Does changing bullet = changing recipe??

[sigma2chi]

I am currently shooting 168gr SMK and have worked up a good recipe, charge/seating depth/etc.,... I am going to start shooting some Berger 175 gr OTM for longer distances and was wondering if I had to start from scratch with the load data. I assume my powder charge might need to be experimented with a little bit but do I need to experiment with seating depths all over again too??

any insight will be MUCH appreciated.

 

[ksthomas]

Changing ANYTHING means you've changed the load. Sometimes pressures will increase, sometimes they'll decrease. Very rarely, they may stay the same. But always, always, ALWAYS understand that you've changed the load.

Your assumption that some experimentation is in order here is spot on, and should be followed. You're on the right track here.

 

[Aflac]

I did recently learn that between using quick load and reading this paper Optimal Barrel Time Paper you can cut down the amount of experimentation required significantly. I prefer using experimentation to prove and refine prediction rather than just wild shots in the dark experimentation.

 

[Pinecone]

Going from a 168 to 175 bullet is a HUGE change.

If you were going from 168 SMK to 168 Amax you might be close, but not with a change in bullet weight.

 

[rduckwor]

Any significant change, powder, brass, bullet = a brand new day.

Good luck,

 

[JB02]

The only instances I have not had to fiddle is when going between AMAX and BTHP Match or 168 Amax/BTHP to 168 SMK. I got lucky too between 175 SMKs and 178 AMAX/BTHP ... that was discovered during a new load workup however.

Experimenting is half the fun, right???

 

[BuzzBoss915]

Switching the bullet is a major change, even if they might be the same weight, the ogive shape is different and flight characteristics will be completely different. You have changed your load even if all you did was go with different brass. Assume nothing and you won't be disappointed. You realize, using a different lot number of the same powder is still changing the load. Chances are, it won't be a huge difference, but you cannot assume it will be exactly the same performance. BB

 

[armorpl8chikn]

I use a level case full of H4831 for every bullet in my 30-06 from 110gr to 190gr. All of them shoot 1/4MOA groups all day long.<<<<<this is="" a="" joke
that was a joke!

168 - 175 is a huge change. Being an old salt in the reloading world, I may not start at the absolute bottom when I switch similar weight bullets. At the same time I am paying very close attention to bullet shape, bearing surface, even bullet makup. If you switch from a 168SMK to a 168gr Barnes TSX and don't change your load you could be in pretty deep poo pretty quick. Those bullets are long for caliber and homogenous. If I was switching from 168SMK to a Nosler 168CC I would have a lot less to worry about and would adjust my new ladder accordingly, ie I wouldn't have to make as many steps in my ladder. After 31 years I know what I can get away with and what I cannot, and where my best loads will likely reside.
When you aren't sure about a thing always err on the side of caution. The one thing I have never had to fiddle with much in my shooting career is seating depth. I usually seat them .015-.025 off the lands and leave them there until I have to chase the throat. I recheck the throat about every 500rounds. If your magazine dictates seating depth then find the bullet that likes a jump, SMK's and Scenars are always a good choice in that scenario.</this>