Berger 7mm 180gr vs 195gr base to ogive
- Thread starter whysman
- Start date
Thanks!
Per Phil w/ Berger the OAL of the new 7mm 195 is 1.648. The OAL for the 180 hybrid is 1.529 so on average the 195 is .119 longer than the 180.
Looking at your measurements, that seems to suggest that the 195's are going to sit 0.06 further into the case, and be roughly 0.059 longer for COAL when seated to the same position in the lands. Roughly the extra length of the 195's is split half and half between increased case intrusion and increased cartridge length.
Per Phil w/ Berger the OAL of the new 7mm 195 is 1.648. The OAL for the 180 hybrid is 1.529 so on average the 195 is .119 longer than the 180.
Looking at your measurements, that seems to suggest that the 195's are going to sit 0.06 further into the case, and be roughly 0.059 longer for COAL when seated to the same position in the lands. Roughly the extra length of the 195's is split half and half between increased case intrusion and increased cartridge length.
I also see that I need to throat my 284 shehane about 50-55K in order to get the same similar jump and distance from the donut region.
Coincidentally, that matches close to Bigg's numbers if he has a .251 FB and throating out an additional .039". I have a .235" and wanted to throat it an additional 0.050" based on my calculations and when I sat a round into my .284 Shehane.
Round on the left is the 195 where I think I am going to want the round to be in order to touch the lands. Might be a little shorter (5-10K) when I make my final decision. Round on the left is the 180 seated out to just touch the lands in my .235 FB. There is some cant to the camera so the ruler might not necessarily coincide with the actual length of the round.
Few observations:
* The bullets are very consistent in OAL and base-to-ogive (as mentioned from the berger team).
* The hollow point is much smaller and they are relatively consistent as well. I tried pointing one for the hell of it and I really do not think there will be a need to point them as I do not envision that much more of a BC increase doing it.
* I can get away with a .235 FB, but will only be able to jump it very slightly before it encroaches on the donut region.
Coincidentally, that matches close to Bigg's numbers if he has a .251 FB and throating out an additional .039". I have a .235" and wanted to throat it an additional 0.050" based on my calculations and when I sat a round into my .284 Shehane.
Round on the left is the 195 where I think I am going to want the round to be in order to touch the lands. Might be a little shorter (5-10K) when I make my final decision. Round on the left is the 180 seated out to just touch the lands in my .235 FB. There is some cant to the camera so the ruler might not necessarily coincide with the actual length of the round.
Few observations:
* The bullets are very consistent in OAL and base-to-ogive (as mentioned from the berger team).
* The hollow point is much smaller and they are relatively consistent as well. I tried pointing one for the hell of it and I really do not think there will be a need to point them as I do not envision that much more of a BC increase doing it.
* I can get away with a .235 FB, but will only be able to jump it very slightly before it encroaches on the donut region.
It seems to vary from lot to lot when comparing 180 hybrids to 195 hybrids. Another guy I know is getting .062 difference with the two lots he has. I'm getting .067 difference with the two lots I have. The neck on my 7LRM is long and the 180 hybrid has the bearing/boat tail junction .105 up the neck. This gives me .282 of bearing in the neck touching the lands. My 195 hybrids have the bearing/boat tail junction .038 up the neck, which is .067 difference. With the two bullets I compared, the 195 was .097 longer than the 180. So the COAL only increased .030 with the 195, 3.579 vs the 180 at 3.549. There is also .067 difference when measuring base to ogive. My gun was chambered a year ago with the anticipation of this bullet. I though I might of went too long with the freebore but I'm glad I did.
Darren
Darren
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