MV SD for Semi Auto's

[RackOpsTactical]

Being newish to presicion reloading not reloading in general, what are you guys getting for muzzle velocity SD and ES out of 223 AR platform rifles? Most of the low SDs I see are out of bolt guns. I'm struggling to get SDs of less than 14-19 out of my loads and 18" AR. Using samples size of 10 rnds and a magnetospeed chrono.

The 223 rifle is built around an 18", 1-8, black hole weaponry SPR brl.

The load I'm using is Lapua brass, 69gr SMK, 24.4 gr H4895, either BR4 or 205M primers. Despensing with RCBS charge lite.

 

[Onyx Z]

I don't remember exactly, but ~10 SD maybe? Try magnum primers. They tend to provide better SD's in 223 in my experience.

 

[NighthawkCG]

That's around where I was for the longest time. How many firings on the brass? I switched my brass (it was old and all stages of hardened) and reworked my load and it went down to just below 10. Had multiple old lots of brass that was sorted by headstamp and some by weight and I couldn't get the SD down. Tried bushing dies, cleaning flash holes, etc. with no good results.

When I reworked my load, I also dropped the charge down a good bit so that may have helped too. Shooting a 18" WOA with WCC brass, 73 eld-m, H4895, and BR4.

 

[RackOpsTactical]

This is my 6th firing with the lapua. I did get better results (less than 10) on the first 2 firings. How much life do you get from the WCC?

 

[NighthawkCG]

Not sure. Bought an ammo can full of it and still on the first go around.

Edited for more info: The WCC does seem to be a bit softer around the rim than the LC. I see some very slight extractor (not ejector) marks on the brass. First few times I shot it I thought it was pressure, but it seems to do it across the board. Think its just a brass thing. Its nothing that would prevent me from loading the brass again, but did have a slight difference than the LC and will be something I keep an eye on in the long run for longevity.

 

[Onyx Z]

That's around where I was for the longest time. How many firings on the brass? I switched my brass (it was old and all stages of hardened) and reworked my load and it went down to just below 10. Had multiple old lots of brass that was sorted by headstamp and some by weight and I couldn't get the SD down. Tried bushing dies, cleaning flash holes, etc. with no good results.

When I reworked my load, I also dropped the charge down a good bit so that may have helped too. Shooting a 18" WOA with WCC brass, 73 eld-m, H4895, and BR4.

No idea on the number of firings. I don't keep track of that on 223. LC brass, 8208 XBR, and magnum primers seems to be the best combo I've found. I've heard Wolf magnum primers provide lower SD's as well, but I haven't tried them yet.

Another trick you could try is a LEE Factory Crimp just light enough where you barely see it on the brass.

 

[RackOpsTactical]

Thanks, my original question is what kind of SDs are people getting out of semi auto rifles in 223.

 

[RogueTanker]

20" WOA 1/7
Lc 16 annealed
24.2 gr XBR 8208 (way over max, no pressure signs at all)
Wolf primer
73gr ELD-M
Coal 2.274
MV- 2884
SD 6

.4 moa

I would also ask your intended range? Vertical stringing doesn't get bad until 600+. If you aren't going that far often I wouldn't worry. Just like people worrying about 1/4 vs 1/2 MOA accuracy, most of the time, the shooter Is the limiting factor. At least in my experience.

 

[RackOpsTactical]

what sample size is that SD, MV, and MOA?

 

[RogueTanker]

5 rounds.

 

[RackOpsTactical]

Based on the limited responses I'm guessing that not that many folks on this site reload 223 for semi auto. I was hoping for more feedback on this.