Cz 550 7mm Rem Mag

[JmarNZ]

Hi everyone, first post for me and looking forward to great advice. I recently bought a CZ 550 7mm Rem mag and it came with a 23.6" barrel, my question is would this length of barrel make much diffrence in velocity when reloading?
Any help would be appreciated.

 

[FEENIX]

Hi everyone, first post for me and looking forward to great advice. I recently bought a CZ 550 7mm Rem mag and it came with a 23.6" barrel, my question is would this length of barrel make much diffrence in velocity when reloading?
Any help would be appreciated.

Welcome to LRH and enjoy! Congrats on a very nice rifle and chambering.

Your load combination (powder capacity/burn rate, primer, bullet type, case capacity, etc ...) affects the velocity for your particular rifle.

For instance, in my .270 AI loads, I can get ~100 more FPS using H4831SC over H1000, Win case handles better pressure than RP case, WLR primers are hotter than BR2s, etc ... Others will be here shortly to chime in.

Find the best combination out of your rifle and have fun with it.

Good luck and happy safe reloading, hunting, and shooting. Cheers!

ADDED:

You might also want to check out/join in the regional forum @ http://www.longrangehunting.com/forums/f83/

 

[MudRunner2005]

Welcome to LRH.

Excellent caliber, but can't tell you much about the gun, as I am not a CZ guru. However, that does seem to be an awefully short barrel length for a 7mmRM, and will be stunting it's velocity a little. I prefer 26" or longer barrels for magnum calibers, that way you get full potential out of them.

So to answer your question, yes, barrel length + slow burning magnum powders will increase your velocity a good bit.

 

[JmarNZ]

Thanks for the reply guys, I'll try my hardest to get book velocities with as my combinations as possible. It's just a shame that I didn"t start this thread before I bought a short 7mm!!lightbulb Any idea what the loss of velocity my be compared to a 24" and 26" barrel?

 

[MagnumManiac]

Welcome!
I would estimate around 100fps less than a 26" barrel, it could actually be a little less.
My 264WM with 26" barrel 4 groove Lilja gets over 100fps more than a factory 6 groove Rem 26" barrel. It depends, only a chrony will tell you for sure.

Cheers.
gun)

 

[FEENIX]

Thanks for the reply guys, I'll try my hardest to get book velocities with as my combinations as possible. It's just a shame that I didn"t start this thread before I bought a short 7mm!!lightbulb Any idea what the loss of velocity my be compared to a 24" and 26" barrel?

Extract from Lilja Barrels ...

Depending on the powder, cartridge capacity and bullet weight, it is normal to see a maximum additional velocity gain of about 25 fps per inch of barrel. The amount of gain decreases as barrel length increases also.

(Lilja Precision Rifle Barrels)

 

[benchracer]

Hi everyone, first post for me and looking forward to great advice. I recently bought a CZ 550 7mm Rem mag and it came with a 23.6" barrel, my question is would this length of barrel make much diffrence in velocity when reloading?
Any help would be appreciated.

Most factory rifles come with 24" barrels in magnum chamberings. You aren't going to see a measurable difference with a barrel that is less than 1/2" shorter than most other factory rifles. It's not worth sweating over. Yes you would gain a bit of velocity with a 26" barrel, but the difference isn't really enough to have much effect on downrange performance.

Some chamberings are more sensitive to barrel length than others. The .264WM, for example, really needs at least 26" of barrel to get the most out of it. I don't believe the same to be true of the 7mm RM.

 

[JmarNZ]

Thanks to everyone for the replies, I feel better about my purchase now. Much appreciated, all the best from New Zealand.

 

[davkrat]

Don't have the data in front of me and I have not shot the two side by side yet but my brother's 22" 7mm Rem Mag reached the same velocity with a grain and a half less H4831 than my 26" barrel did. Not sure if the chrono was on the fritz but since then I have been able to get significantly more velocity out of that load by going to the much slower burning Retumbo. I doubt my brother's shorter barrel would do as well with that slow of a powder. I would not be surprised if you have better luck with a fast to medium speed powder (H4350, R17, H4831).

 

[FEENIX]

Most factory rifles come with 24" barrels in magnum chamberings. You aren't going to see a measurable difference with a barrel that is less than 1/2" shorter than most other factory rifles. It's not worth sweating over. Yes you would gain a bit of velocity with a 26" barrel, but the difference isn't really enough to have much effect on downrange performance

Ditto! I was blessed with a bull elk last year; harvested at 931 yards with a stock SAKO M995 in .300 Win Mag with 23.5" barrel pushing 190 VLD at 3043 FPS.

Worry about it when it is time to re-barrel!