7 mm BR Adventure

[drags]

If I were to build a 7br for deer hunting I would use the 120 gr. NBT, I have shot several deer with a 7mm tcu with the 120 gr. NBT with good results the velocity was a little over 2500 fps.
Drags

 

[Riesel]

The barrel is 22.5" and it was a pleasure to carry before the addition of that night vision scope, IR attachment and suppressor. I usually carry it with the supp. off and screw it on when I get in the blind. Suppressor also causes it to be a bit unwieldy from the additional length. With this setup, I have on several occasions shot a hog in a sounder group and have them return in 20 minutes or so. After the second hog goes down the rest lose interest. . I have no issues running this cartridge as a repeater in the 700 ADL action.

 

[JackT]

Answer to some of the questions..... On real life velocity questions, I have reached 2695 fps using H322 with a Nosler 120 BY. The case is pretty full, it is clearly a compressed load by several percent, but no signs of pressure. Quick Load calculations lead me to believe I am real close to max with little luck of reaching the next optimal barrel time. Having a 0.45" group shooting off bags leads me to be satisfied with the load plus I did try a charge .3 gn higher and the group opened up considerably.

Using H 4895 I reached 2553 using Berger 140s. As with the previous load, had a full case of powder but no signs of pressure. Tried a load with a .1 gn increase and actually saw a slight decrease in velocity, still have yet to figure that out? Happy with sub 0.5 " groups off sandbags and bad eyes to boot. My skill set still has a lot of room for improvement, good round to practice with!

I cobbled together by own blind magazine and need to work the solution to making it a repeater. I have boundaries that may make that a challenge; Kelby Atlas Tactical set up for AICS mags and Remington bottom metal. Need to figure this one out especially given the fact that I also have a 6.5 x 47 Lapua and a 30 Br barrels chambered for the action. Any advice on this would be appreciated.

JT

 

[JackT]

And yes it does have a soft recoil in a rifle light enough to carry in the Texas humidty and heat, or the plains In Wyoming. Really like the #4 contour with flutes!

 

[pslater]

FWIW, I used to shoot a 7BR/XP100 in pistol silhouette back in the early 80's. Stock barrel and action with a custom stock and a 1.5 lb trigger. My bullet choice was the 154 gr. Hornady flat base. Why? Because I saw many shooters 'ring' rams without knocking them over. IMHO, the culprit was usually light for caliber bullets. I never lost a ram with the 154's and shot a 60X leading to a shoot off of 3" dots at 150 meters. Won the bling that day.

To this day, I'm a fan of heavy for caliber bullets. The 145 gr. Barnes LRX should be devastating on game with a rifle length barrel. The only reason I don't shoot the 168 gr. Barnes for hunting is it needs a 1:8 twist barrel and my .284 Win is 1:9.

 

[TorF1]

As a side note:
The 7BR is the best round never chambered in a HK G3, FN FAL shorty, etc. in the old days.
The 7BR fit the "308" class assault rifles' short barrels better than any other round.
-Exellent accuracy
-Great ballisics for size
-Low recoil
-Long barrellife
-etc,etc,

 

[Preacher]

Answer to some of the questions..... On real life velocity questions, I have reached 2695 fps using H322 with a Nosler 120 BY. The case is pretty full, it is clearly a compressed load by several percent, but no signs of pressure. Quick Load calculations lead me to believe I am real close to max with little luck of reaching the next optimal barrel time. Having a 0.45" group shooting off bags leads me to be satisfied with the load plus I did try a charge .3 gn higher and the group opened up considerably.

Using H 4895 I reached 2553 using Berger 140s. As with the previous load, had a full case of powder but no signs of pressure. Tried a load with a .1 gn increase and actually saw a slight decrease in velocity, still have yet to figure that out? Happy with sub 0.5 " groups off sandbags and bad eyes to boot. My skill set still has a lot of room for improvement, good round to practice with!

I cobbled together by own blind magazine and need to work the solution to making it a repeater. I have boundaries that may make that a challenge; Kelby Atlas Tactical set up for AICS mags and Remington bottom metal. Need to figure this one out especially given the fact that I also have a 6.5 x 47 Lapua and a 30 Br barrels chambered for the action. Any advice on this would be appreciated.

JT

99% of the time, when you start to loose velocity with a increase of powder, your tight to the max load for that barrel......

 

[crustyrusty]

hello!! I am a big fan of the 7mm family and I am currently shooting a 280 Rem 700 ADL which was my dads which I inherited after he passed . I purchased a die set, cases bullets already on hand and ordered a set of go-no go headspace gauges for the 7mm BR. I set up 3 dummy rounds of the bullet combos that I want to shoot (120,, 130,,145,,) so now that I have my dummy rounds I found a reamer maker that is willing to take my dummy rounds and and his build sheet that I fill out with spec's that I want... here is the kicker I dont know what numbers I should look for to keep from having to have make a custom Full length re=sizer die as well( this posability was suggested to me by the reamer manufactuer or do I just go with the reamer that is "on file"? the only thing that I would like to change , really is the max OD of the neck ,, just by 2 thousands but if that makes it more of a hassle ........ seee my predicament?

 

[JackT]

Crusty... You have to first decide whether you are going to turn necks or not? My approach is bullet diameter plus 2 times neck thickness plus .002 - .003 equals neck size of reamer.

 

[crustyrusty]

Crusty... You have to first decide whether you are going to turn necks or not? My approach is bullet diameter plus 2 times neck thickness plus .002 - .003 equals neck size of reamer.

well as it just happens I am now measuring my dummy case. what do you suggest? I really dont want to neck turn but if it comes with the territory guess im in the game... ok with bullet seated its .309. or do i measure case with no bullet? ok if its ok with bullet seated, then .309+.002= .311 (thats pretty close to my 280 rem at .310 at neck with bullet seated and accordin to my load book its chamber size is .315)so this case and bullet is not turned, and with a addition of .002 will there be enough room to NOT neck turn?

 

[JackT]

Maybe this will help.... (Reamer neck size minus .002 minus 0.284)divided by 2 equals maximum neck thickness of brass. If the neck thickness of your brass is less than that value, you should be good to go without neck turning.

 

[JackT]

Or if your loaded round is .309 simply order a reamer with a neck size of 0.312 and you are good to go with some room to spare.

 

[crustyrusty]

Or if your loaded round is .309 simply order a reamer with a neck size of 0.312 and you are good to go with some room to spare.

ok I like that and that is what I was thinking too... if it was your gun what would you do?

 

[JackT]

On my gun (which I was setting up for hunting vs target shooting) I knew the new dimension on the barrel was 0.309 and I desired a clearance of 0.003 between the barrel and the case neck. Given the bullet dimension of 0.284, the math told me to trim the necks to 0.011 . This resulted in a loaded round size of 0.306 . That has worked out well for me from an accuracy perspective.

Same logic would suggest ordering a reamer with a neck size of 0.312 if your loaded round is 0.309.

 

[crustyrusty]

ok that is the same math that I came up with and I put that on the spec sheet for the reamer.. so what I found out is it cost the same amount of money for either a complete chambered barell or a un chambered barrel so I am gonna ask for a fully chambered barell that has minimum spec and then use my reamer to finish it out to final spec do you think that is a good Idea?

 

[JackT]

I have no gunsmithing experience, reaming a chamber is way out of league.