.308 bullet comaparison.

[5RWill]

My 5R will be here in a week and I was looking at .30 cal bullets. When I look for bullets I look at BC. And lapuas 155gr scenar and 150gr fmj have really good bcs. I have been looking at beger vlds and there bc is low comared to lapua. I will be shooting long range and was wondering if the bergers are worth giving a try.

[RyeDaddy]

My Remington 700 XCR likes the 175 grain vld's, and the sierra matchkings in the same weight. If you like the lighter weight bullets, Sierra has a NEW version of their 155 grain Palma MatchKing, released at SHOT this year. I believe it's the highest BC in it's weight class. Not sure about part numbers for the new vs. old 155 matchking, but a search should turn it up easily. Availability would be another story.

[Thirdeye]

What's the rifling pitch in your rifle? My LR 308 is 1-10. It loves the 168SMK as well as the Speer HPBT 168. Believe it or not, it also shoots the Hornady 110g V-max bullets really well. I'm gonna start testing the heavier Hornady A-max projos either this week or next. See how she does with secant ogives.

So many projos, so little time. I was telling my shooting partner the other day that by the time you've tested all the projos, all the powder, all the primers, all the seating configurations, all the brass, etc, etc...you've shot out your bbl and its time to start the process all over again!

Guess that's the fun part though.

[5RWill]

Thanks for info on the serrias I had no idea.
My barrel has the same twist as the M24 11.25. I read a review at sniper central and the 155 grain bullets did about just as good as the others all sub moa. I was goin to get a lot of bullets. Like from 150 to 175gr. I'm hoping I can stay with 150 because my barrel is a 24in not 26. And I just realized I just put 5R on there. The rifle is a remington 700 5R going to be bedded in a mcmillan A-5

[30Cal]

A lot of the high BC bullets are... tempermental. I never got very impressive results out of the Lapua 155.

[5RWill]

The higher BC the better long range performance thought right?

[Slamfire]

For bullets of the same caliber and same weight, ignore the BC's put out by the manufacturers.

Bullet makers know folks look at the numbers and some are highly incentivized to give people what they want: high BC’s.

And I don't believe any of them. The only thing I believe is the number of clicks I put on, and what the guy next to me put on his rifle.

Sierra BC’s have always been conservative, other manufacturers seem to have optimistic BC’s.

Bad wind calls make more of a difference on target than a .05 difference in BC.

[RyeDaddy]

Higher BC will hold velocity longer, and drop less for sure, but to achieve a higher BC for a given weight usually the nose of the bullets get longer. This is certainly the case with Berger VLD's. They are very long for the weight, and have a shorter bearing surface, so they kinda have a tendency to be less forgiving as to overall cartridge length. The Bergers can be sensitive to jump length, in my rifle they shoot best when loaded to 2.94" or so, which of course won't fit in the mag, so I have to single load them. Rather than deal with that I go with the MatchKings. Loaded to magazine length the MK's and VLD's perform about the same, but the Sierra's cost less so it makes the decision easier. VLD's are spectacular when you get them right, but they're more work to get there. The 175 grain MatchKings are a piece of cake.

[Unclenick]

For a given weight, the longer the bullet, the more spin it takes to stabilize. There are some good rules of thumb that suggest getting a twist that imparts a gyroscopic stability factor of 1.4 to 1.5 is about the best compromise. Closer to 1 (below which the bullet gets unstable) and the bullet takes too long to recover from nutation post muzzle and takes too long to "go to sleep" which increases average drag over a long distance. Higher than that range and you are spinning more than you need to, tending to exaggerate wobble due to any small asymmetries in the bullet construction and also those due to bullet tilt in the barrel if you didn't achieve zero runout in the cartridge. For those interested, I have an Excel file available for download from my file repository that has proven to be quite successful at all but the transonic velocities (around 1050-1400 fps at sea level). Feel free to grab a copy. There is a more complex one at the online JBM Eskimo Ballistics site that does attempt to cover the transonic range, but I have found the Don Miller approximations in my Excel file to cover more bullets, including those with wider meplats, and to be equally effective in picking a barrel. Especially if you aim at a particular stability factor. Try both and see what you get. Mine lets you enter an existing twist rate, like for your new 5R barrel, then try different bullets to see what lands where you want it? Harold Vaughn likes a stability of 1.4 at launch and Don Miller likes 1.5. Six of one, half dozen of the other, IMHO. Those are close enough to be called an agreement.

Obviously bullet jacket asymmetries vary with the quality of the bullet construction and we have some awfully good ones out there that can spin a lot faster than they need to and still land where they should if they are seated concentrically, as by a sleeved competition type seating die. Berger is known for their VLD designs, but the concentricity is more critical with them. A lot of benchrest shooters think Berger's more conventional bullet shapes have the best consistency among the better known bullet makers. They certainly shoot very, very well and should be given consideration in addition to the VLDs. One fellow I spoke with who owns one of those expensive ultrasonic bullet void detectors says he rejects fewer Bergers than any other brand. I don't know how scientific his sample is, though?

Sierras are the old standby, and that new 155 grain bullet is undoubtedly designed to compete with the Lapua's BC numbers. The reason they are 155 grains is that is the maximum weight bullet the Palma match rules allow, so these bullets are intended to be fired from those 30" long Palma match barrels, that give them a lot of velocity (for a .308) and that usually have a 13" twist when I ask Palma gun owners what they like. All other barrels using these bullets fall into the YMMV category.

I have taken to using the 175 grain SMK in most of my .308 and '06 match barrels when the match gives me a choice. I still have a lot of the 168's from a bulk purchase, but got discouraged when I found they would go unstable as they got into the transonic range and tumble. This happens at about 700 yards from a 24" tube with 10" twist. Sierra's Kevin Thomas told me the late 1950's design was originally intended for 300 meter international matches, and that it works well to 600 yards turned out to be a bonus. The result is that at anything over 700 yards, its POI is anyone's guess. The newer 175 grain design does not have any such issue, and it flies great to 1200 yards and beyond.

Also among the JBM calculators are a couple that let you determine a bullet's BC for yourself either from two velocities taken at a known distance apart or from a bullet transit time over a known distance.

[30Cal]

The higher BC the better long range performance thought right?

Depends on the velocity.

[Unclenick]

That's an excellent point to keep in mind. The superior performance of the higher BC bullet is only certain if it is launched at the same initial velocity and with the same stability factor as the lower BC bullet. Launched at a lower velocity it depends how much better that BC is and on whether it falls into the high drag transonic region of velocities before it arrives at the target? If it does and the bullet it is compared to does not, the advantage can be reversed. Again, it depends how much higher the better BC number is.