Why is 20” ok for 7 PRC but not 7 Rem mag?

[Elk Hunter 338]

I'm still trying to figure out how a belted case rips the fabric of the space time continuum...

GEESSSHHHH that simple.. NITROGLYCERIN

 

[Rosebud]

I'm still trying to figure out how a belted case rips the fabric of the space time continuum...

I could run you through the equation, but I'd run out of space on the forum.

 

[Rosebud]

Is it possible with the availability of affordable chronographs, more education on chamber dimensions, more information on powder burn rates, etc. that people are more educated (potentially anyway) on what used to be passed around as fact when it was nothing more than "urban legends?" Is it possible that people have access to more data and that they can verify data themselves (to some extent) versus just using box values for velocity? It used to be said across the board that you lose 50fps per barrel inch lost or that anything other than a 26" barrel in a magnum was "useless." With chronograph data we can assess that in some cases it's more like 20-30fps lost and with some it's 60-80fps lost. Sometimes it's just about the individual barrel and chamber IMO.

There are many 22" or 24" 7RM rifles available because many have decided the loss in velocity wasn't a huge trade off for their individual purposes. If you want to continue with the 7RM it's been killing well for 60+ years. I think it's less about attacking the introduction of the 7 PRC than it is using whatever you want that fits your purposes. Nothing wrong with either.

When I got my first chronograph , Made by Acme Inc. A subsidiary of Roadrunner enterprise. It was a eye opener. I'd been guessing at velocity, using what was posted on the box and reloading manuals. Most times it was close. Other times way off. Had me afraid to shoot much past three hundred.

 

[Buffalobwana]

When I my first chronograph , Made by Acme Inc. A subsidiary of Roadrunner enterprise. It was an eye opener. I'd been guessing at velocity, using what was posted on the box and reloading manuals. Most times it was close. Other times way off. Had me afraid to shoot much past three hundred.

I remember "just hold 'one deer' high!"

"One deer" is that a metric unit?

 

[AGGRO]

I remember "just hold 'one deer' high!"

"One deer" is that a metric unit?

Yes. We also measure distance by beers. That town is about a 6 pack away. Two beers to Jimmy's house.

 

[Buffalobwana]

Yes. We also measure distance by beers. That town is about a 6 pack away. Two beers to Jimmy's house.

Yes … the good ol days.

 

[Buffalobwana]

Yes. We also measure distance by beers. That town is about a 6 pack away. Two beers to Jimmy's house.

Wait … your description isn't past tense.

 

[bamban]

I've only run a suppressor on 5.56 and never chronographed it. Suppressors will increase some velocity, correct?

Not necessarily. 16-1/2 308. 1st picture just the SF brake/suppressor adapter. 2nd FA762SS attached.

Ammo: LC M118 LR

 

[Calvin45]

There is something to the WSM line that lets them shine with 23" barrels. Powder column stacking or some schit!

According to science !

One thing I have always wondered…do short fat cartridges actually do any better out of shorter pipes OR is it all just a matter of the chamber being included in barrel length???

A 300 h and h and a 300 wsm with the same barrel length will see the hh bullet starting its journey about an inch closer to the end of the pipe. And I constantly see 25-50 fps per inch as an internet rule haha.

 

[Barehandlineman11]

Go 7mag itll do everything that prc will do. Plus dies brass on shelf and **** ton of data

 

[Prairie Sasquatch]

Ever heard the saying "Science advances one death at a time."

I think most human brains like ideas or thoughts about the world to be "complete" at some point. It's simply cognitively easier to make a conclusion and not think about it anymore. Thinking rationally through ideas and changing your mind is difficult for most people.

I learned pretty early in my career that discussing an issue rationally and making an airtight argument with my boss or other higher up in a meeting was not met with encouragement. It was met with hatred. Most especially if it destroyed some long held belief. It wasn't the idea but the cognitive dissonance it caused them. I had in fact shaken their foundations.

It's why people fight so often on the internet over new information.

 

[AGGRO]

Wait … your description isn't past tense.

I have an E-bike

 

[TxHeartShot]

Chat forums tell me 20"-22" 7mm PRC is a great choice!! Same forums trash a 20" 7 Rem Mag.

Once an idea is established in the halls of the chat forums, it might as well have been brought down from the mountain on a stone tablet.

Is it bc the 7mag barrel length debate is well established in chat as gospel, but any new chambering is open to interpretation to justify our own selection bias? (Aka, I "need" a 20" 7mag, so this shiny new thing will work perfectly!)

20 years ago a .308 would have been considered a marginal choice for Elk, now the 6.5 CM is a perfect 600 yard Elk gun. I argue that good marketing persuaded chat forum users to establish this "fact". After all, nobody was running around yelling that the 260 Rem was the perfect 600 yard Elk rifle. (Everyone knows 260 Rem > 6.5 CM … )

So, can someone explain why a 20" 7mm PRC is perfectly acceptable, but same length in a 7 Rem mag would be downright foolishness?

Dang I start a grass fire every time I shoot the7 STW from a prone position and its got a 25" bbl and a radial brake.

 

[AGGRO]

Dang I start a grass fire every time I shoot the7 STW from a prone position and its got a 25" bbl and a radial brake.

Gonna need a catalytic converter.