Cartridge OAL with different powders

[NYDAN]

I think I read somewhere in one of these posts that when you wish to try a different powder with for a particular cartridge and bullet that a good starting point is whatever OAL gave you the best results with the previous powder.

Is it a general rule that once you find the amount of bullet jump for a specific bullet in your rifle, all powders will like that same amount of jump? Or, when you change powders are all bets off and you start all over again with OAL adjustments?

If I have found a good OAL length with IMR 7828 and the 140 AB, then I should try the same OAL with IMR 4831? Should I would expect that some small amount of fine tuning of the OAL would be required with the new powder?

 

[DrMike]

It is a truism that an OAL with a particular bullet will likely be conserved across various load data. If nothing else, it gives you a starting point that you will know each time. However, the general principle still holds that an accurate cartridge will likely maintain the same OAL.

 

[wildgene]

...similar bullets seem to give similar results, but you need to consider the variables. There's a lot of difference between, say, a 165gr. AB & a 165gr. ProHunter, including length, bearing surface, ogive, profile, whether you measure total length or to ogive to set the same jump, etc.,etc.

 

[Ridgerunner665]

With any bullet...I always start at maximum SAAMI length for the round...I often end up staying there too.

 

[hubcap]

Well, I know I do swap from 7828 to IMR-4831 with the 150 LRAB and the 140 AB. I do not make any overall length adjustments . Accuracy remains real good with either powder. I would probably switch to IMR-4831 with no other changes. Just load a few and see what happens.

 

[NYDAN]

Well, I know I do swap from 7828 to IMR-4831 with the 150 LRAB and the 140 AB. I do not make any overall length adjustments . Accuracy remains real good with either powder.

Hubcap, does your Point of Impact change much when you switch between IMR-7828 and IMR-4831?

 

[JD338]

Dan,

If I have a COL that works and I switch powder, I will use the same OAL. You may find that tweaking the COL with a powder change may help fine tune your load.

JD338

 

[hubcap]

Well, I know I do swap from 7828 to IMR-4831 with the 150 LRAB and the 140 AB. I do not make any overall length adjustments . Accuracy remains real good with either powder.

Hubcap, does your Point of Impact change much when you switch between IMR-7828 and IMR-4831?

Yes it will change a little bit. Probably due to changes in velocity more than anything else. A click or two on the scope is usually necessary.