OCW

On vacation a couple days. I spent all day yesterday shooting 50 rounds virgin brass all at 28 grains. Butchs, Eliminator and hundreds of patches. It stopped copper fouling around 30. Brought my fancy Teslong to the range. Shot all 50 in one hole at 100. Not so small a hole that is. Anyway this morning I did this OCW with the once fired brass. 200 yard because it was alittle windy. Brought my fancy new Labradar also. Best group, worst data! Why did I buy this chronograph? Mike

 

BTY, barrel sped up 113 fps in the first 50 rounds. Mike

 

Mike
Is this a new barrel ?

 

I don’t normally start real testing until 200+ rounds on the barrel. Will settle down a ton. I would fire form another 100 rounds and then repeat your test. Good luck!

 

Yes, this is on my 600 midrange f-open rig. Not my kill 6BR coyote destroyer.

 

Well let’s crank up the horse power a bit and get load going 29 grains is still low for a 107 smk

 

I agree, but you gotta do something other than blasting. I'm honing my bench skills and gear. Think I'll go shoot some 500 ( I can see the holes ) and practice my f-open wind reading skills. Tell me, would you load up 28.4 or 28.6?

 

I got case head smear and alittle firm bolt lift. Smear maybe bad word, you know when the bolt turns and the case doesn't. Velocity at 29.0 was 2792. 28"er.

 

Either would be fine for the next 100+ rounds. Then do the same test to fine tune the node. After that work on seating depth to tighten the group up.

 

I think you need more powder.
Can’t really see that cartridge

 

Thats a lot of shots in the life of a barrel to find a load.

 

Here's this morning. These were shots 76-100 with once fired brass. I also shot another 25 virgin so now have 125 through. Limited time tomorrow but will shoot 25 of unfired. Right now seems to like 28.6 and 30 jump. Just checking in you know. Mike

 

@mike a, If you are striving to find a node with the greatest accuracy I might suggest a slightly different protocol.

You are simultaneously combining multiple variables with seating depth and powder charge, while your barrel has still not settled down. I might suggest you check out the Cortina thread on ”long range load dev at 100 yards” to find the node range. Then you can fine tune the seating depth in .003 increments to fine tune the load. I have used this process for 2 different cartridges, with over 12 different barrels and it has been dead nuts accurate. if you follow the protocol to a tee, you will be pleasantly surprised with how small your rounds will group.

 

Ok mike it's looking good! You can actually see the groups shrinking
Now that the coarse seating is done move in smaller increments, I'd move @ .003 for this next step

 

Damn your quick!!

 

@mike a
I think your looking at a accurate but low node at 28.6 you’ll most likely see a couple more as in the example I’ve attached.
I’ve had these lower nodes not hold together at longer ranges like 500 and beyond, I’m not suggesting you run the ragged edge as I do but perhaps consider the next node up.
SS
jim

 

If you did get a slight ejector swipe at 29 grains, then I would not go above that. I would say that you have found the edge of pressure in that rifle.

I have found that the most tunable and forgiving loads tend to show up in the immediate vicinity of 2% off from pressure. 29 grains x .98 = 28.4 grains.

28.4 is exactly the spot where your barrel leveled off. 28.4 and 28.6 have the same height and clock position in relation to your point of aim.

The thing that I don't like about these targets, is that the "flat spot" is at the bottom of the sine wave pattern. It is preferable that it level off at the top of the pattern.

If this were me, I would load 10 each of 28.5 grains at +.005" and -.005" from current OAL and shoot it at distance. If I didn't like what I saw, I would try a different combination.

 

Op here, testing continued. After several OCWs and getting the barrel up to 200 rounds I found 28.6 varget to be a solid node and sadly I get pressure at 29.0. So I did a seat test with 28.6 at 100 yards and got this pic#1. I liked 015 and 030 jump. I loaded up several of each and .015 jump prevailed every time Pic#2. It got a bit windy but .015 seems to be a 1/4 moa shooter. So how do you like my clunker homemade diy F-Open midrange rig. Bighorn tl3 action, Bix n Andy tacsport pro, Shilen Select match prefit with a nut, Sightron 10x50x60, and a used Shehane stock I got from a guy for $50.00. It's the Shadetree rest that makes it all work. Thanx Butch. Life is good! Mike.

 

Glad to see it worked out for you!

 

Very nice! It’s interesting how the 15 jump beat the 30 at 500 yards. Love the blue color on the stock.