herkyguy
Member
- Joined
- Jul 31, 2009
- Messages
- 1,409
So months ago I picked up a CZ527 American in .223. Standard gun with walnut stock and I've got a Leupold MKIII 3.5-10X in the CZ-supplied scope rings.
I planned on setting this up for coyote/fox hunting, so from the start, I've zeroed at 200 yards. Right out of the box and with some PMC 55 grain FMJ, it was shooting about 3" groups at 200 yards. I played with a batch of reloads (40 grain VMAX mostly because it was on sale at the time) and was still not shooting much better.
I took the action out and glass bedded the front lug, then reassembled. Armed with some more handloads (55 Grain VMAX, 40 grain VMAX seated to various depths, and a box of factory American Eagle 55 Grain AR FMJ, I set out again yesterday.
Mixed results ensued. The American Eagle actually shot fairly well. From the bedding, it was off by about 4 inches high and 3 inches right at 200 yards. After getting the elevation dialed in (and shooting a 3 shot string right at 1 MOA), I switched to some 40 grain VMAX bullets seated to Hornady specs (2.2" COL), which also shot a respectable 1.7" 3 shot group and I got the windage dialed in.
So then, I had some additional 40 grain VMAX loaded up with the seating depth set for what I thought was .005 off the lands (COL of 2.26 instead of the original 2.2") and the groups opened up to 3" again. I measured the old fashioned way with a spent case and a bullet marked with a felt tip pen, so there's plenty of room for error in my measurements.
I then switched over to some 55 grain VMAX loaded again to what I thought was right off the lands (COL of 2.65"), but that group was also almost 3" at 200 yards.
A bit frustrated, I went back to my original 40 grain VMAX load with a COL of 2.2" and shot the best group of the day at 1.32" at 200 yards. Photo below.
Leaving my neighborhood that morning, I realized that I'd left my chronograph in the garage and I didn't want to risk going back to the house and being tagged with a honey-do list, so I don't have velocity data, but the winning load was 26.0 grains of H335.
I should add that all the loads with longer COL were well below MAX recommended. I used 2230-C with the 55 Grain VMAX and H335 with the 40 Grain VMAX.
I've already ordered the Hornady COL gauge and brass for .308, 30-06, and .223, so next up on my list is some better measurements, but has anyone else experienced deteriorating accuracy as the bullets are seated closer and closer to the lands? Also, I won't rule out a bad measurement on my part and the possibility that the bullet was actually touching the lands - what, if any, impact would that have on accuracy?
I am aware of the pressure implications, hence the light loads. No indications at all of overpressure throughout the day. I was letting the rifle sit for 5-10 minutes between strings to cool, as it was scorching yesterday.
I planned on setting this up for coyote/fox hunting, so from the start, I've zeroed at 200 yards. Right out of the box and with some PMC 55 grain FMJ, it was shooting about 3" groups at 200 yards. I played with a batch of reloads (40 grain VMAX mostly because it was on sale at the time) and was still not shooting much better.
I took the action out and glass bedded the front lug, then reassembled. Armed with some more handloads (55 Grain VMAX, 40 grain VMAX seated to various depths, and a box of factory American Eagle 55 Grain AR FMJ, I set out again yesterday.
Mixed results ensued. The American Eagle actually shot fairly well. From the bedding, it was off by about 4 inches high and 3 inches right at 200 yards. After getting the elevation dialed in (and shooting a 3 shot string right at 1 MOA), I switched to some 40 grain VMAX bullets seated to Hornady specs (2.2" COL), which also shot a respectable 1.7" 3 shot group and I got the windage dialed in.
So then, I had some additional 40 grain VMAX loaded up with the seating depth set for what I thought was .005 off the lands (COL of 2.26 instead of the original 2.2") and the groups opened up to 3" again. I measured the old fashioned way with a spent case and a bullet marked with a felt tip pen, so there's plenty of room for error in my measurements.
I then switched over to some 55 grain VMAX loaded again to what I thought was right off the lands (COL of 2.65"), but that group was also almost 3" at 200 yards.
A bit frustrated, I went back to my original 40 grain VMAX load with a COL of 2.2" and shot the best group of the day at 1.32" at 200 yards. Photo below.
Leaving my neighborhood that morning, I realized that I'd left my chronograph in the garage and I didn't want to risk going back to the house and being tagged with a honey-do list, so I don't have velocity data, but the winning load was 26.0 grains of H335.
I should add that all the loads with longer COL were well below MAX recommended. I used 2230-C with the 55 Grain VMAX and H335 with the 40 Grain VMAX.
I've already ordered the Hornady COL gauge and brass for .308, 30-06, and .223, so next up on my list is some better measurements, but has anyone else experienced deteriorating accuracy as the bullets are seated closer and closer to the lands? Also, I won't rule out a bad measurement on my part and the possibility that the bullet was actually touching the lands - what, if any, impact would that have on accuracy?
I am aware of the pressure implications, hence the light loads. No indications at all of overpressure throughout the day. I was letting the rifle sit for 5-10 minutes between strings to cool, as it was scorching yesterday.
