Turnbolt53
Well-Known Member
Default is 10mph. Go nuts
Yeah, I would have zeroed that out too, considering we're only talking 1000 yards
Default is 10mph. Go nuts
Well, curiosity got the best of me, so I had to run the numbers at JBM Calculations. Charts are below:
.270 WSM (150gr ABLR @ 3,187fps using 68gr MagPro powder w/G1 BC=0.591)
View attachment 133313
7mm Rem Mag (175gr ABLR @ 2,970fps using 62.5gr RL22 w/G1 BC=0.648)
View attachment 133310
At 1,000 yards, the 'drop' in inches is identical @ 255.9 inches (with a 100 yard 'zero')!
At 1,000 yards, the .270 WSM is still faster at 1,770 FPS vs. the 7mm RM running at 1,699FPS (but the .270's 217 FPS 'head start' is down to only 71 FPS.)
Both are still around 1,100 Ft/Lbs of energy at 1000 yards.
This was surprisingly close. I thought for sure the .284 bullet - with the higher BC - would overtake the .270 by 1000 yards, but not so.
As stated before, the case capacities are identical, so at the same pressure and the same barrel length, the velocities will always slightly favor the 7RM due to the slightly larger bore size.
In fact, the the 7RM will start the high bc 284/160-ish bullets at the same speed as the lower bc 277/150,
Why would you use RL22 for the 7RM? That's a fast powder. You'll hit pressure before reaching velocity potential. Try it with something like 7828, 7977, or H1000.Deep.
And if you go to this website:
https://www.jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi
And plug in these numbers:
.270 WSM (150gr ABLR @ 3,187fps using 68gr MagPro powder w/G1 BC=0.591)
7mm RM (175gr ABLR @ 2970fps using 62.5gr RL22 w/G1 BC =0.648)
You, TOO, could calculate for the wind drift you so desperately seek. Default is 10mph. Go nuts
I got the G1 BCs directly from Nosler's website as of yesterday and plugged those in. I did not use the 'default' values in JBM.There are a few bullets that JBM hasn't updated the BC. Best to verify by Noslers current BC not what was published at their release.
The 'idea' from the OP was to compare the 'max' velocity of the .270 WSM with the 150gr ABLR to the 'max' velocity of the 7mm RM with the 175gr ABLR. I went to the Nosler reloading data, picked the highest velocity (max load) posted for each and posted those numbers (velocity achieved, powder used, and grains used.) I did not "pick" RL22 - Nosler did. It posted the fastest velocity in the powders they tested with that bullet, at a safe pressure.Why would you use RL22 for the 7RM? That's a fast powder. You'll hit pressure before reaching velocity potential. Try it with something like 7828, 7977, or H1000.