Question about same load for different bullets

[Raven243]

Just wondering how much retesting would have to be done if i changed the bullet style or brand but not the weight. Im shooting a 69gr nosler hpbt right now. Would switching to the sierra 69 hpbt or the tipped MKs or say a nosler accu bond or even the bergers take a bunch of retesting. If the bullets weight is staying the same would i have relativaly same results with the same load? The load im using right now is the 69gr nosler hpbt with 25.7gr of varget with the rem. 7 1/2 small BR primer.


Kevin

 

[Milo 2.0]

If you laid all bullets mentioned side by side on a bench and looked at them closely. Especially the bearing surface of each, your question would be answered. All bullet designs generate diff pressures, even same grain weight bullets from the same manufacturer.

 

[barefooter56]

Raven243,
Sometimes you can reduce your testing by making a dummy round of the NEW bullet to find out what its CBTO (cartridge base to ogive). Then , say your seating depth sweet spot for the first bullet was .010 off the lands. Find out what the new bullet needs to be seated to so IT is .010 off the lands. Drop back a grain or two and work your load back up to see if the new bullet needs a different or will work with the same velocity accuracy node. If this doesn't work you will have to start retesting from square one to find the seating depth and velocity accuracy nodes for the new bullet. Hope this helps!

 

[Raven243]

Thanks for the info. But i think ill stick with whats working.

 

[Erik Cortina]

You will have to do a full load work up again with new bullet. Do not fix what is not broken.

 

[Raven243]

After the responses i have read thats what it looks like i would have to do. I really dont want to have to do that. Just thought ide ask. See how feasable it would be. As much as i like test new loads because it gets me to the range shooting, i would rather blast golf balls at 300 than kill paper. It just more fun watching that ball jump around than it is looking at holes.

 

[amlevin]

You will have to do a full load work up again with new bullet. Do not fix what is not broken.

And sometimes that "full load workup" just yields the same powder charge weight. In other words, nothing's certain.

 

[CharlieNC]

On 308 I did full load workup with 155.5, 168, and 175 gr bullets using Varget. Nodes were at nearly identical charges, only slight differencesw which were explained by OBT. Of course pressures and velocities were quite different. In this case it was possible to go up to a higher velocity node with the 155.5, which was pressure limited for the heavier ones. Nodes at the same charges was surprising to me.

 

[ShootDots]

If the bearing surfaces on the bullets are VERY close, you will have to "tinker" a few tenths one way or the other from your known load>>IF you are not at either the top or bottom of your accuracy node. The match bullets you mentioned, although you should still measure them, are probably not TOO different one from the other. However, those Accubonds probably have a considerably longer bearing surface and if they do, you should start out about 2grs UNDER your load. Then there is the matter of seating depth. More than likely each of those bullets will have a preference for a different seating depth than another one. So a ladder test will be necessary with each bullet. UNLESS you are just playing around for the heck of it with various bullets, why not just stick with what you have that works now?

 

[Raven243]

ShootDots, i will be sticking with whats working. Was getting ready to order some more bullets and was just shopping around. Thats kinda why i was asking. Thought if not to much would have changed then ide maybe try something else for fun.