Bullet weight selection

[RockyMtnMT]

300 wm out to 500y bc is almost inconsequential. Trajectory, impact vel, and bullet performance should rule the day.

 

[J E Custom]

From my understanding, and please correct this if incorrect, is that a higher twist rate better stabilizes the bullet's flight, and that bullets need increased stability as their length increases.

I'm not too hung up on BC. I have a thread in the LRH+S section seeking clarification on that. Still plenty to learn there for me... Mainly for drag models though (G1/G7)

Actually, the velocity has the most effect on optimum barrel twist.

Heavy bullets are slower in the same rifle than the lighter bullets and as a results need faster twist rates. Faster lighter bullets need a slower twist rate. The RPM of a bullet helps to stabilize a given bullet
weight and if a twist rate is two fast the RPM goes up and can cause problems with jacket separation and also The center of balance of a bullet may be effected if a RPM is reached that causes the bullet to be rotation-ally unstable. this is the reason ultra high velocity cartridges
normally have slow twist rates.

Faster twist rates can sometimes limit one to heavy bullets only and prevent being able to use a wide variety of bullet weights.
Most barrel makers recommend a middle of the road twist rate so the bullet weight is fairly unlimited. With the trend to make bullets with a Higher BC, the bullet weights have gone up and the common thinking is that we need a faster twist rate for our rifles, and this is true only if you intend to shoot the heaviest bullets in your caliber.

My 308 Match rifle has a 1 in 10 twist and loves bullets in the 168 to 190 grain weight. but when I tried the 220 and 240 grain match kings accuracy fell off so for the 200 to 600 yard matches I had the best success with 168 grain bullets. for the 1000+ yard the 190 to 200 worked best. heavier bullets just weren't as accurate at any distance.

I also went the whole gambit of twist rates on my 223s and found a 1 in 8 perfect for a 223 Rem and the 1 in 15 twist best for the 223 WSM at over 4600 ft/sec and somewhere in between for the other .223 diameters. So to answer your question a faster twist is needed for the heaviest bullets to stabilize them but a slower twist rate is needed for the hot rods for optimum performance.

Don,t get hung up on heavy bullets with high BCs only, unless you intend to shoot only heavy bullets at great distances and plan on high
velocities to get the bullet RPM in the best range for total performance. (Normally a magnum).

If you own a factory rifle chances are that it has a middle of the range twist rate and the best bullets with the most likelihood of shooting great are with the mid range bullet weights.

J E CUSTOM

 

[LDHunter]

J E CUSTOM,

I won't quote your latest post here due to it's length but must say it's the best common sense discussion of bullet weight vs twist rate vs speed I've ever seen. I'd like permission to quote you in other threads with credit of course.

If you haven't already you should write a book(s). Your explanations are so practical and spot on.

Please excuse my ignorance if you already are a writer other than here.

BTW.... I have a Model 700LTR with what is probably a 10 twist barrel and it shoots 168gr Sierra Match Kings so well I've shot very little else in it.

I also have a Model 700LTR in 223 with a 9 twist barrel and after trying to find the perfect bullet for it I settled on the excellent Sierra 69gr Match King. Another match made in heaven.

I don't often go to the ultra high BC bullets because I just don't have many places I can shoot beyond 500 around here but a 6.5 Creed and a 6.5 PRC just showed up in my safe and I have high hopes for both after the first couple of range trips.

LD

 

[mwkelso]

J E CUSTOM,

Thank you for that explanation!
Yes, I am definitely shooting a factory rifle. I haven't found the need to customize yet, as I am pretty new to long range and still have much to learn.
Currently I shoot a Thompson Center Venture chambered in .300 win mag as well as a Weatherby Vanguard chambered in .270. Both are a 1:10 twist, 24" barrel.
Just playing around with the ballistics calculator it does appear true that I hit the top of the performance curve with 190 and 200 grain bullets. Anything heavier than looses performance. However, I haven't put this to the test yet.

 

[Bravo 4]

Hasn't been mentioned but another reason to choose heavier is they will generally penetrate deeper than a lighter of the same design. Example, in my 7mag the 139SST will generally come apart on closer shots. Lots of damage but won't make it out (or to) the other side. I decided on the 162 SST because not only do they have a higher BC but because they open just as fast and have the longer shank to keep them together and drive them through. Haven't "caught" one in a deer yet, and that includes going through both shoulders on occasion and at closer ranges. Lots of terminal performance that pushes all the way through. On the opposite side of that my buddy wants me to load the 139's in his as his thinking is a bullet that doesn't come out the other side "dumps all its energy in the animal". I want two holes and lots of damage.

OP, If you are comparing a 150 core lokt to a 130 Partition then you aren't comparing apples to apples. Not much of a fair comparison on about any level. One is a light fast more heavily constructed "premium" (the original) bullet, the other is a basic cup and core with not much appeal (other than cost and will get the job done for most folks).

 

[mwkelso]

OP, If you are comparing a 150 core lokt to a 130 Partition then you aren't comparing apples to apples. Not much of a fair comparison on about any level. One is a light fast more heavily constructed "premium" (the original) bullet, the other is a basic cup and core with not much appeal (other than cost and will get the job done for most folks).

That's fair. As far as being apples to apples, the 130gr core-lokt shows the same data for performance in comparison to the 150gr core-lokt. The 130gr out performs with both speed and energy. I don't mean to be argumentative, and I see exactly what you're saying. There is no comparison between the core-lokt and a partition, or any other bullet really. They're on totally different levels.
I do agree with you on a bullet traveling through the other side. Almost all shots like that have dropped deer and elk nearly in their tracks for me. The one that I had to track forever was the deer that had a bullet frag apart inside with no exit. Perhaps it was coincidental? But I haven't been a fan of my bullet fragmenting since.
Thanks for your perspective on all the above.

 

[J E Custom]

J E CUSTOM,

I won't quote your latest post here due to it's length but must say it's the best common sense discussion of bullet weight vs twist rate vs speed I've ever seen. I'd like permission to quote you in other threads with credit of course.

If you haven't already you should write a book(s). Your explanations are so practical and spot on.

Please excuse my ignorance if you already are a writer other than here.

LD

Thanks. You are welcome to quote me If you want to just dont be surprised if some don't agree militantly.

I just try to share what took a lifetime to learn to hopefully save others from the same mistakes I have made and learning new things is still being added to. If I have a question that I don't understand I seek help from every source I can find. At 77 I am still learning.

I am not a very good word smith and sometimes have a hard time of explaining things, so I just try to keep/make it logical and factual as i see it.

J E CUSTOM

 

[Deleted member 8840]

1 Twist rate
2 Caliber
3 Bullet weight
4 BC
5 Fps
6 Case size
7 Long or short barrel
8 heavy or light barrel
9 Scope

To answer any question you first need to know what your doing with the rifle. To do most anything that can be done you must have several rifles.
1 Bench rest
2 Hunting
3 Short range
4 Long range
5 Extreme long range
6 Small game
7 Large game
8 Dangerous game
9 Plinking
First thing first APPLICATION. What are you doing with the rifle.

 

[skipglo]

How do you choose the weight of your bullet?
I'm shooting a 300 win mag and have seen a lot of variations of preferred bullet weights. Does the majority of the choice depend on what the barrel likes?
I'm wanting to avoid getting too heavy of a bullet so I don't limit myself to shorter ranges for hunting, and likewise for too light of a bullet.

 

[skipglo]

208 Hornady Eld M. And you're good to go to 1000 yards. Heavy bullets retain more velocity and energy further out than lighter bullets will. That is if you are using High B.C. bullets

 

[mwkelso]

1 Twist rate
2 Caliber
3 Bullet weight
4 BC
5 Fps
6 Case size
7 Long or short barrel
8 heavy or light barrel
9 Scope

To answer any question you first need to know what your doing with the rifle. To do most anything that can be done you must have several rifles.
1 Bench rest
2 Hunting
3 Short range
4 Long range
5 Extreme long range
6 Small game
7 Large game
8 Dangerous game
9 Plinking
First thing first APPLICATION. What are you doing with the rifle.

Application: Hunting for elk, deer
Range: mid to long. No closer than 300, no further than 1k at most. Preferred cap is 800, but the goal is proficiency at 1k.

 

[Deleted member 107796]

Does the majority of the choice depend on what the barrel likes?

I'd say that for the majority of rifles, the above is true. For 300WM and your desired hunting situation, pick some good boat tailed offerings in a weight range you'd like and give them a try.
I have a .308 that clearly prefers 150gn class bullets over 165, and a 300WSM that prefers 180gn class over 165. As a rarity, my wife's Ruger 270 loves everything I've ever shot out of it.

 

[muleystalker]

In all actuality speed doesn't make up for faster barrel twist as most people think. And you don't need a faster twist barrel because the bullets are heavier and going slower. A heavier Bullet is longer than a lighter Bullet and has a longer bearing surface in most cases. Being longer means you need a faster twist to stabilize it, speed doesn't realy change the stability factor much when you run the numbers, altitude affects ituch more than speed of the bullet. Perfect example is most high BC mono's are lighter the the heaviest high BC Bullet in the same cal. And are shooting much faster than the heavier cup and core Bullet but the mono's need as fast a twist barrel or faster than the heavier lead cup and core bullets.

 

[BoomFlop]

muleystalker

I'd have to disagree with you. Higher speed cartridges don't require the twist as the velocity will cause more rotation of the bullet with the same twist. After all, that is what the twist is doing. For example, shot a .308 bullet in a 1-10 twist at 2000 fps and another at 3100 fps and see which one stabilizes better.

I'm not into mono bullets, but I'm unaware of any "high BC mono's". Mono's love speed as they are typically harder than a lead bullet. Without the lead, mono's will be longer to get the same weight, thus requiring twist or velocity.

That is just my opinion.

Have a great day,
Steve