Heavy Berger Bullets in a Factory Chamber (.308)

[Max Power]

I'm curious about giving the heavy --- 200-230gr --- Berger .308 bullets a try. But I've seen a few casual mentions that these won't work in a standard factory chamber. But I haven't seen anything that says decisively where the line is.


My rifle is a Savage Model 10, .308. It's a 1-in-10" twist, so it looks like that won't be a concern.


Is there a definite line where I can be confident that bullets lighter will work, or heavier bullets definitely won't. Or is there so much potential variation that I won't know until I either cast the chamber or buy some bullets and put them in the OAL case gauge?

 

[Dodgedriver]

According to a twist rate chart that, I think I got from Berger, a 10" twist should be good for up to 250 gr. in the .308 caliber. I'm a velocity nut so the chart is all that I have to go by.

 

[Max Power]

Maybe I should clarify.


It's not the twist rate that I'm worried about. Yes, I think 1-in-10 is good to go for the heavy bullets.


My concern is about the length of the bullets.


From what I've read, there may be an issue with there not being enough distance before the lands in a standard factory chamber to seat the bigger, and therefore longer, bullets to the appropriate length.


But I haven't seen anything definitive. And if this is an concern, I haven't seen how heavy you can go before this becomes an issue.

 

[Curmudgeon]

Heavy Bergers, This length table might help. How much freebore with your current bullet? Ogive might be a little different but should get close or just buy the small bullet packs that are available. If Savage is like Remington you shouldn't have a problem.

http://www.jbmballistics.com/ballistics/lengths/lengths.shtml#Berger

 

[Max Power]

Thank you! That was just the information I needed.


The 230gr Target Hybrid is 1.640"


I've been shooting the Hornady 178gr BTHP, which is 1.345"


With the 178gr Hornady, the distance to the lands is 2.230". I've been shooting them .005 back at 2.225".


According to this:


http://www.appliedballisticsllc.com/berger230tgt.html


the bearing surface on the 230gr Berger is 0.495". With a case being 2.005", 2.225" is well within the bearing surface. Middle of the bearing surface on the bullet is 0.495/2=0.2475. OAL with the bullet loaded in a case at the middle of the bearing surface is 2.005+.02295=2.2525.


Unless I'm way off on something, it should at least load into the rifle. I think I will pick up some small packs of different bullets and give them a try. Should be interesting.

 

[Max Power]

On further reflection, I think I should be thinking about the length at the end of the bearing surface, as that's where the bullet touches the lands, not the middle. But I think it still works.

 

[FroggyOne2]

Can you currently load a bullet that the bearing surface of the bullet stays above the neck shoulder junction?

 

[Max Power]

D'oh! I forgot to check this last night when I was at home.


What should I be looking for?

 

[jonbearman]

If I was you,I would stay with the 175 sierra matchkings as many savage owners like me have very good luck with that bullet. What kind of groups did you get with the 178 hornadys as I would like to try them? Really,what leads you to try the extra heavys in the first place just out of curiosity.

 

[Max Power]

This is probably the best group with the 178's (notwithstanding the "flyer").

That's off the bench at 100 yards. Four shots in the group + 1 to the southwest.


This is prone with a bipod and rear bag, also at 100 yards, on a reduced F-Class target.

That's probably more typical of my results.


I'm fascinated by the high ballistic coefficient of the super heavy bullets. According to the JBM calculator, at 1000 yards a change in a full-value wind from 5 to 10 mph moves the 178 Hornady (at 2700fps) 3.9 minutes; the same change moves the 230 Berger (at 2500fps) 2.7 minutes. So in the event of a blown wind call, I might manage to still save a point here or there.


But to be honest, the main reason for my curiosity is that it's a long, cold winter in northern Indiana. Best to have something to occupy my time other than sitting by the window and waiting for spring.


In the end, I wouldn't be surprised if cost and recoil drive me to stay with the 178s, or maybe move to the 185 Bergers.

 

[FFL Medic]

The 210 Bergers shoot VERY well out of my savage 10 twist .308.

 

[Leaddog]

My vote would be for the Berger 185 LRBT's in your barrel.

Dremel two slits in the neck of an empty round. Seat your bullet so that the bearing surface is about .010 above the neck shoulder junction. Measure the OAL of the round. Next.... Chamber the round and remeasure. Do this a couple of times. You'll know quickly if the bullet will work for you.