Copper Monos - How to choose the right weight(and maybe caliber)?

[Petey308]

These answers get right to heart of what I was wondering about. It has given me a whole lot to think about in regard to penetration but also fragmentation. I understand that "more is always better" but recoil management is a real issue. I currently own a 7mm RM but have to constantly practice my recoil management skills. My brother is looking at getting a 6.5 PRC and in helping him do research it got me to thinking "I wonder if I could similar terminal performance with less recoil".

Thank you for taking the time to help me out, it is greatly appreciated.

Recoil management is definitely a valid concern and one a lot don't always think about.

There are definitely many other factors that need to be considered in your choice of cartridge, bullet, rifle, etc.

It's all just puzzle pieces. You can make the puzzle as complicated or as simple as you'd like. Well, maybe not QUITE as simple as you'd like lol, but hopefully you get the point.

 

[Lou270]

My thoughts:

1) Monos, whether the petal shedding or petal keeping variety penetrate plenty. Easy rule of thumb is can go 10-15% lighter than would with a lead/copper bullet. Use the twist recommended by the maker of the particular bullet and not what somebody says on the internet. Some makers recommend higher than others. So long as you follow what the bullet is designed for will be good

2) More energy / penetration is reason to go heavier. Same as with lead core.

3) The million dollar question. Caliber doesn't matter until it does. Some experts say it doesn't some say they can see differences in minute changes like between 270 and 7mm (.007). Personally I think if you are using historically adequate cartridge for game hunted it doesnt matter much. If you are trying to get away with using a low energy or very small caliber for game it probably does

Loup

 

[Dinosaur hunter]

I had the same questions. I had my cartridge selection already made so that one was done. I called and spoke to the guys at hammer bullets and they were extremely helpful on the rest. Biggest question to answer first is what distance you want to shoot and at what. With that info they made a recommendation with a explanation why.
in all honesty I wasn't planning on shooting monos, but after not being able to find the bullet I was after and speaking with them I'm very happy with the outcome.

 

[Franko21]

I had the same questions. I had my cartridge selection already made so that one was done. I called and spoke to the guys at hammer bullets and they were extremely helpful on the rest. Biggest question to answer first is what distance you want to shoot and at what. With that info they made a recommendation with a explanation why.
in all honesty I wasn't planning on shooting monos, but after not being able to find the bullet I was after and speaking with them I'm very happy with the outcome.

I'm stuck in California so monos aren't optional.

 

[Petey308]

I'm stuck in California so monos aren't optional.

To be fair, you're only legally forced to use lead free bullets in California. You can legally use other options such as Dynamic Research Technologies Terminal Shock bullets or other similarly constructed bullets. They actually work extremely well too.

 

[Rich Coyle]

I have been doing a lot of reading and have a couple of questions I am hopoing that people can chime in on:

Question 1 - How do you choose the right projectile weight? Is a 7mm RM shooting a 100 gr monolithic at 3500fps good for everything (deer, hogs, elk, etc.) or at some point do you need to step up to a heaver projectile?

Question 2 - If you do have to go to a heavier projectile what factors do you use to decide the right weight?

Question 3 - Does caliber matter? Is there going to be an appreciable difference in terminal performance between a 130 gr 6.5mm projectile going 3100 fps vs a .308 caliber 135gr projectile going 3100fps?

Thanks for reading this.

1. First question has a couple questions in it. Recently I had a new 7mm rifle built. I ordered three sample packs from Hammer: 120, 131 and 143 grainers. I was going to wee which the rifle liked. But I used ignorant prejudice a times. I chose the 131 strictly on looks and didn't use the other two. A 100 mono started at 3,500 fps is good for at least 250 yards on the game you mentioned.

2. I don't have to go to a heavier weight, so I don't have factors to consider.

3. Years ago I posted on Hunt America a question to those who had hunted various small and large animals on at least two continents over at least two decades. I asked if there was any noticeable difference in killing power in what they used. The vast majority said there was no difference in noticeable killing power from about 7mm up to .375. They seemed to agree above .375 there was an obvious difference in killing power. Generally, they based their comments on heart and lung shots. Maybe some here saw that thread.

I remember recently, I'm 78 so recently could be five or ten years ago, a guy was doing culling work on cape buffalo. He and his partner were using full metal jacket round nose bullets. He was using a .30-06 while his partner used a .375H&H. He said in both cases the buffs would run off a ways before they expired.

 

[FEENIX]

I'm stuck in California so monos aren't optional.

To be fair, you're only legally forced to use lead free bullets in California. You can legally use other options such as Dynamic Research Technologies Terminal Shock bullets or other similarly constructed bullets. They actually work extremely well too.

My family and I just returned from a quick extended getaway/ family reunion in Ontario/Riverside/Redlands. I am reminded of why I left CA nearly four decades ago and never looked back.

The beauty of mono bullets is that you now have plenty of options. Like the lead bullets, there is no one size fits all, and there is no such thing as a magic bullet. Below are some threads/sites that list some of your options/choices:

- https://www.longrangehunting.com/threads/lead-free-bullet-compilation.290864/
- https://www.longrangehunting.com/threads/lead-free-bullet-maker-from-california.305828/
- https://www.longrangehunting.com/threads/interesting-lead-free-bullet-design-concept.309057/
- https://www.cavitybackbullets.com/

I am sure there are more of them out there. But as you can see, the list is longer than most realize. Good luck with your bullet choice. Happy safe hunting.

 

[emp1953]

I have been doing a lot of reading and have a couple of questions I am hopoing that people can chime in on:

Question 1 - How do you choose the right projectile weight? Is a 7mm RM shooting a 100 gr monolithic at 3500fps good for everything (deer, hogs, elk, etc.) or at some point do you need to step up to a heaver projectile?

Question 2 - If you do have to go to a heavier projectile what factors do you use to decide the right weight?

Question 3 - Does caliber matter? Is there going to be an appreciable difference in terminal performance between a 130 gr 6.5mm projectile going 3100 fps vs a .308 caliber 135gr projectile going 3100fps?

Thanks for reading this.

In a given caliber, a lighter bullet is shorter and a heavier bullet is longer. As bullets get longer they require different twist rates to stabilize the bullets. Manufacturers usually list the recommended twist rates needed to stabilize bullets in their line. Let that recommendation be the guide to your starting point. I thought I found a unicorn when I found my .270win would shoot a heavy/long bullet perfectly while having a 1:10 twist and the manufacturer recommended a 1:7 twist. My discovery was based on a limited sample size. I was only shooting at 100yds where the bullet got stabilized just fine. At 200yds the hole on target showed that the bullet was turning sideways and POI was off by 4inches. At 300yds the stabilization was really out the window and POI was off by 10 inches. The place to start is with the manufacturers twist recommendations. Make sure that you know what twist your barrel is. Having a used rifle with a custom barrel can be a challenge sometimes. I have a gun cleaning rod that I used to confirm twist. I insert the rod with a brush with a piece of patch attached into the breech. I mark the rod near the handle with a sharpie and count the rotations as I push it down the barrel. I do this several times in each direction to get some consistency in my numbers. Then I take the length of the barrel, the rifling. Not the barrel including the chamber, you can measure the whole barrel and subtract out the length of a cartridge. This will get you close. Divide the number of rotations on your cleaning rod by the inches of rifled barrel length and voila you'll have something representing a ration 1 inch to "n" rotations or 1:n.

 

[Franko21]

My family and I just returned from a quick extended getaway/ family reunion in Ontario/Riverside/Redlands. I am reminded of why I left CA nearly four decades ago and never looked back.

The beauty of mono bullets is that you now have plenty of options. Like the lead bullets, there is no one size fits all, and there is no such thing as a magic bullet. Below are some threads/sites that list some of your options/choices:

- https://www.longrangehunting.com/threads/lead-free-bullet-compilation.290864/
- https://www.longrangehunting.com/threads/lead-free-bullet-maker-from-california.305828/
- https://www.longrangehunting.com/threads/interesting-lead-free-bullet-design-concept.309057/
- https://www.cavitybackbullets.com/

I am sure there are more of them out there. But as you can see, the list is longer than most realize. Good luck with your bullet choice. Happy safe hunting.

I am currently stuck in CA because my job pretty much requires me to live/work in major metros and my aging parents are here. However, if remote work options are here to stay once Covid is gone, I will be looking at moving to coastal Oregon or Washington. I understand your feelings about California, its like watching a really nice and friendly neighborhood slowly decay as crime, poverty, and neglect all happen right before your very eyes.

Thanks for the information, it is much appreciated.

 

[FEENIX]

I am currently stuck in CA because my job pretty much requires me to live/work in major metros and my aging parents are here. However, if remote work options are here to stay once Covid is gone, I will be looking at moving to coastal Oregon or Washington. I understand your feelings about California, its like watching a really nice and friendly neighborhood slowly decay as crime, poverty, and neglect all happen right before your very eyes.

Thanks for the information, it is much appreciated.

I commend you for taking care of your aging parents - the toughest job in the world no matter where you live. The majority of my relatives, as well as my wife's relatives, still live in CA.

 

[bigngreen]

@Petey308 You spend a lot of time on sectional density but there are two factors to SD, diameter and mass, if a bullet does not shed that frontal area it's dropping more SD than if it blew off 40% of it's weight.?

 

[hunter0528]

Found this website re the twist on standard barrels from various firearms manfacturers

GS CUSTOM USA - Twist Rate by Manufacturer

GS Custom Bullets - Twist Rate by Manufacturer

www.gscustomusa.com

 

[Lee7588]

I have been doing a lot of reading and have a couple of questions I am hopoing that people can chime in on:

Question 1 - How do you choose the right projectile weight? Is a 7mm RM shooting a 100 gr monolithic at 3500fps good for everything (deer, hogs, elk, etc.) or at some point do you need to step up to a heaver projectile?

Question 2 - If you do have to go to a heavier projectile what factors do you use to decide the right weight?

Question 3 - Does caliber matter? Is there going to be an appreciable difference in terminal performance between a 130 gr 6.5mm projectile going 3100 fps vs a .308 caliber 135gr projectile going 3100fps?

Thanks for reading this.

Yes a 100 GR projectile will kill deer, hogs, elk, etc.. is it the best for all things probably not. Shot placement is critical. I kill hogs alot of the time with a 22, I have buddies that use a 17 hmr. Could you kill everything else with a 22 sure, head shots.

When to choose a heavier caliber depends alot on the environment. If you are hunting in and area that has a lot of wind using a heavier caliber would be wise to help with wind drift. With a 7mm mag a 140-160 gr projectile would be an ideal weight, not the best in every aspect but good in all.

Does caliber matter, no there are pro's and con's of all calibers. One might excel in one thing while the other excels in something different. If you don't reload then availability makes a difference, if you reload components availability makes a difference.

If you have a 7 mm mag it is a great all around rifle that you can hunt all big game with I'd probably find a smaller caliber if squirrel hunting though

 

[Petey308]

@Petey308 You spend a lot of time on sectional density but there are two factors to SD, diameter and mass, if a bullet does not shed that frontal area it's dropping more SD than if it blew off 40% of it's weight.?

I'm not entirely sure what you're trying to say and I don't want to assume. I'll just say the following and we can go from there if you'd like.

I do talk a lot about sectional density because I've found it to be extremely pertinent on selecting the right combo of bullet, cartridge, and game I'm after and the distances I anticipate to shoot them at.

You mentioned that there's two factors to SD, diameter and mass. Well, those are two things used to calculate SD, yes, but it's not the only two things that matter regarding terminal performance.

And that's basically my point. My point is a lot of people treat SD as only a variable that relates to penetration and they tend to believe that the higher the number, the more penetration you'll have. That's not entirely true though. It depends greatly upon the construction of the particular bullet and specifically how it inherently behaves terminally.

Then you have to factor in things like impact velocity as well. You can make up for low SD by impacting at a lower velocity because a lower impact velocity would mean less expansion and opposite force on the bullet and it'll thus penetrate further than if it impacted at a much higher impact velocity. Then further still, it also depends on how much or how little the bullet sheds weight and how much or how little it expands outward, increasing frontal diameter.

It's worked amazing for me and I'll swear by it.