30 br Barrel

[MGYSGT]

Still lusting after a 30 br. Still want to shoot 200 thru 600 with it. Am thinking the biggest bullet will be the 155 gr. range. What twist barrel am I looking for? I have my Rem reciever and a stock. The barrel will be Lejia, Kreiger or one of the other quality barrel makers, depends who has what I want. Yes I know the MV for 155 gr bullet will be in the 2400-2500 range, but I think it will be just fine.

 

[davidw3625]

Rumor is 3 groove 1/17 twist....Iwant to say PacNor...

 

[AlNyhus]

Almost all of the 150-ish bullets are made on the 1.150 jackets. On that jacket, a 15 twist is the slowest that will still stabilize that length...provided it's a flat base design. If you're wanting to shoot the boat tail 155's, a 14 twist would be good.

The 17 twists work fine up for jacket lengths up to the 1.080's.

Hope this helps. -Al

 

[GlennL]

Al, I used a Shilen 15t #2 for a 30BR with 150NBT it shot great. It shot the BIB's 118 as good as my 17 @100. @2700 fps. for the 150's.

Glenn

 

[AlNyhus]

Yes, it's the length of the bullet...not the weight...that makes the difference.

A stop at the JBM site and a few taps on their SG calculator ain't a bad way to start a trip down an unknown road..... -Al

 

[chevi_guy]

Al
I'am new at the BR game and have a 6BR. I also am lusting for a 30BR. What is the JBM site and how do I get to it?

 

[Steve Blair]

Yes I know the MV for 155 gr bullet will be in the 2400-2500 range, but I think it will be just fine.

No, you can easily get over 2600 with 155-class bullets with a 26-30" barrel.

Al
I'am new at the BR game and have a 6BR. I also am lusting for a 30BR. What is the JBM site and how do I get to it?

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

 

[tiny68]

My 1:16 twist Douglas 30BR shots the 150 SMK good. Played with it just a little at 300 yds. Only had H4198 powder with me. Needed a slower powder. Tim

 

[MGYSGT]

Looks like the 14 or 15 twist in a 29" or 30" will do the job, depending on the bullet. I would like to shoot the longer bullet in the 150's, but fear a conflict with the shorter/lighter bullets, when shooting 200 and 300. As for barrel grooves, I didn't give it a thought (3, 4, or 5) , is it just personnal preference? What loads are you using to get that 2600-2700 fps. I can only find loads to that 2400-2500 I mentioned in my original post. Again, thanks for the info. This is why I come to this site.

 

[Steve Blair]

H335 will do it. The problem is finding a slow enough powder that is dense enough to achieve pressure. I suspect that ball powders in that same burning rate range will also work. Develop from -10% and increment to the full charge, small cases can be "peaky."

 

[gzig5]

Looks like the 14 or 15 twist in a 29" or 30" will do the job, depending on the bullet. I would like to shoot the longer bullet in the 150's, but fear a conflict with the shorter/lighter bullets, when shooting 200 and 300. As for barrel grooves, I didn't give it a thought (3, 4, or 5) , is it just personnal preference? What loads are you using to get that 2600-2700 fps. I can only find loads to that 2400-2500 I mentioned in my original post. Again, thanks for the info. This is why I come to this site.

What are you planning to have for freebore on the reamer?

 

[MGYSGT]

Freebore? Don't have a clue. What do you suggest based on the multi bullet use. I have been thinking I may have to restrict the bullets to 125 /130 gr. and above or stay at or below that level.

 

[Spook]

rethink your barrel length, you've only got so much case capacity with the 155. .050 fb will be enough for the155's. I shoot them through 14 and 15 twist with good result.

 

[MGYSGT]

Rethink my barrel lenght. Very confusing. What do you mean? I am guessing, too long. I get the .050 FB, but what do you mean about barrel length. Like I said eariler, this is why I come to this site.

 

[gzig5]

You don't need that long of a tube to burn the full load of powder. There just isn't that much in the case and the bigger hole makes the burn more efficient. You could probably do with a 24-26 inch if you want and not lose any velocity and have good accuracy at the same time. I plan on running a 21" for a hunting rifle. I've got a mag length to deal with and will be using the 125-150's. I made up a couple dummy rounds and it looks like I am going to need at least .100" freebore to keep the base of the bullet above the start of the shoulder on a 150gr. The 155 sierra looked similar but the nose was longer. I don't think a zero freebore reamer would be optimal for these heavier bullets from a case intrusion standpoint.

I know you want a 30BR, but for 200-600 yard shooting of just about any kind, a 6BR with 90-108 bullets is going to tear up a 30BR with 150s for wind drift.

 

[MGYSGT]

Thanks for the info. Seems to be a popular conscience that 30 inch is too long. Maybe trim it down to 24-27 inch. I already have a 6mm BR and am just testing the waters with this build of a 30 BR.

 

[tiny68]

You don't need that long of a tube to burn the full load of powder. There just isn't that much in the case and the bigger hole makes the burn more efficient. You could probably do with a 24-26 inch if you want and not lose any velocity and have good accuracy at the same time.

I can absolutely confirm what gzig5 is saying. My first 30BR was Savage 26" with a brake on the barrel. With a full case (34.0 gr) of H4198 I was running 3025 fps with 125 TNTs. I wanted something shorter and lighter w/o the brake so I had my gunsmith chop the barrel to 22". I lost less than 15 fps with the same charge with 4" less of barrel.

I would think a 20-22" would be pretty optimum for a 30BR. Tim

 

[MGYSGT]

Starting to get on board here. Shorter barrel means I can go fatter and stiffer. What dia barrels are we looking at. 1.25"???

 

[P1ZombieKiller]

I know you want a 30BR, but for 200-600 yard shooting of just about any kind, a 6BR with 90-108 bullets is going to tear up a 30BR with 150s for wind drift.

I second that