6.5CM vs 6.5PRC???

[lhp63190]

Bergara Ridgeback 6.5 CM w hornady 143 eldx factory ammo shoots sub half MOA or better in my gun. Granted, it's heavy for a hunting gun. Not sure how their lighter hunting weight models perform but I'd assume pretty good.

I chose the CM in this gun bc I use it as my practice/volume gun so I don't wear out barrels in my hunting guns. Also, I don't like to 8 twist Bergara offers in the PRC. If it would have been a 7.5 twist, it would have been a much tougher decision.

 

[TriggerTime426]

I have both a 6.5 cm and PRC the felt recoil between the 2 is minimal. I handload for both and the prc gets 300 fps more than the cm pretty easily they r both very accurate rounds. As for the choice between the 2, if I were u and were really torn I'd buy a savage 110 111 long action since prc loads a touch longer than SA buy a 6.5 cm new or used take off barrel and order a prefit prc barrel and have the ability to shoot both calibers with the easy swap of a barrel just need head space gauges or a factory round in each caliber. Should be able to have 2 calibers for the cost of a bergara....food for thought

 

[zog]

have the ability to shoot both calibers with the easy swap of a barrel just need head space gauges or a factory round in each caliber.

Aren't the bolt face diameters different between cm and prc? How does a swap work for bolt faces?

 

[zog]

Also, I don't like to 8 twist Bergara offers in the PRC. If it would have been a 7.5 twist, it would have been a much tougher decision.

I'm not too knowledgable about twist rates . . . How would a 0.5 difference be a deciding factor?

 

[lhp63190]

Lots of factors at play here, but the biggest one is the stability in shooting large/heavy for caliber bullets. Berger has a twist rate calculator that tells you when your bullets are stabilized.

Twist Rate Stability Calculator

Our newly updated Twist Rate Stability Calculator not only tells you what your SG is, but it also lets you know if you are reaching your optimized BC.

bergerbullets.com

So in my case, looking at the 6.5 PRC shooting the new Berger 156 EOL at 200 ft above sea level, at a temp of 50 degrees, I would have marginal bullet stability with an 8 twist. My bullet would be fully stable in the exact same conditions w/ a 7.5 twist. My assumption is that you'll start seeing more bullet offerings for 6.5 in the 150+ grain designed for PRC.

Zog -- it looks like you are in Montana, and my guess is that your elevation would mitigate these issues and you'd probably be fine with an 8 twist in a PRC shooting large bullets, but i'm in Texas barely above sea level so it does cause problems for me.

For the record, I learned this lesson the hard way. Back when Broz was doing all the great work on the 300 WM and 215 bergers, I built a 300 WM with a 10 twist and couldn't shoot the 215's out of my gun accurately bc i needed a 9 twist barrel. It was an expensive lesson so I'm much more diligent about twist rates and the bullets i want to shoot.

 

[TriggerTime426]

You are right zog, the prc has a mag face, but that is easily remedied with a 20-30$ bolt face from gun shack, just a option u could utilize rather than buying 2 complete different platforms

 

[TriggerTime426]

I had that same issue with my 300wm...had a 1-11 twist and I wanted to shoot a 200 class bullet nd it didn't shoot to bad but opened up after 3-400 yds, it really only likes 180-185 class

 

[TriggerTime426]

Twist rate should definitely not be overlooked

 

[vortech347]

My savage 10t has an accurate mag. I can load to the lands and fit he mag. View attachment 186437

What are the specs of your rifle? Is it a custom barrel with a different free bore? How long can you load and still fit the mag? And what bullet?

For example, my X bolt can feed from the mag up to 2.98 give or take a few thousandths. With the Berger 144 LRHT I would still be jumping nearly .1 to the lands. But with a 147 ELDM I can get within .02 and still fit in the mag and can just about touch the lands with a 140 eldm.

Some bullets are just too long to fit to mag length with the PRC and the SAAMI freebore of .188 in a short action.

 

[DHBWA]

SHORT RESPONSE:
If you envision spending more time target shooting, choose the 6.5 CM due to lower recoil and available factory ammunition. If you are more interested in hunting, choose the 6.5 PRC

This^^

 

[whirlwindjml]

What are the specs of your rifle? Is it a custom barrel with a different free bore? How long can you load and still fit the mag? And what bullet?

For example, my X bolt can feed from the mag up to 2.98 give or take a few thousandths. With the Berger 144 LRHT I would still be jumping nearly .1 to the lands. But with a 147 ELDM I can get within .02 and still fit in the mag and can just about touch the lands with a 140 eldm.

Some bullets are just too long to fit to mag length with the PRC and the SAAMI freebore of .188 in a short action.

Good job... $@#%.....you caught me in my classic dyslexic dork mode. I reviwed my notes and re checked what i was calculating. Im a long way off the lands. I think i put the ogive measurments in the calc. Currenty .119 off the landssorry to anyone that was effected by that....suprised its shooting so good 1 mile of the lands

 

[vortech347]

Good job... $@#%.....you caught me in my classic dyslexic dork mode. I reviwed my notes and re checked what i was calculating. Im a long way off the lands. I think i put the ogive measurments in the calc. Currenty .119 off the landssorry to anyone that was effected by that....suprised its shooting so good 1 mile of the lands

As long as it shoots good that's all that matters. I had a test load with 147 eldm this last week in my PRC that shot better at .0485 off the lands than .0385. Same powder charge.

The longer jump means less pressure, too.

 

[whirlwindjml]

yes your right. I edit my post to say ICant hit the lands. Im glad you caught that. I was going to unskrew the tube and sell it as new if they used that reemer and buy a new tube. Guess ill live with it now! Jeez i dont even drink anymore and my heads still up the rear sometimes.

 

[Trm82]

6.5 prc for the win