Short barreled 7mm ??? Help me pick - people with experience please

[Longtine88]

What mag box?

M5 Hawkins long action. The 7RM won't gain you any velocity in a shorty over the saum. I use to have 3 7RM's now I have 5 7 SAUMs and 1 7rem mag. All long actions except one that is a short mag setup on 168's.

 

[Ernie]

I had a 22" 7mm Rem Mag. 69.5gr Retumbo behind a 168gr Berger was 3014fps suppressed. It was a great rifle. Probably shouldn't have sold it. I cut it down from 27" changed to Retumbo from H1000 and actually gained 20fps… That said, if you're going to make it 18-20" I probably wouldn't use something like the 7RM or 28 Nosler.

I haven't read through all 8 pages of this thread but when you get that short, especially towards the 18" side of things, the amount of concussion, muzzle blast, and flash isn't pleasant and performance drops off significantly after 21-22". With a muzzle brake it's be absurd. 20" seems to be the point at which you really start getting incomplete combustion of powder. The Army tested this a lot before settling on 22" for the 300 win Mag.

7mm Remington Magnum (7 Rem Mag) Barrel Length Versus Velocity

7mm Remington Magnum (7 Rem Mag) Barrel Length Versus Velocity Since its introduction in 1962, the 7mm Remington Magnum (7 Rem Mag) has developed a strong following, becoming the most popular metri…

rifleshooter.com

Since you have a long action to use I'd stick with something like the 7 SAUM, 7SS, 7 Max or 284 Winchester as far as cartridge capacity. Performance will be nearly identical (yes slightly less…like maybe 50fps) but the shooting experience will be markedly better. Since you're using BDL bottom metal the 7 SAUM and 284 win will likely feed better.

Cody is not looking for efficiency, he is looking for a performance level with a specific barrel length with bullets heavier than you are talking about.
There is a class of muzzle brakes which really do a great job in both in felt recoil reduction and in keeping muzzle rise down
A third area of muzzle brakes that is NOT so well known is that in this group only a few don't have a big concussion to the shooter.
Since I typically run 14-18 inch barrels, I have learned which brake reduces concussion better to the shooter in short barrels-Holland Radial Baffle Brake
I know what a 284 Winchester and a 7mm SAUM does with a 162 or 168 grain bullet in a 18" barrel, and it will not give Cody the performance level he is looking for.
The performance level is way different than 50 fps.

 

[Stgraves260]

Not opposed to them, pretty much the deciding factor will be if my father in law wants to keep the bdl bottom metal or sell it and get a dbm. If that is the case, we will probably look at a 7 max, throated 7 wsm, 7 mega or similar. If he wants to keep the bdl, we will probably go with a 28 nosler

I don't know if I would suggest a 28 Nosler in a 20" barrel. When I did that to a 7mm Rem Mag could not get any accuracy out of it. I could not find a powder to burn fast enough to get a complete burn and it looked like a fire breathing dragon shooting out 2' plus's flames at the end of the barrel. 7 Rem Mag has 82 gr H20 and the 28 Nosler has 93.8 gr H20. I think that flame will be even bigger with that much more capacity available for powder. From my experience you don't want know more than a 6" flame out the end. The smaller the flame, the more efficient and will reach max velocity with whatever powder you use. The lager the flame the less efficient, huge accuracy drop on top of that, and all that punishment on the body from a way overbore round just to push the same velocity's as the short mags or ever the ( hate to say it 7-08 )

 

[Stgraves260]

Cody is not looking for efficiency, he is looking for a performance level with a specific barrel length with bullets heavier than you are talking about.
There is a class of muzzle brakes which really do a great job in both in felt recoil reduction and in keeping muzzle rise down
A third area of muzzle brakes that is NOT so well known is that in this group only a few don't have a big concussion to the shooter.
Since I typically run 14-18 inch barrels, I have learned which brake reduces concussion better to the shooter in short barrels-Holland Radial Baffle Brake
I know what a 284 Winchester and a 7mm SAUM does with a 162 or 168 grain bullet in a 18" barrel, and it will not give Cody the performance level he is looking for.
The performance level is way different than 50 fps.

Agree. I just don't see the point of any of the overbore casings in a 18" or 20" barrel. He would do much better with the short mags or hate to say it the 7-08.

 

[Ernie]

Stgraves,
Nothing wrong with a 7mm-08, with the exception it won't remotely do what Cody wants
Accuracy issues with a 20 inch 7RM...It is definitely NOT a cartridge case capacity/barrel length problem.
My 300 RUM (short barrel) does awesome with a the 230 grain Berger at short and LR, as does my 7mm LRM with 180 Hybrids.
18" 7mm WSM with 180 grain JLK's at a 1K match (5-shot group).
FWIW my 7mm Dakota ( more capacity than a 7RM) 18" is capable of the same accuracy.
Cody is not looking for efficiency, he is looking for a performance level with a specific barrel length with heavy bullets for the caliber.

 

[Stgraves260]

Stgraves,
Nothing wrong with a 7mm-08, with the exception it won't remotely do what Cody wants
Accuracy issues with a 20 inch 7RM...It is definitely NOT a cartridge case capacity/barrel length problem.
My 300 RUM (short barrel) does awesome with a the 230 grain Berger at short and LR, as does my 7mm LRM with 180 Hybrids.
18" 7mm WSM with 180 grain JLK's at a 1K match (5-shot group).
FWIW my 7mm Dakota ( more capacity than a 7RM) 18" is capable of the same accuracy.
Cody is not looking for efficiency, he is looking for a performance level with a specific barrel length with heavy bullets for the caliber.

2300 yards

 

[xsn10s]

Me thinking of my past disclaimers lol.

 

[Stgraves260]

I shot that in Brawley California in the deserts. It was my 260 Rem 27"Krieger Barrel 140 grain Berger's. I could hear the bullet impact, I just didn't know if it was hitting the steel or the wood. So I didn't change anything and fired 4 rounds. When I got up to the target I seen those 4 bullet holes. I had my dad, girlfriend, and some of my cousins and 2 Brawley California police officers with me that day. It's hard to adjust when you can't see your impacts. Basically that would be 4 heart shots on a person.

 

[Ernie]

When I did that to a 7mm Rem Mag could not get any accuracy out of it. I could not find a powder to burn fast enough to get a complete burn and it looked like a fire breathing dragon shooting out 2' plus's flames at the end of the barrel.

What powder and bullet weight did you use?
I use the same powders in my shorty's that longer barrels use.
H-1000: 7WSM
H-1000 and Retumbo: 7 LRM
H-1000, Retumbo and Reloader 33: 7mm Dakota
Reloader 33: 26 Nosler
Retumbo: 300 RUM
Retumbo: 338AX (300 grain SMK)
It is the same with my 7mm-300 PRC....

I get consistent accuracy at distance as well.
I am not looking for efficiency, and Cody isn't either.
If I can get awesome accuracy with 18", I promise you he will do just fine with a 20 or 22 inch barrel

 

[Stgraves260]

What powder and bullet weight did you use?
I use the same powders in my shorty's that longer barrels use.
H-1000: 7WSM
H-1000 and Retumbo: 7 LRM
H-1000, Retumbo and Reloader 33: 7mm Dakota
Reloader 33: 26 Nosler
Retumbo: 300 RUM
Retumbo: 338AX (300 grain SMK)
It is the same with my 7mm-300 PRC....

I get consistent accuracy at distance as well.
I am not looking for efficiency, and Cody isn't either.
If I can get awesome accuracy with 18", I promise you he will do just fine with a 20 or 22 inch barrel

I honestly can't remember. My dad and I did that back in the 90s just before I enlisted.

 

[Ernie]

I shot that in Brawley California in the deserts. It was my 260 Rem 27"Krieger Barrel 140 grain Berger's. I could hear the bullet impact, I just didn't know if it was hitting the steel or the wood. So I didn't change anything and fired 4 rounds. When I got up to the target I seen those 4 bullet holes. I had my dad, girlfriend, and some of my cousins and 2 Brawley California police officers with me that day. It's hard to adjust when you can't see your impacts. Basically that would be 4 heart shots on a person.

I am a little lost with your pics.
Is that a single hit at 2300 yards?
Distance on the wood?
I am not doubting what a 260 can do in terms of accuracy at distance...I don't think anyone here is questioning that.

Of course, who would shoot a 15" 6.5x47 Lapua past a mile at steel and hit it...

This post is about short barrels, accuracy downrange, with enough impact velocity for the bullet to kill well at extreme distances.
The 6.5x47 L, 260 Remington, or 7-08 won't do that

 

[Ernie]

Cody,
18" 7mm-300 PRC with the 190 grain Berger Hybrid has a MV of 2786 fps

 

[xsn10s]

What powder and bullet weight did you use?
I use the same powders in my shorty's that longer barrels use.
H-1000: 7WSM
H-1000 and Retumbo: 7 LRM
H-1000, Retumbo and Reloader 33: 7mm Dakota
Reloader 33: 26 Nosler
Retumbo: 300 RUM
Retumbo: 338AX (300 grain SMK)
It is the same with my 7mm-300 PRC....

I get consistent accuracy at distance as well.
I am not looking for efficiency, and Cody isn't either.
If I can get awesome accuracy with 18", I promise you he will do just fine with a 20 or 22 inch barrel

That Retumbo and RUM and regular mags. I know it worked well with longer barrels. Good to know it works well with short barrels. Wait, that stuff is no good. You don't want it

 

[xsn10s]

Cody,
18" 7mm-300 PRC with the 190 grain Berger Hybrid has a MV of 2786 fps

Ernie do you recall if Cody's FIL was going to put on a can? I do remember talk of a muzzle brake.