Considering downsizing to 6 cm from 7 PRC

[satchamo]

I have a tikka I rebarreled with a 7 PRC. After finishing an AZ elk hunt this week and having a rodeo due to not being able to spot my hits for shit from a non prone position, I’ve decided I need to downsize my caliber.

So I’m considering rebarreling to a 6cm. But have a couple questions from guys who have done this:

- will be running suppressor so want barrel to be 18 or 20 max - what velocities could I expect shooting the 108 match ammo?

- what’s the max terminal range running a shorter barrel (18-20)? I’d really like to be able to stretch to 800 on elk- is this round capable of this?

 

[Hnthrdr]

Terminal performance is tied to velocity, so figured out ( maybe use the box for starters) or look up threads on what eldm factory velocity will be, I think you will want to trend around 22” for 800 yards, just need to ensure that bullet is maintaining above 1800 fps for it to disrupt properly.

 

[Article 4]

A lot of variables here. My 2 cents

I have a 6 Creed and love it for anything up to large deer....never used it on elk and always opt for a 7mm or my 30 Nosler. Living in N Idaho, I usually have shots at 150 yards or 700 + rarely in between. My 6CM runs the 115 Berger and I get 2952 FPS out of a Bart #13 carbon 24" bbl. During testing I pushed it to 3060 but it wasnt the most accurate node and I was starting to see pressure signs with H4350

6mm on elk is up to you...at 800 yards the margin for error with a 243 bullet is miniscule. IMO its not enough, no matter who says they have success with it.

Why do you want such a short barrel? If you are trying to achieve max velocities to ensure penetration and kinetic energy transfer, max velocities are hard to achieve with shorter barrels. You can run a suppressor on a well made #4 or heavier contour in a 24 and be just fine and probably get 150-200 fps more velocity

 

[WyldGoose]

My suppressed 18” 6cm only has 110 rounds through it so far, still watching it speed up, hitting around 2,780 avg with factory 108’s.
At 5k feet where I live, I’m at 1,800 fps slightly passed 700 yds. Hope this helps somewhat…

 

[22Conch]

I have a 6cm creed proof 20" barrel MV 2845 with Factory 108 eldm.

At 1300 ft im at 2360 fps at 300 yds and 1335 ft pds of energy at 500 yds its 2055 fps and 1013 ft pds of energy

 

[mxgsfmdpx]

Yes sir, you will be good to go. My Tikka 6 Creed with 18" barrel, shooting factory 108 ELDMs at 5,000 DA...

At 800 yards the 108 ELDM is 1,800ish FPS. 780ish ft lbs of energy. 5.4 MIL Up. 1.3 MIL Full Value 10 MPH Wind.

I've killed multiple big game animals (elk included) with this gun from 50 yards to 760 yards. It's one thing to "theorize" on it with "advice" on the internet, and another thing to go out and actually do it. Let me know if you have any questions about the kills.

 

[huntnful]

Yes sir, you will be good to go. My Tikka 6 Creed with 18" barrel, shooting factory 108 ELDMs at 5,000 DA...

At 800 yards the 108 ELDM is 1,800ish FPS. 780ish ft lbs of energy. 5.4 MIL Up. 1.3 MIL Full Value 10 MPH Wind.

I've killed multiple big game animals (elk included) with this gun from 50 yards to 760 yards. It's one thing to "theorize" on it with "advice" on the internet, and another thing to go out and actually do it. Let me know if you have any questions about the kills.

Any distinguishable difference in wound on that 1800fps kill at 760 yards compared to ones up around 21-2200+?

I always use 1800 as my theoretical limit, but never killed down at that speed

 

[WKR]

according to science the 6cm doesn't have enough wallop for elk.
I'm not quite sure what the scientific formula for wallop is though
Edit: this was a joke, I don't believe in wallop or knockdown power

 

[Ucsdryder]

I have a tikka I rebarreled with a 7 PRC. After finishing an AZ elk hunt this week and having a rodeo due to not being able to spot my hits for shit from a non prone position, I’ve decided I need to downsize my caliber.

So I’m considering rebarreling to a 6cm. But have a couple questions from guys who have done this:

- will be running suppressor so want barrel to be 18 or 20 max - what velocities could I expect shooting the 108 match ammo?

- what’s the max terminal range running a shorter barrel (18-20)? I’d really like to be able to stretch to 800 on elk- is this round capable of this?

You can’t rebarrel to a 6cm without changing your bolt face. You can probably find someone on here willing to swap bolts though! Then a bolt stop and you’ll be good to go.

Let’s hear about the rodeo? What happened?

 

[mxgsfmdpx]

Any distinguishable difference in wound on that 1800fps kill at 760 yards compared to ones up around 21-2200+?

I always use 1800 as my theoretical limit, but never killed down at that speed

760 shot was a cow elk, purposely shot where the spine and scapula "meet" (think at the very top of first or second rib) as she was on the edge of a wood lot and I didn't want her to get in the woods. She dropped in place occasionally picking her head up slightly. A second shot to the neck severed her trachea and I could see about 4 or 5 last breath steam clouds come up like a chimney. From first shot to death was around 20ish seconds, 0 yards travelled.

Tough to compare to my normal aim point which is 3rd-5th rib but it did the job. Entrance was scapula which had a clean hole with hairline fracture going about 3" down, 2nd rib was broken, spine was partially severed, good fragmentation down into both lungs with broadside lung being massively damaged (elk would have died from shot 1).

 

[Gettin’by]

Made the switch to 6 CM this year. Suppressed 22” Proof shooting factory Hornady Match 108’s at 2918. Altitude of 2200 ft, 1803 MV at 740 yards. Spotted impacts through the scope on Mule Deer as close as 217 yards.

 

[Article 4]

This is supported by Newtons 2nd and 3rd laws on "Whallop" - I cannot do this math but I do understand the premise. BTW, many arguments have been made on this, many on this thread, there is no refuting this accepted theorem which is the basis of all energy action and transference.

The most relevant formula to represent this is the Work-Energy Theorem: "W = ΔKE = 1/2mv² - 1/2mv₀²" where W is the net work done on an object, ΔKE is the change in its kinetic energy, m is its mass, and v and v₀ are its final and initial velocities, respectively; essentially stating that the net work done on an object equals the change in its kinetic energy.

Transfer of energy:

• When a force acts on an object over a distance, it's energy is transferred to the object.
  Newton's second law (F = ma) relates the force acting on an object to its acceleration. By integrating this equation over distance, you can calculate the energy done by that force at that distance.
• The kinetic energy of the bullet is transferred to the target material during the impact, causing localized deformation and damage depending on the target's properties like density and elasticity.

Factors affecting energy transfer:

• Bullet velocity: Higher velocity bullets transfer more kinetic energy to the target.
• Bullet mass: Heavier bullets carry more momentum and can potentially transfer more energy.
• Mass moving at equal velocities: Projectile sizes are relative to the energy transferred and more mass traveling at equal velocities to smaller projectiles, will transfer more energy to the same material (elk)
• Target material properties: Dense and less elastic materials absorb more energy from the bullet, potentially causing greater damage.

Newton's laws of motion are not directly "proven" in the mathematical sense, but rather are fundamental principles that are supported by a vast amount of experimental evidence across various physical phenomena, demonstrating their accuracy in describing the motion of objects within the realm of classical mechanics; essentially, their validity is established by their consistent ability to accurately predict observed motion in a wide range of situations

 

[Clark33]

6mm on elk is up to you...at 800 yards the margin for error with a 243 bullet is miniscule. IMO its not enough, no matter who says they have success with it.

I hate this logic, a bad shot with a 6mm is also a bad shot with a 7mm or 30 cal. Bigger, heavier recoiling cartridges don't make bad shots good ones

 

[satchamo]

You can’t rebarrel to a 6cm without changing your bolt face. You can probably find someone on here willing to swap bolts though! Then a bolt stop and you’ll be good to go.

Let’s hear about the rodeo? What happened?

Yeah I know about the bolt stop swap

I’m mentally trying to come to terms with said rodeo but let’s just say I hit a very large bull and was unable to recover it. Obviously there were a number of factors playing into it but not being able to quickly spot my hits and stay on the bull in the thick brush really screwed me in the end. I had a spotter too and still struggled.

 

[mxgsfmdpx]

I would also like to hear the rodeo story if you don't mind, Arizona can make for some tough shot opportunities. The amount of missed animals here because guys and gals couldn't "get proned out" is numerous.

 

[Ucsdryder]

Yeah I know about the bolt stop swap

I’m mentally trying to come to terms with said rodeo but let’s just say I hit a very large bull and was unable to recover it. Obviously there were a number of factors playing into it but not being able to quickly spot my hits and stay on the bull in the thick brush really screwed me in the end. I had a spotter too and still struggled.

Man I know the feeling. I lost the 2nd biggest elk I’ve ever seen in the wild this year. Mine was with a ML. What a stupid piece of equipment.

How far was the shot? Was tour spotter looking through binos or a spotter? I struggle to spot shots with binoculars. I think just too much micro movements.

 

[satchamo]

Yes sir, you will be good to go. My Tikka 6 Creed with 18" barrel, shooting factory 108 ELDMs at 5,000 DA...

At 800 yards the 108 ELDM is 1,800ish FPS. 780ish ft lbs of energy. 5.4 MIL Up. 1.3 MIL Full Value 10 MPH Wind.

I've killed multiple big game animals (elk included) with this gun from 50 yards to 760 yards. It's one thing to "theorize" on it with "advice" on the internet, and another thing to go out and actually do it. Let me know if you have any questions about the kills.

Awesome this is good info. I had the 1800 number in my head as the stopping point but couldn’t recall.

 

[Article 4]

I hate this logic, a bad shot with a 6mm is also a bad shot with a 7mm or 30 cal. Bigger, heavier recoiling cartridges don't make bad shots good ones

Is it? Hate? Thanks for the productive feedback. Ok Ill play.

Lets say you didn't hit vitals. Lets say you were but a mere 2 - 4 inches away at 800 yards with your impact. Which would you rather have?

Pic 1 - 100 grain bullet impact
Pic 2 - 180 grain bullet impact

All things being the same, velocity, bullet construction etc... a bad shot with a 175 grain or larger 7 or 30 cal has a higher probability of penetration and kill than a 100 grain bullet. Period dot. See post I made above.

 

[Clark33]

Is it? Hate? Thanks for the productive feedback. Ok Ill play.

Lets say you didn't hit vitals. Lets say you were but a mere 2 - 4 inches away at 800 yards with your impact. Which would you rather have?

Pic 1 - 100 grain bullet impact
Pic 2 - 180 grain bullet impact

All things being the same, velocity, bullet construction etc... a bad shot with a 175 grain or larger 7 or 30 cal has a higher probability of penetration and kill than a 100 grain bullet. Period dot. See post I made above.

Brother have you listened to any of the S2H podcasts about bullet lethality? Showing a picture of ballistic gel isn't doesn't mean much.

 

[Article 4]

Brother have you listened to any of the S2H podcasts about bullet lethality? Showing a picture of ballistic gel isn't doesn't mean much.

Yes and debated Form on the subject of energy on multiple threads, while they make good points, their opinions on energy are inconsistent with ballistics science.