6CM vs. 6.5CM

[TX_Diver]

Maybe should be a different thread, but how much does bullet weight affect recoil? 130 vs 147 or 95 vs 108 etc?

 

[Driftin]

Great conversation, seems the 6.5 cm having more splat with a big brake could be the ticket

 

[TimberHunter]

Not enough to matter
I switched barrels back to back and shooting 112s was marginally softer than 147s from the same platfrom.

Thanks for the info. I may skip the 6cm then, I currently have a tikka 6.5cm


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[762 ULTRAMAGA]

Thanks for the info. I may skip the 6cm then, I currently have a tikka 6.5cm


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If you want softer shooting then a 6 BR or Dasher will be the ticket, otherwise yeah a 6 CM isn't going to be much of a difference.

 

[TimberHunter]

If you want softer shooting then a 6 BR or Dasher will be the ticket, otherwise yeah a 6 CM isn't going to be much of a difference.

Appreciate the insight. Ideally it would still be a longer range mule deer hunting gun so I wasn’t sure about dropping down to 6BR or dasher. But it would be a good practice rifle


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[Weldor]

I can say this, the 6cm is tough on meat. Lots of bloodshot. But is a pleasure to shoot and hunt with.

 

[Lawnboi]

Appreciate the insight. Ideally it would still be a longer range mule deer hunting gun so I wasn’t sure about dropping down to 6BR or dasher. But it would be a good practice rifle


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Really comes down to what you are going to use for a barrel length, along with a muzzle device.

I can get away with a lot with a suppressed 6 creedmoor. I can’t get away with anything on a bare muzzle 6.5 creed.

If your bare muzzle or brake and using a longer barrel the BR/dasher/GT becomes a much more viable option. Versus a short suppressed barrel would basically lock me into choosing a 6 creed.

 

[Marbles]

I get it, people that are shooting that much regardless of caliber will need to replace barrels fairly often. The problem I have is that most people talking about barrel life don’t shoot much at all.

Fair, and for someone on a budget shooting that much, getting a 223 is probably the long term solution.

If you want softer shooting then a 6 BR or Dasher will be the ticket, otherwise yeah a 6 CM isn't going to be much of a difference.

I've been wondering about a 6 BRA or 6 GT barrel for the Encore. I need to research some more, but sounds like a better long range option than a 223 for mountain hunting once my daughter is old enough.

Really comes down to what you are going to use for a barrel length, along with a muzzle device.

I can get away with a lot with a suppressed 6 creedmoor. I can’t get away with anything on a bare muzzle 6.5 creed.

If your bare muzzle or brake and using a longer barrel the BR/dasher/GT becomes a much more viable option. Versus a short suppressed barrel would basically lock me into choosing a 6 creed.

How much would a 6 BR or GT loose on a 20 inch barrel?

 

[180ls1]

6.5PRC with the 156EOL.

 

[Lawnboi]

Fair, and for someone on a budget shooting that much, getting a 223 is probably the long term solution.


I've been wondering about a 6 BRA or 6 GT barrel for the Encore. I need to research some more, but sounds like a better long range option than a 223 for mountain hunting once my daughter is old enough.


How much would a 6 BR or GT loose on a 20 inch barrel?

I can only guess around 2700 or below, at comfortable pressure. Low enough that I would choose to build a creed.

 

[Driftin]

Good info guys. Thanks for all the input. I just pulled my tikka 308 barrel off to rebarrel. Look like I’m going for the 6.5 cm.

 

[khuber84]

Not enough to matter
I switched barrels back to back and shooting 112s was marginally softer than 147s from the same platfrom.

I believe in equal weight hunting style rigs, there's a noticeable difference of 140s at 2800, VS 105s at 3050fps. Especially suppressed, def more push. Brake.......nah not much.

 

[762 ULTRAMAGA]

I believe in equal weight hunting style rigs, there's a noticeable difference of 140s at 2800, VS 105s at 3050fps. Especially suppressed, def more push. Brake.......nah not much.

I guess it depends on your setup but with a 12ish lb rifle using a Nomad LT I literally couldn't tell much other than the 6 creed seemed snappier while the 6.5 had a slower slightly longer recoil impulse

 

[wapitispokes]

I'm planning on setting up a lower recoil rifle for long range big game hunting (would like to have the option to kill out to as close to 800 yards as possible) to be used on whitetail, mule deer and elk. The plan would be to use factory ammo and to dial for long range shots. I liked the idea of going smaller in caliber and getting a 6CM or something similar but as I started comparing the 6CM to the 6.5CM, the only actual advantage I could find in the 6CM is slightly less recoil (appears to be almost negligible based on information I could fine online) while the 6.5CM appears to have the following advantages:

- Higher BC which also means less wind drift (comparing 108ELDM and 147ELDM)
- More accessible factory ammo
- Longer effective range on big game (will dip under 1800 FPS at a longer distance than 6CM using above referenced bullets)
- Longer barrel life

Is any of what I'm saying above inaccurate or am I missing any other important factors that should be considered?

Forgive me if I missed some details. I think there are a few considerations that would be helpful to know.

1. What is your current level of experience and proficiency with longer distance shooting (probably anything past 300 yards and ideally to 600 yards with wind...)
2. What will your new rifle weigh?
3. How will it be used for hunting (backpacking, day hunts, or within a few hundred yards of a vehicle off a fixed rest?).
4. I know you said that "your plan" is to use factory ammo. But, is that by choice or because at present you are not able to reload?
5. How is your access to a 600 yard range with variable winds & how often can you make time to practice there?
6. How is your access to professional training / ability to commit to attending long range shooting training?
7. What is your sensitivity to costs. i.e., upfront, vs consumable, vs. higher upfront capital costs to drive down long term operating costs
8. What are your time limitations ? For example, a) more time and more capital = maybe you could reload and drive down future costs although some will warn you that it is a rabbit hole and a hobby that won't save any money and they are probably correct. b) Less time, maybe a family = walking a finer tightrope. c) Really busy, fairly open budget = KISS principle, no reloading, just one barrel, "get 'er done".

We are lucky to have so many on this forum with vastly more field and range rifle experience than me. In view of that, I was a bit reluctant to comment, however my objectives are similar to yours and I have a wee bit of experience so you might appreciate my thought process.

Here is the punch line to my long discussion below:

• The cost of a second barrel is almost an afterthought. So, get two - one in a practice chambering and one in a somewhat more potent chambering. The choice of chamberings will depend on a number of factors including whether or not you reload and what else you might like to do with your rifle.
• Or get one barrel in a chambering that is a "safe bet" (like 6.5CM) and shoot the heck out of it while you decide if you need an additional barrel or different chambering. After a year of practice and hopefully some long range shooting classes you'll probably feel much better informed to narrow down future choices.

Somewhat like you, I am currently in the process of building a rifle using modern components and with the objective of developing a "shootable" rifle along with confidence and proficiency for "longer" shots if necessary Another key goal is incorporating a suppressor. My target all-in weight is <= 8.5 lbs. (Come to think of it, my newest rifle was purchased 30 years ago and was customized by Gordy Gritter about 16 years ago...preceding modern range finders and suppressors among other things...thus it feels like to a good time to update..)

I desire the lowest recoiling cartridge that will be sufficient given my target species at my maximum proficiency range in mountainous field conditions, which I'm quite sure will never be more than 600 yards and probably not more than 500 yards.

Given my assumed range limitations (which are shorter than yours), I think any of 6CM, 6.5CM, 6.5PRC and others in between will be "just fine" for the "hunting" barrel. Within my range limitations (perhaps 500 yards, maybe but probably not 600 yards), the lowest recoiling of the three will likely support better actual field proficiency and therefore a longer maximum range vs. a higher recoiling "larger caliber".

If my shooting proficiency improves with dedicated practice, or I feel I need a "larger" hunting cartridge (perhaps for Elk), it is no big deal to purchase a new barrel in an "upsized" chambering like 6.5PRC or 7SAUM and/or go with a longer barrel. Either will work adequately with a short action.

My primary hunting barrel will be carbon wrapped and suppressed, likely in 6CM, but possibly 6.5CM. Like I said, I don't think it will make a ton of difference which one I choose given my target species and expected maximum range of proficiency during the life of that barrel. And hopefully I will shoot enough to burn it out and replace it.

I will have a second "practice" barrel potentially in a traditional steel configuration (not carbon wrapped) most likely chambered in 6BR, but possibly 6BRA or .223. This barrel will have the same length as the hunting barrel and also be threaded for a suppressor. Sure, the practice barrel will be heavier than the hunting barrel, but I'm okay with the slightly heavier weight and probable better barrel life from an all-still barrel.

I have a 6BR "no turn neck" barrel on my Gordy Gritter customized Model 7 and I really enjoy it. The 22" barrel sends a 95 grain BIB bullets downrange at a pretty good velocity through the 22 inch barrel. I'd be happy to use that barrel on whitetails to a good long distance. It is a sweet shooter and easy to reload.

Because I can reload, the cost of practice cartridges is not a material consideration to me. I will probably select a barrel with a practice chambering with a standard ".308" size bolt face to match the bolt for the "hunting" barrel. That pretty much leads me to a practice cartridge of 6BR or 6BR improved. But if I did not reload, I would probably chamber the practice barrel for .223 and suffer the +/- $500 cost of a separate bolt for the smaller .223 case head. For the non-reloader, I think the cost of the second bolt would quickly be offset by cheap off the shelf practice .223 ammo.

I think of the "shooting system" as incorporating the completed rifle, ammunition, tools and reloading equipment, range fees, travel and range time. The least expensive cost of the "system" is the barrel. Especially a steel "practice" barrel.

The cost of a second barrel is almost an afterthought. So, just get two in different chamberings.

Or get one barrel that is a "safe bet" (like 6.5CM) and shoot the heck out of it while you decide if you need an additional barrel or different chambering.

As your next hunt approaches and after practicing a Lot, you might determine that your max sensible range is improving but is still less than your long term goal of 800 yards. The cartridge (and bullet) selection become a lot less important as the maximum proficient range becomes shorter - and especially if that range is <=500 yards.

Why train with an 800 yard cartridge, potentially in a heavy 800 yard rifle, with recoil that will reduce proficiency at shorter ranges, if the shooter may never need more than a 500 yard cartridge due to the shooter's own proficiency limitations?

If you haven't seen or heard the following - below is a link to one of the better videos I've seen on maximum effective range and following that I've included a second suggestion without a link.

Little Crow Gunworks Maximum Effective Range

There are also some great discussions on EXO's podcast interviewing "Form" from "Shoot2hunt".

 

[Jon Boy]

Anybody compared recoil of 130 6.5 to a 108 in 6? After running the recoil calculator it looks like 2 ft lbs of recoil difference and the ballistics are nearly identical. I’m curious how much that 2 ft lbs is felt. Not sure if it’s worth 5-800 bucks for a new barrel.