Sierra vs Nosler loading manual on 69 BTHP, 223

[Boatschool02]

All,
Working up loads for 1 in 7 twist 16" Krieger AR barrel smithed by Compass Lake with their chamber.

Looking to work with RL-15 for the 69 grain bullets based on both WOA and CL recommendations.
First few attempts with the 69 SMK and WOA's recommended ladder from 24.0 and 24.8 grains of RL-15 have yielded a few 4-5 shot groups in the 3/8-1/2" range at 100 yards, generally performing better in the bottom half with 0.2 grain increments hand weighed on a Gempro 250.

For reference, I've shot 5 shot, 5 group ladders in the 5/8"-7/8" range with everything from 52/53 SMKs, 53 VMAX, and 55 Blitzking using H335 and RL-7. In truth, most groups have 4 of the five shots under 1/2" with one that gets away. (Photo attached.) All that is to say, I know the gun will shoot. With a 20X VX-3 scope, I think I'm consistent within 1/8-1/4" at worst.

That being said, my attempts with the Nosler CC 69 have been awful, all well over 1" with the same RL-15 loads in the same new or once fired Lapua Brass. Same CCI BR4 primers. Same COAL. Whidden Dies. The only bullet that performed worse was the 60 grain VMAX, which exhibited considerable vertical stringing with both RL-15 and H335.
When referencing the Nosler site vs Sierra, I see they suggest a lighter load for their 69 grain bullet with the same COAL.

Sierra Min: 23.3 Max: 25.7
Nosler Min: 22.5 Max 24.5 (Best accuracy reported at 23.5)

Any thoughts on why this is?
1. Bad 69 BTHP = 69 BTHP assumption on my part?
2. Extremely small Nosler case volume of 27.5 vs the typical 28.0-30.6 listed on this site's caliber specific page? (Of note, Nosler not included in the test data.)

Any speculation regarding bullet weight vs powder speed with my short barrel?

I've gone up to 25.2 with the RL-15/69SMK combo and have only shown moderate signs of primer flow/flattening, but at that point, the groups were opening up to 1"+.

My priority is 200 yards and in plinking and occasional varmint accuracy over extreme velocity. This is just a fun project to test the limits of a well-built, short AR.

Thanks in advance.

 

[mac86951]

What reloading dies are you using?

 

[civil82]

What are you using for a handguard/forearm?

 

[Boatschool02]

Hello,
Whidden Full Length die and micrometer seater.
--
Mega Arms MML billet upper with integrated forearm.
Thanks,

 

[Boatschool02]

 

[mac86951]

I've seen picky barrels before, and I've seen more bullet variation in Nosler vs others. My WOA barrel prefers to launch Noslers ~100fps slower than Sierra or Hornady. Try all three. I've seen plenty of picky barrels. Sierra would be my bet. Berger has a great 70gr vld too.

-Mac

 

[Boatschool02]

Mac,
Thanks for the input. Good point.
No doubt some of my perspective is naivety as a new reloader.
My running hunch is that the Sierras of all types are just very jump tolerant.
At 200 yards my best average across five groups was the 55 blitzing with three of five groups coming in around 1.2" despite changing wind conditions. These are not up to bench rest snuff by any means, but well within the realm of what I thought possible/respectable for a 16" barrel.
CLE's "how to" page suggests that an 80 grain bullets might need to be loaded out to 2.435 (Sierra lists 2.550 with a standard chamber) which means my mag length loads are jumping approx 190 thousands.

Interesting that you mention the 70VLD. The attached picture shows my first three charges of RL-15 (23.6, 23.8, and 24.0) with the 70 VLD. So far, the most visual example of "coming into focus." Once again, I could only muster 4 out of 5. Even more strange that both groups 2 and 3 leaked one out to the left. (Black circles are a US Dime aiming mark for my VX-3 target dot.)
Luke

 

[mac86951]

25.0 varget was my vld load, now switching to N140. Was left flier shot first or last?

I am having a heck of a time with 77 Sierra for concentricity. I couldn't figure out how I'd have excellent groups and bad groups in the same 50. I picked up a concentricity gauge and was surprised to see my Forster dies pushing these in all kinds of directions. Bullet seating stem just didn't fit this bullet well. Now I'm happy and have good repeatable accuracy. I'm not sure about the whidden dies, but this was something I overlooked.

-Mac

 

[Fotheringill]

On first two targets- how hot was was your barrel?

 

[wapiti25]

I have not had good experiences with nosler bullets. I had some old noslers in one rifle that shot good for me, bought a new box and the bullets were .005" smaller in dia and would not shoot. I called nosler and was told that nothing was wrong with their bullets. I do not buy noslers now. I was a model maker and I do know how to use a "mic".

 

[Boatschool02]

- I'd say my last shot is out about half of the time. Artifact of my competitive days and ongoing struggles with sports psychology.

- I try to shoot about one shot per minute and then take a break after every 5x5 ladder to clean, rehang targets, etc. I have the full barrel diameter before the gas block, so it doesn't seem to heat up too quickly. Wish I could give a better answer. Definitely something I'll work to be more aware of going forward.

 

[Boatschool02]

Last month testing 55 Blitzking with H335. I was impressed with the first four groups. Overall, the least dispersion of any bullet. Several better groups with the 69SMK, but the bad groups were worse as well.

 

[A_Gamehog]

My best results were with Nosler 69's and 8208XBR (24.5 grains). Beats every bullet made. 5 shot groups all touch but I shoot a 24" barrel.
Norma brass
CCI 450's
8208XBR
Nosler CC

 

[mac86951]

Given last shot, practice with a zoom cap dummy in last position (first in mag), this will let you know if mag spring is weak, or last round issue, or help train shooter (Unless you are single feeding). Finally shoot groups round Robin with 1 shot at each target and rotate through.

16" heavy barrel, I'd suggest 10 rapid fire foulers /sighters to get barrel temp up.

16", I've seen many fliers with carbine or mid length gas tubes. This will mean you have extra work getting powder charge variation down for consistency, likewise show us a pic of fired uncleaned case heads (looking for case head swipe).

What position are you shooting, or what is your bench setup. Inconsistent bag riding can do this too (egw bag rider, or choate A2, etc...)

 

[Boatschool02]

Mac,
I don't understand what you're looking in a picture of the spent casing.
None of my loads are within 0.5 grains of Sierra max loads.
I shoot with a Harris Bipod and kneeling roll as a rear bag.
My stock is not ideal for this style of shooting, but that is all part of the challenge.
When I was building the rifle, I found countless internet statements regarding what was not possible regarding length, twist, bullet weights, etc. I bought premium components and have been working diligently through hand loading to see just how much performance can be wrong out of a 16" barrel.
I hand weigh every charge down to 0.02 on the Gempro. Brass was weight sorted into 1 grain groups of 50 from an original lot of 300.
Any/all input welcomed.
Thanks,

 

[mac86951]

Mac,
I don't understand what you're looking in a picture of the spent casing.
None of my loads are within 0.5 grains of Sierra max loads.
I shoot with a Harris Bipod and kneeling roll as a rear bag.
My stock is not ideal for this style of shooting, but that is all part of the challenge.
When I was building the rifle, I found countless internet statements regarding what was not possible regarding length, twist, bullet weights, etc. I bought premium components and have been working diligently through hand loading to see just how much performance can be wrong out of a 16" barrel.
I hand weigh every charge down to 0.02 on the Gempro. Brass was weight sorted into 1 grain groups of 50 from an original lot of 300.
Any/all input welcomed.
Thanks,

Just keep an eye out for case head swipe. That will typically shows up and marrs your brass well before pressure signs with ARs, especially as you load slower powders for heavier bullets. It's a sign that the gas system is trying to eject the brass too early. You'll see this by watching for the signature smudge of the ejector on the case head.

If you run into that and want to keep your brass you have a couple options, either reduced powder charge or faster powder and work up again; or tuning the gas system to your load by various methods Inc. Adjustable gas block.

Depending on who smithed your barrel etc... Case head swipe may/may not be prevailent. Shorter than rifle length gas systems IME are far more sensitive to a sudden surge of this, though equally correctable.

I've also seen in some rare combinations that case head swipe can affect accuracy, but certainly reload ability.

-Mac

 

[Longtrain]

Unfortunately there are a number of variables that could be dictating your results. All things being equal, change primers, Wolf SRM consistantly give me the smallest SD and ES, Winchester SR the largest. You need to also look at consistant neck tension, jam/jump and concentricity. I only single load when testing. Although some get good results jamming into the lands, I never have and always jump my bullets, an average of 25 thous. and some as much as 40 thous. If you really want to get the most accurate loads, you need to think like a benchrester, only change one variable at a time when testing, start with a barrel with 15-20 rounds down it after cleaning and let the barrel cool between shots. Good luck.