7mm Rem Mag barrel length

[kalebiscool]

Does anyone have some info on 7mm Rem mag velocity vs. barrel length? I have a 24 inch barrel on a Savage action and was looking to re-barrel . Any info would be appreciated. dang wife wont let me buy a chrony....

 

[Shriner]

Why re barrel ? With all cal's you gain or lose vel with differant barrels lts ,gain a little with longer ,lose with shorter. What range shots do you want go for 200yd 500yd 1500yd ,hunting or target , if hunting 50-300 yd the 24" barrel should be just right.

 

[JCW355]

I've got some chrony info I'll have to dig up when I get home later tonight.

 

[Ksmirk]

Here's the thousand dollar question, what are you going to use the rifle for? what bullets would you like to shoot? do you reload? if your going to rebarrel are you going to stay with the 7RM or change to something different. Different bullets will need a different twist rate but pretty much a 1-9 twist will cover all your bases. Do you want a heavy barrel or a skinny light barrel. See it's kind hard to answer without some info. As for velocity you can use 30fps per inch and be close either add or subtract but I feel a 7RM should have at least a 26" tube to burn up all that powder the case holds. Later,

Kirk

 

[doctorjj]

Maybe this will help:
http://www.loadammo.com/Topics/October05.htm

As you can see the 7mm mag is one of the most affected by barrel length changes.

 

[kalebiscool]

Thanks doctor, that was a very informative read. I was stunned by the amount of velocity per inch of barrel the 7mm gained.I would like to shoot at longer range, (target practice at more than 500 yards). I have no idea on the barrel contour or twist. I do know i will be shooting more than a 150 grain round. not sure if 170 or 175 would be the way to go. I am guessing 175 so that its less resistant to environmental effects. Which i would guess put me at about a 1 in 9 twist maybe? While changing calibers has crossed my mind i have too much 7mm rem mag brass to let it all go to waist!

I guess im really just looking for anyone that has built a 7 mag and done some of the footwork in developing a load that worked well for them. would just like some info to get started.


Wow..4 helpful posts in 1 day. thanks for the help guys, im glad i have finally found a gun forum with helpful people.

 

[Thorgrim]

I've got a 7mm RM project in the works. Going with 26" Broughton 5.5 (Sendero taper) 1-9" twist, McMillan HTG, Seekins base+rings, Nightforce 3.5x15x50 R1, OD finish, running Norma brass, w/ Berger 168 & 180's for starters......being built by longshotrifles (Chris Matthews). Should be finished soon.

 

[kalebiscool]

That sounds awesome. Alot more than i can afford but let me know how it shoots! What twist did you go with?

 

[udiablo]

Like Thorgrim, I have another 7mmRM build in the works, currently.

It's on a Rem700LA, barrel is a Krieger 5R MTU, to finish at 26" long, 1-9 twist.

I shoot 168gr SMKs and Bergers, and 175gr Bergers.

Have had others over the years (currently have 2 more), so have spent a lot of time with the 7mmRM.

For a dedicated "hunting" rifle, you might consider a 24" barrel, but I just don't like giving up 200fps velocity for the sake of lopping 2" off the barrel.

Regardless, a 1-9 twist should let you stabilize the heavier bullets, 168gr & 175gr.

I rarely mess with lighter bullets.

Would not consider going longer than a 27".

 

[JCW355]

I've got some chrony info I'll have to dig up when I get home later tonight.

Sorry, I couldn't find it. I'll find it someday when I'm not wanting to find it.