FPS to powder charge

[longshot270]

Sorry for the bad title, but I have a question which back in the day seemed like it made sense, but now not really. I used to shoot and reload a fair amount. Family, etc has made a huge change in available free time, but I started digging through my reloading books again and might get back into it. So my thought back in the day was this. I buy a box of factory ammo which is loaded with "x" bullet. It shoots great. I buy "x" bullet, and with the aid of a chronograph I load up until I get the same fps as factory bullet. Now initially I was thinking this should be all fine, but is it? If using a completely different powder and different burn rates, etc. could I be overpressuring the gun? I thought same fps should equate to same pressure. But now I have numerous rounds of loaded ammo from 10 years ago I am not overly confident I want to shoot. All advice is welcome.

[fish_e_o]

sometimes you can't get the same stuff as factory

powder is most common to be different

[elkhunter11]

Just because you are getting the same velocity, with the same bullet, does not mean that it will shoot the same. And no, the same velocity does not mean the same pressure, if you are using a different powder.

[sillyak]

Definitely not a good idea!!!

X bullet at Y velocity will differ in pressure depending on the powder used. You need to work up a new load whenever you change any single component. You may or may not reach Y velocity safely with a given powder.

[32-40win]

Sometimes there is a reason, for certain powders not being shown with a certain bullet in the manuals. also. Sometimes that powder gave erratic results, which they would not publish. Sometimes they just didn't try it.
Each gun is different, yours may not gain speed & pressure the way theirs did. And there isn't a given rate of increase in speed vs pressure for any powder in the suggested loads they show, too many variables to do that.

[longshot270]

Maybe I need to add more information also. I used "my" powder and was able to match factory velocities with the same bullet. Is it possible to have an overpressure situation with this combination. I am matching Weatherby factory performance which might add to the scenario. Or am I worrying too much?

[petew]

Is "your" powder listed in the load tables for that cal./ bullet? Is your load within the safe range published ?

[elkhunter11]

I used "my" powder and was able to match factory velocities with the same bullet. Is it possible to have an overpressure situation with this combination

Absolutely it's possible! You don't appear to comprehend just how the different powder formulations effect pressure and velocity. Just look at the manuals and it's very apparent that some powders will produce more velocity than others for a given pressure. Simply adding more of one powder to try and attain the velocity reached with another powder can dramatically increase the chamber pressure, to the point where a structural failure can take place.

[longshot270]

That's what I started thinking, thanks for your information. I will see if I can find what I was using compared to loading info. online possibly to see what's what.