223 600 Yard Groups

[APGE]

Hi Folks,

I did some testing with my 223 FTR rifle at 600 yards yesterday. Adjusting charge weight only, 5 shot groups ranged from 2" to just over 4". The node I am on seems to be narrow and 0.1gr difference of H4895 changes things a bit.

My question to the brains trust is what sort of vertical should I expect at 600 yards?

I usually aim to get my vertical at a repeatable "half x-ring" at any distance, but I wonder if this simply isn't achievable with a 223 and heavy bullets at distance. The groups shot during testing were certainly taller than they were wide, for the most part, and shot in the low 0.2s or less at 100 yards.

If the 2" charge is repeatable, it may well be a good load, but I can't help wondering if I can't wring a little more out if.

The rifle was built primarily to shoot at 300, but I would like to keep my options open at 600. A 308 will be employed at any greater distance.

Finally, with such a small case being run fairly hot, what are your experiences with switching primers? Does the charge generally need to be worked up again? I'm currently using federal gold medal, but have CCI BR4, CCI450 and Remington 7 1/2s on hand and was considering loading up to shoot 4 groups of my best loads, switching only the primers.

@Laurie @Ned Ludd I assume you two are the resident experts on these matters, but anyone's input would be appreciated

Thanks for your help.

 

[marazzi59]

If your concerned about the small node, you might need to refine how you measure powder. You might need to weight to a single kernal of powder which is possible with higer end scales and tricklers. As for changing primers on a hot load, for safeties sake I would back off the powder charge 10% and work back up.

 

[skiutah02]

For 5 shot groups at 600y from the 223 using 80gr bullets I think consistent 2" groups in no wind are quite possible and could be sub-3" for 20 shots. For 90 gr bullets, My experience is that consistent 5-shot 2" groups are also possible but harder to achieve. For 20-shots, if you can maintain CONSISTENT sub 3" groups with 90s you will be firing on all cylinders in the reloading room and wind calling. Under the ideal match conditions, you will be able to stack a bunch in a really small area, but one or two will "open" the group up. For example with the 90vld,

 

[Ned Ludd]

I am of a similar opinion as Drew, who certainly knows what it takes to get a .223 F-TR rifle shooting extremely well. Maintaining 0.5 MOA vertical can certainly be done at 600 yd with the .223/90s, but that also requires no errors from the trigger-puller. I am usually good for [at least] one jerked trigger or missed wind call during a match, but as long as the shot stays inside the 10-ring, cleans with high X-counts are certainly possible with a load that may not consistently yield perfect 0.5 MOA vertical.

You mentioned that "the groups shot during testing were certainly taller than they were wide". That at least suggests to me you may want to re-visit seating depth. In my hands, seating depth is probably the most critical aspect of getting the most out of a .223 with 90s. In a properly tuned load with 90s, I expect a single ragged hole at 100 yd, with comparable vertical and horizontal spread (i.e. not taller than it is wide, or vice versa). In my years of shooting the .223/90 VLD/H4895 combination, I have observed that there are usually two "sweet spots" with regard to seating depth within the range I typically test. One will be from somewhere around .004" to .007" into the lands. The other will be from around .018" or .021", to about .024 to .027" or so, off the lands. The optimal seating depth window into the lands is typically only about half as wide as the the one off the lands (i.e about two .003" increments wide versus only one). For that reason and because of the potential for increased pressure (spikes) when seating bullets into the lands, I have always used the seating depth window around .021" off the lands. However, shooters will occasionally find that seating the 90s into the lands is noticeably better with their setup. Regardless, optimizing seating depth to produce tight groups with comparable horizontal and vertical is critical for getting the most out of that combination. Stringing in either direction might mean the tuning isn't quite there yet.

Other considerations with the .223/90 VLD combination are largely due to small case size. As compared to the larger .308 Win case, everything seems to matter even more in order to get the best precision. That includes accuracy of powder weight, internal case volume, etc. In my hands, sorting brass by weight as a surrogate for internal volume can be helpful. I routinely determine water volume for weighed cases and have found the correlation between weight and internal volume to be quite good for Lapua .223 Rem brass. In my hands, cases that fall near the lowest or highest ends of the weight/volume spectrum can generate average velocities that differ by as much as 30 fps or more, an effect that is far less pronounced with my .308 loads. It just seems that with the .223/90 VLD combination, everything has to be "just so". My suggestion would to keep working with your load, possibly re-visiting seating depth if nothing else, and see what that might buy you. I have always viewed load development as "work in progress", rather than a static or one-time process, so I suspect if you tweak things a bit more, you might observe some small, but noticeable improvement. Nonetheless, it sounds like you've already got your setup working pretty darn well, so quantum leaps in precision from what you already have are going to be unlikely. The question of how much more time, effort, and barrel life to put into scratching uot that last little bit of precision is one that only the end user can decide for themselves. Good luck with it!