What you procedure for changing bullets within the same weight?

[Comrade Mike]

Say I'm shooting 140 grain FMJ's and I've found a powder sweet spot. Now I want to shoot 140 grain match hollow points seated to the same depth. Can I just swap bullets and use the same powder charge? Or should I back off a grain or so and take 10 rounds to work back up?

 

[rcmodel]

If you are not already at a MAX load?

You could switch bullets without working back up.

However, the 'sweet spot' powder charge will almost never be the same for two different brands or bullet designs.

If you want maximum accuracy with the Match bullets, you need to work up the best load for them again.

rc

 

[jmr40]

I agree with RC, especially if the bullets are from the same manufacturer. If not it might not be a bad idea to back off just a little even if you're not right at max.

 

[jmorris]

Depends on the load and bullets. Going from lead or plated to FMJ's could rase pressures.

Reducing the volume in the case will do the same thing.

When in doubt, lower the load and work back up.

 

[jmorris]

FWIW when my brother and I started reloading, almost 30 years ago, we had loads for 38/357, 9mm, 45 that all used the same powder and charge, just to keep things simple.

All it took was picking the right bullets/seating depth.

 

[Reefinmike]

Err... not sure if anyone noticed this, but you are switching from FMJ to HP. A hollow point takes a little lead out of the top and puts it in the rear of the bullet. HP's of same bullet profile generally have a longer bearing surfaces and longer overall length... Meaning that If you seat them at the same OAL, the HP will be deeper in the case, reducing case volume and increasing pressure. I dont load 40 so im not sure on best powders etc etc, but for example My book lists a max load of 7.8gr of powder XXXX for a 135gr FMJ. for a hollowpoint, the max for the same weight bullet is 6.3 grains of powder xxxx!!!!!!


I would certainly back off the powder charge and rework your load. You cant switch from a fmj to a HP without reworking the load.

edit:im not sure why I assumed you were loading 40... not sure what you're shooting but id certainly rework the load

 

[Arkansas Paul]

It's been mentioned already, but it bears repeating. If you're at max or close to it, work it back up. If not, load some up and see how they shoot. Don't be surprised if the sweet spot is different though.
The .40 is a high enough pressure round already. Don't take any silly chances with it.

 

[jmorris]

Err... not sure if anyone noticed this, but you are switching from FMJ to HP. A hollow point takes a little lead out of the top and puts it in the rear of the bullet. HP's of same bullet profile generally have a longer bearing surfaces and longer overall length... Meaning that If you seat them at the same OAL, the HP will be deeper in the case, reducing case volume and increasing pressure

Better pointed out than I did in #4.

 

[ArchAngelCD]

When using the same type of bullet with the same profile you can usually use the same load but when a drastic change is made in bullet type you will probably need to rework your load. (like said above several times)

If you're trading one FMJ bullet for another FMJ bullet from another company of the same weight you can usually use the same charge weights. Same goes for trading off JHP bullets and so on. Also like said above, don't use the same data when going from a jacketed bullet to a lead bullet.