Developing loads again between RN and FN bullets of same weight

[rtracer13]

I imagine the answer is yes, but wanted to verify with other reloaders as I've still got a lot to learn in reloading. Once you have found a load that works best for your rifle for a specific grain size of bullet - Do you work up loads again if you change the shape of the bullet.. (ie. changing from a pet load of 150 gr RN bullets to 150 gr FN... or from 165gr spire tip to 165gr SPBT)?

If so, have you ever noticed much variance in the amount of powder that becomes the new pet load with that specific bullet shape?

 

[22to45]

The rule for safety is to back off your load a bit when ever you change a variable. the brand of brass, the brand or shape of bullet, the brand of primer, and of course the brand of powder. With bullets it is the hardness of the jacket and the length of contact on the barrel that can make a difference in pressure. As you can imagine, if it takes a bit more pressure to start the bullet in the rifling, and there is a bit more surface bearing on the barrel, the powder will burn hotter and the pressure will go up.

 

[jbmauser]

I always start at the min loads and work up from there anytime a component is changed(different brand case, bullet shape, etc) just to be safe. However most reloading manuals I have list the same powder charge for all bullet types of the same weight. I have switched from a RN to Spitzer style bullet a few times and found I could use the same powder charge safely. Accuracy and velocity were also very close in those instances as well. Stick to published load data and you should be safe.

 

[rtracer13]

I always start at the min loads and work up from there anytime a component is changed(different brand case, bullet shape, etc) just to be safe. However most reloading manuals I have list the same powder charge for all bullet types of the same weight. I have switched from a RN to Spitzer style bullet a few times and found I could use the same powder charge safely. Accuracy and velocity were also very close in those instances as well. Stick to published load data and you should be safe.

This is what I was meaning too.. Using a reloading manual and my pet loads have typically bean either low end or below 10% of the maximum recommended loads.

The only component change would be the bullets.. powder and primer staying the same.

 

[John Y Cannuck]

I the manufacturer is the same, and you are not stepping up to a premium grade bullet that may have a different jacket material, or construction, I'd only back down a bit, say 5% for such a change.
Likely you'll find it's fine to use the same load, but, bearing length is generally different between a round nose, and a flat point, so caution rules.

If we're talking about a 30-30 here, I'd likely just go for it, higher pressure guns require more caution.