Experience with 125-grain Nosler BT in .308 for deer?

[CarJunkieLS1]

Real question about sectional density because I’m not that well versed.

Assuming 100% weight retention of both bullets (the 120 7mm & 125 308), other than penetration what effect does the SD have on the killing power?
Given these modern bullets that retain their weight if you're not shooting long range what's the advantage to a higher sectional density? I don't think either would be lacking any penetration at hunting distances.

I'm no expert but if both bullets being compared will both fully expand and give an exit wound then sectional density is of little importance IMO. It however would matter if larger game like moose and bear were in consideration also in a combat situation where barrier penetration may be an advantage.

 

[Newtosavage]

The reason the 7mm 120 was brought up and I think it's relevant is because them and the .308 125 are both "tough" bullets that perform and penetrate above their weight class.

I have zero experience with the .308 125's but a friend of mine uses them in his daughters .308 and she hasn't had any deer lost and always gets exits. He loads them to 2700fps.

OP if their is any doubt about them switch to the Accubond and not worry. I just wish Nosler would make the 7mm 120 Accubond but instead it's 140 and heavier only.

I loaded up some 125 AB's last night along with my 125 BT's. Going to the range this weekend. I also loaded some 125 BT's for my Tikka '06 over RL-7 and Varget, just to see what I'd get. Should be interesting to compare group sizes between my '06 and .308

I've never tried RL-7 in my '06 but if it works well, that sure would be handy since I load it in my 7.62x39 and .308 already.

 

[LoonWulf]

RL-7 SEEMs fast to me, but playing with quickloads, it actually seems to look pretty good for the really light bullets.

 

[horsey300]

Real question about sectional density because I’m not that well versed.

Assuming 100% weight retention of both bullets (the 120 7mm & 125 308), other than penetration what effect does the SD have on the killing power?

Given these modern bullets that retain their weight if you're not shooting long range what's the advantage to a higher sectional density? I don't think either would be lacking any penetration at hunting distances.

The assumption of 100% weight retention is too unrealistic. S.d. is partly about penetration, and partly used to figure out how much retention to expect on impact, if both bullets are impacting at 2900 fps, and both bullets are of similar construction, the lower s.d. is not just less likely to penetrate, it is less likely to get full penetration after impacting solid bones, more likely to shatter/separate, and lose more mass faster. The exceptions are of course the monometals and bonded bullets like the much praised accubond. Velocity and s.d. combined decide the true effectiveness of the impact and wounds inflicted. Low s.d. and higher velocity make for shallow wounds generally speaking, thus varmint class bullets. In the X39 and BO cartridges a 125 will have more penetration and uniform mushrooming than a full house .308 or .30-06 or win mag round. If mv is kept lower, (as in the reduced loads given earlier for the young lady's 2700 fps deer load) then we reduce the risk of too shallow of a wound, but at higher velocities the bullet is much less effective. The 120 gr 7mm is a classic much in the same way that the 308 150gr loads are a classic. The 6.5 120 (while giving up frontal diameter and mass ever so slightly) gains more length and thus s.d., even though it is the same weight of the 7mm big brother, and thus will withstand even higher velocity impacts and still deliver a more reliable wound tract deeper.
If we're playing with bonded bullets or monometals, we can afford to give up more s.d. and still expect to get reliable wounding as the construction itself differs greatly from the traditional cup and cores or polymer tipped hollow points (btips ssts etc). For example the lower s.d. 125 accubond will outpenetrate the 125 btip exponentially while being driven at higher velocities with little risk of jacket separation on impact and still provide more reliable downrange wounding than the monometals.
I believe @Newtosavage is on the right track with the X39 firing btips at it's inherently lower velocities and the accubonds in the faster class cartridges, reducing the chances of too shallow of wounding without needing to sacrifice velocity and range. I look forward to results from the field on these if he's willing to share to add to my compilation.

 

[Newtosavage]

I hope I get to!

 

[larueminati]

The assumption of 100% weight retention is too unrealistic.

I was just using that as a hypothetical.

 

[Lloyd Smale]

I shoot the 130 grain speer hp out of my Kimber montana 308 because its about the only bullet ive found that is accurate in it. Most loads go 2 inch or more for 5 shots at a 100 yards and that 130 does 3/4s of an inch. Ive shot proabably a dozen deer doing crop damage killing between 100 and 350 yards with that gun and load and it decks deer and does no more damage with a PROPERLY placed shot then a 150 does. If you don't want to do meat damage don't shoot them in the meat! I have no doubt the 125 bt would give about the same results.

 

[d2wing]

Bullet selection is important, but even big deer are no more than 15 inches thick at the widest. As long as you reach the heart or Lungs the deer will die. Quartering shots are tougher. I always use soft points. Anything from.223 55 gr to 180 gr 30-06 works well if you can shoot providing the bullet expands without fragmenting. Therein lies the rub. Proper shot placement.

 

[Charliefrank]

I've never tried the 125's on deer. I use the 150's for them. They work beautifully. The 125 ballistic tips are devistating on coyotes though. Pelt damage is severe.