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Posted: 8/23/2006 2:00:55 PM EDT
I have been using 150gr ballistic tip .308 ammo in my Savage 10FP and my AR10T. It shoots great and is very accurate. Same in my 110FP, 150gr ballistic tip .30-06. I just recieved some heavier ammo that I had ordered, 168gr boattail hollow point in .308 and some 180gr ballistic tip in .30-06. Let's say that they are as accurate at 100 yards as the picture above. I don't know yet as I have yet to shoot them. What are the advantages/disadvantages of the heavier ammo? Does the heavier weight give you a little more range or more accuracy at the same range as opposed to the lighter bullets? More silly questions. Why is the ballistic tip more accurate than FMJ and what makes a boat tail HP accurate? I would think the open tip would either slow it down or affect accuracy. |
They should have a lower BC, which means they will retain their velocity longer as they go downrange. I stress 'should' as you inidicated they are ballistic tiped. If not, well at least their penetration should be improved 
The jacket is a more consistant thickness/mass. The FMJ is mass produced, variations in jacket thickness can effect mass (which changes point of impact) and stability (think of an out of balance tire). Consistancy is the key to accuracy.
1) They are produced more carefully with higher QC producing a more consistant bullet (see my comment on consistancy) 2) The HP is a product of the process of manufacting the jacket to a uniform thickness (see the consistancy quote). 3) the BT on the round reduces the BC by allowing a smooth airflow over the rear of the projectile; reducing the BC helps in maintaining the velocity over distance (see my comment earlier in the post). |
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Much of a bullet's accuracy comes from the BASE of the bullet, not the tip as is commonly believed. FMJ bullets don't have very uniform bullet bases, as the base is open. HP bullets (of which ballistic tips are a sub-class) are constructed with the closed part of the jacket at the base instead of at the tip. This allows the bullet base to be very uniform, and makes for much more accurate bullets. As Forest mentioned, the uniformity of the jacket's thickness also plays an important part in the accuracy equation. Premium bullets are generally made to higher tolerances in such areas as jacket uniformity, though this raises the production cost of the bullet. FMJ bullets are seen as low-cost, high-volume bullets where uniformity (and accuracy) is less important. -Troy |
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30-06 Nosler Ballistic Tips in 180-gr. have a high Ballistic Coefficient of .507 and they slice through the air much easier than standard grade bullets. Heavier weighted bullets will maintane their velocity (better than light weight projectiles) over longer distances. A more aerodynamic bullet means increased downrange energy. As a real-world example, Nosler's 180-gr. AccuBond - which is basically a bonded version of the Ballistic Tip, also has a high BC of .509 and here's a little data that is amazing: When comparing a bullet's energy in a 30-06 versus a 300 Win Mag, if you put a premium 180-gr. Nosler AccuBond bullet in a 30-06 at 2,750 fps MV and compare it to a plain jane Winchester 180-gr. Power Point in a 300 Win Mag at 2,960 fps MV, the 30-06 AccuBond will have an amazing 104 ft. lbs more energy at 300 yards: that's right - 2,005 versus 1,901 (Source: Winchester's 2005 Ammo Catalog, p. 10 - 13). So you see the 180-gr. AccuBond with a BC of .509 easily makes up for and passes the 210 fps velocity advantage the 180-gr. Power Point had because of its much lower BC of only .349. In this case, the 30-06 180-gr. AccuBond outperforms a 300 Win Mag 180-gr. Power Point at 300 yards. |
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FYI: Nosler says that beginning with the 30 caliber 180-gr. Ballistic Tips (and larger), the jacket's profile is changed or upgraded to a much stronger contour similar to the AccuBond (shown below). The lead core is also hardened over the 165-gr. and below bullets in smaller calibers - to include the 150-gr. you're considering.  Lighter weight bullets like 165-gr. 30 caliber and lower (shown below) do not have the thicker contour which starts in the middle of the shell and goes down to the base.  In summary, one might infer that the 180-gr. Ballistic Tip is simply a non-bonded version of the AccuBond.  |
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Thanks for the replies. Another question. I know that most standard military rounds in both 7.62 NATO and .30-06 are right about 147-150gr, so it sounds like the surplus and 150gr FMJ from say, Georgia Arms, are most suited to a Garand, an 03A3, or an AR10A2 service rifle. Are rifles such as the Savage 10FP, 110FP, and AR10T happier, so to speak, with the heavier bullets? |
| Target rifles will generally shoot everything fairly well. 168-gr. in .308 diameter bullets is considered to be the optimum weight in that caliber. Suggest you select a couple of bullets that suits your needs and then fine-tune things down to one load your rifle also likes . |
My Savage 10FP seems to love 175gr and 168gr bullets. You notice the difference in trajectory once you start flinging them 500+ yards. Did you measure that group? How big was it? |
Actually, I have never measured it. I should. I still have that target. That was a 5 shot group. ETA: I measured it. 1/2 inch from center to center on the holes farthest apart. |
I am not considering the 150gr ballistic tip, that's what I have been using. I just got the heavier stuff today and have yet to shoot it. The group shown above was with 150gr ballistic tips from Georgia Arms. |
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