.223/H335/55gr. FMJ data?

[jhansman]

I am getting signs of pressure with 24.5 gr. of H335 in this load, using CCI 400 primers, LC brass, and Hornady 55 gr. bulk FMJBT bullets, all out of my Saiga .223. Primers are flattening and cratering, so before I shoot anymore of these I'd like to hear what others who shoot this bullet/power combo load at. Hodgdon says 23.0 to 25.3, so I figured I was safely in the middle here. Any suggestions are more than welcome. TIA.

 

[DssG19]

I use 22.5grs of h355, over a 55gr fmj, very accurate load, nice recoil. If you're using 5.56 brass the pressures can spike just a bit, when I use LC my 22.5grs is perfect.

 

[rg1]

24.5 grains of H335 using RP, LC, WCC brass and Remington 7 1/2 primers shows no pressure signs in my AR's. Actually 25 grains doesn't either. I seat the Hornady 55fmj's to 2.220" and crimp. 24.5 grains in the 20" barrel gets approx. 3050-3080 fps with my loads.
Have not used CCI 400 primers. Is it possible the headspace in your rifle is near maximum saami spec and in resizing you're possible pushing the shoulder back too much or beyond factory length? If either or both conditions exist your primers could be unseating enough to slam back against the bolt on firing and flattening. The firing pin would push the case forward against the shoulder of the chamber, then when fired the primer could be pushed back against the bolt, as the case swells to fit the chamber it reseats the primer and can flatten it making it look like high pressure. Just a possibility.

 

[jhansman]

Hmmm, interesting thoughts on the headspace and such. I hadn't considered that, but you're making me think. I think I'll start running this down with a lighter load, say 23 or 23.5 gr., just to see if it shows a difference in the primer. I've also got some H322 I can compare with. Thanks!

 

[dagger dog]

Hornady lists 23.2 grs of 335 as Max with their #2267 BT-FMJ with Win brass and WSR primer. The Hodgdon manual I have has the same grain loading you state but the brass used in the Hodgdon manual is Winchester and not LC and the primer is WSR, and the 55gr bullet is a Sierra.

In using any military brass you have to drop the charge because the military brass is thicker with less internal volume which = higher pressure for the same charge in a non-military case.

When you mis match componets you have to start by dropping the charge weight and working up in small increments, to stay safe.

Get out the HAMMER!

 

[jhansman]

Thanks for the Hornady data, dagger dog, as I do not have their manual. I'll definitely drop the powder down to accomodate the LC brass. Weird, 'cause previously fired rounds did not show these signs. Back the bench...

 

[Walkalong]

Regardless of headspace issues, it still takes pressure to crater primers. If you are pushing your shoulder back too far and creating artificial headspace, that is a different problem. It will show up in signs of case impending head separation in a limited number of firings. It won't cause pressure signs, but it will decrease brass life considerably, and be dangerous if you don't catch it before a case head separation occurs.

 

[GooseGestapo]

I was going to say it's due to the LC milspec brass.

Also too, are you trimming the brass?

I always use commercial brass, and trim to min. spec. 26.0gr with FMJ has never given any pressure signs, neither has 27.2gr of BLC2.

 

[jhansman]

Yeah, I trim to 1.750" after a full resize. You all have me convinced that I overloaded this brass. Think I'll go make up some lighter rounds. Thanks to all!

 

[rg1]

Here's an informative article on loading .223 Rem that shows various case brand weights and internal volumes.
http://www.6mmbr.com/223Rem.html

Here's one range trip chronographing H335 in a Colt AR 20" barrel 1/7 twist. Tested in July with 90degree temperature.
Cases used were RP and WCC using RP 7 1/2 primers and Hornady 55fmj's
RP CASE versus WCC CASE
23.2 grains of H335--2863fps 23.2---2846fps
24------------------2975 24-----3005
24.5----------------3080
25.3----------------3162 25.3--3200fps
____________________________________________
Winchester 55 fmj
RP case--24.5 H335---2979fps
WCC case--24.5------2977fps
_________________________________________
Hornady 55 gr SP
RP case--23.2---2845fps
WCC-----23.2---2829
RP-------24-----2960
WCC-----24-----2969
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62 gr fmj military surplus
RP case--24 grains of H335---2949fps
________________________________
Sierra 5th Edition Manual with their 55fmj bullet and H335 tested in an AR with 1/7 twist 20"
23.6--2700fps 24.3--2800 25--2900 max 25.7--3000
___________________________________
Hornady 7th edition manual used a Rem 700 bolt action 26" barrel with Win cases and Win primers and Horn. 55fmj's
They showed 20.8--2800fps 21.6--2900 22.4--3000 max 23.2--3100
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Hornady also showed a max charge of H335 with their 68gr bthp that was 23.8 grains max at 2700fps. This was shot in an AR
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Just to add to the equation and confusion. use at your own risk.