Chronograph neccessary for load development?

I too have one, but rarely use it - none of my loads are at book max except one 6mmBR load, and i am able to shoot far out to check loads. Also, i too have found that groups change further out - like mentioned, meh at 300 may be super at 800. I didn't believe this, but verified by shooting this load 3x at both ranges... my example is my 'under 500yd match quality load' is 29.3 H4895/105 Hybrid/6mmBR - 1/2 MOA load - shoot it at 800-1000, it is still good, but 3/4-1 MOA load (moreso 1 MOA with vertical dispersion)... Next, 30gr varget /105 Hybrid, is 1/2-3/4 MOA at 200-400, until the barrel heats up - but at 800-1000, it is still 3/4 MOA with much less vertical than the H4895 load.
 
I seldom use mine anymore. I can shoot out to 800 on my own range faster than I can set up the chronograph. In the end you have to believe the target.

Chronographs and 100 yard groups are for those without longer ranges to work with. Hopefully they can gain some comfort from their predictions of what a load is "supposed" to do while not having to deal with the unpleasantness and uncertainty of accepting what it really does.
 
Dogleg said:
I seldom use mine anymore. I can shoot out to 800 on my own range faster than I can set up the chronograph. In the end you have to believe the target.

Chronographs and 100 yard groups are for those without longer ranges to work with. Hopefully they can gain some comfort from their predictions of what a load is "supposed" to do while not having to deal with the unpleasantness and uncertainty of accepting what it really does.
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Yes that is my next outing. Hope this close range load is happy when stretched out.
 
I found a cheap, used one on EE. Priceless. Erratic loads, and uh-oh...that's a bit zippy are both shown early even before a target or rifle demonstrates it.

EDIT:ADD-ON: I acquired it for working with cast/reduced loads loads, but once you have one you sling everything over it. Getting cast at an even 1050fps has proven harder to find than an extra 50fps on your fav.
 
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350 Mag said:
I like to use one.

Once your velocity reaches "book" maxs its time to watch out for other subtle signs. If your primers start to change or you get sticky extraction(case head expansion) its time to back off.
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Yes and there are points where the gains, despite increasing powder weight, are negligible. This is also an area where a chrony is useful.
 
I have one, it's fun to shoot.
Other than that, for me, it's pretty useless.

I use results to reverse engineer, if I need to know a number.
 
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bearhunter said:
stubblejumper is right but he should have went into more detail. IMHO the magnetospeed is far more practical and consistent than a chrony. Others may have another opinion.

Now, here is one way to get very close approximation of velocities if you can't afford one or are waiting for one. It works reasonably well but isn't as precise as a magnetospeed or chrony. Start with the suggested starting load. Say five cartridges. Shoot them at 100 yards. Use the same aiming point from a rest and don't try to make any adjustments. What you're looking to do is get a group on the target as a reference point

Next, load up five more cartridges with a stouter charge. If you're loading something like a 30-06 or 308Win I suggest 1 grain increments until you get close to maximum specs. I also suggest you load up all of these increments in one sitting so that you don't have to make a lot of trips over a long time to and from the range.

NEVER CHANGE YOUR AIMING POINT. WHY???? Because then you lose your reference point. With each increase, measure how high the impact is from your original group. This measurement will give you an approximate velocity. HOW??? Some manuals have reference tables, such as Hornady, which will tell you how high your trajectory is as different ranges with varying velocities. This reference will give you a pretty good idea of how fast your bullet is traveling.

It's simple but it works well enough for most uses and gives you a reasonable idea of pressure. The best early indication of high pressure I know of is sticky bolt lift after a cartridge is fired. When this happens, STOP. DON'T use any more cartridges with that load. DON'T use any with hotter charges either. Likely you won't have a KABOOM but you are approaching the limits of your brass at the very least. Go back and try the load just before the bolt lift was sticky.

Now, check which load gave you the tightest group and sight in for it. You may want to tweak it a bit by seating the bullet at different depths, which is often more important than reducing or increasing a powder charge. Chasing flyers is often fixed by changing to a hotter primer etc. When you change any component, you must start all over again. That includes different manufacturers of brass or different lots of brass and even powder/primers/bullets.
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A barrel vibrates when fired. When the bullet exits, the muzzle may be whipping up or down. If it is going up, the faster rounds will hit lower (not higher) on the target at 100 yards. At long range, the velocity differences may show up, but not at anything at 300 or less.

Each rifle does this, in one direction or another. It is a good thing to know. For long range shooting, you want the muzzle flipping up, known as positive compensation.

My old long range target rifle was a #4. At 1000 yards a variation of 1.0 gr of powder had almost no impact on where the bullet hit the target. The slower shots were flipped a little higher.

Research "rifle barrel compensation". It is a very old technique.
 
bearhunter said:
stubblejumper is right but he should have went into more detail. IMHO the magnetospeed is far more practical and consistent than a chrony. Others may have another opinion.



Next, load up five more cartridges with a stouter charge. If you're loading something like a 30-06 or 308Win I suggest 1 grain increments until you get close to maximum specs. I also suggest you load up all of these increments in one sitting so that you don't have to make a lot of trips over a long time to and from the range.



It's simple but it works well enough for most uses and gives you a reasonable idea of pressure. The best early indication of high pressure I know of is sticky bolt lift after a cartridge is fired. When this happens, STOP. DON'T use any more cartridges with that load. DON'T use any with hotter charges either. Likely you won't have a KABOOM but you are approaching the limits of your brass at the very least. Go back and try the load just before the bolt lift was sticky.

Now, check which load gave you the tightest group and sight in for it. You may want to tweak it a bit by seating the bullet at different depths, which is often more important than reducing or increasing a powder charge. Chasing flyers is often fixed by changing to a hotter primer etc. When you change any component, you must start all over again. That includes different manufacturers of brass or different lots of brass and even powder/primers/bullets.
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A sticky bolt lift is a definite sign of pressure. A well made rifle with equal bearing on locking lugs usually has a sticky bolt only after exceeding proof round pressure (often around 75,000 psi).

At the factory, each rifle gets a proof round. The tester has a wood mallet to pound open sticky bolts. He seldom needs it. Most bolts open smoothly. So if you get a sticky bolt, you are probably beyond proof pressure and your brass won't last long.

If you are using a certain powder, a given pressure will yield a certain velocity. If the book shows the max velocity with that powder, you have max pressure when you hit that velocity. There can be a 200 fps difference in rifles, with the same powder charge, so the max powder charge is just a guide. Your rifle will max out with more or less powder. The velocity is your best indicator of pressure. And that you can measure.
 
Ganderite said:
A barrel vibrates when fired. When the bullet exits, the muzzle may be whipping up or down. If it is going up, the faster rounds will hit lower (not higher) on the target at 100 yards. At long range, the velocity differences may show up, but not at anything at 300 or less.

Each rifle does this, in one direction or another. It is a good thing to know. For long range shooting, you want the muzzle flipping up, known as positive compensation.

My old long range target rifle was a #4. At 1000 yards a variation of 1.0 gr of powder had almost no impact on where the bullet hit the target. The slower shots were flipped a little higher.

Research "rifle barrel compensation". It is a very old technique.
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Funny how the sport has to reinvent the wheel every now and then.... if more shooters understood this, they would spend less time with a chronie and more time plotting their targets at distance.... and getting higher scores

Jerry
 
Ganderite said:
A sticky bolt lift is a definite sign of pressure. A well made rifle with equal bearing on locking lugs usually has a sticky bolt only after exceeding proof round pressure (often around 75,000 psi).

At the factory, each rifle gets a proof round. The tester has a wood mallet to pound open sticky bolts. He seldom needs it. Most bolts open smoothly. So if you get a sticky bolt, you are probably beyond proof pressure and your brass won't last long.

If you are using a certain powder, a given pressure will yield a certain velocity. If the book shows the max velocity with that powder, you have max pressure when you hit that velocity. There can be a 200 fps difference in rifles, with the same powder charge, so the max powder charge is just a guide. Your rifle will max out with more or less powder. The velocity is your best indicator of pressure. And that you can measure.
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how true.... Then you can bush the firing pin hole to delay any signs of primer cratering.... and the toss this all into SR reinforced case head brass.

pretty hard to see pressure signs when all the "escape valves" are taken out of the equation.

Jerry
 
You can develop good, accurate loads without a chronometer. Chronometer is like the speedometer in your car, it's one of the tools you can use to make decisions but you need to pay attention to the road and it doesn't drive the car for you.

Accuracy is still more important than a chronometer for most of us, most of the time. I find a chronometer most useful when I'm venturing outside the realm of published reloading data. That said, I do use my chronometer regularly and I wouldn't choose to go without it given the choice.
 
Mystic Precision said:
how true.... Then you can bush the firing pin hole to delay any signs of primer cratering.... and the toss this all into SR reinforced case head brass.

pretty hard to see pressure signs when all the "escape valves" are taken out of the equation.

Jerry
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I'm going a bit off topic, but I come across people loading ammo for antique firearms talking about watching their brass for pressure signs - in a firearm that has a working pressure less than 15K. Which means they could be well over proof level before they start seeing pressure signs in the brass. In a lot of the old guns the first sign of pressure you might see is when the firearm fails. This is where a chronometer becomes very useful.
 
jethunter said:
I'm going a bit off topic, but I come across people loading ammo for antique firearms talking about watching their brass for pressure signs - in a firearm that has a working pressure less than 15K. Which means they could be well over proof level before they start seeing pressure signs in the brass. In a lot of the old guns the first sign of pressure you might see is when the firearm fails. This is where a chronometer becomes very useful.
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I agree and that can be extended to non-antiques such as firearms that are chambered in pistol rounds such as 38 Special.

I'm one of those people who have used smokeless in the Snider-Enfield and I found the plastic Fiocchi 24 gauge shotshells were useful to warn about pressure as the very thin brass casehead would deform at anything above about 15K psi whereas solid brass shotshells would not.
 
jethunter said:
I'm going a bit off topic, but I come across people loading ammo for antique firearms talking about watching their brass for pressure signs - in a firearm that has a working pressure less than 15K. Which means they could be well over proof level before they start seeing pressure signs in the brass. In a lot of the old guns the first sign of pressure you might see is when the firearm fails. This is where a chronometer becomes very useful.
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In these type of antique firearms, their lock up is weak, sloppy and the brass will quickly expand under any decent pressure. The original cases were also weak compared to anything 20th Century. Didn't take much pressure to cause all manner of function issues so shooters took care and were careful. Trying to push those old gems to anything near modern pressures would indeed cause destruction.

Today, we can offer a rifle that will function well beyond MODERN proof pressure ratings. This puts huge strain on the metal and parts. We see the damage in lug galling, bent recoil lugs, broken bolt handles, and receiver peening. Some super sized loads have even strained the barrel enough that the CHAMBER is oversized vs how it started life.

Thankfully, nothing let go BUT that is simply a matter of time before we hear of actions failing with "safe" loads. Remember that steel can only take so much abuse..... its properties change with higher pressure pounding and it can let go with actual safe loads because it is weakened to the point of failure.

This is where the Chronie will save your butt. If you have load data that is rated with PRESSURE ratings and speeds from proper sources, the odds you can create more speed from similar components and still have less pressure is slim to nil.

you will hear of 6.5X47L's pushing 140gr bullets over 2800fps. That 100fps OVER print data means the loads are running elevated pressures. Will that fired brass show any pressure signs in a well designed rifle... NOPE but the action and barrel did experience that extra pressure.

Will the load shoot well at LR? Will it stay in tune over the match weekend? How will it affect the lifespan of that action?

Chronograph tuning is hit and miss BUT knowing your output will certainly help you make safer decisions about your input

YMMV

Jerry
 
"Today, we can offer a rifle that will function well beyond MODERN proof pressure ratings. This puts huge strain on the metal and parts. We see the damage in lug galling, bent recoil lugs, broken bolt handles, and receiver peening. Some super sized loads have even strained the barrel enough that the CHAMBER is oversized vs how it started life.

Thankfully, nothing let go BUT that is simply a matter of time before we hear of actions failing with "safe" loads. Remember that steel can only take so much abuse..... its properties change with higher pressure pounding and it can let go with actual safe loads because it is weakened to the point of failure."

Well said.
 
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