to confirm the leveling off. Almost invariably, the most accurate and consistant load occurs as the velocity curve begins leveling off. I know, a 3 shot group isn't statistically valid, but it seems to come quite close for my needs. This is how I developed my load for my .338 Mag. using the 225 gr. Northfork. All of this of course is with powder charges within safe limits. FWIW. Bear in Fairbanks [ 12-05-2003, 23:37: Message edited by: Bear in Fairbanks ] | |||
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| one of us |
Or of course it all could be chalked up to wishful thinking on the part of others (kinda gives new meaning to the phrase "extreme spread"). With the distinct possibly too that theirs are off and yours is not. The guns I own and shoot seem to be very trackable and for the most part very predictable. Based on loading manuals very near what they have used for test barrels. .221 FB 16 1/4" 40 gr. vmax 3230 fps avg. .260 Rem. 22" barrel 95 gr. vmax 3208 FPS avg. .300 WM 26" barrel 180 Part. 3025 fps avg. I guess I never wished they were faster than what they are. Thats why they make bigger cartridges. | |||
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| one of us |
quote:Bob. Yup! We sure do. However, let's look at this aspect. You buy a new rifle in 30-06, the latest model, say a Rem. 700, or you pick it. This rifle, in the case of the rem. is also chambered to the R.U.M. rounds developing roughly 60,000 P.S.I. while the 30-06 is kept tp 48,000-50,000 P.S.I. tops due to weaker rifles that were made in the past. Now, considering the Rem. 700 (or your choice of rifle) is considered strong enough to hold 60,000 P.S.I. from a round that will give even greater bolt thrust due to it's size, why can't a 30-06 be loaded to that same 60,000 P.S.I. and what kind of velocity will be achieved at that level? John Wooters once wrote that he had a 150 gr. bullet load that reached 3100 FPS safely in a 24" barreled 30-06 with a 1 in 12" twist. Kind of looks like that is in the magnum level of velocity to me. FWIW, I have come close to that level as well using a custom Mauser with 24" barrel and the 1 in 12" twist. Several othe cartridges have be deliberately underloaded by the factories for the same reason, early weak rifles that they were first chambered to. Rounds like the 7x57, .257 Robt. and .35 Whelen. I wonder just how well would those perform, should they be upgraded to 60,000 P.S.I.? Just a simple point to ponder. Paul B. | |||
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one of us |
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one of us |
We must have the same chrongraph! ALL of my reloads in 15 different calibers run slower than what people post. In 22 years of reloading this has run true. I think it's proof of the old adage; "The first liar doesn't have a chance here." | |||
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| <Savage 99> |
DennisF, This Pact is an early one and is the most basic model. It has small switches inside which allow it to be set for various screen distances but the distances are specific and cannot be tweaked. The orginal screens had a simple eye that looked thru a slot in the plastic holder. This system gave logical readings but it had a narrow range of view. It was also on my homemade 5' screen holder. The new Pact screens have some sort of a plastic prysm in them. While I have measured their spacing and it's right on 2' they read low. Pact told me to try reversing them. I reversed one of them and the velocities are closer to reality. Another thing is that the spreads are a lot less with the Oehler than the Pact ever reported. | ||
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| one of us |
No one seems to do a simple suggestion of sending the chrony back to the manufacturer and have it tested. Beeman is right on by checking it out with 22 Rimfire ammo, and compare. As those of us with 30/06 magnums, also remember that, factory ammo is usually over rated in velocity, so don't call us that much of a liar. Seating the bullet out farther and touching or just short of touching the lands has a lot of variation on velocity also. Some of us experiment with handloading and others just handload to make their ammo costs cheaper. We also have a lot of critics who don't try what we say, and just criticize it. I had one person contact me off line after criticizing an '06 load. So after I asked him if he had tried it, or was just 'saying' "that's impossible"? He had not tried it, but once he duplicated what I did, he got the same results I did. I handload to know the parameters of my individual rifles. In the real world, for deer especially, a 100 or 200 fps is not really going to make a lot of difference at 200 yrds anyway. My little $69.00 chrony has been testing the same loads right beside a Oehler and Pack Chronographs, and the results were all pretty much the same. However a lot of guys on here, who have never seen my chronograph like to tell me it must be broken. That is as dumb as if I countered back,, they must not know how to handload. What results YOU get are should be what matter, regardless of what some one else is getting. YOU are shooting your rifle and they are shooting theirs. So what does it matter in the scope of things, 30/06 "Magnum" or not??? | |||
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| one of us |
Being from Alabama and old and slow my Chrono must self adjust and slow down for us Southern folks also. These dang things are getting smarter all the time. | |||
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| one of us |
Fairbanks Bear, I have the cheapo model of Chrony. I bought it when they first came out and it is still ticking. It tells me exactly what I want to know which is how fast my bullets are going. | |||
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quote:Chronographs are all pretty much the same. The trick is getting over your fears. Get an 18" drop tube and stuff in more powder. Publishers of reloading data are just to timid. Who's to say that 80,000+ PSI is risky? The important consideration is the extra couple of hundred feet per second. | |||
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My chony tells me my 357 mag and 44 mag loads are slower by 200 fps than I have been telling myself. They kick hard and make lots of noise, I really believed that Hodgdon load data. I wanted to believe. | |||
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| <Savage 99> |
quote:This post has to be in jest. If it's not then hold everything! Any thing at all that looks wrong when pressures are involved should be enough for a person to determine or have a proffesional determine the cause of the concern be it primer pockets, loads over the manuals suggestions or anything else. ------------------------------------------------- Seafire, If you found my post in the Archives about the Pact you would understand that I called the manufacturer. [ 12-07-2003, 01:10: Message edited by: Savage 99 ] | ||
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| one of us |
There are two types of handloaders: 1) Load book fundamentalists 2) Handloading experimenters My favorite reaction to one of my loads was from a fundamentalist when he told me I was crazy and dangerous and was going to ruin things for the whole gun culture with my accidents. When I showed him the same load in an OLD load book, he said it was ok then. My reaction to all this insanity is simple, I have to write a load book. -- A society that teaches evolution as fact will breed a generation of atheists that will destroy the society. It is Darwinian. | |||
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| one of us |
you may be getting a dose or reality!! ![[Smile]](images/icons/smile.gif){kind=icon} Shoot 5 or 10 shots, take the high and low out and average them, that will probably correct the situation...worth a try anyway... | |||
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| <eldeguello> |
Oddball, have you tried chronographing some .22 long rifle ammo, which has a pretty well-estblished velocity standard? If so, what does your chrony say about that? If not, try some! (BTW, I got my first chronograph in the 1960's, and have had several since then. Up until the mid-1980's, I found that data taken from the manuals of those days was pretty valid in most of my guns too. Over the last several yeats, I have purchased several new manuals from the likes of Barnes, Nosler, Speer, etc., and have found their data these days doesn't even produce the velocities they say, and some of their data is WAY OFF!! For example, one RE22 load given in one of these manuals for their 175-grain bullet in the 7mm Rem Mag. showed a MV of + - 2900 FPS, and actually only gave around 2600! Of course, all rifles are individuals, but in mine, it took nearly 5 more grains of powder, over and above the published MAX load, to give the claimed 2900 FPS. This increased charge was worked up to carefully, and showed no more pressure signs that the book max. did! This is just one example, and this (old) rifle still gives velocities pretty much in line with what the old manuals say it should! [ 12-08-2003, 18:49: Message edited by: eldeguello ] | ||
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