Loss of accuracy after switching to Lapua brass?

[The_Savage]

hello everyone,

I recently worked up a load with the 73 grain Hornady ELD match in 5.56 NATO. I worked them up using once fired brass that appeared to be Lake City based on the headstamp that I got from some full metal jacket plinking ammo that I used up. I used 28.0 grains of PowerPro 2000 MR, and the accuracy was great, getting less than one half MOA at 100 yd with 5 round groups. I went to measure the velocity, however, and it had too high of a standard deviation for me. I did some research on the internet, and found out that Lapua brass is supposed to be the most consistent brass and the best out there, So I ordered 100 cases, fire-formed them, and loaded them with the same CBTO, powder charge and bullet and primer. I went to test the new load out and... they sucked. All 5 round groups were way over an inch, and were way worse at 200 yards. So I figured I'd have to do some more load development. I lowered the grainage by one grain, and worked my way back up to 28 with 0.3 grain increments in between. The best group I got out of these was slightly under one MOA (0.97), and I'm wondering if brass can affect this accuracy THIS much. the Lapua brass is very consistent and does seem to be lasting for a lot of loadings, so I hate to see this brass not perform as well as the lake City brass which didn't last for very many loadings before the primer pockets became loose. any help you guys can provide will be appreciated;thanks in advance!

 

[MEHavey]

Did you load for same velocity -- measured?

 

[AJC1]

Your pressure dropped because the lapua brass has more volume. The neck tension changed likely a lot. You will have to start over completely.

 

[Demi-human]

So, Standard Deviation isn’t everything, as you’ve just evidenced.

Less brass in a case means more powder is needed to make the required velocity the barrel needs to be accurate. 28 grains is not your top anymore.

How fast are you losing LC brass? Lapua is a bit pricey to be blowing out the pockets...

 

[lordpaxman]

I went to measure the velocity, however, and it had too high of a standard deviation for me.

That’s a tease... You have to tell us the numbers now. You aren’t the first, and won’t be the last to see precision doesn’t always track SD. If you’re shooting longer distances, lower SDs mean the world of difference.
I’m not a PowerPro 2000 user but I’m wondering if your loads are at the max for your gun? I’d be tempted to do a ladder test with the Lapua brass and work it back up. As others have commented, case volume matters, but it could just be the primer/powder/bullet/neck tension combination. Good luck!

 

[Blue68f100]

I agree with the others your case volume is larger with the Lapua and your velocities are lower. You can measure the case volume of both and it will give you an idea of how much more powder will be needed to get them to mach. It's a test I do when I have different lots of brass. Neck tension will also be different.

I always let the paper trump the SD numbers. I've had some loads over the years that the SD was very high but always shot good. If the load is balanced to the harmonics of the barrel it auto compensates. But it all depends on how far your going to be using the loads. Past 500 yrds it starts to impact on accuracy.

 

[entropy]

If you're doing that kind of loading and didn't know the difference in volume you'd experience.....that and why would you waste Lapua brass on 5.56 loads. I'd save those for bolt action .223 loads, where they'd make a difference.

 

[243winxb]

Standard dies will over work the thicker walled case necks. Buy bushing die.

 

[hardheart]

that and why would you waste Lapua brass on 5.56 loads.

at what MOA is Lapua brass not a waste, since he was at <0.5 before changing brass?

 

[Toprudder]

I would be very happy with 0.5moa from cheap and readily available brass.

To improve the SD with the cheaper brass, look at annealing and turning necks. The latter showed a significant improvement for me. This makes for more consistent neck tension.

 

[entropy]

at what MOA is Lapua brass not a waste, since he was at <0.5 before changing brass?

When his MOA went all wonky because he did not factor in case capacity differences.

 

[AJC1]

When his MOA went all wonky because he did not factor in case capacity differences.

When your at .5 moa and you dont realize that changing brass most likely will show zero improvement based on platform.

 

[The_Savage]

Well I tried the LC brass, and it made no difference; it was still inaccurate. The group must've been a fluke. I'm just going to stick with my 0.97 MOA load. I guess I expected better from a stainless steel varmint barrel from White Oak Armory for $300 when my 308 savage shoots better for $280 for the whole rifle. Thanks for all the help anyway!

 

[Blue68f100]

You should do a new load workup for the new barrel. Also it may take 100 rounds for the barrel to stabilize. Also it's common to get Cu fouling on new barrels due to roughness. Clean your barrel with some copper fouling solvent and make sure it's not from fouling. Once they smooth out it should be more consistent. If fouled you can polishing the bore using Butches Bore Shine Paste on a jag/patch. This will help it smooth out faster.

 

[AJC1]

Well I tried the LC brass, and it made no difference; it was still inaccurate. The group must've been a fluke. I'm just going to stick with my 0.97 MOA load. I guess I expected better from a stainless steel varmint barrel from White Oak Armory for $300 when my 308 savage shoots better for $280 for the whole rifle. Thanks for all the help anyway!

Jonnys reloading bench did a series of videos with that barrel and a few others. Assuming that their product has any consistency you should be able to learn a lot from his ocw testing. Compare barrel lengths of yours and his and if close you should have a decent roadmap. If length is different then back to square one.

 

[Demi-human]

Well I tried the LC brass, and it made no difference; it was still inaccurate. The group must've been a fluke. I'm just going to stick with my 0.97 MOA load. I guess I expected better from a stainless steel varmint barrel from White Oak Armory for $300 when my 308 savage shoots better for $280 for the whole rifle. Thanks for all the help anyway!

Does an incomplete load work up, blames barrel, then compares to a completely different platform and cartridge.

Evidently Lapua is so good its not the brass...

If you have to vent, that’s fine, but I don’t see where you’ve put in a semblance of proper work up.
Shots in the dark.
And evidently banking on one fluke group.

I’ll have to take that White Oak knows what it’s doing.
If you said an ARStoner barrel from Midway, maybe, but if it truly was a deficient barrel White Oak would fix it.

I don’t know what isn’t working, but casually blaming rifle parts won’t get it done.
If the barrel is new, was it installed properly? I thought the brass was new?
How many things did you change at once?
We’re these chronographed too?
The Savage is a Red Herring. Everyone knows they shoot great, what has that to do with your load work up?

 

[AJC1]

Does an incomplete load work up, blames barrel, then compares to a completely different platform and cartridge.

Evidently Lapua is so good its not the brass...

If you have to vent, that’s fine, but I don’t see where you’ve put in a semblance of proper work up.
Shots in the dark.
And evidently banking on one fluke group.

I’ll have to take that White Oak knows what it’s doing.
If you said an ARStoner barrel from Midway, maybe, but if it truly was a deficient barrel White Oak would fix it.

I don’t know what isn’t working, but casually blaming rifle parts won’t get it done.
If the barrel is new, was it installed properly? I thought the brass was new?
How many things did you change at once?
We’re these chronographed too?
The Savage is a Red Herring. Everyone knows they shoot great, what has that to do with your load work up?

Hay buddy I resemble those savage remarks

 

[AJC1]

Dont give up and dont be sour. I have provided you what I think is helpful information. If you need a good test setup for the barrel, get some 69smks and load up some tac or varget and go test. That lapua brass with those powders and that bullet should get moa or better or something is very wrong.

 

[JFrank]

Your pressure dropped because the lapua brass has more volume. The neck tension changed likely a lot. You will have to start over completely.

In addition to this excellent explanation, any change in the recipe move the node slightly, I always fall back to an abbreviated ladder of some type to re - establish or confirm. it just goes with the territory....

 

[The_Savage]

Hello everyone, I'm sorry for my sour attitude; I've become frustrated with this build and sort of became impatient, but from now on I'm going to take my time and not give up and continue to test more combinations.

There seems to be some confusion about the barrel. I purchased the barrel about 6 months ago, so it's by no means new and I have about 600 rounds through it of various powder, case, bullet and primer combinations. as to whether or not it was installed correctly, I believe it was, but as a precaution I've uninstalled it and reinstalled it carefully following the instructions along the way and taking my time. I also took the liberty of retorquing all the screws on my scope mount down, and applying loctite to them to ensure that the scope isn't loose. I also noticed that it might be possible that the screws for my bipod could be touching the gas block, which may cause the barrel to possibly not be free floating, so I moved it backwards so that the screws were nowhere near the block, and gave the barrel a thorough cleaning. Hopefully these steps ensure that the rifle itself is accurate.

Over the next week I plan on taking my best groups and testing various seating depths to find the best accuracy among them, and if one MOA is the best I can manage, I think I would be content with that, but here's hoping to better results. Sorry again to White Oak Armament and the users of this forum for being such a Debbie Downer, and all I have to do now is try some different combos, and maybe give that 69 SMK suggestion a try.

 

[Toprudder]

Good luck, and let us know what you find.

 

[The_Savage]

Alright, I think I found a good load. I used 27.7 grains of PowerPro 2000-MR, CCI 450 primer, Nosler 70 grain RDF .224" bullet, and Lapua brass. 18 shots across my Magnetospeed chrono averaged 3015 FPS, with a 26 FPS extreme spread, and an SD of 9. The conditions were 87% humidity, 61°F, 30 mmHG pressure, and 20 mph winds. I shot a 5 and a 7 shot group, and both were under 1 MOA. Anyway, I'm extremely pleased with these components, and I'd like to thank y'all for the help!