What charge weight do you think I should try next? I usually see a more well defined "sweet spot" when doing a OCW test.
This is a .308 Win using a 175 gr SMK and IMzr-4064
This is a .308 Win using a 175 gr SMK and IMzr-4064
- Thread starter ShtrRdy
- Start date
41.4 looks pretty good. I'd try 41.3 and 41.5.
Something between your first two groups or possibly what’s after your last group if you don’t have pressure problems
I’m with quietmike, work around 41.4. You have 0 vertical stringing in that group.
No it isn't. The lack of vertical spread is what you want in a ladder test.
Thats not a ladder test. You are looking at POI for an OCW test.
True, but vertical stringing is still what you're looking to avoid.
Vertical has nothing to do with OCW at this point in testing. Groups have nothing to do with OCW at this point.
POI looks most consistent between 42.3-42.9. If those charge weights aren't making too much pressure thats where I would want to be. If they are I would back down and look in-between 41.4 and 41.7.
The 175 SMK and 4064 is a pretty well vetted combo. Some .308 brass has significantly different volume than others.
POI looks most consistent between 42.3-42.9. If those charge weights aren't making too much pressure thats where I would want to be. If they are I would back down and look in-between 41.4 and 41.7.
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The 175 SMK and 4064 is a pretty well vetted combo. Some .308 brass has significantly different volume than others.
I have always had best luck with 42.2 at 2.830” in several rifles.
So why do you think this load will work in every rifle out there? It won't shoot in mine!
So adjust the coal a little.
Or short throated.
41gr looks good to go, and would be ky first choice. Same POI and tight group size
41.5/41.6 seems like a tight node.
Similar POI, but group size varies fro. 41.4 and 41.7. If you wanna push a bit higher, safely, I would work on this powder charge.
41.5, 41.6, 41.7, 41.8, 41.9
To verify the POI. Once you find the center node, adjust bullet seating depth to a good group size.
42.9 might be the center of a node, but it's a running it close to being over pressured. If you shot it 90 degree weather and left the ammo in the sun with no heavy bolt lift, flattened primers, ect, than you're good to go for 42.9.
If you did this on fireformed brass, you're good to go. If you did this teat on virgin brass, be prepared to adjust your load a bit.
41.5/41.6 seems like a tight node.
Similar POI, but group size varies fro. 41.4 and 41.7. If you wanna push a bit higher, safely, I would work on this powder charge.
41.5, 41.6, 41.7, 41.8, 41.9
To verify the POI. Once you find the center node, adjust bullet seating depth to a good group size.
42.9 might be the center of a node, but it's a running it close to being over pressured. If you shot it 90 degree weather and left the ammo in the sun with no heavy bolt lift, flattened primers, ect, than you're good to go for 42.9.
If you did this on fireformed brass, you're good to go. If you did this teat on virgin brass, be prepared to adjust your load a bit.
What is your rifle? What is your bullet length? What is your bullet bto? What is your jump length from 2.800”? What brass are you using? What primers? Is your bore clean? Are you annealing your cases? How much? Are you using any lube in the case neck? How many rounds down your barrel?
When you guys try different seating depths, what size steps do you like to use? 0.010"?
I go in .005 increments
+1
It's an AO build with a Brux barrel shooting 210M's and Lapua brass. Yes I do anneal. My gun shoots great with 43 GRS of Varget at 20 thou off with 175 SMK's. It will not shoot your load.
I was just wandering why you think your load will shoot in every 308. All rifles are different.
They may be different but they all shoot good loads well.
Can you provide the data I asked for? Cuz the rifles I shot this load the bullet jumping 50-65 thou.
Can you provide the data I asked for? Cuz the rifles I shot this load the bullet jumping 50-65 thou.
Update -- I did a couple things based on everyone's suggestions and did some shooting this morning. This target has two experiments on it.
On the left most bulls-eye I tried a couple rounds using the 41.1 gr load to see if it would be anything like the original. It didn't match up too well.
On the center and right most bulls-eye i took steel head and frost1235 suggestion and tried one more step up. The middle one is the same charge as before and the right one is 0.3 gr more. That looks very promising. I plan to load up some more like that and measure velocity with the Magnetospeed. These were with new Lapua brass so I'll need to tweak the load for once fired.
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