Muzzle Velocity vs. Accuracy for Hunting

B

BridgeguyMI

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I recently did a load work up for a 30-06 168g Barnes TTSX using H4350 in a Remington 700 SPS Stainless with a 1:10 24" barrel and a Bell and Carlson stock. I am trying to decide if I should choose the load with the highest muzzle velocity or the load with the best accuracy. This round will be used for more lives no range hunting. The following are my loads, fps, std dev, and group. All the 3 shot groups were 0.6 or better.
Weight FPS SD Group (5 shots)
52.0 2511 11 1.240
52.7 2544 19 1.106
53.4 2561 17 1.090
54.4 2623 12 1.271
55.0 2657 18 1.260
 
That depends on what your hunting. If it's deer sized animals, I'd go for accuracy every time. If I were hunting big game I would want penetration and accuracy both.
With deer a 30-06 has no trouble with penetration with mid range loads.

It's a loaded question. Sometimes the most accurate load is the hotter ones, sometimes it isn't. Depends on what your rifle likes.
 
As stated earlier it seems like a loaded question. A large number of shooters do not understand how velocity really works. They just know that it is faster and more energy at the muzzle.

To really incorporate velocity you have to match the bullet to get what you want. For example, if you are using a hollow point and you really want it to mushroom and deliver all it terminal velocity on the intended target than you need higher velocity. If you really want penetration than a lower velocity will deliver that with the same bullets.

Using the Barnes triple shock bullets on hogs and deer at approximately 2600 fps using a 70 gr bullet has made me realize that this bullet does not mushroom well for me but all kills have been one shot kills at less than to hundred yds. But penetration is Thru and Thru.
 
BridgeguyMI,

The spread in group size is only 1.16:1. You would need to have 16 shot groups for that to fall outside the 95% confidence range. In other words, at five shots the difference isn't large enough that random variation in group size would not account for it. You'd need to repeat the experiment three times and get the same order in group size and the same load producing the smallest group before you could really believe the difference isn't just random.

The good news is, unless you do succeed in proving one of those loads is actually any more accurate than the others, you can pick whatever velocity you want from among them and shoot it with equal confidence in shot placement.

For more on this topic, this article is a good read.
 
168Gr. ttsx that is the one with the plastic tip that helps the bullet open-up.
I haven't used any Barnes on game yet although I have read that they don't loos weight in most cases do to the solid copper design. That is very important. Weight = Kinetic energy. They are often noted for passing through most of the time. That is also a good thing for hunting. I like it for the blood trail... You might have a good load for hunting Elk if you stay with in 300 Yds. Target practice can get costly so I can see why you might use only 3 shot groups.

I have always went with accuracy. My reason is if you only have a small target do to conditions you can still make the shot. The velocity isn't going to make much difference when you are passing through.

If you can't hit the target you loose.

Unclenick has a good point if you want more accuracy but at a cost.

Decisions decisions decisions :rolleyes:
 
If I can get 3 shots under 1" that is more accuracy than you can use in hunting conditions. That is my goal, all the speed I can safely get and still keep it under MOA. I wouldn't give up 100 fps for .3" more accuracy in a hunting rifle/load. On a target rifle, yes.

Your fastest load is pretty slow for a couple of reasons. I load 58-58.5 gr of H4350 with 165/168 Noslers and Hornadys for about 2900 fps and still get under 1 MOA. I load 150 gr TTSX's in my 30-06 at 3000 fps and 130's in my 308 at 3050 fps. ( 58.5 gr of H4350 is below a max load with the bullets I'm using, not copper BTW) Copper load data is different.

Copper bullets need speed, 168's are borderline too heavy for 30-06 and are better in a 300 WM. I wouldn't go heavier than a 150 gr copper bullet in 30-06 and I'd try to get 3000 fps or as close as possible with it. Even 130's at around 3300 fps would work.

A 130 gr TTSX next to a 180 gr corelokt. Copper is lighter and tougher than lead. The 130gr copper bullet will behave much like a 180gr conventional bullet after impact giving similar penetration and expansion. A 168gr copper bullet at 30-06 speeds is too slow to reliably expand except at close range.



Copper bullets expand and work well if impact speeds are above 2200 fps. At speeds below 2000 fps they rarely expand and act like FMJ. Since even the lightest 130 gr bullets are likely to give complete penetration on most game the best results with copper is to go light and shoot them fast. Conventional lead bullets would come apart at those impact speeds, not copper.

Typical expansion with lead borrowed from noslers website.

{Need to get prior permission to borrow copyrighted images -see board policy on posting copyrighted materials.}

Typical expansion with copper

{see Nosler site.}

Here is a good article about what to expect with copper at various impact speeds.

http://www.thediyhunter.com/big-gam...hock-bullets-tsx-ttsx-243-wssm-270-wsm-rifles
 
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Excellent article Unclenick. Thanks. Looks like I will have to fire a lot more groups to draw any statistical conclusions. Back to the bench and the range :D
 
I am trying to decide if I should choose the load with the highest muzzle velocity or the load with the best accuracy.
Click to expand...

You are asking the wrong question!!!!

First you should be asking at what range 90% of your hits will be at. And second if the impact speed will fully expand the bullet upon hit.

It doesn't matter how accurate your shot is if the bullet completely goes through the animal with doing min damage and possible not being able to find the animal after it has left the spot at which you shot it.

The same problem exist for a round that does min penetration at long distance and just leaves the animal wounded and does not kill.

So determine how far (or close) you are willing to shoot and at what speed you need to have the bullet traveling at when the bullet hits. That will answer your question.

Good hunting and stay safe.
Jim
 
Forrest and trees!

BridgeguyMI wrote:

Thanks. Looks like I will have to fire a lot more groups to draw any statistical conclusions. Back to the bench and the range :D
Click to expand...

Bguy,

You may have picked up on Unclenick's hint of sarcasm. But if not I'll come out and say it straight:

Those groups you are comparing are NOT statistically different.
So you should consider them all equal accurate and precise.
Thus there's no trade-off between accuracy and velocity to even worry about.



Now back to the big picture - I believe
No one HAS to settle for a lower velocity load that is more accurate!!!
It comes down to how much load work-up and rifle experiments your willing to do.
This strategy is however, a topic for much longer discussions.



But, with the work you have already done,
Its possible you could take the highest velocity load you have worked-up and experiment with bullet seating depth
AND find a depth that is more accurate.

Just a caution if you proceed - Since your working with a load that's near maximum,
Make sure you do not get the cartridge over all length out to the point that the bullet touches the barrel rifleings.


...
 
Well, I hadn't intended sarcasm, but rather a point of irony that the perceived degree of inaccuracy actually indicated that the accuracy of any of the loads was just dandy for hunting all but varmints just the way they are.


BridgeguyMI,

I've occasionally seen accuracy sweet spot come and go in a half grain span, so the other suggestion I would make is to cut the size of your load increments down a little. Dan Newberry suggests 0.7-1.0% of charge weight. So, 0.4 grains in that cartridge with your powder charge levels would be a good step size. See Newberry's OCW method for one way of identifying a good charge weight. He only uses 3-shot groups, but compares 3 at a time, which helps with statistical errors a bit. But if his OCW ladder doesn't work at that level, go to five per charge weight and compare 15 at a time.
 
Go with accuracy.

We're lucky. We tend to always get the best accuracy at just under or at max loads. Thats contrary to what most people say, but it works for us.

If its a varmint gun, we work it up at summer temps. If its a big game hunting load, for here thats between -10* and 35*. So we generally work up loads at 20*-40* because its to cold to play at -10*.
What I'm saying is try and work your load at the approximate temps that you'll be using it in for best results.

I am also a firm believer in adjusting the seating depth to fit the gun's throat first and leaving the chrono off until I have the most accurate load for a powder. Than I'll drag it out and see if its the speed that I want.
The ES and SD mean nothing to me, though some guys think its everything. The group size is what you should be concerned with.
My neighbor worked up a supposedly good load for his 380 using nothing but a chrono. No target. Had no idea how it shot. Everyone is different I guess.

Thats just my 2 cents and it works for me.
 
Personally I would not have an issue with any of the group sizes you posted.

That said, and like others have pointed out the velocity at which your driving those heavier Barnes bullets at will limit the effective range at which they will reliably expand at due to their lower starting velocity.

When my pop and one of his brothers were still alive their "hunting " loads consisted of pulling the 147gr ball out of the top of mil surp cases, neck sizing the case and inserting a 150gr Sierra Pro Hunter. The velocity was just about where you are and I can honestly say they put all manners of game on the ground with them. However as jmr40 pointed out, that is the difference between a lead base and all copper bullet. You will get a much wider range of performance out of the lead based one than the all copper of the same weight. However also like mentioned dropping the weight to the 130gr Barnes you will gain the needed velocity and performance as well.

When I work up loads for the 30-06's I use on occasion I try to target the velocity range of around 2850fps. While it isn't the highest I CAN go it is usually favorable to the bullets I am using such as the Hornady, Speer, or Nosler cup and core types. I know the drops of this range intimately having shot it most of my life, and even at 400yds these loads will effectively put a fat hog or deer on the ground in short order. The load range is very accurate out of the rifles i use across the board with those type bullets. I start out will all of the bullets seated to fit the magazine length. When I hit this velocity range I stop adding powder, and start seating the bullets a bit deeper in .005" increments. It usually only takes a few changes in length for the groups to come together into a nice ragged cluster. To be honest I have found that it is usually only a step or two away from being right at 3.250"OAL. I can easily set the seater up to that length and have great hunting grade accuracy, but they won't be tearing the edges out from the initial hole.

I hope you find what your looking for, but to be honest I might switch to a bit lighter bullet if going to the TTX or TTSX types due to your location, or possibly switch to one of the Accubond or Partition if you want controlled expansion and don't have to deal with the lead rules.
 
16 Shot Groups

Unclenick wrote: Well, I hadn't intended sarcasm, ...
Click to expand...

Oops, sorry.

Just when you mentioned those 16 shot groups, I figured you really didn't mean for him to repeat with 16 per step.
 
Oh. No. That would be a lot of shooting, except to verify the one load you settle on after the other testing narrows them down. If you look at ammunition manufacturer's methods of determining the accuracy of different lots of ammo, and there have been a half dozen of them over the decades, they are generally done with 100 and sometimes 200 or even 300 rounds using a machine rest gun, and ignore diameter in favor of the CEP, the radial SD, the mean radius, the minimum half count diameter, etc. Most hunting rifles from the very hot magnums down to medium power have best accuracy lives of 1000 to 5000 rounds, depending on the chambering, and we are usually not interesting in throwing away a big portion of that on accuracy testing. So we are faced with attempting to draw conclusions from minimal data.

That is not a new problem in statistics. Trying to get useful data from small numbers owing to the cost of collecting bigger data sets is something statisticians have tackled for about 100 years. The T-distributions by Gosset (aka, Student) and degrees of freedom work by Fisher were all pretty much done in the first quarter of the 20th century, but are still used to try to draw inferences from small samples today.

The basic mistake most people make is in not realizing that the statistics on a chronographs or from a test targets are only estimates of what the whole population of rounds fired during their barrel's accuracy life will behave like. These estimates have variability of their own from sample to sample. The SD and the mean and other numbers you get from those tests are limited in accuracy not only by the sample size, but by the fact the gun's chamber geometry gradually changes as it wears and because shooting conditions are almost never exactly the same from one range session to the next, much less in the field or at a match or how much coffee the shooter drank that morning. So the best load is always something of a moving target.

The above is the reason loads that seem to shoot well in all guns chambered for them, like the Federal Gold Medal 308 Winchester match load using the 168 grain MatchKing, are desirable to identify. Dan Newberry's method that I linked to in my earlier post is geared toward trying to identify them. If you have such a load, then the wear and changing conditions all come to have less effect during the life of the barrel than they otherwise would.
 
Consistent accuracy is far more important than high velocity. Said accuracy doesn't mean MOA either. If you're getting a consistent 1" and a bit, you're fine.
Mind you, you're 52 plus grains appears to be over max. No H4895 data on their site for a 168 out of an '06. (None for a .300 Win Mag either.) You really need a Barnes manual if you don't have one.
 
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