Accuracy, standards and evaluation in reloading

Lionhill

Lionhill

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I switched brass about two weeks ago. New to reloading I did not expect the variation that this change would have had on my accuracy. When shooting at 100 yards, the change was nominal, but still accurate. When I reached out to 200 yards, things went to poop.
The new brass was lighter, thinner walls, less pressure and less velocity.

So let me ask you gurus this: If your measuring for constants in your reloading process, Is in this order the recipe for accuracy in testing:

Bullet weight - non variable (I use a .30 165 SST hornady bullet)

Brass uniformity - weight and brand

Primer uniformity - same primers used in all testing

Bullet velocity (loading to keep the pressures even to maintain a constant speed)

then;

Brass length

Seating depth

So: I am shooting a .308 out of a rem 700 heavy barrel. I "had" a good load with Fed gold brass, but not a good supply for that brass. I switched to Win brass, same load of powder (my error) and my shooting went for a big poopy. Accurate at 100 yards, but low by 5 inches at 200 - which I attribute to the bullet going too slow. The drop "should" have been only 1.5 inches, using the reference in the reloading manual/bullet calculators.

Last question: Once you have your powder load traveling at recommended speeds (2800 FPS) is the process of working load much easier and accurate?

In order to reload for accuracy, is a chronograph a must?

Thanks

LH
 
I would say that a chrono is a must for accurate repeatable LR loading, but maybe that's just me. Any component change can give you large variances, which is why you only change one thing at a time, then test, etc. The Win cases are obviously larger capacity then the Fed cases, so increasing your load to up the speed only makes sense, but more powder will also change the way that the pressure curve rises in the case as it burns, so that can also change POI and accuracy, even with the same bullet speed. It's a delicate dance, at best. - dan
 
I use Lapua brass and sort to within 1 gr. Never touch the primer pockets (sometimes don't even clean them beyond tumble) except to make sure the flash hole is clear. I alway use Fed 210M for .308 and 205M for .223. Brass length is checked about every 5 loadings. Seating depth is .005 off the lands.
Powder charge is weighed every time to as close as the digital scale will get.

In order to reload for accuracy, is a chronograph a must?

The chronograph will give you the velocity of your ammo fired from your rifle. Velocity does not always equal accuracy. Who really cares how fast the bullet gets to the target, as long as it gets to the same place everytime.
Develope the load that is the most accurate in your rifle, then check the velocity if you really need to know.
 
Actually Maynard, it's more a case of checking deviation then worrying about absolute speed. If your chosen load has a range of (for example) 2815 fps -2835 fps, 20 fps, you can usually figure that it will group better then one where your shot to shot variation is, say, 125 fps. I still think it is a very important tool in the search for accuracy. Your milage may vary, however. - dan
 
You need a chronograph, no question. Without one you are pretty much in the dark. I would hate to go back to trying to work up a load for power or accuracy without one.

Generally speaking, light brass runs to better consistency than heavier brass. If you change brass, you might be lucky or, as you experienced, accuracy may drop off. If accuracy is good at a hundred but drops off at longer range, it indicates that a significant velocity variation exists in your loads, which can again be confirmed with a chronograph.

Bullet weight is still a variable, and if you shoot 5 shot groups it might be useful to weigh your bullets and group them into groups of 5 of similar weight. Same goes for the brass.

Brass prep is critical. Neck run out should be kept to a minimal, and case length should be trimmed for consistency. I uniform primer pockets and flash holes, because it makes me feel better to do it. I think when you do all you can towards making your ammo consistent, you have increased the accuracy potential of your system.

You say that the bullets struck low at 200, but this is not a reflection of accuracy, only of velocity and ballistic coefficient of the bullet. It is normal for groups to be larger at 200 yards than at 100, and if your groups opened up to 2" at 200 yards, you are still shooting MOA.
 
Lionhill, I think you have forgotten a cardinal rule - When changing a component, any component, work up your load from scratch. You cannot assume anything relates to anything else even if its the same brand/part but different lots.

With fireformed Win cases, size, prime and seat bullets as you did before but work up your load again in 2 tenths increments. I bet you will find the same accuracy and POI but with a significantly different powder charge.

If you run out of something, start over again and retest. Big reason why I buy my components in bulk. Saves alot of time then retesting every 150rds.

A chronograph is a useful tool but not critical with a common cartridge like the 308. Data is so well defined that finding an accurate load is easy. Accurate Velocity, however, is totally dependent on the barrel. Some are fast and some are slow. Most in the 308 (same length and twist) will fall within a 100fps range for any given bullet weight.

I do use a chronie to confirm my velocities for my drop charts. I do check to ensure that I am not way too hot and on occasion I do check for velocity variations. I don't get all work up about chronie data because the error in any chronie is larger then the velocity spreads I am looking for. I prefer holes in paper.

Test at 200 to 300yds and if it groups there, it will group as far as you want to go. I rarely load test at 100yds because the data can be misleading.

Good luck.

Jerry
 
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mysticplayer said:
A chronograph is a useful tool but not critical with a common cartridge like the 308.

Jerry
Click to expand...

Thanks for all of the replies. I asked the question about the Chrono because, like all the other variables in reloading, if you can standardize or measure an effect of a load, you get closer to a firm handle on repetition.

I have read that 2800 FPS is a good speed for .308 in my grain of bullet weight. If I could make a load to speed, then tweek for accuracy - that would be better? I would rather not spend more on gadgets, but it seems difficult to find published loads that have all the variables of brass, bullet and load of powder in a list.

LH
 
My suggestion is to work up loads starting at minimum and evaluate every load for accuracy only. Forget about speed. If you have a chronograph, check standard deviation of 5-shot groups. Generally, good accuracy corresponds with low standard deviations. I got best accuracy from a .308 Win with 165 grain bullets at relative low velocities. Group brass according to weight.
 
mysticplayer said:
.

A chronograph is a useful tool but not critical with a common cartridge like the 308. Data is so well defined that finding an accurate load is easy. Accurate Velocity, however, is totally dependent on the barrel. Some are fast and some are slow. Most in the 308 (same length and twist) will fall within a 100fps range for any given bullet weight.

I do use a chronie to confirm my velocities for my drop charts. I do check to ensure that I am not way too hot and on occasion I do check for velocity variations. I don't get all work up about chronie data because the error in any chronie is larger then the velocity spreads I am looking for. I prefer holes in paper.
Jerry
Click to expand...


A chronograph is useful beyond simply measuring the speed of your bullet, provided you know how to interpret the information it is giving you. For example, when you are forced to make a component change, you can get back to your known accurate velocity quickly. Checking the extreme spread confirms you are back on track. Without knowing the true velocity you might be 100 fps from your optimal velocity (pressure) and you will not know if the change on paper is due to the different component, meteorological conditions, or your load.

It does not matter how common the cartridge you are loading if you wish to load non-standard components. Suddenly your garden variety .308 is a virtual wildcat. Let's say you wish to work up a load for an unlisted powder or perhaps want to try a bullet from a custom maker. The charge to bullet weight data you have been used to might not apply, this is particularly true if you make the change to VLD or ULD bullets.

You can determine the maximum load using a chronograph. As you increase the charge weight, watch to see where the velocity plateaus. This is a safer way to determine maximum pressure, than it is to look for pressure indicators on the brass. Differences in hardness between brands of brass makes watching for pressure signs unreliable. Once the maximum charge has been determined with those specific components, you can work backwards from that point to find your most accurate load.

Extreme spread is an indication of the potential accuracy of a load, but you cannot measure it without a chronograph. A load might shoot well at 100 yards but if the ES is high, it cannot shoot well at long range. This allows you to fine tune your long range loads at close range, which is less frustrating than finding out that the load that gives you a one hole group at 100 won't stay on paper at 500, never mind 1000.

A chronograph is like anything else, you get what you pay for. If you are concerned about accuracy within 10 fps, you need more distance between your screens. I use a 6' spread, but the distance between screens is not adjustable on a hundred dollar chrony. You could set up two chronies, but then the problem is which one to believe. If you've invested several thousand dollars into a target rifle and loading equipment why not have the advantage of a good chronograph.
 
I think people take max velocity too seriously. Yes it is a "nice to know" thing. However if you have a very accurate load that works at the distance you plan to shoot, I would go with that, over more velocity.
The load I use in my target rifle will shoot 1/2 MOA or better elevation at 1000 yards. This is with me holding the rifle with a jacket and sling, using iron sights. I have used this same load for about 4-5 years, never knowing what velocity I was getting. I clocked it last year and found out it was 2940 fps with a 10 fps SD out of my 30 inch barrel. If this load was only getting 2800 fps, who cares, it works.
 
maynard said:
I think people take max velocity too seriously. Yes it is a "nice to know" thing. However if you have a very accurate load that works at the distance you plan to shoot, I would go with that, over more velocity.
The load I use in my target rifle will shoot 1/2 MOA or better elevation at 1000 yards. This is with me holding the rifle with a jacket and sling, using iron sights. I have used this same load for about 4-5 years, never knowing what velocity I was getting. I clocked it last year and found out it was 2940 fps with a 10 fps SD out of my 30 inch barrel. If this load was only getting 2800 fps, who cares, it works.
Click to expand...

I agree... the proof is in the pudding. You can work up loads from the mass of available data out there. If it consistently hits the target in MOA or sub MOA at any distance, who gives a hoot about the FPS. Testing various load combinations is all what reloading is about.
 
And then there is case neck uniformity . . . try to connect with a experienced reloader for a two - five hour short course. It is a long process to learn from reading and trying. My club offered a course a couple years ago.
 
maynard said:
I think people take max velocity too seriously. Yes it is a "nice to know" thing. However if you have a very accurate load that works at the distance you plan to shoot, I would go with that, over more velocity.
The load I use in my target rifle will shoot 1/2 MOA or better elevation at 1000 yards. This is with me holding the rifle with a jacket and sling, using iron sights. I have used this same load for about 4-5 years, never knowing what velocity I was getting. I clocked it last year and found out it was 2940 fps with a 10 fps SD out of my 30 inch barrel. If this load was only getting 2800 fps, who cares, it works.
Click to expand...

Perhaps, but maximum pressure is useful as a place to start when looking for the best accuracy. If a handloader works up the maximum load for his rifle, then works backwards to find the best accuracy, he will not be as inclined to push the pressure envelope if his groups are teasing him. If he is working away from maximum pressure he could conceivably find his accuracy load in fewer rounds, and he can concentrate on those things critical to accuracy, without worrying about pressure issues.

Why would we care what the velocity is of our accuracy load? Let's assume you unexpectedly had to change one of your components other than the bullet. It might be nice to know what the velocity was of your accuracy load. In short order you could work back up to the velocity you know is accurate with that bullet, have it confirmed by the velocity reading from the chronograph, and the accuracy confirmed by the ES. To me that is a huge advantage over starting from scratch with load development.
 
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Cart Summary


Shopping Cart is emptyF-1
Features: Gives numbered shot velocities • Velocity stays on display until you shoot again • Used 9 volt alkaline battery with 48 hrs. of continuous use • Stereo jack for optional remote or printer.
F-1 CHRONY ·
Mfr. # F1 CHRONY · 61084
$119.95 x [ADD TO CART] F-1 MASTER CHRONY ·
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And if you call Chrony direct, they sometimes have refurbished chronys fo rabout $75 or so...

I bought my Chrony years ago for abotu $65....And I have since shot it next to 2 Oehler chronograohs, and the results were always the same, or wihtin a few fps of each other.

If I was to buy one today, I'd probably get a fancier model, but then again..maybe not.;)


I honeslty don't understand the resisitance to using a chronograph. They are cheap. They can let you knwo when you are in a danger area when you dont' get traditional pressure signs (sometimes the case wiht custom rifles buiilt to tight tolerances and/or Ackley cartridges)
 
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Oehler Chronograph




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I have always liked gadgets (calculators, then computers and electronic gismos), and fast things (fast cars, high velocity rifles, fast computers)--the list never stops. So naturally, when Oehler first made affordable chronographs available to the public, I had to have one. I bought my first Oehler Chronograph about 20 years ago when light screens first hit the market. A chronograph is a simple tool and only does one thing. It measures the velocity of a bullet. From that one measurement a wealth of information can be gained by a hunter or shooter if you know how to use the information. We'll look at how the P35 works and try to explain how the ODHA uses the information to develop loads and improve our shooting.

The P35 comes with three light screens, three defusers, a bar to hold the light screens, and an optional printer. As you have probably already figured, the light screens are set up in front of your shooting bench on the bar so you can shoot "through" them. Actually, you shoot through the beam of light that is projected up from the screen toward the top to the orange defuser. When the bullet cuts through the first beam, it starts the clock in the chronograph, and when it passes through the second screen the time is recorded. When it passes through the third screen, the time is again recorded and the two measurements are compared for consistency. The times are not averaged, they are only used to prove the measurement has been taken correctly. If sun glare or some other problem occurs at the shot, the P35 will reject the reading, rather than give you a guesstimate.

So what can you do with the info? First of all you will know the exact velocity of your ammo and can zero your rifle properly. Every rifle is different and every batch of ammo is different. Velocity can vary up to 300 feet per second (fps) or more. One of the most popular rifle calibers used is the 3006. Most ammo in that caliber is 250 fps slower than advertised, and hand loads can't do much better. When the ammo is going 250 fps slower than you think it is, hitting a deer at 300 yards becomes a guessing game. If you know the true velocity, you can zero your rifle properly.

Is there still enough power there to get the job done when velocity is 300 fps slower than it should be? That's the next thing you can figure out with the P35. If you know the true velocity of your bullet and the weight, you can calculate the power at any given range. Plug the figures into the JBM web page and it will give you energy at any desired range. You'll need the ballistic coefficient for the calculation. Most hunting bullets are around 0.350 to 0.400. You can use 0.375 to get a close estimate or you can get it from loading books or on-line data. Sierra Bullets has a complete listing on-line.

How much is that bullet dropping at 300 yards? That also can be obtained using the JBM calculator. It will print the trajectory at any desired yardage interval. Just plug in the numbers and read it off.

If you are a hand loader, the chronograph is your best friend. It keeps records of your series of shots and gives you the standard deviation between shots, the average velocity, and the highest and lowest velocity of the series. How does this help? Consistency in velocity means accuracy. When you shoot five shots of a given load and the velocities of all the shots are very close, you can almost bet the load will also be very accurate as well.

You can also use the P35 to help you develop max loads safely. Notice I said help!! Nothing can replace good, safe loading practices and common sense while loading ammo. But, as pressure increases, velocity increases (up to a point). When your velocities start approaching maximum associated with the particular load you are developing, you can bet the pressure is getting to the max also. The chrono will also teach you that more powder does not always mean higher velocities. Only so much powder can be burned in the barrel and you may even see velocities fall off or get very inconsistent when the powder charge is increased.

My P35 has been a great aid to me for many years. It has performed perfectly for me and the battery will last the average shooter about five years. Those orange defusers seem to work very well in all natural light conditions. I have never tried using the P35 indoors. I know that it will not work work florescent lighting because the fore sent bulbs blink continuo sly. This blinking triggers the calculator so you will have to try incandescent lights if you use the chrono inside.

The basic P35 will run you about $200. A little expensive but well worth the money. A good investment for hunting club, shooting club, or the individual shooting enthusiast.

If you want to see a grown man cry, just clock the velocity of his '06!!

Good Shooting,

Chester
 
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