7prc suppressed barrel length question

[birddogswosu]

Hello I am wanting to put together a hunting rifle that is in 7PRC that will be suppressed

I want to rifle to be as short barreled as possible. Is 16” too short for the caliber? Also with the short barrel would I be better off with a smaller 7-08 caliber? I like the idea of the High BC bullets to help compensate for the lower velocities from running a suppressor and a short barrel.

 

[N555]

Yeah I heard you need the barrel length to take advantage of the PRC case capacity to get that PRC velocity.
For a 16 inch you might as well just slightly hot load 7-08 or 308.

 

[JmacD]

You’re definitely not going to be able to take advantage of the case capacity in my opinion. I’ve been contemplating a similar project. I had settled on nothing shorter than a 20 inch barrel. But, I am no expert.

 

[jmorris]

I want to rifle to be as short barreled as possible. Is 16” too short for the caliber?

There is no "too short", just how big of a velocity hit you are willing to take. You could make it a pistol if you wanted to.



I'd probably rather have a long 7mm BR than a short 7 PRC, especially if "quiet" was what I was after.

 

[mavracer]

You're playing a game of diminishing returns, ultimately you're the one that needs to decide if the juice is worth the squeeze.
Even from a 16" barrel a cartridge capable of holding 80gr of powder will have more velocity than one that's only capable of 50gr. But it will be far diminished from the difference from a longer barrel.
Another thing to consider is at the 16" mark the exit pressure and related gas volume will be for the sake of discussion about doubled and that's going to significantly effect the suppressor's abilities to suppress.
You can play some with baffle design and how they're stacked but ultimately volume will come to play.
IMHO one would be far better off with a 7mm/08 with an 18" barrel with a 8" suppressor than a 16" PRC with a 10" suppressor.

 

[birddogswosu]

You're playing a game of diminishing returns, ultimately you're the one that needs to decide if the juice is worth the squeeze.
Even from a 16" barrel a cartridge capable of holding 80gr of powder will have more velocity than one that's only capable of 50gr. But it will be far diminished from the difference from a longer barrel.
Another thing to consider is at the 16" mark the exit pressure and related gas volume will be for the sake of discussion about doubled and that's going to significantly effect the suppressor's abilities to suppress.
You can play some with baffle design and how they're stacked but ultimately volume will come to play.
IMHO one would be far better off with a 7mm/08 with an 18" barrel with a 8" suppressor than a 16" PRC with a 10" suppressor.

This is the info I’m looking for. Thanks for the help.

 

[adcoch1]

It depends on your goals, weight, carry comfort and balance, etc for finished product. Find out what overall length you can live with, set a bullet weight and velocity goal, then start looking at what gear gets you there. If I was going 7prc I would get as much barrel length as possible, minimum 20" for my needs. Any shorter and I'd be looking at different cartridges, and possibly even different bore sizes.

 

[horsemen61]

I wouldn’t go less than 20 inches

 

[birddogswosu]

It depends on your goals, weight, carry comfort and balance, etc for finished product. Find out what overall length you can live with, set a bullet weight and velocity goal, then start looking at what gear gets you there. If I was going 7prc I would get as much barrel length as possible, minimum 20" for my needs. Any shorter and I'd be looking at different cartridges, and possibly even different bore sizes.

I’m after a light, handy rifle in a hard hitting caliber. Shorter the better because the suppressor will add 8”. I’m trying to find the best balance to make a superior hunting rifle. I know if I go too short with the barrel I will loose too much velocity and suppress ability with the 7PRC. At that point I should just switch calibers.

 

[horsemen61]

I’m after a light, handy rifle in a hard hitting caliber. Shorter the better because the suppressor will add 8”. I’m trying to find the best balance to make a superior hunting rifle. I know if I go too short with the barrel I will loose too much velocity and suppress ability with the 7PRC. At that point I should just switch calibers.

Yes you are correct if I were you I’d look into the 7MM 08 or if you want to get out there
7 SAW in weird territory I think you could do an 18 inch 7MM 08

 

[jmr40]

A 16" 7 PRC will still be faster than a 24" 7-08. A lot faster than a 16" 7-08. It'll be louder, but that's what the suppressor is for.

The PRC from a 24" barrel will shoot a 175gr bullet to 3000 fps. I'd estimate about 250-300 fps slower from a 16" barrel so call it 2700 from a 16" barrel. That's still 200 fps faster than you can do with a 24" 7-08. Cutting the 7-08 down by 8" will result in less velocity loss, maybe 150-200 fps. But if you shoot both from a 16" barrel the 7 PRC will still have a 400 fps advantage. That's a lot of speed to give up.

Without the suppressor the 7-08 makes sense because the muzzle blast will be less of an issue. But with a suppressor go big. That's what they're for.

Or, if you're comparing a 16" PRC to a 24" 7-08. The 200 fps advantage to the PRC isn't worth it.

 

[adcoch1]

A 16" 7 PRC will still be faster than a 24" 7-08. A lot faster than a 16" 7-08. It'll be louder, but that's what the suppressor is for.

The PRC from a 24" barrel will shoot a 175gr bullet to 3000 fps. I'd estimate about 250-300 fps slower from a 16" barrel so call it 2700 from a 16" barrel. That's still 200 fps faster than you can do with a 24" 7-08. Cutting the 7-08 down by 8" will result in less velocity loss, maybe 150-200 fps. But if you shoot both from a 16" barrel the 7 PRC will still have a 400 fps advantage. That's a lot of speed to give up.

Without the suppressor the 7-08 makes sense because the muzzle blast will be less of an issue. But with a suppressor go big. That's what they're for.

Or, if you're comparing a 16" PRC to a 24" 7-08. The 200 fps advantage to the PRC isn't worth it.

It's true, the prc is a rocket, but I would rather put up with a longer rifle barrel than a step bigger suppressor weight wise. Length and usability is kinda subjective, but given the option of a 16" 7mm-08 or a 16" 7mm prc, suppressed or not, well, I'm not picking the prc. But if that same gun has a 22" barrel, even with an 8" suppressor hanging off the end, well, then the prc juice is worth the squeeze to me.

 

[Gtscotty]

A lot of folks who haven't tried it discount the idea of short barrel suppressed magnums, but in my experience if you want the extra power in a shorter package and plan on running a can anyway, using a step larger cartridge size is the way to go.

For instance, I probably could have achieved similar velocities to my 18" 300 WSM and 17" .280 AI with heavily loaded long barrel .30-06 and 7mm-08 respectively. That would have been antithetical to my goal of setting up lightweight, reasonable length suppressed hunting rifles in that power range. Better to burn a bit more powder and go with the shorter barrel for those goals, in my experience.

17" .280 AI


18" .300 WSM


19" 7mm PRC


OP,
There are some other folks who have built shorter barrel 7mm PRCs over on the hide who have chrono information that might help with your decision of whether to go short on a 7mm PRC.

7mm PRC

Being a lefty not as many options as what I'd like. Wanted a short barrel an stayed budget friendly since I was gonna cut it. Savage Apex Hunter. Weight is with Otter Cree Labs Polonium 30 on the end. Gonna do some development this week with 4831sc,560,RL23 an 565 maybe RL26. Peterson brass...

www.snipershide.com