I agree with focusing on safe loads first, just trying to help with the original problem when you do get back to reloading for it.
- Thread starter bbowles
- Start date
Last edited:
I would load 24.4grs and retest. Maybe you are getting bullet setback during feeding?
This is my favorite explanation on AR gas systems.
AR15BARRELS.COM - Randall's description of AR gas operation and how everything works in harmony
There is a reason why the manuals say start at the bottom load and work up, some combinations of chamber, brass, powder lot, bullet jump, and primer hit pressure early. It could also be as simple as you jumped the gun on load development with new brass. For todays science project maybe check the water weight in one of your new cases, a once fired case, and that same fired case after sizing. Once fired brass is going to give you different results for a bunch of reasons. After the first firing, the changes slow down.
What's your bullet jump? If you have at least 0.025", maybe repeat the pressure ladder with your once fired brass. Did you take the case head measurements at the very edge of the extractor groove with a narrow tool? The bottom of the extractor groove should give a similar number. If the measurement is taken with a standard micrometer with one edge at the extractor groove, you'll pick up the normal expansion of the case body ahead of the pressure supporting head.
You have a chrono too? That's the biggest red pill of them all. The good news is many of the things that help concentricity also help velocity variations.
From your first post, it looks to me like you're pretty squared away on reloading and load development. Maybe only a couple steps from having the big things figured out. It may be as simple as working you're working with unfired brass. The measure, think, and figure out what's going on approach will get you through this quickly.
My go to load for 223s with 1:9 twist or faster and enough chamber is 24.3 grains of Varget, Rem 7.5 primers, LC01 brass, and 77 SMKs. I load to AR magazine length and the bullets jam at 2.400" for 0.140" jump. I get ~2750 fps from a 24" barrel. Case heads and extractor grooves show growth at 24.7 grains. I use the cheap Hornady 55 grain soft points a lot for fire forming because they're ~$9/k and shoot well.
I too have found this to be a big factor in run out.
No problem, I'll keep an eye out for them.
Hey guys, I attached a pic of some of worst cases with ejector ring. Actually pics look worse than actual. As I had to look hard to see the ring on many of the cases. OF&B has been helping me with this and concluded I have a gas problem but probably best to keep the gas block on my Daniel Defense as it is fixed and not adjustable. Not sure if different buffer spring, etc. would help but will just live with it. I think part of problem is my LC 13 cases are new unfired with only 1.444" headspace yet my rifle headspace is 1.463". So after my fire forming should be better.
So have decided with OF&B's help that will be best to load somewhat mild loads for fire forming and then do load development. Then I can get back to my original thread to reduce runout. Thanks especially to OF&B for all the help! I will be considerable time fire forming the 500 cases and then report back. If anyone has other guidance as to my overgassing/gas timing would be much appreciated. Thanks!
So have decided with OF&B's help that will be best to load somewhat mild loads for fire forming and then do load development. Then I can get back to my original thread to reduce runout. Thanks especially to OF&B for all the help! I will be considerable time fire forming the 500 cases and then report back. If anyone has other guidance as to my overgassing/gas timing would be much appreciated. Thanks!
.019" of slop is unacceptable.
918v,
I agree but have had both new unfired brass from LC 13 and Lapua with exact same 1.444" of headspace. My rifle is 1.463" and after fire form move back to 1.460". What can I do about this brass? OF&B measured some of his new brass and also said his wasn't anywhere close to 1.444". He even told me couldn't be wrong measuring with my Sinclair bump gage since the same gage comes up with 1.463" time and again after firing. Wonder if this much headspace is causing my slight ejector rings?
I agree but have had both new unfired brass from LC 13 and Lapua with exact same 1.444" of headspace. My rifle is 1.463" and after fire form move back to 1.460". What can I do about this brass? OF&B measured some of his new brass and also said his wasn't anywhere close to 1.444". He even told me couldn't be wrong measuring with my Sinclair bump gage since the same gage comes up with 1.463" time and again after firing. Wonder if this much headspace is causing my slight ejector rings?
I just skimmed through this post so sorry if this statement was made already .RCBS said to size the case with the neck expander lock nut loose .Then when pulling the handle back up and the expander in the neck area keep pressure on the case and tighten the lock nut on the expander shaft .This helped some one in a post to cure his case run out after sizing .So if your dies use a lock nut for the expanding stem ,you might try this .
Your unfired brass should be longer than that at the shoulder. In theory, it could cause the marks by slamming against the bolt face. I dunno. Try some FC ammo. It should be longer. Then you'll know.
bbowles
"WHY" would Lake City and the Army sell new unfired brass?
Lake City loads the cases that pass quality control standards, so again why are these cases being sold.
Because they "FAILED" military quality control standards, and if these cases failed the hardness test it could be why you are seeing the ejector marks on the rear of your cases. If these LC cases are rejects then this also explains the excessive case runout
Now go out and buy some commercially loaded ammunition and see if these "control" cases have ejector marks and excess runout.
Do you actually think the U.S. Army is selling the ammunition below?
I get that I don't know squat when it comes to reloading. This is why I am on here to learn. Guess I don't even know history of LC. Wish I would have just bought 500 or so of Lapua and went with that. Trouble is the lapua was also 1.444 but had no ejector or other pressure signs that I could see up to max Sierra published data.
In fact, only cases had ejector rings was LC and factory hornady match 75. Same ejector rings on those and they only got me about 2400 fps in my DD 16". Shot winch match 69, xm193 55 (2960 fps), am eagle 55, fusion 62, PMC 55, tulammo 55, winch varmint express 55, rem hypersonic 62 (2680 fps), DRT 55, horn varmint express 55 vmax, Barnes vortex 55 tsx and none showed ejector rings.
Just trying to learn how to reload for accuracy, high end for velocity and safety. I go backwards a lot but also slowly learning. Started this fun about 6 months ago. Wish I could soak up a tenth of what you guys know.
Thanks for your patience and your knowledge.
In fact, only cases had ejector rings was LC and factory hornady match 75. Same ejector rings on those and they only got me about 2400 fps in my DD 16". Shot winch match 69, xm193 55 (2960 fps), am eagle 55, fusion 62, PMC 55, tulammo 55, winch varmint express 55, rem hypersonic 62 (2680 fps), DRT 55, horn varmint express 55 vmax, Barnes vortex 55 tsx and none showed ejector rings.
Just trying to learn how to reload for accuracy, high end for velocity and safety. I go backwards a lot but also slowly learning. Started this fun about 6 months ago. Wish I could soak up a tenth of what you guys know.
Thanks for your patience and your knowledge.
Similar threads
