I'm thinking of doing 1-9 barrel for my next 7mm rifle, talk me out of it.

bitbythebug said:

I just sold my 28 Nosler with a 1-8 twist barrel. It wouldn't shoot the 180 ELD-M's at all. They disintegrated before reaching the target. I was told they were spinning to fast and coming apart, I couldn't refute that. I am building a 7-300prc and am leaning towards the 1-9 twist for it. I did all the calculations on the Berger stability calculator, and it said the 9 twist stabilizes even the 195 Berger's. I was hoping the slower twist wouldn't disintegrate thinner skinned bullets, like the ELD-M. I love the 180's and would like to stay in that area for hunting but would like to be able to shoot the heavier Berger. I can order either barrel from Bartlein. Where am I going wrong with my thinking?

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Tell the barrel maker what bullet you plan to shoot, they should have an answer for you.

But man they do the deed on impact! Seems the faster the better.
Bonded

TAWS said:

I have a 7mm REM. Mag with a 26 inch SS barrel with an 8-1 twist, and 5R rifling. I am getting 3130 out of the 175 ELDX and 3170 out of 162 ELDX. It is a factory rifle. Reloader 26 and 25, (25 with the 162 bullet) and it has been a wonderfully accurate rifle. I am going after a big whitetail deer this weekend, hangs out in the back 40, and we will see.

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Not to digress but this is what I'm talking about!!! +1 for the good old 7RM. What's wrong with a 175 going 3130 with much less case capacity than a 28 or a 7-300... Where are the haters who claim your speeds are bogus?..some of them are commenting on this very thread.

OP I've heard many of the same trouble you've had. The 180eldm were hard to keep together in my buddy's 28. Seems there are many options. Twist it slower or slow it down. Neither of which I feel is the best option for the 28. It's a hotrod so I feel it should be run as one. I plan on running an 8 twist hot and using a bullet that will handle it. I'd bet he 7-300prc would be fine for the 8 twist but like many have said a 9 should run the 180s just fine!!

Country Bumpkin said:

Someone check my math.

I don't know what velocity you were getting with the ELD-M's out of your 28 Nosler, but just to play games I'll assume it was 3,000 fps. If you had a 1:8 twist, we know that your bullet was spinning 12"/8" or 1.5 times in 1 foot (someone check me please). So at 1.5 revs per foot, times 3,000 fps = 4,500 rps… times 60 seconds is 270,000 rpm. Apply the same to a 1:9 twist and you get 240,000 rpm. Is an extra 30k RPM too much…?

I have no idea how fast is too fast (I googled it and it seems like none of the smart ppl are willing to put a number on it because there are too many variables).
This was some interesting reading (if this is against the rules I'll happily delete my post).

You are being redirected...

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Thank you

southpa said:

Not to digress but this is what I'm talking about!!! +1 for the good old 7RM. What's wrong with a 175 going 3130 with much less case capacity than a 28 or a 7-300... Where are the haters who claim your speeds are bogus?..some of them are commenting on this very thread.

OP I've heard many of the same trouble you've had. The 180eldm were hard to keep together in my buddy's 28. Seems there are many options. Twist it slower or slow it down. Neither of which I feel is the best option for the 28. It's a hotrod so I feel it should be run as one. I plan on running an 8 twist hot and using a bullet that will handle it. I'd bet he 7-300prc would be fine for the 8 twist but like many have said a 9 should run the 180s just fine!!

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Agreed. Nothing wrong with a 7rm. Less work, no necking down or fire forming. Unless you just wanna go faster lol.

I shoot a lot of 7mms. Its been pretty steady for me that 9s are not good for the high bc bullets, at least not where I am. 8s do much better for me with the eldm, a tip and berger.

bitbythebug said:

I never thought that a faster twist was a negative. I instinctively want the 1-8 but the 28 Nosler has me spooked. Maybe it was the rifling's. Would you get the 8 or the 9?

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If you are going to use all copper bullets then the faster twist rate is needed. I have changed to faster twist rate barrels to stabilizes the copper bullets in my new rifles. My older rifles are slower twist rates, and I don't feel they'll work with copper bullets to stabilizes correctly. That's my take on copper bullets. Have wonder what would happen with jacketed bullets in a faster twist rate. What I have read about others having the same problems with faster twist rate barrels. So it's a choice of what you want to shoot in that rifle.
Believe me I don't have anything against all copper bullets, it's seem to be step forward in creating a better round for hunting.
Presently I am setting up an older 7mm Rem Mag rifle for a friend. I am staying with the original barrel, do it being almost brand new to start with. I have had some experience with the 700 Rem, 7mm RM. Was able to get them to group in the 1/2" size with 5 shot A 100yds out of the box.

I have also read stability enters into the hunting equation both during flight to the target and after impact. That a more stable bullet will better continue on a nose forward path with less yaw and change in direction through the critter. Which is how bullets are designed to perform. With hunting we have to be concerned with terminal ballistics as well as external ballistics and accuracy.

Left Hand Dave said:

I have also read stability enters into the hunting equation both during flight to the target and after impact. That a more stable bullet will better continue on a nose forward path with less yaw and change in direction through the critter. Which is how bullets are designed to perform. With hunting we have to be concerned with terminal ballistics as well as external ballistics and accuracy.

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Berger hunting bullets, as well as the ELDM are not intended to be stable or nose forward throughout the target. Their terminal performance is actually triggered by instability and rapid fragmentation of the jacket and lead core.

I do think faster RPM's might aid in fragmentation, but it's just theory

Another question would be do those types of bullets fragment better as designed if they are nose forward? Don't have any idea how a regular guy could test it. Guess it all comes down to make the best informed decision you can and if it works out go with it. Although I suspect a large number of members here are never satisfied and always looking for a better mouse trap.

WeiserBucks said:

Bonded bullets are nearly impossible to spin apart in flight.

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They also prove to be devastating when spun really fast, just like all Barnes bullets.

The person stating that spinning a bullet as slow as you can get away with is just plain wrong for a hunting situation. You want your bullet spinning faster to utilise that spin for terminal ballistics affect.
I ran a 13" twist barrel for my Palma rifle, it barely spun the 155g Palma bullet enough, but did fine for targets. Was useless at subsonic.

Cheers.

bitbythebug said:

I just sold my 28 Nosler with a 1-8 twist barrel. It wouldn't shoot the 180 ELD-M's at all. They disintegrated before reaching the target. I was told they were spinning to fast and coming apart, I couldn't refute that. I am building a 7-300prc and am leaning towards the 1-9 twist for it. I did all the calculations on the Berger stability calculator, and it said the 9 twist stabilizes even the 195 Berger's. I was hoping the slower twist wouldn't disintegrate thinner skinned bullets, like the ELD-M. I love the 180's and would like to stay in that area for hunting but would like to be able to shoot the heavier Berger. I can order either barrel from Bartlein. Where am I going wrong with my thinking?

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I ran into guys having issues with 1 in 8 barrels in 28 nosler before I built mine. They were blowing up 195 bergers. After a phone call to berger's tech guy about it, I decided to back my barrel off to 1 in 8.5 twist. I couldn't be happier with that barrel and rifle.

What are you crazy ? 1 in 9 in a 7mm RM ? You know who shoots 7mm RM in 1 in 9 ? The Taliban , thats who ! You know who else ? The Communist's !

Don't do it , for America !

I will admit I have not read all of these responses so forgive me if someone mentioned this already. If looking at a Bartlein barrel in 7mm they make a 1-8.7 twist, it has been perfect in my 7 RUM with the Berger 175 elites and the 180 hybrids. I also had that same barrel spun on my boy's 280AI to spin lighter copper bullets and both shoot very well. Hope this helps and best of luck, Jason