I’m putting this out there because it’s dumber not to ask than ask a dumb question.
When looking at a powder manufacturer’s published Min/Max loads for the same powder, calibre and weight but different designs of bullets, presumably tested in the same barrel, what parameters produce the considerable variances in recommended Min/Max powder weights?
I use Vihtavuori because it is reliably available in the UK. Not necessarily so for US powders.
If I knew what bullet design factors produce these wide variances in Min/Max loads for same weight but different designs of bullets, it would be some guidance and I might be better placed to answer my own questions.
If only that was answered re this mammoth post, that would help!
Vihtavuori used 27.5" 1:10 barrel, Large Rifle Magnum primers, Lapua cases trimmed to 2.714
My Blaser factory match fluted barrel is 27" 1:10 and I’m using Lapua and Peterson cases with Fed GM215M primers.
Cases run through Widden click adjustable sizer bushing dies & micrometer seater. Dies made to my fire formed brass.
So, for hand-fed, bumped 0.002" and seated 0.020" off the lands, where do I start with my two 300gr of choice?
300gr Hornady A-Tip BC1 0.863 OAL 1.865
300gr Parker Productions Alu-Tip BC1 0.960 OAL 1.930 (New owners of Rocky Mountain Bullets)
My plan is to use Dan Newberry’s method and assume 92.40gr as the max, back off 7% to 85.93 gr as a cold shot and then 1% increments to first signs of pressure.
Seems a reasonable plan?
But what about my:
265gr Cutting Edge LZR BC1 0.800 OAL 1.813
265gr Cutting Edge MTH BC1 0.780 OAL 1.913
For lower weigh bullets, Vihtavuori recommends N565 or N560 but the only figures available are:
My plan is to start at 77.38gr (83.2 gr -7%) and then 1% increments.
Then for N560
Even less information, so my plan is to start at 75 gr, because you have to start somewhere!
When looking at a powder manufacturer’s published Min/Max loads for the same powder, calibre and weight but different designs of bullets, presumably tested in the same barrel, what parameters produce the considerable variances in recommended Min/Max powder weights?
I use Vihtavuori because it is reliably available in the UK. Not necessarily so for US powders.
If I knew what bullet design factors produce these wide variances in Min/Max loads for same weight but different designs of bullets, it would be some guidance and I might be better placed to answer my own questions.
If only that was answered re this mammoth post, that would help!
Vihtavuori used 27.5" 1:10 barrel, Large Rifle Magnum primers, Lapua cases trimmed to 2.714
My Blaser factory match fluted barrel is 27" 1:10 and I’m using Lapua and Peterson cases with Fed GM215M primers.
Cases run through Widden click adjustable sizer bushing dies & micrometer seater. Dies made to my fire formed brass.
So, for hand-fed, bumped 0.002" and seated 0.020" off the lands, where do I start with my two 300gr of choice?
300gr Hornady A-Tip BC1 0.863 OAL 1.865
300gr Parker Productions Alu-Tip BC1 0.960 OAL 1.930 (New owners of Rocky Mountain Bullets)
My plan is to use Dan Newberry’s method and assume 92.40gr as the max, back off 7% to 85.93 gr as a cold shot and then 1% increments to first signs of pressure.
Seems a reasonable plan?
But what about my:
265gr Cutting Edge LZR BC1 0.800 OAL 1.813
265gr Cutting Edge MTH BC1 0.780 OAL 1.913
For lower weigh bullets, Vihtavuori recommends N565 or N560 but the only figures available are:
My plan is to start at 77.38gr (83.2 gr -7%) and then 1% increments.
Then for N560
Even less information, so my plan is to start at 75 gr, because you have to start somewhere!
Last edited: