Nosler Accubond Long Range problem

[Engineering101]

Lots of good thoughts have been provided regards this problem. I appreciate it. I also appreciate those of you who are going to jack up the velocity to see what these bullets do when really pushed. I am very interested in your results.

If this does turn out to be a problem with the rifle it will be one for my personal record book as to how bad things can get. To go from sub MOA to missing 4 sheets of notebook paper with a few added grains of powder is something I've never seen regardless of how fast I pushed the bullets - unless the scope came loose or broke.

Since loose mounts and broken scopes don't get fixed by taking a few grains of powder out of the case this is not likely a scope problem. Since this barrel was installed by an amature (me) one has to question the gun smithing but, I have other rifles with the barrel nut torqued they same way that all shoot great, so it is not likely an issue with barrel nut torque.

The rifle shoots lights out with the original 260 Rem barrel so it isn't other parts of the rifle like the HS Precision stock or a screwed up bedding block which pretty much leaves only the barrel or the bullet. The barrel doesn't shoot all other bullets great but accuracy is within normal limits for a factory barrel. So far the 150 gr ABLR is the only bullet that makes it go completely haywire.

I've got a very similar 7mm WSM using a small shank Savage short action with a custom Brux barrel. The 168 gr ABLRs shoot fine in that rifle though I have not pushed them past 2,950 fps. I do have some 150 grain 7mm ABLRs that I will push to the pressure limits just to see what they do.

As I mentioned, this problem was exhibited in two different 270 WSM barrels but they are the same part number. However, one of those (let us call that barrel number one) has a 3-port Muscle brake installed which would change the harmonics. I'm going to put that barrel back on the action and retest now that I have more bullets and am paying close attention to how they behave.

I also just bought another Bushnell Elite 6500 in the 4.5 X 30 to use as a scope to setup my rifles. I'll stick that on the rifle as it is more compact than the tactical scope I've got on the rifle now which should change the harmonics a bit and to get another data point to totally eliminate the possibility of it being some strange scope issue.

Thanks again for your help sorting this out.

 

[elkaholic]

Lots of good thoughts have been provided regards this problem. I appreciate it. I also appreciate those of you who are going to jack up the velocity to see what these bullets do when really pushed. I am very interested in your results.

If this does turn out to be a problem with the rifle it will be one for my personal record book as to how bad things can get. To go from sub MOA to missing 4 sheets of notebook paper with a few added grains of powder is something I've never seen regardless of how fast I pushed the bullets - unless the scope came loose or broke.

Since loose mounts and broken scopes don't get fixed by taking a few grains of powder out of the case this is not likely a scope problem. Since this barrel was installed by an amature (me) one has to question the gun smithing but, I have other rifles with the barrel nut torqued they same way that all shoot great, so it is not likely an issue with barrel nut torque.

The rifle shoots lights out with the original 260 Rem barrel so it isn't other parts of the rifle like the HS Precision stock or a screwed up bedding block which pretty much leaves only the barrel or the bullet. The barrel doesn't shoot all other bullets great but accuracy is within normal limits for a factory barrel. So far the 150 gr ABLR is the only bullet that makes it go completely haywire.

I've got a very similar 7mm WSM using a small shank Savage short action with a custom Brux barrel. The 168 gr ABLRs shoot fine in that rifle though I have not pushed them past 2,950 fps. I do have some 150 grain 7mm ABLRs that I will push to the pressure limits just to see what they do.

As I mentioned, this problem was exhibited in two different 270 WSM barrels but they are the same part number. However, one of those (let us call that barrel number one) has a 3-port Muscle brake installed which would change the harmonics. I'm going to put that barrel back on the action and retest now that I have more bullets and am paying close attention to how they behave.

I also just bought another Bushnell Elite 6500 in the 4.5 X 30 to use as a scope to setup my rifles. I'll stick that on the rifle as it is more compact than the tactical scope I've got on the rifle now which should change the harmonics a bit and to get another data point to totally eliminate the possibility of it being some strange scope issue.

Thanks again for your help sorting this out.

I came into this thread late and admit I haven't read much of it, but from reading your posts, it sounds VERY much like improper bullet balance. Maybe just one bad lot. Who knows? One thing is for sure from my bullet making experience; every time you add a component, or process, to bullet making, you risk accuracy! Here is what I know about the ABLR: It has a thick jacket which is not inherently as accurate as a thin jacket. This is why target bullets ALWAYS have thin jackets in a cup and core style bullet. The bullet is bonded: this gives opportunity for defect. The bullet has a void in the nose, and then a tip added: This can provide imbalance easier than a conventional bullet. Again, I would lean toward rotational velocity being the culprit as the most likely. When some of you test, watch for some of the bullets grouping fairly well with fliers that are well out of the group. This is another sign of a bullet on the ragged edge. It will be interesting to see what others find out.......Rich

 

[Lefty7mmstw]

He had tested the Long Range Accubond and the Ballistic Tip, both have similar jacket design, both very thick heavy jacket designs.

Still feel my first step would be to try a conventional cup jacketed bullet just to see if its a bullet design issue and if it repeats the same results, its very likely a mechanical issue.

From the nosler cross sections the regular nos bt looks like it has a lot more bearing surface with a lead core and rather thin jacket where obduration would be easy than the lr accubond. Has anyone actually cross sectioned similar weight/ bore examples of these to see if their pictures are anywhere near accurate?? I hate to ruin a couple of the only box I have to get measurements. The lr looks like it has a hell of a tough heel on the pictures so that could be a likely problem with an out of spec bore.
I don't put much stock in savage getting their bores right after we got a rifle marked 243 a while back from them at our lgs that had a 25 caliber bore on it. The chamber had no step from the chamber to the throat and shot like a shotgun with nearly every bullet tried. The 70 gr. speer tnt was the sole shootable bullet in that rifle. The whole bullet has a paper thin jacket and there's a heck of a lot of bearing surface so any engaugement seems to be enough to get her to spin well.

 

[winmag]

From the nosler cross sections the regular nos bt looks like it has a lot more bearing surface with a lead core and rather thin jacket where obduration would be easy than the lr accubond. Has anyone actually cross sectioned similar weight/ bore examples of these to see if their pictures are anywhere near accurate?? I hate to ruin a couple of the only box I have to get measurements. The lr looks like it has a hell of a tough heel on the pictures so that could be a likely problem with an out of spec bore.
I don't put much stock in savage getting their bores right after we got a rifle marked 243 a while back from them at our lgs that had a 25 caliber bore on it. The chamber had no step from the chamber to the throat and shot like a shotgun with nearly every bullet tried. The 70 gr. speer tnt was the sole shootable bullet in that rifle. The whole bullet has a paper thin jacket and there's a heck of a lot of bearing surface so any engaugement seems to be enough to get her to spin well.

I can try with a Dremmel Tool, but it has a grinding/metal cutting disc, so I dunno how it'll turn out, nor how accurate any measuring would be after that heat.
Ill take baby steps, & cut slow to see if I can get some pics up.

We don't know for sure yet if there is a problem, or if this is an isolated incident, but with Roy flingin' out of a 270AM at Rockstar Velocities, we'll soon find out!

 

[elkaholic]

If someone wants to send me a couple, I will perform an autopsy...Rich

 

[winmag]

I can try with a Dremmel Tool, but it has a grinding/metal cutting disc, so I dunno how it'll turn out, nor how accurate any measuring would be after that heat.
Ill take baby steps, & cut slow to see if I can get some pics up.

We don't know for sure yet if there is a problem, or if this is an isolated incident, but with Roy flingin' out of a 270AM at Rockstar Velocities, we'll soon find out!

Ok
It's official that I will NEVER be invited to join the Mythbusters for Employment!

Disclaimer;
I Love Nosler bullets. So incase anyone ever googles this, let it be known that my "methods of autopsy" are beyond Crude, & more inline with the way a cave man would do things if Dremnel tools were invented in cave man times.
I used a vice, & a Leatherman to hold said projectile, & a Dremmel tool with a metal cutting disc.
My cut is way off center, & more crooked than Obamacare.
Too much heat was transferred while cutting thru the thick brass base. So much heat I fact, that the grey tip made a "pop" sound & popped clean out of the cavity it was anchored in & flew somewhere onto the floor, under my cabinets. No doubt to become a treasure to some bug who lives there.
So, while I got the job done, it was anything but scientific, & my findings have 0 bearing other than showing my version of the cross section is in fact similar to the Picture Nosler posts of the ABLR.

Without further a due' here are my pictures. One post at a time. Remember, "cavemen" don't know how to post multiple pics in one post.... (that sounded weird)

 

[winmag]

Note, my cut was WAAAAY off center. I apologize.
Oh, & that crooked thick part by the bearing surface o give junction is from being squished a tiny bit in the vise....
Sorry guys. I have many tools, but a bandsaw, & jewelers tools aren't on that list. Nor do i have nimble fingers!

Amazing how those bullets jump around when you go cuttin' into em'!

 

[winmag]

Crude measurement from meplat to base of cavity.
***Very Crude Measurement***

 

[winmag]

Again,
I apologize for my methods.

I still have a hard time cutting up shootable bullets, especially these, which prove even more difficult to get, in the middle of a "component recession".


Rich ill be flinging you a PM after a quick game of hide & seek, that I promised to my kids.....
Gimme about a 1/2 hr hahaha

 

[LONGSHOOTER]

You could try putting a fine mill file across it to try to improve the cut.

 

[royinidaho]

winmag,

U do my kinda work!

I too have an adversity to chopping up precious projectiles.

Next try, cut a groove in a board. Metal putty the bullet in the groove. Go from there

 

[winmag]

winmag,

U do my kinda work!

I too have an adversity to chopping up precious projectiles.

Next try, cut a groove in a board. Metal putty the bullet in the groove. Go from there

Ahhh,
Young grasshopper should've consulted the master BEFORE I squished it in a vise

Good call Roy,
I may have some JB Weld layin around somewhere. Goodness knows I've got boards, drills, table saws, etc to make a sweet bullet torturing rig. I just didn't think far enough out of the box.
The vise was on the bench, so it never occurred to me.
By the end of the Autopsy, I had the feel for exactly when to quit cranking on the handle and not have the bullet fly out as i cut into it. Also knew just how hard crank it before I squished it. Trial & error, ya know.

I had a What Would Roy Do? moment when that bullet got hot & I heard the sound of rice crispie's as the tip shot out of it. Pop!
All I could think of, as I stood there in disbelief, was, Roy would just superglue that sucker back in! I laughed the whole time I searched for it.

 

[bigngreen]

Looks interesting!! Sizable section of unsupported nose that the tip would push against at launch. Can't wait for more results gun)

 

[Fiftydriver]

From the nosler cross sections the regular nos bt looks like it has a lot more bearing surface with a lead core and rather thin jacket where obduration would be easy than the lr accubond. Has anyone actually cross sectioned similar weight/ bore examples of these to see if their pictures are anywhere near accurate?? I hate to ruin a couple of the only box I have to get measurements. The lr looks like it has a hell of a tough heel on the pictures so that could be a likely problem with an out of spec bore.
I don't put much stock in savage getting their bores right after we got a rifle marked 243 a while back from them at our lgs that had a 25 caliber bore on it. The chamber had no step from the chamber to the throat and shot like a shotgun with nearly every bullet tried. The 70 gr. speer tnt was the sole shootable bullet in that rifle. The whole bullet has a paper thin jacket and there's a heck of a lot of bearing surface so any engaugement seems to be enough to get her to spin well.

I am sure the bullets match their picture in the box. I was just reffering to the fast that both have a very heavy, thick base of solid guilding metal.

Sounds like that Savage barrel should have been returned for a new one!!!