[shaggy430]

I don't have a chronograph, but how accurate is the fps listed in manuals for rifle information?

Any tips on calculating fps without a chronograph is appreciated.

[Walkalong]

There is none that is dependable. Too many variables.

[ChristopherG]

A chronograph is the only way. What you find in loading manuals can only be used as an approximation for any given load in any given gun. Usually the listed velocity is higher than a load seems to perform in any real-life gun.

[45ACPUSER]

No way to guess! Each gun is a rule unto itself! You need to have hands on data, not some wishful thinking!

[USSR]

shaggy430,

There is only one guarantee; your velocity will not be the same as listed in the reloading manual.;)

Don

[ranger335v]

".. how accurate is the fps listed in manuals for rifle information?"

Book projections have been high by as much as 300 fps in several of my rifles. Only knew it after getting chronograph.

[mongoose33]

Get a chronograph (yeah, like you've never heard that before!).

I was shooting w/ a friend yesterday and he brought his .44 magnum revolver. He takes it with him when he goes fishing out west, as bear defense.

It's a beastie, and I was curious how much greater power it was producing than my .45 ACP rounds, which I have loaded to 800fps w/ a 200gr bullet.

So we pulled out the chrono and I shot a couple rounds through the wickets. Speed? 1190 and 1192 fps. So the velocity is 50 percent higher, and given that he was shooting heavier bullets than I was, his knockdown power (for a bear!) is significantly greater than my .45.

W/O the Chronograph, who would know (well, other than those of us who are experienced enough to know, a group in which I have no membership). :)

You can get a good chrono for just over $100 (the Competition Electronics ProChrono).

I think you'd find it changes how you view, and do, reloading. No more guessing what you've got in your gun. You KNOW.

[fprefect]

You can get a reasonably close "estimate" using bullet drop. Zero the rifle at 100 yards for example and measure the impact points at 200 or 300 yds. Go to the balistic table in the reloading manual of the bullet you are using, find the bullet drop that most closely matches your actual results and the velocity shown in the manual will give you a rough estimate. For the best results use the manual of the "brand" of bullet you are using.

I usually use a 200 yd zero and will give you 2 impact points above and below your aim point when fired at 100 and 300 yds For example when firing a Sierra 53 gr hp at 100 yds ( 200 yd zero) and your impact point is approx 1.25" high, and when fired at 300 yards your impact point is approx. 6.5" low, check the Sierra manual for a velocity for THAT bullet that comes close to producing this ballistic arc which in this case is 3400 fps. Obviously not as accurate as chronograph, but a good estimate. The numbers take into account the approx 1 1/2 inches that the sight is mounted above the bore.

F. Prefect

[SlamFire1]

If you read articles from the 50's, no one had chronographs. Only Arsenals and ammunition companies, and Phil Sharpe.

Wildcatters used to claim warp speed velocities based on bullet drop tests. If their load was tested over a chronograph they got very upset, because it popped their bubble. :evil:

[fprefect]

Wildcatters used to claim warp speed velocities based on bullet drop tests. If their load was tested over a chronograph they got very upset, because it popped their bubble.

I am in 100% agreement that wildcatters would do anything within their power to "produce" the highest possible muzzle velocity using bullet drop and also agree that reloading manuals can show muzzle velocities that can differ by well over 100 fts from their test barrel and the rifle be used by the reloader.

But the only time I had access to a chronograph, I wanted to test about a dozen 22 PPC rounds that I had mistakenly charged with 2 grains less powder for a load that had consistently produced sub 1/4 MOA accuracy in a 40X rifle with a Shilen select match barrel over a period of over 2 years. Even though these accidentally produced "reduced loads" so to speak, were (according to the reloading manual) slightly outside the typically accepted muzzle velocity "window" for the 22 PPC that will produce the best accuracy, they still grouped almost as well as the loads I had been using for a couple of years that produced the best accuracy in that particular rifle WITH the additional 2 grains of powder.

Just by chance another member was at the range one day and had a chronograph set up testing some handgun loads, and I asked if I could chronograph 5 or 6 of the rounds with the lower powder charge against those I had been using with the 2 grain higher load. I had already tested several of them based upon bullet drop which indicated they should have been producing about 200 fps less MV. And low and behold the chronograph showed almost exactly that.

As I stated above I can see how wildcatters might take results of a bullet drop test that would indicated the highest MV, but the ballistics tables in the back of most reloading manuals are NOT calculated by actual test firings, but are produced using pure mathematics and the physics of a ballistic arc, produced by specific bullet with a known ballistic coefficient, and if the shooter honestly takes the results he obtained on the range, the MV should be fairly accurate, and in this particular case, it was.

F. Prefect

[alfack]

I've always found that my loads fall very near the published loads for velocity. I must have the same length barrels that the manual publishers do, or something.

As others have said, there is no way unless you use the bullet drop method. You could use a laser bore sighter to put a target out at 200 yards, then put one out at 100 and see if you go through both ;)

But after all of that hassle, you could have just bought a new chrony from midway for $70.