7mm prc

[StumpyJohnson]

For us copper only states, the chamber dimensions and twist rate will lend themselves longer copper bullets imo.

 

[scdogman]

9 is not the standard twist in many factory 7mm rem mag. My savage is 9.5 and some Remington are 9.25.

I will never own another 7mm that is not a 8 or faster.

Corrected

 

[Fiftydriver]

Berger's stability calculator says their 180 grain hunting bullet at 2975fps (Hornady's 180 load velocity) has only marginal stability at 1:9 twist @32 degrees @ sea level. Going to 1-8, bumps the same well into "comfortable stability" range.

Not sure that anybody should decide for everybody else that they don't need that much bullet or more.

not sure anyone is telling anyone else what to shoot, just offering real world experience from testing the 7mm as much as most anyone else alive…... There comes a point where the drop in velocity potential starts to reduce the ballistic performance of a cartridge and a slightly lighter bullet, with still very good BC and higher velocity will outperform a heavier bullet. It all depends on the cartridge being used of course. But out to 1000 yards, comparing a 180 gr berger to a 195 gr berger in a round of this size, the 180 will match the 195 in most criteria. Stepping up to a larger case will give the big 195 an advantage, going even smaller and a 168 class bullet may be the best balance of velocity and speed for long range performance. Most commecial ballistic and stability calculators will be overly conservative to MAKE SURE everything works and they dont get flooded with hate mail!! Not sure if you have ever looked through the berger loading manual but they are EXTREMELY conservative. Not a bad thing for most loaders for sure.

 

[Fiftydriver]

I was stating hornady got in right making 8 the standard.

My post was stated wrong. I will never own a 7mm that is not a 8 twist or faster.

Sorry for the confusion. My 28 is a 8 twist. I was trying to find a 7.5 for my 7mm prc build.

For the class of 7mm your using, you can get away with those faster twists. These days however, and for many years now, those are mid sized 7mm rounds. You put a 7.5 twist on a PRC and it will shoot fine because its velocity potential will result in rpm levels that most bullets can survive. Put a 7.5 twist on something like my 7mm Allen Mag and you better be shooting solids or you will effectively have a useful range of 20 yards and a shotgun pattern left from the bullet frags, its all relative, lots of variables come into play when recommending proper twist rates for a certain application.

 

[Raingull]

not sure anyone is telling anyone else what to shoot, just offering real world experience from testing the 7mm as much as most anyone else alive…... There comes a point where the drop in velocity potential starts to reduce the ballistic performance of a cartridge and a slightly lighter bullet, with still very good BC and higher velocity will outperform a heavier bullet. It all depends on the cartridge being used of course. But out to 1000 yards, comparing a 180 gr berger to a 195 gr berger in a round of this size, the 180 will match the 195 in most criteria. Stepping up to a larger case will give the big 195 an advantage, going even smaller and a 168 class bullet may be the best balance of velocity and speed for long range performance. Most commecial ballistic and stability calculators will be overly conservative to MAKE SURE everything works and they dont get flooded with hate mail!! Not sure if you have ever looked through the berger loading manual but they are EXTREMELY conservative. Not a bad thing for most loaders for sure.

Thanks for the unnecessary education.

There are many reasons to shoot heavier bullets by the by. Some of us live at sea level in cold climates where stability takes a bit more.

Thank goodness we never hear about or see stability issues, on account of how conservative bullet makers are!

 

[Raingull]

The 7PRC is a great cartridge that Hornady got right.

That belief is not rare nor ignorant.

If somebody wants to assert they know better than Hornady, Berger, Sierra (who recommends at least a 1:8 twist for their 180gr+ bullets as well), etc... They can go right ahead. I'm sure Hornady would just love their input.