300 Win Mag accubond consistency issue

[David-A]

Just wondering if anyone has had issues with newer ammunition.

I'm shooting 300 win mag 180 gr AccuBond in a Browning x-bolt. In the past these have worked very well with good groups at 100 and 200 yd's. Almost sub MOA. I mounted a new Zeiss v4 6-24 on and zeroed it at 100 with an old box of accubonds. Sub moa as usual. I ran out and opened a new box from a different lot and ahhh bullets were all over the place about 3 inches higher and 4 moa. The new ammunition has silver primers my old ammo has brass. Not sure if that makes a difference. I tried a different lot I had a few weeks later and the same thing. Tried some of my very accurate deer rounds and they grouped sub moa. What has happened.
I bought most of my ammo during covid times in Canada. We were limited to 2 boxes when a shipment came in so I slowly acquired 10 boxes with different lots. I have not tried any of the newer lots yet.

 

[bkordon]

Welcome to the forum. There are number of individuals with considerable more expertise than I do, but I might start with checking your rings and bases to be sure something didn't shift or has come loose. Another question would be is all the ammunition from the same loading ( Trophy Grade or Custom, etc). I understand different lots, but different loadings could have different specs. I'm curious to see what others think.

 

[David-A]

Yes everything is tight. The ammo is all nosler trophy grade AccuBond 180 grain. I also shoot Fed berger 185 hybrid hunter and they group well.

 

[bkordon]

I'm not going to speculate and let the experts take it from here.

 

[JD338]

I think I would...
1. Try the newer lot
2. Start reloading. You can find a load for your rifle and have repeatable results

JD338

 

[cloverleaf]

"The new ammunition has silver primers my old ammo has brass. Not sure if that makes a difference."

I copied this because I was afraid I had read it wrong. In my experience, All the factory ammo I have shot from Rem, Winchester and Hornady, and Norma had "brass" colored primers from the factory. Never had silver primers unless they were reloads. Is that somthing particular to Nosler? Just seems odd to go to 4inch groups w/ a different box of factory ammo. I've been usining Rem. brass predominately in my 250 Savage for 30 years. Groups arent Stellar but they typically run 1.5-2in, unless Im not doing my part. Just wondering....CL

 

[wvbuckbuster]

I'd say the increase in group size was due to being different lot than your old ones that your rifle preferred. As for primers being different color, saw a picture posted of factory loads during covid that had both colored primers. Take Jim's advice and start reloading. That way you can develop a load just for your rifle and it's a good hobby to boot.
Dan.

 

[salmonchaser]

I have seen observable differences in factory ammo going from lot to lot. Nothing as extreme as your experience however. I would make a note of the lot numbers, capture a good photograph of the lot number, boxes and cartridge base and contact Nosler directly. I’ve been on the forum for 10 years or so and don’t recall a Nosler official logging in to address an issue with any of their products.
Seems likely Nosler may have been trying to make do with what ever they could get their hands on at that time.
Your rifle seems capable of shooting good groups, if you know some one who re-loads you might invest some time, a little money and put together a box of reloads and see how they perform before jumping in with both feet.
I’ve had my reloading equipment since Christmas 1966, no idea what a basic set up costs now but would bet the price of 3 boxes of Nosler trophy grade would cover it. If you’ve more than one center fire rifle it really starts to make sense.
Worst case scenario you’ve several boxes of good components, pull the bullets, scatter the powder in your yard, it’s mostly nitrogen, help your grass grow and work up your own loads.
An awful lot of us here have loaded for the 300 WM. It is inherently a well behaved cartridge and you should be able to get one MOA reliably. I’ve used Accubonds from Alaska to Arizona to Africa. I think they are worth the effort getting them to shoot in any rifle you hunt with.
Good luck and welcome to the forum.

 

[PJGunner]

The different color primers strikes me as odd. Too, apparently possibly several different lots of ammo as well. Each one of those different lots could be using the same powder but different lots of that powder. Could even be a different powder altogether. Also brass is probably from different lots. If all else appears good, it could even be the shooter having a really bad day.
With ll that said, I've been reloading my ammo for targets and big game hunting for years. I started in 1954 and within two years after that was using my handloads exclusively for targets and hunting. About the only time I buy any factory ammo is if I buy a new rifle or handgun, The ammo for the hand gun is generally to see how the gun shoots. Basically the same for rifle ammo primarily to see how accurate the gun might be and to set up my sizing die if radically different. I'm honestly not sure when I last hunted using factory ammo.
It'll sure be interesting when there is answer to this situation.
Paul B.

 

[RL338]

Going from shooting 1 minute to 4 minute with the same bullet is hard to believe. Yes a powder change to a different primer can cause an accuracy issue but what you’re seeing is quite extreme.

 

[JD338]

Agreed. Maybe tear down one round (new and old) and weigh the powder charge. Also se if the two powder charges look the same or different. Might as well deprime and inspect the primers and finally weigh the cases.

JD338

 

[Blkram]

Sounds like one of the two main variables, or a combination of both, is the issue for you.
1) The newer production lots are going to be different than your older lots. Different lots of powder used in production from your initial lots to the newer lots is the main issue here. And even if you do/are handloading, the powder we can buy is different than the commercial grade powder available to the ammunition manufacturer, and will produce different results.
2) The difference in primers are also going to produce different results. Every handloader can see measurable differences in performance when changing from one brand of primer, lot of primers, and even type of primers (large rifle to magnum rifle, or regular to match).

During COVID, and pre-COVID during the various component shortages, even the manufacturers were having issues obtaining components and keeping up with production for the commercial markets, leading to changes in production, and this may be the root cause in the issue being experienced. If you can find old stock on the shelf somewhere, at a gunshow, or even from online forums of people selling ammo privately, buy what you can when you find it, of the same box type as what works in your rifle (unless you're lucky enough to find more of your lot number and can get that!), to keep ammo on hand.

Other than that, try some other ammo and see what else your rifle prefers in current production.
As much as I love AccuBonds, I am really liking what I am seeing in performance from Federal's Terminal Ascent ammunition, both in accuracy on target, and performance on game in the field.

 

[NYDAN]

I have seen that Nosler changes their loads for a particular cartridge over time. Below are pictures of boxes from two different 300 WSM 180 AccuBond loads. On the surface they appear to be the same. However, when you look at the velocity and trajectory table on the back of the box you can see that they are different loads. One has a stated muzzle velocity of 2900 fps and the other has a muzzle velocity of 2950 fps. These are different loads.





I dare say that the different lots of cartridges you have could very well have different loads in them. Especially since you see different primers.

 

[David-A]

Yes I was going to try them. Its just frustrating I tried many brands until I found accubonds worked well. I stocked up on ammo when it was available, now it's useless. In Canada they are now $140 a box