Is there a mathematical relationship that one can use to translate a given load to a different weight projectile?

[want2learn]

I secured a good group using 36.8 gn of Varget and the 136 gn Scenar projectile for my 6.5x47 bolt action rifle......and as is my fortune i ran out of 136 gn projectiles....

I do however have an unopened box of 123gn Scenar.

I was wondering, is there a mathematical relationship that one can use to translate the load to a different weight projectile...for example is it wise to use the same weight of Varget as worked well with the 136gn projectile or should i add a set fraction more of Varget?

I could envision that there might be a formula that relates powder weight or pressure or velocity with the weight of a projectile that might translate assuming a similar BC?

thanks

 

[mdmp5]

In a perfect system maybe. Too many variables to try to science that out. Just gotta perform the grunt work unfortunately.

 

[Supersubes]

I secured a good group using 36.8 gn of Varget and the 136 gn Scenar projectile for my 6.5x47 bolt action rifle......and as is my fortune i ran out of 136 gn projectiles....

I do however have an unopened box of 123gn Scenar.

I was wondering, is there a mathematical relationship that one can use to translate the load to a different weight projectile...for example is it wise to use the same weight of Varget as worked well with the 136gn projectile or should i add a set fraction more of Varget?

I could envision that there might be a formula that relates powder weight or pressure or velocity with the weight of a projectile that might translate assuming a similar BC?

thanks

The problem is that it’s more complicated than just bullet weight. Bearing surface lengths, bullet diameter, the presence of a pressure ring, etc.

The 123, and it’s big brother the 139, are some of the most tolerant bullets around. Jump it .020, use your 36.8 charge, and i’ll bet it shoots every bit as good as the 136 did. Do a small charge progression to see where it tops out at if you like.

 

[padom]

Short answer, no.

Ive shot many thousands of 123L and 139L Scenars in 20+ 6.5x47L barrels. All 26" in Lapua brass. Unfortunately I havent shot any of the 123L over Varget, just H4350. But I have shot 130 AR Hybrids and 139L over Varget so here are some OCW targets to get you close.



130 AR Hybrid Varget OCW




130 AR Hybrid Varget Seating Depth Test





Here's the 123 Lapua over H4350 in Lapua brass



123L H4350 OCW

 

[want2learn]

thank you. very grateful for the help and information