Nosler Accubond Long Range problem

[royinidaho]

Engr'ng101,

As was said a pic is worth 1k words.

The boolets haven't arrived, yet but . . .

The lower right, the highest velocity, group is very familiar to me.

In a 3 groove, 8 twist, 30" Lilja barrel groups shape like the identified group resulted when the following bullets were pushed:

Bergers of any weight @ 3200+
Original WC 195 rbbts at AM velocities - after 400 rounds through that bbl.

Every so often the 195s would dust.

However, Hornady 140 BTSPs, Nosler 130/140/150 BTs and ABs shot lights out at all velocity.

Man! How I hated to see banana shaped groups!!!

I'm strongly leaning towards jacket failure.

 

[Pdvdh]

Engr'ng101,
I'm strongly leaning towards jacket failure.

Yep, it's a safe bet it'll be the bullets - based on two different rifles and three different barrels eating them for lunch at 3000 fps.

 

[bigngreen]

It'll be interesting to see what the "jacket separator" revels when these are shot at the speed of Roy, I hope they survive because if they don't it will be a huge kick in Noslers sack if they've made a thick jacketed, bonded bullet that can't handle 3000+ fps!!

 

[gamehawker]

It'll be interesting to see what the "jacket separator" revels when these are shot at the speed of Roy, I hope they survive because if they don't it will be a huge kick in Noslers sack if they've made a thick jacketed, bonded bullet that can't handle 3000+ fps!!

Now that would really suck because I plan on shooting the 150gr @3,360 fps and the 168gr @ 3,180 fps out of my twin Remington 700 Sendero SF 7mm STWs.

 

[Lefty7mmstw]

Now that would really suck because I plan on shooting the 150gr @3,360 fps and the 168gr @ 3,180 fps out of my twin Remington 700 Sendero SF 7mm STWs.

I'm going try to get an accurate load going up to 3,300-3,350 fps with my 7stw this weekend with the 150 7mm alr. I've got a 10" twist so the rotational stresses will be a touch less than rem's 9.ish, but they'll still beat up on her if the pill isn't built well. I'm going to play with rl25 first, but rl33 or aa8700 may well be the ticket for a gray poof a few feet off the end of the bbl..

 

[elkaholic]

Looking at all the evidence so far, Roy may not even hit the target when the velocities are pushed! Better hope it was just a bad lot........Rich

 

[gamehawker]

I talked to Mike at Nosler (he is the only tech in the reloading dept.) today and I told him there was a discussion on this forum about the ABRL not performing over 3,000 - 3,200 fps. He said the that is wasn't aware of any problem. Yesterday he talked to a 7mm Weatherby shooter and his reloads with the 168gr. are under .5 MOA and they were a pretty hot load (around 3,100 fps).

He asked which grain we were talking about and I told him the 150gr. He again has not heard of any problems or any negative feedback in the field about the 150gr.

Looking forward to seeing Roy's test results.

 

[Joshuak12]

Just wanted to a) subscribe and b) say thanks to all for the excellent discussion. Threads like this with lots of experienced shooters and reloaders chiming in (and no dumb ****ing matches) are incredibly informative for guys like me who are relative novices in the reloading game.

 

[MontanaRifleman]

The plot thickens.....

 

[longarm]

Well, I tried something a little off the track. See what you think of this. I posted a target below. I think it illustrates the problem I have been having with the 270 WSM using the 150 grain Nosler Accubond Long Range bullets even though I shot the target with a different rifle and ABLR bullet.

The target was shot with a Savage 7mm WSM using the 7mm 150 grain ABLR bullet (first cousin to the bullet in question). That rifle has a 4-groove Brux barrel attached and as the target shows has some issues with these bullets – however it is not near as bad as the factory barrel on the 270 WSM. All loads were H4831SC fired at 200 yards.

Shots in group number 1 averaged 2,871 fps which used a low stress load of 63.0 grains and group size was decent at 1.156".

Loads for group number 2 were bumped up 1 grain to 64.0 grains of H4831SC which resulted in an increase in average velocity of 64 fps to 2,935 fps. Group size of 0.734" indicates good barrel timing – the bullet is leaving the barrel at a favorable time (low barrel distortion and movement).

Loads for group number 3 were bumped up another grain to 65.0 grains with average velocity up another 56 fps to 2,991 fps and is just starting to get into trouble with 1 flyer opening the group to 1.781".

Loads for group number 4 were bumped up another grain to 66.0 grains with average velocity was up only 27 fps but nevertheless over the magic 3,000 fps to 3,018 fps and things hit the fan with a group of 4.093". There are some bad barrel/bullet interactions going on.

These ABLRs act more like Bergers than Accubonds when shot with a load that is out of tune with the rifle which means that they can shoot really bad. I don't recall the original Accubonds every doing that.

In my factory barreled 270 WSM I think the same thing is going on as with the 7mm WSM but the 270 WSM, for whatever reason, amplifies the effect by a factor of about 5 which results in bullets that go clear off the paper. I may have to reevaluate my original thought that this has to be a bullet problem. The bullets may be more sensitive than I'm used to seeing but I'm beginning to think that they are just what Nosler intended to make.

I think Kirby may have been right in his initial assessment – this is most likely a problem with barrel harmonics and not with the bullet.

Having said that, I'm still interested to see what the high velocity and expansion test results show. I'm betting the ABLRs hold up well but from what I've seen so far they don't always act nice and friendly like the original Accubonds.

I have used 4831sc for 130 grain Accubonds in a 270 WSM at 3260 fps and also for 140 grain Accubonds at 3420 fps in a 270 Dakota. I think 4831sc is too fast for 150 grain projectiles from your target of the 7mm WSM, ie, you need a slower powder such as Retumbo or H1000. Your correct load if you want to use 4831sc is 64 grains with the 150s. Once you go past this, your velocity is not consistent any more, possibly your pressure is creeping up too high and your rifle starts to shoot all over the place.

 

[winmag]

I knew I'd read this somewhere on LRH.
MMERS Post in the Long Range Shooting Section of LRH:

Accubond LR Comparison and G7 BC Test
A hunting companion called me last week inquiring if I had any luck locating the Long Range AccuBonds (LRAB) for his 7 Rem Mag he recently purchased. "Not yet," I informed him. He has portrayed several times not being comfortable hunting with what he called "exploding" bullets. With the new line of LRABs advertised, he was quite interested in their performance. I informed him I had recently acquired two boxes of the 30 Cal 210 LRAB's and would be willing to test a few around 1000 yards with the results used to help him with his decision on a direction for a bullet to use in this new rifle. I also was not willing to invest more than 40 total rounds during tests to save barrel life on my rifle.

With the name Long Range, an appropriate starting point for testing would be with bullet consistency and evaluating the advertised G7 ballistics coefficient. I used the Berger 230 Grain Hybrid Tactical OTM with an advertised G7 BC of .368 for comparison to the LRAB advertised G7 BC of .366.




Pictured left to right for visual comparison are the 30 cal Berger 230gr Hybrid OTM, 30 cal Nosler 210gr LRAB, 338cal Berger 300gr Hybrid OTM, and 338 cal Nosler 300gr AccuBond.


I decided to evaluate the LRAB with comparison to the Berger OTM in four areas:
1. Base to Comparator length.
2. Weight.
3. Short range precision to include muzzle velocity variation.
4. Computer generated G7 BC drop results tested at ranges near 1000 yards specifically for the LRAB. I have shot the OTM's for the past few years and have confidence in their advertised G1 and G7 BC's.

Base to Comparator Length and Weight


Twenty bullets each were randomly selected, measured, weighed and placed back into their box. Sorting was not conducted. Length was measured using a Sinclair bullet sorting stand and quick sorting comparator. Weight was measured using a Sartorius M-prove scale.


Berger OTM
Average Weight - 230.07 grains
SD .091 grains
Average base to comparator length - .789"
SD .00074"

LRAB
Average Weight - 210.31 grains
SD .221 grains
Average base to comparator length - .766"
SD .00078"

Short Range Precision (Group Size in MOA) and Muzzle Velocity Variation


Three shot groups were taken with each bullet at 100, 200 and 300 yards. Average group size was measured in MOA. An Oehler M-35p chronograph measured the muzzle velocity of each shot. The rifle used during testing was an accurized Remington 700 LA fitted with a 30" Lilja 1-10" twist barrel chambered with a SAAMI reamer in 300 RUM and skim bedded in an HS Precision stock. A Nightforce 8-32X56 NXS scope with NP-R1 reticle topped the rifle and finished with a Sinclair bipod. Rounds were loaded three grains below estimated MAX charge with an OAL of 3.660" thus allowing just enough room for clearance in the magazine. Free bore was approaching 170 thousandths of an inch for each. Keep in mind load development was not conducted and results could have varied by conducting load development. I was more interested with the muzzle velocity standard deviation results considering the LRAB was not as precise in bullet weight as the Berger's.

Berger
Average three shot MOA .64
Average Muzzle Velocity 2960 ft/s, SD 15 ft/s

LRAB
Average three shot MOA .96
Average Muzzle Velocity 3136 ft/s, SD 11 ft/s

LRAB G7 BC

Ten additional LRAB's were loaded using an estimated MAX charge and zeroed. The four shot average zero muzzle velocity was 3222 ft/s.

The next morning a target was set up at 960 yards. Adjustments were made for wind and spin drift. Three shots were taken using the advertised G7 BC of .366 utilizing my ballistics engine. The group measured 18" low and 9" in size.
Note the vertical.

The target was then placed at 1095 yards for my last three shots. The first shot hit low just missing the target. I adjusted up 2.25 MOA and fired my last two rounds. The two shot group measured 12" low and was 11" in size.
Note the vertical.

The advertised LRAB G7 BC of .366 is significantly above a corrected G7 BC required for my particular firing solution for the ranges noted above.

Of particular interest is the vertical displacement of the two groups. While two groups do not support near enough data to draw any form of validity, the results look promising. Both LRAB groups additionally measured approximately the same average MOA as in the short range testing while under slight wind and mirage changes (less than 3 MPH). The vertical displacement appears promising. I would consider the LRAB of having the potential of being a formidable long range hunting bullet compared to their current AccuBond design with further tested G7 BC validation and hand load development.
__________________
Shoot CONFIDENT, Shoot SMART, Shoot STRAIGHT

 

[winmag]

Guess tho pics didn't copy, but the thread is currently on page (13?) in the Long Range Shooting section of LRH if you wanna look at the pics, & read/compare these threads.

 

[Engineering101]

gamehawker

As I said in my original post, I talked to Nosler's tech guy (Mike) on 30 August and told him of this problem with the 270 cal 150 gr ABLR. He said that he had heard of no problems and mentioned that the bullets were shooting good in some of the other calibers. He said he would check with the guys that tested the bullets at Nosler to see how fast they ran them and get back with me to let me know what he found. He never called back.

Mike apparently is going senile because we talked for 10 minutes or so about this and I made it very clear what bullet I was talking about. He also forgot to check with Nosler's testing department and he apparently forgot to call me back.

Disappointing to say the least.

 

[gamehawker]

gamehawker

As I said in my original post, I talked to Nosler's tech guy (Mike) on 30 August and told him of this problem with the 270 cal 150 gr ABLR. He said that he had heard of no problems and mentioned that the bullets were shooting good in some of the other calibers. He said he would check with the guys that tested the bullets at Nosler to see how fast they ran them and get back with me to let me know what he found. He never called back.

Mike apparently is going senile because we talked for 10 minutes or so about this and I made it very clear what bullet I was talking about. He also forgot to check with Nosler's testing department and he apparently forgot to call me back.

Disappointing to say the least.

Well, why don't you call Mike back, refresh his memory about your conversation and see if he has checked with the guys that tested the bullets at Nosler to see how fast they ran them?

My understanding is that he is the only tech at Nosler so he's probably really busy. But if you call him he usually has time to talk to you.