Home Forums Hunting & Shooting Ask The Gunwriters .270 Win./150 gr. Velocities...

Have heard from friends that have tried'em... with poor results out of 1:10 twist Bbl's.

Appears to be hit/miss.



That's what I'd be lookin' for.

Was considering a 1:8 twist .270 Win. Bbl. to facilitate it.




GR

Apparently you believe in the same misconception that many do--that bullets started to "destabilize" at longer ranges due to reduced velocity.
This is exactly the opposite of what happens, as there are two forces at work in bullet stabilization: Air pressure on the front of the bullet, which tends to destabilize the bullet, and gyroscopic spin, which stabilizes the bullet.

Air pressure comes from velocity, which decreases far faster than bullet spin. This is why bullets become MORE stable as range increases, until they drop to around the speed of sound--which is far below the velocity of higher-BC hunting bullets drop to at ranges out to 800+ yards.

Have gotten excellent accuracy with 150-grain .270 ABLR's, but as with many newer high-BC bullets, they "liked" being seated deeper.

You might also try JBM's stability program, which unlike others provides an input for plastic-tip length. The late Don Miller, the guy who developed the stability formula most programs are based on these days, eventually found that plastic tips were so light (and sharp) that they had little affect on bullet stability. The JBM program gives the 150 ABLR an SG of 1.375 even at "standard atmospheric conditions" of 59 F. at sea level in a 1-10 twist, which is more than enough to stabilize them. Around here, in typical hunting-season conditions, the SG is over 1.5.

The big reason even well-stabilized bullets tend to shoot larger groups at longer ranges is wind, which as I pointed out in another thread increases at about twice the rate of range.

There’s a video, and I think it’s on You Tube, about some guys shooting pistol bullets into ice at an angle where the bullets bounce back out onto the ice. They keep spinning like crazy for a long time. It’s amazing how powerful that spin is.

Just going by anecdotal data - from reloaders who have tried the bullet in otherwise precise 1:10" rifles for that bullet weight... and, as a group, can't get'em to shoot well.

... except from higher twist-rate Bbl's.




GR

Haven't experienced that in at least three .270's--all factory rifles with 1-10 twists. But I did experiment some with seating depth, which I've found tends to help considerably with ABLRs in other calibers and weights.

For example, my custom 6.5 PRC regularly groups 5 handloads with 129 ABLRs into half an inch or less, even though it only weighs around 7-1/2 pounds scoped. But it didn't do that until I seated them about .1 inch off the lands.

Seen the same thing. .075 to .125 and they seem to run great. But then again in a few other 270’s nothing could make them shoot well. Life’s too short to dote on a single bullet anyhow.

Yeah, I suspect a lot of it depends not only on the chamber throats in various rifles, but the particular batch of bullets.

By the way I just got done putting together the load data from the 15 .270 Winchesters I've handloaded for over the decades, for my upcoming LITTLE BOOK OF RIFLE HANDLOADS THAT WORK. It's a collection of handloads that have worked well in more rifles (or even most rifles) in a certain chambering, along with brief observations about the cartridges and loads. That's how I know the 150 ABLR has shot well in more than one rifle, along with the info on seating depth. We're planning on having the book out by early fall, but that always depends on variables, just like handloading!

For sure. I’ve had a few rifles just balk at them and others be somewhat easy. Concentric rounds and all that haven’t mattered, they just wouldn’t do it. The next gun eats them alive. Same as the Interbonds and Sciroccos. When they work they make you smile. When they won’t they make you wanna buy Federal Blue Box.

Yep!

Would also add that I've encountered rifles that wouldn't shoot Bergers, but they've usually had extra-long throats--especially Weatherby Magnums, even though they'd shoot other bullets (in particular monolithics) very well. But one of the reasons many of us are compulsive experimenters is rifles are always "interesting"...

That’s what I saw. My biggest frustration to date was a MK5 300 Wby and 210 ABLRs. I was ready to throw in the towel. Switched to Partitions and it thought it was a tuned 223.

Thanks for the info! But am not surprised....

For a .270 that will be used in varied terrain and from deer to elk would you guys prefer a 22 or 24 inch barrel?

Never seen a problem with a 22” barrel on a 270 myself.

I have the rifle that shoots a junk 277/130 btsp speer into. 6 for 5 shots and the 150 lrab into 2". Knowing this is a very accurate rifle, I contacted Nosler and spoke to the balasticians about the lrab.

I was told the lrab uses a different copper and it can have issues in rifles with sharp leades as it can "stall" or dwell in the throat as pressure increases from the burn event. If using slow powders, mag primers, short jumps and sharp bores.....it's all working against that bullet.

Like Mule Deer, I seated deeper and used a lee FC die and it was an instant change of over an inch.

Nosler mentioned using magpro powder as it tends to "self lubricate" according to the balistician I spoke with, or at least that's what I heard from his description.

I had initially thought my rifle would not stabilize the 150 based on groups, but all holes were dead round and so I turned to the rock bluff 1200 yards out and even though I was shooting 2" at 100 I was still very close to if not inside moa at the wall....which made me want to make this bullet work.

It can be a fickle beast, but does fly very well and the 3 I've sent into bulls did what they're supposed to.

I saw where you use a crimp, I also wonder if you couldn't increase neck tension a thou or so to get the same effect? Never thought of trying that in problem rifles when the ABLR isn't responding well.

I tried increasing neck tension but ended up with seating inconsistencies.

I was afraid of that. Makes sense.

Informative and encouraging.

Thanks y'all.

This is one bullet I really wanted in the bag for the .270 Win.


Look forward to the new book, JB.




GR

Unless you want max velocity from a full charge of slow powder...?

As the .270 Win. is already a high pressure cartridge, a 22" Bbl. works fine, and is a bit easier to handle in the field.




GR