Need Help reducing SD

[Outcome]

I've been reloading .223 for about a year now. And I'm having a hell of a time getting my SDs below 14. Looking for specific tips on what guys do to reduce them. I don't have the money for an annealer or a concentricity gauge yet, and I dont neck trim, just a heads up. I also did a few searches and couldn't find much other than generic how to reload guides.

Brass: from IMI razer core 77gr otm
Projectile: Sierra 77gr HPBT
Primer: CCI 4500
Powder: Varget

Chrono: Magnetospeed v3
Rifle: AR15 w/ 16.1" Criterion Barrel reamed by CLE .223 wylde, Badger Gas Block (I've made sure its aligned multiple times).

I'm getting and SD of 17-25 using IMI 77gr OTM
And SD of 14-20 from hand loads.

Setup.
De-prime/resize using Hornady Custom grade.
Clean in UL cleaner
trim, chamfer if needed
Swage PP Crimp
Throw charge 0.1 low and trickle up
seat bullet 1/3rd way rotate 120, 2/3rd rotate 120, fully seat.
measure @ ogive +/-0.001in

I just picked up
Flash hole deburr
Primer Pocket Uniformer
VLD Chamfer
Started sorting projectiles

Thanks for your help. looking to really refine my technique before I get into the barrel burner cartridges.

 

[Supersubes]

How’s the accuracy? How many firings on the brass? You ever tried checking a the water capacity of your cases? What about bullet jump, is it close to the lands? If so, back it off, the 77 smk won’t care. What is swage PP crimp? You can get set up to anneal for less than $30.


For a 16” AR, id personally call it good if the accuracy is there.

 

[Marksman10x]

Hello Outcome,

My guess is your charge weight, although precisely measured, is probably incorrect, or at least not optimal. Since you have a magnetospeed, I recommend doing a chronograph test. This is probably the most fool-proof method becasue it uses objective data to make a charge weight decision. Dan Newberry's OCW and ladder tests require a more subjective interpretation.

Step 1: Determine your maximum safe load
Step 2: Load three rounds of each charge weight in 0.2 grain increments (larger increments for larger calibers) 8-12 chargeweights. .015 - .030" off the lands should work very well for the Sierra, but if you are restricted by your magazine, load as long as you can.
Step 3: Shoot all rounds with Magnetospeed attached (24-36 rounds)
Step 4: Determine average velocity for each charge weight
Step 5: Determine the difference between each avg velocity
Step 6: Look for the groups with the smallest avg velocity differences. There will be two or three charge weights that have almost identical velocities.
Step 7: Load to the middle of these charge weights, this should be a great charge weight with very low standard deviations.
Step 8: Adjust seating depth in .002 - .003" increments for 8-12 groups. You'll usually either see the groups tighten up to a point then start opening up again--load to that tight group. Or, sometimes you will see two or three groups that tighten up and all hit to the same POI. In that case, load to the middle seating depth just like you did with the powder charge weights.


Some Resources:

http://optimalchargeweight.embarqspace.com

http://www.accurateshooter.com/technical-articles/long-range-load-development/

http://www.65guys.com/10-round-load-development-ladder-test/
ONE ROUND PER CHARGE WEIGHT DOES NOT WORK--USE THREE AND GET AN AVG--TRUST ME--AND THAT KILLS ME TO SAY BECAUSE I AM A HUGE WSU FAN (the shirt Scott is wearing).

 

[Marksman10x]

Here is a screen shot from Hodgdon's site:

EXAMPLE OF WHAT I WOULD DO:

Step 1: Load one round each of 22.5, 22.8, 23.1, 23.4, 23.7, 24, and 24.3 grains. I would NOT expect to shoot all these rounds, but they should allow you to find the maximum load that is safe in your gun with your chamber. Start low and work up, look for pressure signs and stop as soon as you see indications of high pressure. This may be above or below the listed max load. Be careful especially since you are using a semi-auto. Bolt actions are easier because you can feel the bolt lift get heavier as pressure increases.

Step 2: Say 23.7 is your max load. Then load three rounds at each charge weight of 21.9 22.1 22.3 22.5 22.7 22.9 23.1 23.3 23.5 23.7 (30 rounds)

Step 3: Go to range with Magnetospeed attached and shoot all 30 rounds, 10 at a time, then let barrel cool. Shoot low to high for first group, then high to low for second group, then low to high again--same as OCW.

Step 4: Avg the velocity for each group and write down.

Step 5: Write the difference between the avg velocity on the same paper.

Step 6: Look for the groups with the smallest avg velocity difference. For example suppose 22.9 23.1 and 23.3 all had velocites within 12 ft/sec of each other...

Step 7: ...then you would load 23.1 and do seating depth tests if you want.

Step 8: Suppose you loaded to 2.260" like it says on the Hodgdon website...then I would load longer if possible, but if you are limited by a magazine, then you have to go shorter. So if shorter, I'd load 2.260, 2.257, 2.254, 2.251, 2.248, 2.245, 2.242, 2.239, 2.236, 2.233" and look for an obvious shrinking and then opening of groups or a plateau of two or three groups that all have the same relative POI.

 

[Marksman10x]

Well Fuck Ballz, why didn't that screen shot show up..well it said the starting load is 21 grains and max is 23.7 with a Sierra 77 and Varget, and that the seating depth is 2.260"

 

[Outcome]

Brass is once fired Bullets are seated to mag length which gives me a base to ogive length of 1.176 +/- 0.0005 using a starret caliper w/ Hornady comparator. I dont have my databook with me but I have Chamber OAL and the jump is a bit.
I'm shooting mil brass so Im swaging the primer pocket crimp instead of reaming it.
Accuracy is sub MOA but gun is capable of well under sub 0.5 MOA av.

Target charge weight was found using QuickLOAD and OBT, I then did a OCW to determine the correct load. 23.5gr happens to be within a margin of error for OBT and OCW (which was cool to see). Will be doing a tall target test once Ive got my SDs lower. Ive done a few OCWs, they actually lead me to forking out more money for a Magnetospeed over a chrono (was planning on a labradar, but the MS won out in the end for me).

I follow the steps laid out above but with 5 rnds instead of 3, but +0.3gr instead of +0.2gr.
My max case vol is 31.5gr av for this lot +/- 0.2gr. My Calc max load is 25.5 via QuickLOAD. I show zero pressure signs at Hodgdens Max charge.

Thanks for the help so far.

EDIT: primers are seated using RCBS hand priming tool.

 

[NighthawkCG]

I struggled with pretty much the same numbers and then ran out of some season to continue testing. I'm down to about the same SD.

I tried several workups like Marksman suggested. While good in theory, with high SD, it probably means your ES is up there too. That means of the group of three per charge weight, two are close and one is far out. I even went out multiple days and tried the test. Over the long run, the spreads are similar and SDs remain in teens at best to 20s.



https://www.snipershide.com/shooting/forum/sniper%C2%92s-hide®-advance-marksmanship-unit/sniper-s-hide-reloading/6801998-223-hates-me-any-thoughts

I've done a lot of CCI 450s, and tried BR4s with similar results. Wondering if I switch to something else if that help. Other than that, we have a slightly different method with very similar results - decent accuracy, but high SDs.

No problem loading any other caliber down better. Just 223.

 

[Outcome]

Yeah my ES is pretty high for what I want, and really the only one I truly care about. I only shoot at 100yds for zeroing and load development, otherwise I'm lucky with my local range having steel well outside of my capabilities.