Nosler Accubond Long Range problem

[Fiftydriver]

With the 150 grain projectiles in the 270 WSM, The Hodgdon Reloaders' Guide gives maximum loads as:

Retumbo 70g 3071 fps 63000 psi
H1000 67.5g 3001 fps 62,800 psi
H4831 60g 2962 fps 63,100 psi

This is consistent with my own findings that when moving to the 150 grain projectiles from 130 and 140 grains, Retumbo or H1000 gives better results than H4831sc.

In a factory chamber, its VERY common that you have to use 2-3% more powder to get the same listed velocity and pressures as documented in most reloading manual simply because factory rifles have looser spec chambers, throats and bores compared to most test rifles used by the reloading companies which will use match barrels most often with match chambers. In my experience, most reloading data listed in manuals about the only useful information in them is the velocity output.

Velocity is simply a function of pressure and time. Often in a factory rifle it takes more powder to reach the listed velocity simply because of the looser specs in the barrel. That is why its always best to shoot over a chronograph so you KNOW your velocity. If your getting the same velocity using a listed powder and bullet in a loading manual, you will roughly be loading to the same chamber pressure even though you may need more or less powder to get to that same velocity level.

 

[Fiftydriver]

Engineering101,

In your first post you stated that you used 60 grains of 4831sc with the 150 Accubond in your 270 WSM and this was accurate. This is a maximum load as seen in my post above. When you went above this maximum load,( by a few grains I suspect to get over 3000 fps) the accuracy disappeared. I think that the design of the 270 WSM case (much like Ackley Improved cases) might be masking the excess pressure so you are not seeing it by the usual pressure signs. However, I get the usual pressure signs when I load more than the maximum load of 67 grains of 4831sc with the 130 Accubond in my 270 WSM. If you switched and worked up slowly to 70 grains of Retumbo, I think you would get over 3000 fps without the problems with the 150 grain LR Accubond when using more than 60 grains of H4831sc.

The Nosler bullet SHOULD NOT loose any accuracy pushing it WELL over 3000 fps no matter what pressures are behind the bullet. I have NEVER seen a nosler Ballistic tip or Accubond that ever had a single issue with velocity up to and including 4000 fps with 270 and 7mm bullets in my 270 and 7mm Allen Magnum. Something is wrong with this combination and that is what the OP is trying to figure out, why is this bullet going to heck over 3000 fps as it SHOULD NEVER do.

He is not trying to find a load that will WORK with this combo, whats to find out whats wrong with his combo as this bullet should easily be able to be driven well over 3000 fps no matter what powder or pressure is behind it in the chamber and bore.

I think your kind of missing the point of this post. Point is these bullets should never loose accuracy at a hair over 3000 fps and the goal is to find out why this is happening. If its the bullet that is the problem, the testers that will be shooting them out of the 270 Allen Magnum and 7mm STW should show some serious bullet failures. If those two rifles shoot these bullets accurately, the problem is obviously with the OPs rifle. Again, this is the goal of this post, to find out if the problems the OP is seeing is bullet related or rifle related, not to find an accurate load that will work.

 

[winmag]

The Nosler bullet SHOULD NOT loose any accuracy pushing it WELL over 3000 fps no matter what pressures are behind the bullet. I have NEVER seen a nosler Ballistic tip or Accubond that ever had a single issue with velocity up to and including 4000 fps with 270 and 7mm bullets in my 270 and 7mm Allen Magnum. Something is wrong with this combination and that is what the OP is trying to figure out, why is this bullet going to heck over 3000 fps as it SHOULD NEVER do.

He is not trying to find a load that will WORK with this combo, whats to find out whats wrong with his combo as this bullet should easily be able to be driven well over 3000 fps no matter what powder or pressure is behind it in the chamber and bore.

I think your kind of missing the point of this post. Point is these bullets should never loose accuracy at a hair over 3000 fps and the goal is to find out why this is happening. If its the bullet that is the problem, the testers that will be shooting them out of the 270 Allen Magnum and 7mm STW should show some serious bullet failures. If those two rifles shoot these bullets accurately, the problem is obviously with the OPs rifle. Again, this is the goal of this post, to find out if the problems the OP is seeing is bullet related or rifle related, not to find an accurate load that will work.

Hey Kirby,
I agree, we need to First determine if there is a velocity, and or, pressure ceiling, to confirm weather its the rifle, or the bullet.
I'm still hopefull this is an isolated case. But like stated, when Roy gets done with his testing, we'll know alot more, & won't have to speculate.
There are posts from other LRH guys pushing the ABLR well over 3100, & even 3200 with sub MOA groups to around 1k.
However they are doing it with the 210, 30 cal not 270, or 7mm.
I don't see a design problem there, BUT that doesn't mean the ABLR design is good to go all the way across the board. There may be a design issue with the 270, & 7mm 150's.
The truth will stand on its own, so I guess all we can do is anxiously wait for Roy's results.

 

[MontanaRifleman]

There are posts from other LRH guys pushing the ABLR well over 3100, & even 3200 with sub MOA groups to around 1k.

That was with the 308 210's.. Might be a different jacket? We should have a very good idea what is very soon.

 

[LONGSHOOTER]

Longarm,

I think you're onto it. Being unfamiliar with the cartridge, I didn't know his load was over book max (107%).

 

[Pdvdh]

Longarm,

I think you're onto it. Being unfamiliar with the cartridge, I didn't know his load was over book max (107%).

The original poster has a lot of experience reloading for firearms and he knows how to fine tune a load for a rifle. Groups went from less than moa to greater than 12 moa at 3000 fps in one rifle with some extensive testing, and degraded to about 4 moa in a second rifle with limited testing. A second barrel placed on the original Savage rifle resulted in a similar experience. He's already replaced scopes in a troubleshooting effort and the problem persists. So he's got two bad rifles and a third bad barrel, if the barrel/gun combinations are to blame. If it is the barrels/rifles/scopes, the OP is the unluckiest guy in the world.

With respect to using powder charges that exceed book max, that's a non-issue. Most of the loads developed by the members of this Forum exceed the maximum powder charges listed in the reloading manuals and the end result is superb accuracy.

 

[LONGSHOOTER]

The first thing I thought when reading the OP was "what powder charge is max?".

My next thought was "not enough info".

I have a 300 WM SAMMI max chamber that does not like going over book max. But, it likes book max. Should I try for the next node? No.

 

[Pdvdh]

I called off my trip to the hills to tune up for going a mile with the 375 to work on this project.

Should be a fun day.

Give'm heck Roy. The bullets that is...

 

[winmag]

That was with the 308 210's.. Might be a different jacket? We should have a very good idea what is very soon.

Ya, read the next line.

I dunno on the jackets. Could be.
Maybe a bore diameter-bullet ratio no one noticed till now at certain pressure?
Could be anything. Could be nothing.
I noticed Noslers 270WSM Box ammo with this bullet is advertised at 2960 fps. Coincidence? Maybe, but I doubt they failed to think many/most of us would run em a little hotter. They are advertised as LR after all, & most of us tend to shove on whatever we load, within a safe, accurate, & consistent parameter. You'd sure think/hope they tested them higher. If not, Nosler is gonna have egg on their face.
It's all speculation at this point.
We'll know more soon. Come on Roy, the suspense is killing us

 

[Pdvdh]

I have a 300 WM SAMMI max chamber that does not like going over book max. But, it likes book max. Should I try for the next node? No.

Question? When you exceed maximum book powder charges with your 300 WM, does your group size grow 10 to 20 times the size you had just prior to exceeding maximum book listed powder charges? If not, then I'd suggest that Engineering101 is experiencing an issue with a cause that is different than what you experienced with your 300 WM.

 

[LONGSHOOTER]

Question? When you exceed maximum book powder charges with your 300 WM, does your group size grow 10 to 20 times the size you had just prior to exceeding maximum book listed powder charges? If not, then I'd suggest that Engineering101 is experiencing an issue with a cause that is different than what you experienced with your 300 WM.

I don't see any 10-20x group sizes. But I do see him leaving the node.

Why not move to 100 yards, and document? Was it his intention to push the envelope? Why not steps to shrink the group?

 

[MontanaRifleman]

I don't see any 10-20x group sizes. But I do see him leaving the node.

Why not move to 100 yards, and document? Was it his intention to push the envelope? Why not steps to shrink the group?

This isn't about trying to find an accurate load/node. It's about trying to determine if these bullets have a high velocity failure point. There seems to be some evidence that they do. Once they've been fired from another rifle at higher velocities we will know.

 

[Pdvdh]

I don't see any 10-20x group sizes. But I do see him leaving the node.

Why not move to 100 yards, and document? Was it his intention to push the envelope? Why not steps to shrink the group?

He did shoot at 100 yards. His groups enlarged from 0.656" at 100 yards, and less than 1.5" at 200 yards, to completely missing 4 sheets of 8.5" x 11" paper. See the underlined statements from the OP below. The reason you don't see (pictures of) any 10-20 times group sizes is because the bullets never even landed on a target that was a minimum of 17" x 22" square. The OP states he doesn't know what group size they shot because the bullets didn't strike his target, however "it had to be at least a foot to miss all that paper". His group size went from 0.656" to greater than 12". Thus, increased by a multiplication factor of at least 18.

I shot a 3 shot group of 0.656" at 100 yards using my 270 WSM with the new 150 grain ABLR and 60.0 gr of H4831SC, 26" bbl, COAL of 2.915". In two different barrels with different scopes I've seen the same thing. Get near 3,000 fps and the bullets go all over the place. At 2,966 fps they grouped under 1.5" at 200 yards, but at 3,000 fps I can miss 4 sheets of notebook paper while aiming at the center, then go 4 inches right and then hit point of aim and then back to no bullet hole at all.

I'm guessing that they will shoot a lot better as did the 150 ABLR bullets however all shots today landed on my 8.5" X 11" target paper whereas the ABLRs wouldn't stay on 4 of those targets thus I don't know what group size they shot when they went bad but it had to be at least a foot to miss all that paper.

 

[LONGSHOOTER]

Yes, if he's missing the target at 200, shouldn't he move it to 100? I can't see groups that aren't on the paper, whether you say 10-20, or whatever.